Publications by authors named "Peter Odermatt"

147 Publications

Low Sensitivity of Real Time PCRs Targeting Retrotransposon Sequences for the Detection of Complex DNA in Human Serum.

Pathogens 2021 Aug 22;10(8). Epub 2021 Aug 22.

National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine Hamburg, 20359 Hamburg, Germany.

While hybridization probe-based real-time PCR assays targeting highly repetitive multi-copy genome sequences for the diagnosis of complex or complex from human serum are well established, reports on the evaluation of respective assays for the identification of complex DNA in human serum are scarce. Here, we assessed the potential use of the retrotransposon sequences and from , and for the diagnosis of Asian infections. Based on available sequences and newly provided and sequences, hybridization probe-based real-time PCRs targeting and of the complex were designed both as consensus primer assays as well as multi-primer assays for the coverage of multiple variants of the target sequences. The assays were established using plasmids and DNA. While the consensus primer assays failed to detect DNA in human serum samples, the multi-primer assays showed positive or borderline positive results but only in 9.8% (6/61) of serum samples from patients with confirmed infections. Some cross-reactions with samples positive for or were observed but with the -PCR only. In spite of the low sensitivity, the presented experience may guide future evaluations of complex-specific PCRs from human serum.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/pathogens10081067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8398367PMC
August 2021

Community-based management of epilepsy in Southeast Asia: Two intervention strategies in Lao PDR and Cambodia.

Lancet Reg Health West Pac 2020 Nov 9;4:100042. Epub 2020 Oct 9.

INSERM U1094, Univ. Limoges, CHU Limoges, IRD, Neuroépidémiologie Tropicale, Institut d'Epidémiologie et de Neurologie Tropicale, GEIST, 2 rue du Docteur Marcland, 87025 Limoges, France.

Background: Epilepsy affects more than 50 million people worldwide, 80% of whom live in low- and middle-income countries (LMICs). In Southeast Asia, the prevalence is moderate (6‰), and the main public health challenge is reducing the treatment gap, which reaches more than 90% in rural areas.

Methods: This 12-month comparative study (intervention vs. control areas) assessed the community effectiveness of two different strategies for the identification and home follow-up of people with epilepsy by Domestic Health Visitors for epilepsy (DHVes). In Lao PDR, DHVes were health center staff covering several villages via monthly visits; in Cambodia, DHVes were health volunteers living in the villages.

Findings: At baseline, the treatment gap was >95% in Lao PDR and 100% in Cambodia. After 12 months, the treatment gap in Lao PDR decreased by 5·5% (range: 4·0-12·2) in the intervention area and 0·5% (range: 0·4-0·8) in the control area (<0·0001). In Cambodia, the treatment gap decreased by 34·9% (range: 29·0-44·1) in the intervention area and 8·1% (range: 6·7-10·2) in the control area (<0·0001). Among the PWEs followed at home by the DHVes, the proportion adhering to drug treatment was 85·2% in Lao PDR and 78·1% in Cambodia. The cost associated with strategy implemented in Cambodia, compared with the control area, was lower than the cost associated with strategy implemented in Lao PDR."

Interpretation: The treatment gap was significantly reduced with both intervention strategies, but the effect was larger in Cambodia. The results of this cost analysis pave the way for scaling-up in rural areas of Lao PDR and Cambodia, and experimental adaptation in other LMICs.

Funding: The study was funded by the Global Health Department of Sanofi and Grand Challenges Canada (grant number 0325-04).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.lanwpc.2020.100042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8315387PMC
November 2020

Patients with severe schistosomiasis mansoni in Ituri Province, Democratic Republic of the Congo.

Infect Dis Poverty 2021 Mar 25;10(1):39. Epub 2021 Mar 25.

Nanomedicine Translation Group, Intensive Care Unit, University Hospital Basel University of Basel, Petersgraben 4, 4031, Basel, Switzerland.

Background: Severe hepatosplenic complications arise in patients with chronic Schistosoma mansoni infection after heavy exposure to disease agents in endemic areas. These complications are rarely reported and, hence, underestimated.

Case Presentation: We report on eight patients with severe morbidity associated with S. mansoni infection in Ituri Province, northeastern Democratic Republic of Congo (DRC). The patients were identified during a community-based survey in 2017; one patient was seen at the district hospital. After taking the patients' history, a clinical examination and an abdominal ultrasonographical examination were performed. S. mansoni infection was diagnosed in fecal (Kato-Katz technique) and urine (point-of-case circulating cathodic antigen test) samples. These eight patients with severe intestinal and hepatosplenic complications were identified from four villages with high S. mansoni infection prevalence and related morbidity. The patients' ages ranged from 19 to 57 years; four patients were women. Three patients reported hematemesis. Two patients were severely anemic. All patients reported non-specific abdominal symptoms, such as diarrhea (six patients), abdominal pain (seven patients), and blood in the stool (five patients), as well as weight loss (two patients). Abdominal ultrasonography revealed ascites in four patients. All patients had portal hypertension with hepatomegaly (seven patients) or splenomegaly (five patients). Of the six patients with a discernable liver parenchyma pattern, five displayed pattern F and three patient displayed pattern E. Liver parenchyma was not visible for two patients with severe ascites. An S. mansoni infection was confirmed in six patients, with infection intensity ranging from light to heavy. All S. mansoni positive patients were treated with praziquantel (40 mg/kg body weight) and referred to the district hospital for follow-up. One patient with severe ascites died two weeks after we saw her. Due to security and accessibility reasons, the villages could not be visited again and the patients were lost to follow-up.

Conclusions: Our observations of patients with severe schistosomiasis document the severe degree of endemicity of S. mansoni in the province and suggest an urgent need for adequate schistosomiasis control measures that target vulnerable population groups and address severe complications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40249-021-00815-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7992822PMC
March 2021

Strongyloides stercoralis prevalence and diagnostics in Vientiane, Lao People's Democratic Republic.

Infect Dis Poverty 2020 Sep 21;9(1):133. Epub 2020 Sep 21.

University of Basel, Basel, Switzerland.

Background: Despite the high prevalence of strongyloidiasis in the Laotian population, Laotian hospitals still lack diagnostic capacity to appropriately diagnose Strongyloides stercoralis infections. This cross-sectional hospital-based study was conducted to assess the prevalence of Strongyloides stercoralis infection among hospitalized patients treated at Mahosot Hospital, the primary reference hospital of Lao People's Democratic Republic (Lao PDR), and to validate feasible methods for diagnosing S. stercoralis infection at hospital's laboratory.

Methods: Between September and December 2018, stool samples of 104 inpatients were investigated for S. stercoralis infection by wet smear, Baermann technique, Koga Agar plate culture (KAPC), and real-time detection polymerase chain reaction (RTD-PCR) at the Infectious Diseases Ward of the Mahosot Hospital in Vientiane. The sensitivity, the specificity, the negative predictive value (NPV) of each diagnostic test, as well as their combination(s) was calculated using a composite reference standard (CRS). The correlation of the different test methods was assessed by chi-square or Fisher's exact test. Cohen's kappa coefficient was used to assess the diagnostic agreement of the different test methods.

Results: The overall prevalence of S. stercoralis infections among the study population was 33.4%. The cumulative infection prevalence statistically significantly increased from the lowest age group of 40 years and below (22.4%), to the medium (40.0%) and to the oldest age group of 61 year and above (72.7%)(P = 0.003). The cumulative infection prevalence of CRS was considerably higher in male (40.4%) compared to female patients (28.1%), but not statistically different (P = 0.184). The diagnostic sensitivity of Baermann technique, KAPC, RTD-PCR, and the combination of Baermann technique and KAPC were 60.0, 60.0, 74.3, and 77.1%, respectively. Only 13 patients (37.1%) of the total 35 S. stercoralis patients diagnosed with any technique had a simultaneously positive diagnostic test with Baermann, KAPC and RTD-PCR.

Conclusions: We identified Baermann technique and KAPC to be currently the most feasible and implementable standard methods for diagnosing S. stercoralis at a hospital setting such as Mahosot Hospital and provincial and district hospitals in Lao PDR and other low- and middle income countries in Southeast Asia.

Trial Registration: This study was approved by the National Ethics Committee for Health Research in Lao PDR (reference no. 083/NECHR) and by the Ethics Committee Northwest and Central Switzerland (reference no. 2018-00594).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40249-020-00750-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7507821PMC
September 2020

Cross-reaction of POC-CCA urine test for detection of Schistosoma mekongi in Lao PDR: a cross-sectional study.

Infect Dis Poverty 2020 Aug 12;9(1):114. Epub 2020 Aug 12.

Lao Tropical and Public Health Institute, Ministry of Health, Vientiane Capital, Lao People's Democratic Republic.

Background: The point-of-care circulating cathodic antigen (POC-CCA) test is increasingly used as a rapid diagnostic method for Schistosoma mansoni infection. The test has good sensitivity, although false positive results have been reported among pregnant women and patients with urine infections and hematuria. We validated the POC-CCA test's ability to diagnose Schistosoma mekongi infection in Lao People's Democratic Republic (Lao PDR), where S. mekongi is endemic. Of particular interest was the test's specificity and possible cross-reactivity with other helminth infections.

Methods: We conducted a cross-sectional study of children and adults in the provinces of Champasack (Schistosoma mekongi and Opisthorchis viverrini endemic), Savannakhet (O. viverrini endemic) and Luang Prabang (soil-transmitted helminths endemic) between October 2018 and April 2019. POC-CCA and urine dipstick tests were administered to all study participants, while an additional pregnancy test was offered to women. Two stool samples were collected from participants and examined with a Kato-Katz test (two smears per stool). Logistic regression was used to associate potential confounding factors (predictors) with POC-CCA test results (outcome).

Results: In S. mekongi-endemic Champasack, 11.5% (n = 366) and 0.5% (n = 2) of study participants had positive POC-CCA and Kato-Katz test results, respectively. Only one of the two Kato-Katz positive patients was also POC-CCA positive. In Champasack and Luang Prabang, where S. mekongi is not endemic, the POC-CCA test yielded (presumably) false positive results for 6.0% (n = 22) and 2.5% (n = 9) of study participants, respectively, while all of the Kato-Katz tests were negative. POC-CCA positive test results were significantly associated with O. viverrini infection (1.69, 95% confidence interval (CI): 1.02-2.77, P = 0.042), increased leukocytes (adjusted Odds Ratio (aOR) = 1.58, 95% CI: 1.15-2.17, P = 0.005) and hematuria (aOR = 1.50, 95% CI: 1.07-2.10, P = 0.019) if the observed trace was counted as a positive test result. Two pregnant women from Champasack province had POC-CCA positive tests.

Conclusions: We observed a cross-reaction between the POC-CCA test and O. viverrini infection. To some extent, we can confirm previous observations asserting that POC-CCA provides false positive results among patients with urinary tract infections and hematuria. In S. mekongi-endemic areas, POC-CCA can be applied cautiously for surveillance purposes, keeping in mind the considerable risk of false positive results and its unknown sensitivity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40249-020-00733-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7424653PMC
August 2020

Opisthorchis felineus infection, risks, and morbidity in rural Western Siberia, Russian Federation.

PLoS Negl Trop Dis 2020 06 29;14(6):e0008421. Epub 2020 Jun 29.

Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.

Background: The liver fluke, Opisthorchis felineus, is widely distributed throughout Europe and large parts of the Russian Federation. In Western Siberia, information about opisthorchiasis is lacking although infection may lead to severe liver and bile duct diseases. We aimed to assess the current prevalence of O. felineus infection along with associated risk factors and morbidity in rural Western Siberia.

Methods: We conducted a community-based, cross-sectional study in the rural Shegarskiy district, Tomsk Oblast, Russian Federation. All household members (≥ 7 years) present on the survey day were enrolled (n = 600). Two stool samples per person were examined for helminth eggs, using PARASEP (DiaSys Ltd, UK). The number of eggs per gram (EPG) of feces was recorded. Each study participant was interviewed to determine risk factors, using a pre-tested questionnaire. An abdominal ultrasonography examination of liver and bile ducts was performed with a mobile, high resolution ultrasound device. In total, 488 persons completed assessments (two stool samples, completed questionnaires); of those, 436 individuals had an ultrasonography (US) examination.

Results: We observed a prevalence of O. felineus infection of 60.2%. Significant risk factors for infection were the consumption of river fish (odds ratio from adjusted analysis [aOR] 2.4, 95% CI 1.52-3.95, p<0.001), particularly stock fish (OR from multivariable analysis [mOR] 3.2, 95% CI 2.63-3.80, p<0.001), smoked fish (mOR 1.5, 95% CI 1.24-1.72, p<0.001), frozen fish (mOR 1.6, 95% CI 1.29-2.02, p<0.001), and raw fish (mOR 1.4, 95% CI 1.05-1.84, p = 0.02); and fishing activities (mOR 1.2, 95% CI 1.03-1.43, p = 0.019). Women had a higher risk of infection than men. Infection was associated positively with age and negatively with socio-economic status. The respondents' general awareness of opisthorchiasis was quite high (93.2%), but their knowledge about infection transmission and prevention was insufficient. Children aged 7-18 years old had a lower level of awareness compared to adults. The abdominal ultrasonography results demonstrated a strong association between O. felineus infection and gallbladder stones (mOR 2.8, 95% CI 1.33-6.04, p = 0.007) and periductal fibrosis of intrahepatic bile ducts (mOR 1.9, 95% CI 1.08-3.46, p = 0.026).

Conclusion: O. felineus infection is highly prevalent in rural regions of Western Siberia, and associated with severe hepatobiliary pathology. Identified risk factors will be used to develop a comprehensive targeted O. felineus infection control program.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pntd.0008421DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7351239PMC
June 2020

The Global Prevalence of Infection.

Pathogens 2020 Jun 13;9(6). Epub 2020 Jun 13.

Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, 37024 Verona, Italy.

Strongyloidiasis is a common neglected tropical disease in tropical and sub-tropical climatic zones. At the worldwide level, there is high uncertainty about the strongyloidiasis burden. This uncertainty represents an important knowledge gap since it affects the planning of interventions to reduce the burden of strongyloidiasis in endemic countries. This study aimed to estimate the global strongyloidiasis prevalence. A literature review was performed to obtain prevalence data from endemic countries at a worldwide level from 1990 to 2016. For each study, the true population prevalence was calculated by accounting for the specificity and the sensitivity of testing and age of tested individuals. Prediction of strongyloidiasis prevalence for each country was performed using a spatiotemporal statistical modeling approach. The country prevalence obtained from the model was used to estimate the number of infected people per country. We estimate the global prevalence of strongyloidiasis in 2017 to be 8.1% (95% CI: 4.2-12.4%), corresponding to 613.9 (95% CI: 313.1-910.1) million people infected. The South-East Asia, African, and Western Pacific Regions accounted for 76.1% of the global infections. Our results could be used to identify those countries in which strongyloidiasis prevalence is highest and where mass drug administration (MDA) should be deployed for its prevention and control.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/pathogens9060468DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7349647PMC
June 2020

Nutritional and health status of children 15 months after integrated school garden, nutrition, and water, sanitation and hygiene interventions: a cluster-randomised controlled trial in Nepal.

BMC Public Health 2020 Feb 3;20(1):158. Epub 2020 Feb 3.

Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.

Background: It has been suggested that specific interventions delivered through the education sector in low- and middle-income countries might improve children's health and wellbeing. This cluster-randomised controlled trial aimed to evaluate the effects of a school garden programme and complementary nutrition, and water, sanitation and hygiene (WASH) interventions on children's health and nutritional status in two districts of Nepal.

Methods: The trial included 682 children aged 8-17 years from 12 schools. The schools were randomly allocated to one of three interventions: (a) school garden programme (SG; 4 schools, n = 172 children); (b) school garden programme with complementary WASH, health and nutrition interventions (SG+; 4 schools, n = 197 children); and (c) no specific intervention (control; 4 schools, n = 313 children). The same field and laboratory procedures were employed at the baseline (March 2015) and end-line (June 2016) surveys. Questionnaires were administered to evaluate WASH conditions at schools and households. Water quality was assessed using a Delagua kit. Dietary intake was determined using food frequency and 24-h recall questionnaire. Haemoglobin levels were measured using HemoCue digital device and used as a proxy for anaemia. Stool samples were subjected to a suite of copro-microscopic diagnostic methods for detection of intestinal protozoa and helminths. The changes in key indicators between the baseline and end-line surveys were analysed by mixed logistic and linear regression models.

Results: Stunting was slightly lowered in SG+ (19.9 to 18.3%; p = 0.92) and in the control (19.7 to 18.9%). Anaemia slightly decreased in SG+ (33.0 to 32.0%; p < 0.01) and markedly increased in the control (22.7 to 41.3%; p < 0.01), a minor decline was found in the control (43.9 to 42.4%). Handwashing with soap before eating strongly increased in SG+ (from 74.1 to 96.9%; p = 0.01, compared to control where only a slight increase was observed from 78.0 to 84.0%). A similar observation was made for handwashing after defecation (increase from 77.2 to 99.0% in SG+ versus 78.0 to 91.9% in control, p = 0.15).

Conclusions: An integrated intervention consisting of school garden, WASH, nutrition and health components (SG+) increased children's fruit and vegetable consumption, decreased intestinal parasitic infections and improved hygiene behaviours.

Trial Registration: ISRCTN17968589 (date assigned: 17 July 2015).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12889-019-8027-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6998817PMC
February 2020

Patients with severe schistosomiasis mekongi morbidity demonstrating ongoing transmission in Southern Lao People's Democratic Republic.

Acta Trop 2020 Apr 28;204:105323. Epub 2019 Dec 28.

Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland; University of Basel, Basel, Switzerland. Electronic address:

Chronic infection with Schistosoma mekongi may result in severe hepatosplenic morbidity. We report on eight patients with severe morbidity due to S. mekongi infection. The patients were diagnosed, treated and followed-up between 2007 and 2010 in Khong district, Southern Lao People's Democratic Republic (Lao PDR), eight years after the end of a control intervention. S. mekongi control programmes aimed to prevent morbidity and mortality associated with infection. The patients were visited and interviewed annually. In addition, clinical and abdominal ultrasound examinations were performed and faecal and blood samples were examined. The patients' ages ranged from 6 to 66 years. Of the eight patients, three were children and five were adults. The four youngest patients (aged 6-27 years) significantly improved after praziquantel treatment. One patient (age 46 years) worsened between 2007 and 2010. Two patients died due to bleeding of the oesophageal varices. One patient was lost to follow-up. The leading clinical signs were ascites, splenomegaly, collateral veins on the abdomen and a poor general nutrition status. Ultrasonography disclosed advanced liver fibrosis patterns in all patients; in seven patients, fibrosis pattern E or F was revealed, as per the Niamey protocol (pattern A normal, pattern B to F pathological with increasing severity). Stool microscopy revealed that five patients were co-infected with hookworm and Opisthorchis viverrini. The youngest patient (aged 6 years) was born after the schistosomiasis control program had ended. From her severe morbidity, we can conclude that S. mekongi transmission was on-going in Khong district, and that even in areas with low S. mekongi transmission intensities, severe morbidity from schistosomiasis can develop quickly. Early diagnosis and treatment are imperative, and close monitoring is required.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.actatropica.2019.105323DOI Listing
April 2020

Morbidity associated with Schistosoma mekongi and concurrent helminth infection in Lao People's Democratic Republic.

Acta Trop 2020 Apr 28;204:105324. Epub 2019 Dec 28.

Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland; University of Basel, P.O. Box, CH-4003 Basel, Switzerland. Electronic address:

In 2006, some 7 years after the halt of a multi-year schistosomiasis control programme, a study was conducted in the southern part of Lao People's Democratic Republic to determine the morbidity associated with Schistosoma mekongi and concurrent helminth infection. In two S. mekongi-endemic districts, Khong and Mounlapamok, 640 individuals aged 9-40 years were randomly selected. Two stool samples were obtained from each participant and subjected to the Kato-Katz technique for helminth diagnosis. Morbidity was assessed by clinical examination and abdominal ultrasonography. Multiple logistic regression analysis was employed to relate S. mekongi infection with morbidity indicators. In Khong district, S. mekongi prevalence was 13-fold higher than in Mounlapamok district (57.7% vs. 4.4%, p < 0.001). Likewise, we observed significantly more often palpated hepatomegaly (15.5% vs. 5.4%) and splenomegaly (9.6% vs. 0.4%). Abdominal ultrasonography revealed that, in Khong district, liver and spleen morbidity occurred more frequently (e.g., enlarged left liver lobe: 89.2% vs. 68.7%, p < 0.001). Single species infection with S. mekongi was associated with enlarged peri-portal vein (adjusted odds ratio (aOR) 47.7, 95% confidence interval (CI) 4.2-85.7, p = 0.002), as was S. mekongi-Opisthorchis viverrini co-infection (aOR 2.2, 95% CI 1.1-4.5, p = 0.020). In conclusion, our study shows that in 2006, several years after the halt of the Lao schistosomiasis control programme that emphasised preventive chemotherapy, S. mekongi infection again had reached high prevalence rates. Infection with S. mekongi was associated with substantial hepatosplenic morbidity. Schistosomiasis control measures were re-instigated in 2010. In view of the ultimate goal to eliminate schistosomiasis, rigorous surveillance and public health responses tailored to the social-ecological settings and long-term programme commitment are warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.actatropica.2019.105324DOI Listing
April 2020

Strongyloides stercoralis: Spatial distribution of a highly prevalent and ubiquitous soil-transmitted helminth in Cambodia.

PLoS Negl Trop Dis 2019 06 20;13(6):e0006943. Epub 2019 Jun 20.

Swiss Tropical and Public Health Institute, Basel, Switzerland.

Background: Strongyloides stercoralis is a neglected soil-transmitted helminth that occurs worldwide, though it is particularly endemic in tropical and subtropical areas. It can cause long-lasting and potentially fatal infections due to its ability to replicate within its host. S. stercoralis causes gastrointestinal and dermatological morbidity. The objective of this study was to assess the S. stercoralis infection risk and, using geostatistical models, to predict its geographical distribution in Cambodia.

Methodology / Principal Findings: A nation-wide, community-based parasitological survey was conducted among the Cambodian population, aged 6 years and older. S. stercoralis was diagnosed using a serological diagnostic test that detects IgG antibodies in urine. Data on demography, hygiene and knowledge about helminth infection were collected. S. stercoralis prevalence among 7,246 participants with a complete data record was 30.5%, ranging from 10.9% to 48.2% across provinces. The parasite was ubiquitous in Cambodia; only five south-eastern provinces had prevalence rates below 20%. Infection risk increased with age for both men and women, although girls under the age of 13 and women aged 50 years and over had lower odds of infection than their male counterparts. Open defecation was associated with higher odds of infection, while having some knowledge of the health problems caused by worms was a protective factor. Infection risk was positively associated with nighttime maximum temperature, minimum rainfall, and distance to water; it was negatively associated with land occupied by rice fields.

Conclusions / Significance: S. stercoralis infection is rampant in Cambodia. Control programs delivering ivermectin are needed to manage the parasite. However, the high cost of this drug in Cambodia currently precludes the implementation of control initiatives. Donations, subsidies or affordable generics are needed so that S. stercoralis, which infects almost a third of the Cambodian population, can be addressed through an adequate control program.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pntd.0006943DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6586258PMC
June 2019

Mortality of neurological disorders in Tanzania: analysis of baseline data from sample vital registration with verbal autopsy (SAVVY).

Glob Health Action 2019 ;12(1):1596378

a Department of Epidemiology and Public Health , Swiss Tropical and Public Health Institute , Basel , Switzerland.

: Neurological disorders (ND) have a profound consequence on human productivity, quality of life and survival. There are limited data on the burden of ND in Tanzania due to insufficient coverage of civil and vital registration systems. : This study was conducted to estimate mortality of ND in all ages in Tanzania using data from the Sample Vital Registration with Verbal Autopsy (SAVVY) study. : Multistage random sampling was employed to select 23 districts, 1397 census enumeration areas and 154,603 households. During the baseline survey conducted between 2011 and 2014, deaths which occurred 12 months prior to the baseline survey were documented followed by verbal autopsy interviews. Causes of death were certified using International Classification of Diseases. : The baseline survey enrolled a total of 650,864 residents. A total of 6645 deaths were reported to have occurred 12 months before the date of survey. Death certification was available for 5225 (79%) deaths. The leading causes of death were cerebrovascular diseases with a cause-specific mortality fraction (CSMF) of 1.64% (95% CI: 1.30-1.99) and 3.82% (95% CI: 2.92-4.72) in all ages and adults older than 50 years, respectively. Stroke accounted for 92% of all cerebrovascular deaths. Mortality of epilepsy was estimated with a CSMF of 0.94% (95% CI: 0.68-1.20); meningitis with a CSMF of 0.80% (95% CI: 0.56-1.04); cerebral palsy and other paralytic syndromes with a CSMF of 0.46% (95% CI: 0.27-0.65); and intrauterine hypoxia in neonates with a CSMF of 2.06% (95% CI: 1.12-3.01). Overall, mortality of ND was estimated with a CSMF of 4.99% (95% CI: 4.40-5.58). : The SAVVY survey provides estimates of mortality burden of ND in Tanzania. The study provides a basis for monitoring trends of ND and contributes to advancing knowledge of the burden of diseases. Integrating morbidities measures into the SAVVY design will provide comprehensive measures of burden of ND taking into account lifetime disabilities created by ND.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/16549716.2019.1596378DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7011788PMC
October 2019

Is Opisthorchis viverrini Emerging in Cambodia?

Adv Parasitol 2019 6;103:31-73. Epub 2019 Mar 6.

Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.

Opisthorchis viverrini infection is widely prevalent in Southeast Asia. In Cambodia information on this helminth infection is scare. Recent reports suggest that O. viverrini is an emerging public health problem. We aimed to synthesize all information in relation to the infection, epidemiology, and morbidity of O. viverrini in Cambodia; from published as well as thus far unpublished sources. First reports on O. viverrini date back to 1995. In 2006 an O. viverrini initiative was launched by the national helminth control program. Since then O. viverrini has been reported in all - except two - provinces. Villages with high prevalences (>20%) were found in provinces from Preah Vihear to Takeo. The infection has a highly focal distribution. In many villages no infections were detected. O. viverrini infection was also reported in cats, dogs and intermediate hosts. No report on morbidity associated with O. viverrini was found. The current evidence suggests that O. viverrini infection remains underreported in Cambodia. It is likely that the transmission will further increase in the future with potentially serious consequences for human health.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/bs.apar.2019.02.002DOI Listing
October 2019

Elimination of Schistosomiasis Mekongi from Endemic Areas in Cambodia and the Lao People's Democratic Republic: Current Status and Plans.

Trop Med Infect Dis 2019 Feb 7;4(1). Epub 2019 Feb 7.

Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, PO Box, 4002 Basel, Switzerland.

The areas endemic for schistosomiasis in the Lao People's Democratic Republic and in Cambodia were first reported 50 and 60 years ago, respectively. However, the causative parasite Schistosoma mekongi was not recognized as a separate species until 1978. The infection is distributed along a limited part of the Mekong River, regulated by the focal distribution of the intermediate snail host Neotricula aperta. Although more sensitive diagnostics imply a higher figure, the current use of stool examinations suggests that only about 1500 people are presently infected. This well-characterized setting should offer an exemplary potential for the elimination of the disease from its endemic areas; yet, the local topography, reservoir animals, and a dearth of safe water sources make transmission control a challenge. Control activities based on mass drug administration resulted in strong advances, and prevalence was reduced to less than 5% according to stool microscopy. Even so, transmission continues unabated, and the true number of infected people could be as much as 10 times higher than reported. On-going control activities are discussed together with plans for the future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/tropicalmed4010030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6473609PMC
February 2019

Pooled Population Pharmacokinetic Analysis of Tribendimidine for the Treatment of Infections.

Antimicrob Agents Chemother 2019 04 27;63(4). Epub 2019 Mar 27.

Swiss Tropical and Public Health Institute, Basel, Switzerland

Opisthorchiasis, caused by the foodborne trematode , affects more than 8 million people in Southeast Asia. In the framework of a phase 2b clinical trial conducted in Lao People's Democratic Republic, pharmacokinetic samples were obtained from 125 adult and adolescent -infected patients treated with 400 mg tribendimidine following the design of a sparse sampling scheme at 20 min and 2, 7.75, 8, and 30 h after treatment using dried blood spot sampling. Pharmacokinetic data for the metabolites deacetylated amidantel (dADT) and acetylated dADT (adADT) were pooled with data from two previous ascending-dose trials and evaluated using nonlinear mixed-effects modeling. The observed pharmacokinetic data were described using a flexible transit absorption model for the active metabolite dADT, followed by one-compartment disposition models for both metabolites. Significant covariates were age, body weight, formulation, and breaking of the enteric coating on the tablets. There were significant associations between cure and both the dADT maximum concentration and the area under the concentration-time curve ( < 0.001), with younger age being associated with a higher probability of cure. Modeling and simulation of exposures in patients with different weight and age combinations showed that an oral single dose of 400 mg tribendimidine attained therapeutic success in over 90% of adult patients. Our data confirmed that tribendimidine could be a valuable novel alternative to the standard treatment, praziquantel, for the treatment of infections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/AAC.01391-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6437521PMC
April 2019

Case Report: Two Cases of Cholangiocarcinoma in Patients with Infection in Western Siberia, Russian Federation.

Am J Trop Med Hyg 2019 03;100(3):599-603

University of Basel, Basel, Switzerland.

Cholangiocarcinoma (CCA) is a cancer with high mortality owing to its aggressiveness and resistance to therapy. The liver flukes of the Opisthorchiidae family have been recognized as risk factors of CCA. infection occurs in Western Siberia, the biggest endemic area in the Russian Federation, and is associated with chronic inflammation of the bile ducts, which may be linked to severe hepatobiliary morbidity. We report two cases of confirmed CCA who had a chronic infection. Both cases presented unspecific symptoms at the onset of the disease, a stage when severe pathological changes already had occurred. Both patients were living in endemic areas but did not receive any antihelminthic treatment. This report underlines the need for assessment of infection as a causative factor of CCA. The results will provide further arguments for control of in the Russian Federation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.18-0652DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6402895PMC
March 2019

Association between helminth infections and diabetes mellitus in adults from the Lao People's Democratic Republic: a cross-sectional study.

Infect Dis Poverty 2018 Nov 6;7(1):105. Epub 2018 Nov 6.

Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, PO Box, 4002, 4051, Basel, Switzerland.

Background: As a result of epidemiological transition, the health systems of low- and middle-income countries are increasingly faced with a dual disease burden of infectious diseases and emerging non-communicable diseases. Little is known about the mutual influence of these two disease groups. The aim of this study was to investigate the co-occurrence of helminth infections and diabetes mellitus in adults in Lao People's Democratic Republic (Lao PDR).

Methods: We conducted a cross-sectional study among 1600 randomly selected adults aged 35 and older from four different socio-economical and ecological provinces. Information on socio-demographics, risk factors and health conditions was obtained from personal interviews. Clinical assessments including anthropometry (height, weight, waist and hip circumference) and blood pressure measurements were also conducted. Diabetes was classified based on self-reported diagnoses and a point-of-care glycated haemoglobin (HbA1c) test from finger prick blood samples. Stool samples for helminth diagnosis were examined with formalin-ether concentration technique for intestinal parasitic infections. The independent associations of helminth infections with diabetic status and HbA1c were assessed using multiple regression analyses.

Results: The prevalence of pre-diabetes and diabetes was 37.3% and 22.8%, respectively. Fifty-six percent of diabetic cases were undiagnosed and 85% of diagnosed diabetic cases had poor glycemic control. Participants from rural areas and from southern parts of the country had higher infection rates, with Opisthorchis viverrini, being the most common helminth infection (30.5%). We found a positive association between Taenia spp. infections and HbA1c (β = 0.117; 95% CI: 0.042-0.200) and diabetes mellitus risk (OR = 2.98; 95% CI: 1.10-8.05). No other helminth species was associated with glycated hemoglobin.

Conclusions: Hyperglycaemia and diabetic rates in Lao PDR are alarmingly high, but consistent with other high rates in the region. Given the high rates of under-diagnosis and poorly-controlled glycaemia in diabetes mellitus patients, routine diabetes screening and treatment is essential for the local healthcare system. Large longitudinal cohorts integrating biomarkers are warranted in the search of causal diabetes mellitus risk factors in the region. Common intestinal helminth infections, including O. viverrini, are unlikely to explain the high diabetes mellitus rates observed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40249-018-0488-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6219195PMC
November 2018

Intestinal parasite infections and associated risk factors among schoolchildren in Dolakha and Ramechhap districts, Nepal: a cross-sectional study.

Parasit Vectors 2018 Sep 29;11(1):532. Epub 2018 Sep 29.

Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.

Background: Infections with soil-transmitted helminths and pathogenic intestinal protozoa pose a considerable public health burden, particularly in low- and middle-income countries, including Nepal. We assessed the extent of intestinal parasite infections among schoolchildren in two districts of Nepal and determined underlying risk factors.

Methods: A cross-sectional survey was conducted between March and May 2015 in the districts of Dolakha and Ramechhap, Nepal. A total of 708 children, aged 8-16 years from 16 purposively selected schools, were enrolled. Each child provided a single stool sample that was subjected to a suite of copro-microscopic diagnoses for intestinal protozoa and helminths. Drinking water samples from different sources at schools (n = 29), community places (n = 43) and households (n = 562) were analysed for contamination with thermotolerant coliforms (TTC). A questionnaire was administered to determine individual- and household-level risk factors of intestinal parasite infections. Self-reported symptoms were assessed and a clinical examination was undertaken by a physician. Haemoglobin was measured and used as a proxy for anaemia. Mixed logistic regression models were applied to investigate associations.

Results: The overall prevalence of intestinal parasite infections was 39.7%. Trichuris trichiura (30.9%), Giardia intestinalis (30.5%) and hookworm (30.2%) were the predominant intestinal parasite infections. Children from households lacking soap for handwashing were at higher odds of intestinal parasite infections than children who had soap [adjusted odds ratio (aOR) 1.81; 95% confidence interval (CI): 1.13-2.89; P = 0.01]. Children from households without freely roaming domestic animals showed lower odds of G. intestinalis compared to children from households with freely roaming animals (aOR 0.52; 95% CI: 0.33-0.83; P = 0.01). One out of three (31.0%) children suffered from fever and 22.4% had watery diarrhoea within a two-week recall period. Anaemia was diagnosed in 23.6% of the children. Water contamination with TTC showed no clear association with intestinal parasite infection.

Conclusions: Intestinal parasites are common among schoolchildren in the two surveyed districts of Nepal. An important risk factor was lack of soap for handwashing. Our findings call for efforts to control intestinal parasite infection and emphasis should be placed on improvements in water, sanitation and hygiene interventions.

Trial Registration: ISRCTN17968589 (date assigned: 17 July 2015).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13071-018-3105-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162948PMC
September 2018

Development and Evaluation of a Multiplex Quantitative Real-Time Polymerase Chain Reaction for Hookworm Species in Human Stool.

Am J Trop Med Hyg 2018 11;99(5):1186-1193

Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Australia.

Hookworm disease caused by , , and affects half a billion people worldwide. The prevalence and intensity of infection of individual hookworm species are vital for assessing morbidity and generating targeted intervention programs for their control. The present study aims to evaluate a multiplex real-time quantitative PCR (qPCR) assay to determine the prevalence and egg intensity of all three hookworm species and compare this with standard microscopy and published genus-based conventional and real-time multiplex qPCRs. Performance of the diagnostic assays was evaluated using DNA extracted from 192 fecal samples collected as part of a soil-transmitted helminth (STH) survey in northern Cambodia. The prevalence of hookworms as detected by the multiplex hookworm qPCR of 84/192 (43.8%) was significantly higher than that using microscopy of 49/192 (25.5%). The hookworm multiplex qPCR showed very good agreement for the detection of both (Kappa 0.943) and spp. (Kappa 0.936) with a multiplex STH qPCR. A strong and moderate quantitative correlation between cycle threshold and eggs per gram (EPG) feces was obtained for the hookworm qPCR for seeded DNA egg extracts ( ≥ 0.9004) and naturally egg-infected individuals ( = 0.6848), respectively. The newly developed hookworm quantitative multiplex qPCR has the potential for application in anthelmintic efficacy trials and for monitoring the success of mass deworming programs targeting individual species of anthroponotic and zoonotic hookworms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.18-0276DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221243PMC
November 2018

Analysis of interventions against the liver fluke, opisthorchis viverrini.

Math Biosci 2018 09 27;303:115-125. Epub 2018 Jun 27.

Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4002, Switzerland; University of Basel, Basel, Switzerland.

We adapt a population-based model of Opisthorchis viverrini transmission dynamics to determine the effectiveness of three different interventions. The model includes the definitive hosts, humans; the reservoir hosts, dogs and cats; and the intermediate hosts, snails and fish. We consider the interventions: education campaigns to reduce the consumption of raw or undercooked fish, improved sanitation and treatment through mass drug administration. We fit model parameters to a data set from two islands in southern Lao PDR. We calculate the control reproduction number, simulate different scenarios and optimise the interventions with optimal control. We look at the potential of the interventions to eliminate transmission within 20 years. The model shows that education and improved sanitation need a very high coverage to fulfil the goal of elimination, whereas annual drug distribution at medium coverage is sufficient. The best solution is a combination of drug distribution at a medium level of coverage and as high as possible coverage of education and improved sanitation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mbs.2018.06.008DOI Listing
September 2018

Magnitude and factors associated with nonadherence to antiepileptic drug treatment in Africa: A cross-sectional multisite study.

Epilepsia Open 2017 06 30;2(2):226-235. Epub 2017 Mar 30.

Centre for Geographic Medicine Research (Coast) Kenya Medical Research Institute Kilifi Kenya.

Objectives: The epilepsy treatment gap is large in low- and middle-income countries, but the reasons behind nonadherence to treatment with antiepileptic drugs (AEDs) across African countries remain unclear. We investigated the extent to which AEDs are not taken and associated factors in people with active convulsive epilepsy (ACE) identified in cross-sectional studies conducted in five African countries.

Methods: We approached 2,192 people with a confirmed diagnosis of ACE for consent to give blood voluntarily. Participants were asked if they were taking AEDs, and plasma drug concentrations were measured using a fluorescence polarization immunoassay analyzer. Information about possible risk factors was collected using questionnaire-based clinical interviews. We determined factors associated with nonadherence to AED treatment in children and adults, as measured by detectable and optimal levels, using multilevel logistic regression.

Results: In 1,303 samples assayed (43.7% were children), AEDs were detected in 482, but only 287 had optimal levels. Of the 1,303 samples, 532 (40.8%) were from people who had reported they were on AEDs. The overall prevalence of nonadherence to treatment was 63.1% (95% confidence interval [CI] 60.5-65.6%) as measured by detectable AED levels and 79.1% (95% CI 73.3-84.3%) as measured by optimal AED levels; self-reported nonadherence was 65.1% (95% CI 45.0-79.5%). Nonadherence was significantly (p < 0.001) more common among the children than among adults for optimal and detectable levels of AEDs, as was the self-reported nonadherence. In children, lack of previous hospitalization and learning difficulties were independently associated with nonadherence to treatment. In adults, history of delivery at home, absence of burn marks, and not seeking traditional medicine were independently associated with the nonadherence to AED treatment.

Significance: Only about 20% of people with epilepsy benefit fully from antiepileptic drugs in sub-Saharan Africa, according to optimum AEDs levels. Children taking AEDs should be supervised to promote compliance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/epi4.12052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5719857PMC
June 2017

Association between gastrointestinal tract infections and glycated hemoglobin in school children of poor neighborhoods in Port Elizabeth, South Africa.

PLoS Negl Trop Dis 2018 03 15;12(3):e0006332. Epub 2018 Mar 15.

Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.

Background: Low- and middle-income countries are facing a dual disease burden with infectious diseases (e.g., gastrointestinal tract infections) and non-communicable diseases (e.g., diabetes) being common. For instance, chronic parasite infections lead to altered immune regulatory networks, anemia, malnutrition, and diarrhea with an associated shift in the gut microbiome. These can all be pathways of potential relevance for insulin resistance and diabetes. The aim of this study was to investigate the association between common gastrointestinal tract infections and glycemia in children from non-fee paying schools in South Africa.

Methodology: We conducted a cross-sectional survey among 9- to 14-year-old school children in Port Elizabeth. Stool and urine samples were collected to assess infection status with parasitic worms (e.g., Ascaris lumbricoides, Enterobius vermicularis, and Trichuris trichiura), intestinal protozoa (e.g., Cryptosporidium parvum and Giardia intestinalis), and the bacterium Helicobacter pylori. Glycated hemoglobin (HbA1c) was measured in finger prick derived capillary blood. All children at schools with a high prevalence of helminth infections and only infected children at the schools with low infection rates were treated with albendazole. The association of anthelmintic treatment with changes in HbA1c 6 months after the drug intervention was also investigated.

Findings: A high prevalence of 71.8% of prediabetes was measured in this group of children, with only 27.8% having HbA1c in the normal range. H. pylori was the predominant infectious agent and showed an independent positive association with HbA1c in a multivariable regression analysis (β = 0.040, 95% confidence interval (CI) 0.006-0.073, p<0.05). No association of HbA1c with either any other infectious agent or albendazole administration was found.

Conclusion: The role of H. pylori in diabetes needs confirmation in the context of longitudinal treatment interventions. The specific effect of other gastrointestinal tract infections on glycemia remains unclear. Future studies should integrate the measurement of biomarkers, including immunological parameters, to shed light on the potential mediating mechanisms between parasite infections and diabetes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pntd.0006332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5871004PMC
March 2018

How elimination of lymphatic filariasis as a public health problem in the Kingdom of Cambodia was achieved.

Infect Dis Poverty 2018 Feb 20;7(1):15. Epub 2018 Feb 20.

National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, 477 Betong Street (Corner St.92), Village Trapangsvay, Sanakat Phnom Penh Thmey, Khan Sensok, Phnom Penh, Cambodia.

Background: Endemicity of lymphatic filariasis (LF) in Cambodia was proven in 1956 when microfilariae were detected in mosquitos in the Kratié province. In 2001, an extensive study confirmed the presence of both Brugia malayi and Wuchereria bancrofti microfilariae. In 2003, the Ministry of Health established a national task force to develop policies and strategies for controlling and eliminating neglected tropical diseases (NTDs), with the goal of eliminating LF by 2015. This article summarizes the work accomplished to eliminate LF as a public health problem in Cambodia.

Methods: The National Program to Eliminate Lymphatic Filariasis made excellent progress in the goal towards elimination due to strong collaboration between ministries, intensive supervision by national staff, and advocacy for mobilization of internal and external resources. Mass drug administration (MDA) with diethylcarbamazine citrate and albendazole was conducted in six implementation units, achieving > 70% epidemiological coverage for five consecutive rounds, from 2005 to 2009. In 2006, in 14 provinces, healthcare workers developed a line list of lymphedema and hydrocele patients, many of whom were > 40 years old and had been affected by LF for many years. The national program also trained healthcare workers and provincial and district staff in morbidity management and disability prevention, and designated health centers to provide care for lymphedema and acute attack. Two reference hospitals were designated to administer hydrocele surgery.

Results: Effectiveness of MDA was proven with transmission assessment surveys. These found that less than 1% of school children had antigenemia in 2010, which fell to 0% in both 2013 and 2015. A separate survey in one province in 2015 using Brugia Rapid tests to test for LF antibody found one child positive among 1677 children. The list of chronic LF patients was most recently updated and confirmed in 2011-2012, with 32 lymphoedema patients and 17 hydrocele patients listed. All lymphedema patients had been trained on self-management and all hydrocele patients had been offered free surgery.

Conclusions: Due to the success of the MDA and the development of health center capacity for patient care, along with benefits gained from socioeconomic improvements and other interventions against vector-borne diseases and NTDs, Cambodia was validated by the World Health Organization as achieving LF elimination as a public health problem in 2016.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40249-018-0394-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5819284PMC
February 2018

Strongyloides stercoralis and hookworm co-infection: spatial distribution and determinants in Preah Vihear Province, Cambodia.

Parasit Vectors 2018 01 12;11(1):33. Epub 2018 Jan 12.

Swiss Tropical and Public Health Institute, Basel, Switzerland.

Background: Strongyloides stercoralis and hookworm are two soil-transmitted helminths (STH) that are highly prevalent in Cambodia. Strongyloides stercoralis causes long-lasting infections and significant morbidity but is largely neglected, while hookworm causes the highest public health burden among STH. The two parasites have the same infection route, i.e. skin penetration. The extent of co-distribution, which could result in potential high co-morbidities, is unknown in highly endemic settings like Cambodia. The aim of this study was to predict the spatial distribution of S. stercoralis-hookworm co-infection risk and to investigate determinants of co-infection in Preah Vihear Province, North Cambodia.

Methods: A cross-sectional survey was conducted in 2010 in 60 villages of Preah Vihear Province. Diagnosis was performed on two stool samples, using combined Baermann technique and Koga agar culture plate for S. stercoralis and Kato-Katz technique for hookworm. Bayesian multinomial geostatistical models were used to assess demographic, socioeconomic, and behavioural determinants of S. stercoralis-hookworm co-infection and to predict co-infection risk at non-surveyed locations.

Results: Of the 2576 participants included in the study, 48.6% and 49.0% were infected with S. stercoralis and hookworm, respectively; 43.8% of the cases were co-infections. Females, preschool aged children, adults aged 19-49 years, and participants who reported regularly defecating in toilets, systematically boiling drinking water and having been treated with anthelmintic drugs had lower odds of co-infection. While S. stercoralis infection risk did not appear to be spatially structured, hookworm mono-infection and co-infection exhibited spatial correlation at about 20 km. Co-infection risk was positively associated with longer walking distances to a health centre and exhibited a small clustering tendency. The association was only partly explained by climatic variables, suggesting a role for underlying factors, such as living conditions and remoteness.

Conclusions: Both parasites were ubiquitous in the province, with co-infections accounting for almost half of all cases. The high prevalence of S. stercoralis calls for control measures. Despite several years of school-based de-worming programmes, hookworm infection levels remain high. Mebendazole efficacy, as well as coverage of and compliance to STH control programmes should be investigated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13071-017-2604-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5767026PMC
January 2018

Mathematical analysis of the transmission dynamics of the liver fluke, Opisthorchis viverrini.

J Theor Biol 2018 02 29;439:181-194. Epub 2017 Nov 29.

Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4002, Switzerland; University of Basel, Basel, Switzerland.

We develop and analyse two population-based models of the transmission dynamics of the worm parasite Opisthorchis viverrini. The life cycle of O. viverrini includes humans, cats and dogs as definitive hosts; and snails and fish as intermediate hosts. The first model has only one definitive host (humans) while the second model has two additional hosts: the reservoir hosts, cats and dogs. We define reproduction numbers and endemic equilibrium points for the two models. We use prevalence data for the five hosts from two islands in Lao People's Democratic Republic to estimate distributions of parameter values. We use these distributions to compute the sensitivity index and the partial rank correlation coefficient of the basic reproduction number and the endemic equilibrium point to the parameters. We calculate distributions of the host-specific type-reproduction number to show that humans are necessary to maintain transmission and can sustain transmission without additional reservoir hosts. Therefore interventions targeting humans could be sufficient to interrupt transmission of O. viverrini.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jtbi.2017.11.020DOI Listing
February 2018

Opisthorchis felineus infection prevalence in Western Siberia: A review of Russian literature.

Acta Trop 2018 Feb 27;178:196-204. Epub 2017 Nov 27.

Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Postfach, 4002, Basel, Switzerland; University of Basel, Petersplatz 1, 4001, Basel, Switzerland.

In this study we reviewed Russian scientific literature (scientific publications, book chapters, monographs) published between 1 January 1979 and 31 August 2015 from two sources: Main database of the Russian Scientific Electronic Library (eLIBRARY, http://elibrary.ru/), and the Scientific Medical Library of Siberian State Medical University (http://medlib.tomsk.ru/). Specifically, the review details the infection prevalence of Opisthorchis felineus (O. felineus) in Western Siberia, Russian Federation. From the primary key words screening, 1591 records were identified from which 32 Russian-language publications were relevant. The lowest O. felineus infection rate of 0.4% was reported in Tatarstan Republic, and the highest reached 83.9% in the Khanty-Mansiysk Autonomous Okrug. The infection prevalence was lower in children than in adults and increased with age. O. felineus infection was detected more often in indigenous population than in migrants. Infection intensity in western regions (Permskaya, Bryanskaya Oblast) was low and varied from 15 to 336 eggs per gram stool (epg), while in endemic regions it reached more than 2000 epg. In some settlements the mean intensity infection was 5234 epg. The high rates of intensity were registered in regions with a high prevalence of infection. Based on obtained data, a map of O. felineus infection prevalence in Western Siberia was developed. After mapping the results, the highest prevalence was detected in Tyumenskaya Oblast with over 60%, while the Tomskaya Oblast had the lowest prevalence at fewer than 19.0%. Khanty-Mansiysk Autonomus Okrug, Altaiskii Krai, Novosibirskaya Oblast and Omskaya Oblast had an average level of O. felineus infection of 20-39%. According to the results of the review, Western Siberia must be considered as highly endemic region for opisthorchiasis in the Russian Federation. The development of a control program specific for the Russian community is warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.actatropica.2017.11.018DOI Listing
February 2018

Efficacy and safety of tribendimidine versus praziquantel against Opisthorchis viverrini in Laos: an open-label, randomised, non-inferiority, phase 2 trial.

Lancet Infect Dis 2018 02 16;18(2):155-161. Epub 2017 Nov 16.

Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.

Background: Praziquantel is the only option for treatment of the liver fluke infection Opisthorchis viverrini. Tribendimidine could be an alternative drug. We aimed to assess the efficacy and safety of a single, oral dose of tribendimidine, compared with praziquantel administered in two doses, in participants with O viverrini infection.

Method: We did an open-label, randomised, non-inferiority, phase 2 trial in children (8-14 years) and adolescents and adults (≥15 years) in Champasack province, southern Laos. Participants infected with O viverrini were randomly assigned (1:1), via a computer-generated block-randomisation procedure (block sizes of two, four, and six), to receive a single, oral dose of tribendimidine (200 mg for children, 400 mg for adolescents and adults) or two oral doses of praziquantel (50 mg/kg bodyweight and 25 mg/kg bodyweight, 6 h apart). Physicians assessing adverse events and laboratory personnel were masked to treatment allocation, but the investigators administering treatment and the participants could have recognised the treatment group based on differences in the number, appearance, and odour of the tablets. The primary outcomes were cure rate, defined as no parasite eggs in stool at 3 weeks' follow-up, and egg reduction rate. We did available-case analysis of all participants with primary endpoint data. The non-inferiority margin for the difference in cure rates between the groups was pre-specified as -3 percentage points. Adverse events were monitored at 3 h and 24 h after treatment. This trial is registered, number ISRCTN96948551.

Findings: Between Feb 1, and April 30, 2014, we assigned 607 participants with confirmed O viverrini infection to receive tribendimidine (n=300) or praziquantel (n=307). 11 participants (five in the tribendimidine group and six in the praziquantel group) did not provide stool samples at 3 weeks' follow-up and were excluded from the available-case analysis. 276 (93·6%) of 295 participants in the tribendimidine group were cured compared with 293 (97·3%) of 301 participants in the praziquantel group. The difference in cure rates between the two groups was -3·8 percentage points (95% CI -7·1 to -0·4), thus the lower limit of the confidence interval exceeded the non-inferiority margin. In both treatment groups, egg reduction rates were 99·9%. Adverse events were of mild and moderate intensity and were more frequent in the praziquantel group than in the tribendimidine group (odds ratio 4·5, 95% CI 3·2-6·3; p<0·0001). The most frequent adverse events were headache, vertigo, nausea, and fatigue.

Interpretation: Tribendimidine has a slightly lower cure rate than praziquantel and non-inferiority was not shown. However, tribendimidine has a similar egg reduction rate to praziquantel and leads to fewer adverse events and thus might complement praziquantel in O viverrini control programmes, particularly in settings co-endemic for hookworm.

Funding: Joint Global Health Trials scheme from the Wellcome Trust, Department for International Development, and Medical Research Council.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S1473-3099(17)30624-2DOI Listing
February 2018

Strongyloides stercoralis is associated with significant morbidity in rural Cambodia, including stunting in children.

PLoS Negl Trop Dis 2017 Oct 23;11(10):e0005685. Epub 2017 Oct 23.

Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.

Background: Strongyloides stercoralis is a soil-transmitted nematode that can replicate within its host, leading to long-lasting and potentially fatal infections. It is ubiquitous and highly prevalent in Cambodia. The extent of morbidity associated with S. stercoralis infection is difficult to assess due to the broad spectrum of symptoms and, thus, remains uncertain.

Methodology/principal Findings: Clinical signs were compared among S. stercoralis infected vs. non-infected participants in a cross-sectional survey conducted in 2012 in eight villages of Northern Cambodia, and before and after treatment with a single oral dose of ivermectin (200μg/kg BW) among participants harboring S. stercoralis. Growth retardation among schoolchildren and adolescents was assessed using height-for-age and thinness using body mass index-for-age. S. stercoralis prevalence was 31.1% among 2,744 participants. Urticaria (55% vs. 47%, OR: 1.4, 95% CI: 1.1-1.6) and itching (52% vs. 48%, OR: 1.2, 95% CI: 1.0-1.4) were more frequently reported by infected participants. Gastrointestinal, dermatological, and respiratory symptoms were less prevalent in 103 mono-infected participants after treatment. Urticaria (66% vs. 11%, OR: 0.03, 95% CI: 0.01-0.1) and abdominal pain (81 vs. 27%, OR: 0.07, 95% CI: 0.02-0.2) mostly resolved by treatment. S. stercoralis infection was associated with stunting, with 2.5-fold higher odds in case of heavy infection.

Conclusions/significance: The morbidity associated with S. stercoralis confirmed the importance of gastrointestinal and dermatological symptoms unrelated to parasite load, and long-term chronic effects when associated with malnutrition. The combination of high prevalence and morbidity calls for the integration of S. stercoralis into ongoing STH control measures in Cambodia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pntd.0005685DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695629PMC
October 2017

Transmission of Opisthorchis viverrini, Schistosoma mekongi and soil-transmitted helminthes on the Mekong Islands, Southern Lao PDR.

Infect Dis Poverty 2017 Sep 4;6(1):131. Epub 2017 Sep 4.

National Institute of Public Health, Ministry of Health, Vientiane Capital, Lao PDR.

Background: Prevalence of Opisthorchis viverrini, Schistosoma mekongi and soil-transmitted helminths (STH) remains high in Lao People's Democratic Republic (Lao PDR), despite control efforts including mass-drug administration, education and communication campaigns. New approaches are required to advance helminth control.

Methods: An ecohealth study was conducted on two Mekong islands in Southern Laos. Demographic and behavioural data were collected by questionnaire. Human and animal reservoir stools were examined. Bithynia spp. and Neotricula aperta snails were examined using shedding. Fresh water fish were examined using digestion technique. Multivariate random-effects analysis was used to find risk factors associated with helminth infections.

Results: Human infection rates with O. viverrini, hookworm, S. mekongi, Trichuris trichiura, Ascaris lumbricoides and Taenia spp. were 60.7%, 44.1%, 22.2%, 4.1%, 0.6% and 0.1%, respectively. Heavy intensity infections were 4.2%, 3.6% and 1.8% for O. viverrini, S. mekongi and hookworm, respectively. O. viverrini and S. mekongi infection rates among dogs and cats were 25.0% and 14.7%, respectively. Of the cats tested, 53.1% were infected with O. viverrini. Prevalence of O. viverrini and S. mekongi in snails was 0.3% and 0.01%, respectively. Overall prevalence of O. viverrini infection in fresh water fish was 26.9%, with the highest infection rates occurring in Hampala dispa (87.1%), Cyclocheilichthys apogon (85.7%) and Puntius brevis (40.0%). Illiteracy and lower socioeconomic status increased the risk of O. viverrini infection, while those aged 10-16 years and possessing latrines at home were less likely to be infected. Household dogs and cats that consumed raw fish were significantly and positively associated with O. viverrini infection of the household members. For S. mekongi, children under 9 years old were exposed significantly to this infection, compared to older age groups.

Conclusions: There is a pressing need to design and implement an integrated helminth control intervention on the Mekong Islands in southern Lao PDR. Given the highly dynamic transmission of O. viverrini, S. mekongi, STH and extended multiparasitism, annual mass-drug administration is warranted along with environmental modifications, health education and improved access to clean water and adequate sanitation to consolidate morbidity control and move towards elimination.

Trail Registration Number: Our findings presented here are from a cross-sectional study, therefore, it has not been registered.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40249-017-0343-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5582398PMC
September 2017

Comparison of novel and standard diagnostic tools for the detection of Schistosoma mekongi infection in Lao People's Democratic Republic and Cambodia.

Infect Dis Poverty 2017 Aug 10;6(1):127. Epub 2017 Aug 10.

Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.

Background: Given the restricted distribution of Schistosoma mekongi in one province in Lao People's Democratic Republic (Lao PDR) and two provinces in Cambodia, together with progress of the national control programmes aimed at reducing morbidity and infection prevalence, the elimination of schistosomiasis mekongi seems feasible. However, sensitive diagnostic tools will be required to determine whether elimination has been achieved. We compared several standard and novel diagnostic tools in S. mekongi-endemic areas.

Methods: The prevalence and infection intensity of S. mekongi were evaluated in 377 study participants from four villages in the endemic areas in Lao PDR and Cambodia using Kato-Katz stool examination, antibody detection based on an enzyme-linked immunosorbent assay (ELISA) and schistosome circulating antigen detection by lateral-flow tests. Two highly sensitive test systems for the detection of cathodic and anodic circulating antigens (CCA, CAA) in urine and serum were utilized.

Results: Stool microscopy revealed an overall prevalence of S. mekongi of 6.4% (one case in Cambodia and 23 cases in Lao PDR), while that of Opisthorchis viverrini, hookworm, Trichuris trichiura, Ascaris lumbricoides and Taenia spp. were 50.4%, 28.1%, 3.5%, 0.3% and 1.9%, respectively. In the urine samples, the tests for CCA and CAA detected S. mekongi infections in 21.0% and 38.7% of the study participants, respectively. In the serum samples, the CAA assay revealed a prevalence of 32.4%, while a combination of the CAA assay in serum and in urine revealed a prevalence of 43.2%. There was a difference between the two study locations with a higher prevalence reached in the samples from Lao PDR.

Conclusions: The CCA, CAA and ELISA results showed substantially higher prevalence estimates for S. mekongi compared to Kato-Katz thick smears. Active schistosomiasis mekongi in Lao PDR and Cambodia might thus have been considerably underestimated previously. Hence, sustained control efforts are still needed to break transmission of S. mekongi. The pivotal role of highly sensitive diagnostic assays in areas targeting elimination cannot be overemphasised.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40249-017-0335-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5550959PMC
August 2017
-->