Publications by authors named "Pham-Duc Phuc"

27 Publications

  • Page 1 of 1

Microbial contamination and associated risk factors in retailed pork from key value chains in Northern Vietnam.

Int J Food Microbiol 2021 Mar 17;346:109163. Epub 2021 Mar 17.

International Livestock Research Institute, Hanoi, Viet Nam.

Pork and pork products are important staple food in the diet of Vietnamese consumers. The safety of pork, including biological contamination, is a concern to several public authorities and value chain actors. This cross-sectional study aimed to identify Salmonella and total bacterial count (TBC) contamination of cut pork sold in different outlets, and determine the potential factors leading to contamination. A total of 671 pork samples were collected from different retail channels in three provinces in Northern Vietnam. Hygiene conditions and practices at pork vending premises were also observed and recorded. Data analysis used descriptive statistics and regression analysis. Overall, Salmonella prevalence in retailed pork was 58.1%. Salmonella contamination in pork from traditional retail, modern retail and food services were 60.5%, 50.9% and 80.5%, respectively. Eighty percent and 68% of fresh pork in canteen and street food was contaminated with Salmonella. Only a small proportion of a subset of the pork samples (6.2%) tested met the Vietnamese standard requirement for TBC contamination. Average concentration of TBC in fresh pork in traditional retail, modern retail and food services were 6.51 (SD: 0.64), 6.38 (0.65), and 6.96 (0.85) LogCFU/g, respectively. Transport time, use of the same tools for pork and other types of meat, storage temperature, and environment hygiene are important factors that might affect microbial contamination. The findings underline the high level of microbial contamination, which requires practical interventions to improve food safety hygiene practices and behavior of pork retailers.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2021.109163DOI Listing
March 2021

International, Transdisciplinary, and Ecohealth Action for Sustainable Agriculture in Asia.

Front Public Health 2021 5;9:592311. Epub 2021 Feb 5.

Animal and Human Health Program, International Livestock Research Institute, Nairobi, Kenya.

Sustainably intensifying agriculture to secure food for people, while minimizing the human, animal, and environmental health impacts is an unprecedented global food security challenge. Action research is needed to understand and mitigate impacts, with Ecosystem approaches to health (Ecohealth) emerging as a promising framework to support such efforts. Yet, few have critically examined the application of Ecohealth principles in an agricultural context, particularly in Southeast Asia where agricultural intensification is rapidly expanding. In this paper, we evaluate the strengths, challenges, and opportunities of agriculture-related Ecohealth projects in low-resource settings of Vietnam, Thailand, Indonesia, and China, drawing on a case study of the Field Building Leadership Initiative (FBLI). To do this, we used a developmental evaluation framework involving several iterative cycles of document reviews, interviews, focus groups, and outcome harvesting with researchers, partners, and community members involved in FBLI. Results highlight the importance of transdisciplinarity, participation, and knowledge-to-action principles in co-generating knowledge and co-developing practical solutions. Implementing such principles presents challenges in terms of coordinating regional collaborations, managing high workloads, meaningfully engaging communities, and ensuring ongoing monitoring and evaluation. To address these challenges, there is a need to strengthen capacity in integrated approaches to health, improve institutionalization of Ecohealth, foster community engagement, and systematically monitor and evaluate efforts. Ecohealth holds significant promise in improving food security, but only when considerable time is spent developing and implementing projects with communities.
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http://dx.doi.org/10.3389/fpubh.2021.592311DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7892777PMC
February 2021

Understanding Antibiotic Residues and Pathogens Flow in Wastewater from Smallholder Pig Farms to Agriculture Field in Ha Nam Province, Vietnam.

Environ Health Insights 2020 5;14:1178630220943206. Epub 2020 Oct 5.

Center for Public Health and Ecosystem Research, Hanoi University of Public Health, Hanoi, Vietnam.

Background: Contact with livestock wastewater on farms and in communities can pose a risk to human and animal health.

Methods: This cross-sectional study was conducted in 180 households and 24 pig farms (96 wastewater samples) to explore information about pig production, livestock waste management, antibiotic use, and to analyze antibiotic residues and microbial contamination, respectively.

Results: Of the 120 households raising pigs, biogas systems were the most commonly used to treat animal waste (70%), followed by compositing (19%), and the remaining respondents discharged waste directly into drains or ponds (11%). The majority of respondents (78%) used antibiotics to treat and prevent disease in pigs, but 32% of them did not know of any disadvantages of antibiotic abuse. ELISA assays were performed on half of the wastewater samples (n = 48), demonstrating that residues of flouroquinolones and sulfonamides were present in 6.3% (3/48) and 22.9% (11/48) of tested samples, respectively. The average residual level of sulfamethazine was 27.8 ug/l. Further, concentrations exceeding regulatory levels in Vietnam were found in nearly all samples. spp. was also found in 57.3% of samples, though prevalence rates varied across the different sites. Finally, was found in 8.4% of samples, and was found in 5.2% of samples.

Conclusions: This study suggests that livestock wastewater carried potential harmful pathogens and antibiotic residues that could come into contact with humans in the community. Thus, appropriate operation and application of livestock wastewater treatment (such as biogas or composting) and management should be a continued focused.
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http://dx.doi.org/10.1177/1178630220943206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543113PMC
October 2020

Spatiotemporal analysis of historical records (2001-2012) on dengue fever in Vietnam and development of a statistical model for forecasting risk.

PLoS One 2019 27;14(11):e0224353. Epub 2019 Nov 27.

National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.

Background: Dengue fever is the most widespread infectious disease of humans transmitted by Aedes mosquitoes. It is the leading cause of hospitalization and death in children in the Southeast Asia and western Pacific regions. We analyzed surveillance records from health centers in Vietnam collected between 2001-2012 to determine seasonal trends, develop risk maps and an incidence forecasting model.

Methods: The data were analyzed using a hierarchical spatial Bayesian model that approximates its posterior parameter distributions using the integrated Laplace approximation algorithm (INLA). Meteorological, altitude and land cover (LC) data were used as predictors. The data were grouped by province (n = 63) and month (n = 144) and divided into training (2001-2009) and validation (2010-2012) sets. Thirteen meteorological variables, 7 land cover data and altitude were considered as predictors. Only significant predictors were kept in the final multivariable model. Eleven dummy variables representing month were also fitted to account for seasonal effects. Spatial and temporal effects were accounted for using Besag-York-Mollie (BYM) and autoregressive (1) models. Their levels of significance were analyzed using deviance information criterion (DIC). The model was validated based on the Theil's coefficient which compared predicted and observed incidence estimated using the validation data. Dengue incidence predictions for 2010-2012 were also used to generate risk maps.

Results: The mean monthly dengue incidence during the period was 6.94 cases (SD 14.49) per 100,000 people. Analyses on the temporal trends of the disease showed regular seasonal epidemics that were interrupted every 3 years (specifically in July 2004, July 2007 and September 2010) by major fluctuations in incidence. Monthly mean minimum temperature, rainfall, area under urban settlement/build-up areas and altitude were significant in the final model. Minimum temperature and rainfall had non-linear effects and lagging them by two months provided a better fitting model compared to using unlagged variables. Forecasts for the validation period closely mirrored the observed data and accurately captured the troughs and peaks of dengue incidence trajectories. A favorable Theil's coefficient of inequality of 0.22 was generated.

Conclusions: The study identified temperature, rainfall, altitude and area under urban settlement as being significant predictors of dengue incidence. The statistical model fitted the data well based on Theil's coefficient of inequality, and risk maps generated from its predictions identified most of the high-risk provinces throughout the country.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0224353PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6881000PMC
April 2020

Knowledge, attitudes and practices of livestock and aquaculture producers regarding antimicrobial use and resistance in Vietnam.

PLoS One 2019 25;14(9):e0223115. Epub 2019 Sep 25.

Center for Public Health and Ecosystem Research, Hanoi University of Public Health, Hanoi, Vietnam.

The use of antibiotics in livestock production is considered a major driver of antibiotic resistance on a global scale. In Vietnam, small- and medium-scale livestock producers dominate the domestic market and regulatory pushes have done little to decrease antibiotic use. In order to inform future policy directions, this study aims to explore knowledge, attitudes, and practices amongst livestock producers to identify their perspectives on antibiotic use and resistance. A total of 392 small- and medium-scale producers specialized in pig, poultry and aquaculture production participated in the study. The results showed that the primary reason for antibiotic use reported by producers was for the treatment of infections (69%). However, prophylactic use was also evident, with farmers reporting other reasons for antibiotic use such as "animals display abnormal symptoms or behaviour" (55%), the "weather is about to change" (25%), or "animals on neighboring farms fall ill" (27%). Only one-fifth of producers demonstrated favorable attitudes towards antibiotic use and preventing antibiotic resistance. Moreover, administering antibiotics remained the preferred countermeasure directly applied by farmers at the first indication of disease (17%), compared to enacting hygiene (10%) or quarantine (5%) measures. The results showed divergent trends amongst producers, with pig producers demonstrating higher levels of knowledge, more favorable attitudes, and higher self-reported utilization of good practice. Better knowledge, attitudes, and practices were also associated with producers who engaged in efforts to explore information on antibiotic use and resistance, which improved incrementally with the number of sources consulted and hours invested. However, there were some areas where increased knowledge or more favorable attitude scores did not translate into better practices. For instance, producers with higher levels of formal education performed significantly better than those with lower education in terms of knowledge and attitude, though both groups reported similar practices. The findings of this study may support future interventions to prevent both antibiotic misuse and the development of antimicrobial resistance.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0223115PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6760827PMC
March 2020

Simulating Cross-Contamination of Cooked Pork with from Raw Pork through Home Kitchen Preparation in Vietnam.

Int J Environ Res Public Health 2018 10 22;15(10). Epub 2018 Oct 22.

Veterinary Epidemiology Unit, School of Veterinary Medicine, Rakuno Gakuen University, 582 Bunkyodai Midorimachi, Ebetsu, Hokkaido 069-8501, Japan.

Pork is the most commonly consumed meat in Vietnam, and is a common contaminant. This study aimed to assess potential cross-contamination between raw and cooked pork in Vietnamese households. Different scenarios for cross-contamination were constructed based on a household survey of pork handling practices (416 households). Overall, 71% of people used the same knife and cutting board for both raw and cooked pork; however, all washed their hands and utensils between handling raw and cooked pork. The different scenarios were experimentally tested. First, was inoculated on raw pork and surfaces (hands, knives and cutting boards); next, water used for washing and pork were sampled to identify the presence and concentration of during different scenarios of food preparation. Bootstrapping techniques were applied to simulate transfer rates of cross-contamination. No cross-contamination to cooked pork was observed in the scenario of using the same hands with new cutting boards and knives. The probability of re-contamination in the scenarios involving re-using the cutting board after washing was significantly higher compared to the scenarios which used a new cutting board. Stochastic simulation found a high risk of cross-contamination from raw to cooked pork when the same hands, knives and cutting boards were used for handling raw and cooked pork (78%); when the same cutting board but a different knife was used, cross-contamination was still high (67%). Cross-contamination between was not seen when different cutting boards and knives were used for cutting raw and cooked pork. This study provided an insight into cross-contamination of , given common food handling practices in Vietnamese households and can be used for risk assessment of pork consumption.
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http://dx.doi.org/10.3390/ijerph15102324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6210979PMC
October 2018

Risk factors associated with Salmonella spp. prevalence along smallholder pig value chains in Vietnam.

Int J Food Microbiol 2019 Feb 6;290:105-115. Epub 2018 Oct 6.

Veterinary Epidemiology Unit, School of Veterinary Medicine, Rakuno Gakuen University, 582 Bunkyodai Midorimachi, Ebetsu, Hokkaido 069-8501, Japan. Electronic address:

The objective of this study was to investigate the prevalence of, and risk factors for, Salmonella contamination along the smallholder pig value chain in northern Vietnam. Repeat cross-sectional (for farm and pork shops) and longitudinal (for slaughterhouses) studies were carried out in Hung Yen and Nghe An provinces in four sampling periods over a year (April 2014 to February 2015). In total, 72 pig farms and 217 pork shops were visited during the period, and 13 slaughterhouses were visited four times. Information on management and hygiene practices was collected using checklists and questionnaires, and risk factor analyses at the farm, slaughterhouse, and pork shop levels were performed using generalized mixed-effects models with the significant levels 10%. Salmonella prevalence was 36.1%, 38.9%, and 44.7% on pig pen floors, pig carcasses in slaughterhouses, and cut pork in pork shops, respectively. The risk factor for Salmonella prevalence on pig pen floors were having a pig pen next to a household (p = 0.06) and free access to the farm by visitors (p = 0.06). Our slaughterhouse model found a single risk factor for carcass contamination: slaughter area close to lairage without hygienic measures (p = 0.03). For pork shops, presence of flies or insects on pork at shop (p = 0.02) and use of a cloth at pork shop (p = 0.02) were risk factors. The Salmonella prevalence on pig carcass and cut pork was significantly lower in winter compared to that in other seasons. Our study results highlighted the need of improving farm hygiene at farm level, and pork hygiene practices to avoid cross-contamination at the slaughterhouse and market levels, to reduce the risk of salmonellosis through pork consumption in northern Vietnam.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2018.09.030DOI Listing
February 2019

Community Participatory Interventions to Improve Farmer Knowledge and Practices of Household Biogas Unit Operation in Ha Nam Province, Vietnam.

J Public Health Manag Pract 2018 Mar/Apr;24 Suppl 2:S28-S35

Center for Public Health and Ecosystem Research, Hanoi University of Public Health, North Tu Liem District, Hanoi, Vietnam (Mr Luu, Mss Nguyen, Pham, and MacDonald, and Drs Nguyen-Viet and Pham-Duc); National Institute for Animal Science, Thuy Phuong, North Tu Liem District, Hanoi, Vietnam (Dr Dinh-Xuan); and International Livestock Research Institute, Vietnam, Ba Dinh, Hanoi, Vietnam (Dr Nguyen-Viet).

Context: The use of biogas systems to treat livestock waste is a common practice in Vietnam. However, farmers' knowledge and practices of the safe and appropriate use of household biogas units (HBUs) are still limited and could negatively impact human, animal, and environmental health.

Objective: To assess the effectiveness of an intervention to improve knowledge and practices of biogas operation among farmers in 2 communes of Ha Nam Province, Vietnam.

Design: A community-based intervention approach.

Setting: This study was conducted from 2015 to 2016 in 2 communes of Ha Nam Province, Vietnam.

Participants: Only farmers with HBUs (N = 399) participated in this research. Farmers were assigned to either an intervention group or a control group at a ratio of 1:2.

Intervention: Two intervention steps were implemented over a 6-month period as follows: (i) the core farmer group trained in 6 steps of HBU safe handling practice; and (ii) the core farmer group conducted peer-to-peer communication with its neighbors in the commune using the provided material.

Main Outcome Measure(s): Farmers' knowledge and practices in biogas operation were assessed by a structured questionnaire. The questionnaire was administered before (baseline) and after the intervention (follow-up) to both the control and intervention groups.

Results: There was a significant difference in the knowledge and practices of biogas operation between the 2 groups, in which farmers in the intervention group demonstrated better understanding of the related topic than the control group (P < .05, t test). A linear regression model indicated that baseline and follow-up scores in both knowledge and practices of the intervention group were higher than those of the control group. After the intervention, the mean difference score in knowledge and practices between the intervention and control groups was 5.0 and 2.0 points, respectively (P < .01).

Conclusion: A community-based intervention approach could be applied to improve knowledge and practices among farmers in using biogas systems. However, further studies should be conducted to assess the sustainability and effectiveness of this model.
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http://dx.doi.org/10.1097/PHH.0000000000000727DOI Listing
November 2019

Turning poop into profit: Cost-effectiveness and soil transmitted helminth infection risk associated with human excreta reuse in Vietnam.

PLoS Negl Trop Dis 2017 Nov 27;11(11):e0006088. Epub 2017 Nov 27.

Center for Public Health and Ecosystem Research, Hanoi University of Public Health, North Tu Liem, Hanoi, Vietnam.

Human excreta is a low cost source of nutrients vital to plant growth, but also a source of pathogens transmissible to people and animals. We investigated the cost-savings and infection risk of soil transmitted helminths (STHs) in four scenarios where farmers used either inorganic fertilizer or fresh/composted human excreta supplemented by inorganic fertilizer to meet the nutrient requirements of rice paddies in the Red River Delta, Vietnam. Our study included two main components: 1) a risk estimate of STH infection for farmers who handle fresh excreta, determined by systematic review and meta-analysis; and 2) a cost estimate of fertilizing rice paddies, determined by nutrient assessment of excreta, a retailer survey of inorganic fertilizer costs, and a literature review to identify region-specific inputs. Our findings suggest that farmers who reuse fresh excreta are 1.24 (95% CI: 1.13-1.37, p-value<0.001) times more likely to be infected with any STH than those who do not handle excreta or who compost appropriately, and that risk varies by STH type (Ascaris lumbricoides RR = 1.17, 95% CI = 0.87-1.58, p-value = 0.29; Hookworm RR = 1.02, 95% CI = 0.50-2.06, p-value = 0.96; Trichuris trichiura RR = 1.38, 95% CI = 0.79-2.42, p-value = 0.26). Average cost-savings were highest for farmers using fresh excreta (847,000 VND) followed by those who composted for 6 months as recommended by the WHO (312,000 VND) and those who composted for a shorter time (5 months) with lime supplementation (37,000 VND/yr); however, this study did not assess healthcare costs of treating acute or chronic STH infections in the target group. Our study provides evidence that farmers in the Red River Delta are able to use a renewable and locally available resource to their economic advantage, while minimizing the risk of STH infection.
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http://dx.doi.org/10.1371/journal.pntd.0006088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5720817PMC
November 2017

Household Exposure to Livestock and Health in the CHILILAB HDSS Cohort, Vietnam.

Asia Pac J Public Health 2017 Jul;29(5_suppl):72S-83S

1 Hanoi University of Public Health, Hanoi, Vietnam.

In Vietnam, pigs and poultry are predominantly produced by small-scale farmers, creating challenges for zoonotic disease management. The objective of this study was to characterize practices related to livestock and manure management and to measure association with 3 self-reported health symptoms (coughing, fever, and diarrhea/nausea/vomiting) in a region currently undergoing health transitions. We analyzed cross-sectional survey data collected from a subset (N = 5520) of the Chi Linh Health and Demographic Surveillance System cohort in Chi Linh district, Vietnam. Bivariate analyses indicated that female gender was a significant risk factor for all 3 health symptoms, whereas age (≥60 years), suburban living, low education level, and household wealth were risk factors for 2 symptoms. Overall, we found no indication that biogas production or exposure to livestock and manure adversely affected human health. Efforts to control zoonotic disease transmission should prioritize utilization of veterinarians, enhanced farm biosecurity, and improvements to commune drinking water/wastewater infrastructure.
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http://dx.doi.org/10.1177/1010539517712758DOI Listing
July 2017

Seasonal and geographical distribution of bacillary dysentery (shigellosis) and associated climate risk factors in Kon Tam Province in Vietnam from 1999 to 2013.

Infect Dis Poverty 2017 Jun 21;6(1):113. Epub 2017 Jun 21.

International Livestock Research Institute (ILRI), Room 301-302, B1 Building, Van Phuc Diplomatic Compound, 298 Kim Ma Street, Ba Dinh District, Hanoi, Vietnam.

Background: Bacillary dysentery (BD) is an acute bacterial infection of the intestine caused by Shigella spp., with clinical symptoms ranging from fever to bloody diarrhoea to abdominal cramps to tenesmus. In Vietnam, enteric bacterial pathogens are an important cause of diarrhoea and most cases in children under 5 years of age are due to Shigella strains. The serogroups S. flexneri and S. sonnei are considered to be the most common. The main objective of this study was to, for the first time, assess the seasonal patterns and geographic distribution of BD in Vietnam, and to determine the climate risk factors associated with the incidence of BD in Kon Tum Province, where the highest rate of bacillary dysentery was observed from 1999 to 2013.

Methods: The seasonal patterns and geographic distribution of BD was assessed in Vietnam using a seasonal-trend decomposition procedure based on loess. In addition, negative binomial regression models were used to determine the climate risk factors associated with the incidence of BD in Kon Tum Province, from 1999 to 2013.

Results: Overall, incidence rates of BD have slightly decreased over time (except for an extremely high incidence in 2012 in the north of Vietnam). The central regions (north/south central coast and central highlands) had relatively high incidence rates, whereas the northwest/east and Red River Delta regions had low incidence rates. Overall, seasonal plots showed a high peak in the mid-rainy reason and a second smaller peak in the early or late rainy season. The incidence rates significantly increased between May and October ("wet season") across the country. In Kon Tum Province, temperature, humidity, and precipitation were found to be positively associated with the incidence of BD.

Conclusions: Our findings provide insights into the seasonal patterns and geographic distribution of BD in Vietnam and its associated climate risk factors in Kon Tum Province. This study may help clinicians and the general public to better understand the timings of outbreaks and therefore equip them with the knowledge to plan better interventions (such as improving water, sanitation, and hygiene conditions) during peak seasons. This can, in turn, prevent or reduce outbreaks and onwards transmission during an outbreak.
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http://dx.doi.org/10.1186/s40249-017-0325-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5480122PMC
June 2017

Food Safety Perceptions and Practices among Smallholder Pork Value Chain Actors in Hung Yen Province, Vietnam.

J Food Prot 2016 09;79(9):1490-1497

International Livestock Research Institute, 298 Kim Ma Street, Hanoi 10000, Vietnam.

Pork safety is an important public health concern in Vietnam and is a shared responsibility among many actors along the pork value chain. We examined the knowledge, perceptions, and practices regarding food safety, disease, and health risk among selected pork value chain actors (slaughterhouse owners and workers, people living around slaughterhouses, pork sellers, consumers, and veterinary and public health staff) in three districts in Hung Yen Province, Vietnam. We randomly selected 52 pork value chain actors to be surveyed through questionnaires, observation checklists, key informant interviews, and focus group discussions. Most slaughterhouse workers acquired knowledge and experience of food safety through "learning by doing" rather than from training by a veterinary or public health professional. Both slaughterhouse worker and pork seller groups had some accurate perceptions about pig diseases and foodborne diseases; however, misperceptions of risk and, especially, of zoonoses were present. Furthermore, while workers and sellers often use cloths to dry the meat and clean equipment, they did not think this was a risk for meat contamination. Moreover, when sellers wear protective equipment, such as gloves, masks, or hats, consumers perceive that the sellers may have health issues they are trying to conceal and so consumers avoid buying from them. The perceived freshness of pork, along with trust in the seller and in the pork production process, were strong indicators of consumer preference. And yet, pork value chain actors tend to trust their own individual food safety practices more, rather than the practices of other actors along the chain. Veterinary and public health staff emphasized the gap between regulations and food safety practices. Education and training on food safety risks and proper handling are priorities, along with integrated and intensive efforts to improve food safety among pork value chain actors.
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http://dx.doi.org/10.4315/0362-028X.JFP-15-402DOI Listing
September 2016

Ascaris lumbricoides egg die-off in an experimental excreta storage system and public health implication in Vietnam.

Int J Public Health 2017 Feb 22;62(Suppl 1):103-111. Epub 2016 Nov 22.

Center for Public Health and Ecosystem Research (CENPHER), Hanoi University of Public Health, Hanoi, Vietnam.

Objectives: We studied the influence of different additive materials (lime, and rice husk) and aeration conditions on Ascaris lumbricoides egg die-off in 24 vaults of an experimental excreta storage unit.

Methods: Excreta samples were collected once every two weeks over a 181-day period. Temperature, pH, and moisture content were recorded. A. lumbricoides eggs were quantitatively analyzed by the Romanenko method, which identified and counted live and dead eggs.

Results: From the first sampling (0 storage day) to the final sampling (181 storage days) the average percentage of viable A. lumbricoides eggs decreased gradually from 76.72 ± 11.23% (mean ± SD) to 8.26 ± 5.20%. The storage time and the high pH value significantly increased the die-off of helminth eggs. Over 181 storage days, all vaults option effectively reduced A. lumbricoides eggs die-off.

Conclusions: The best vault option, with aeration and 10% lime per total weight, met the WHO standard for excreta treatment on the 111th storage day.
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http://dx.doi.org/10.1007/s00038-016-0920-yDOI Listing
February 2017

Quantitative risk assessment of human salmonellosis in the smallholder pig value chains in urban of Vietnam.

Int J Public Health 2017 Feb 11;62(Suppl 1):93-102. Epub 2016 Nov 11.

International Livestock Research Institute, Nairobi, Kenya.

Objectives: To quantify salmonellosis risk in humans through consumption of boiled pork in urban Hung Yen Province, Vietnam, using a quantitative microbial risk assessment.

Methods: We collected 302 samples along the pork value chain in Hung Yen between April 2014 and February 2015. We developed a model in @Risk, based on microbiological, market, and household surveys on cooking, cross-contamination and consumption, and conducted sensitivity analysis.

Results: Salmonella prevalence of pen floor swabs, slaughterhouse carcasses and cut pork were 33.3, 41.7 and 44.4%, respectively. The annual incidence rate of salmonellosis in humans was estimated to be 17.7% (90% CI 0.89-45.96). Parameters with the greatest influence risk were household pork handling practice followed by prevalence in pork sold in the central market. Wide confidence interval in the incidence estimate was mainly due to the variability in the degree of reduction in bacteria concentration by cooking, and pork consumption pattern.

Conclusions: The risk of salmonellosis in humans due to boiled pork consumption appears to be high. Control measures may include improving the safety of retailed pork and improving household hygiene.
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http://dx.doi.org/10.1007/s00038-016-0921-xDOI Listing
February 2017

Diarrhea risks by exposure to livestock waste in Vietnam using quantitative microbial risk assessment.

Int J Public Health 2017 Feb 11;62(Suppl 1):83-91. Epub 2016 Nov 11.

Center for Public Health and Ecosystem Research, Hanoi School of Public Health, Hanoi, Vietnam.

Objectives: The aim of this paper was to assess the diarrhea risks caused by various pathogens among those exposed to biogas wastewater through different activities.

Methods: Application of quantitative microbial risk assessment (QMRA) of biogas wastewater was conducted in Hanam Province, Vietnam. A total of 451 representatives from households that use biogas were interviewed about their practices of handling biogas plant and reuse of biogas effluent for irrigation. In addition, 150 samples of biogas wastewater were analyzed for Escherichia coli, Cryptosporidium parvum, and Giardia lamblia. Risk characterization was calculated using Monte Carlo simulation.

Results: The annual diarrhea risk caused by exposure to biogas effluent through irrigation activities ranged from 17.4 to 21.1% (E. coli O157:H7), 1.0 to 2.3% (G. lamblia), and 0.2 to 0.5% (C. parvum), while those caused through unblocking drains connected to biogas effluent tanks were 22.0% (E. coli), 0.7% (G. lamblia), and 0.5% (C. parvum).

Conclusions: Further measures are needed to reduce the risk by either improving the microbial quality of biogas effluent or by ensuring the use of personal protective measures when exposed to biogas wastewater.
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http://dx.doi.org/10.1007/s00038-016-0917-6DOI Listing
February 2017

Exposure assessment of chemical hazards in pork meat, liver, and kidney, and health impact implication in Hung Yen and Nghe An provinces, Vietnam.

Int J Public Health 2017 Feb 5;62(Suppl 1):75-82. Epub 2016 Nov 5.

International Livestock Research Institute, Hanoi, Vietnam.

Objectives: This study assesses the risk of exposure to hazardous chemical residues in pork meat, liver, and kidney collected at wet markets in Nghe An and Hung Yen provinces and discusses health impact implication.

Methods: 514 pig feed, kidney, liver, and pork samples were pooled and qualitatively and quantitatively analyzed for tetracyclines, fluoroquinolones, sulphonamide, chloramphenicol, β-agonists, and heavy metals. We compare the results with current regulations on chemical residues and discuss health implications.

Results: Legal antibiotics were found in feed. Tetracycline and fluoroquinolones were not present in pork, but 11% samples were positive with sulfamethazine above maximum residue limits (MRL); 11% of packaged feed and 4% of pork pooled samples were positive for chloramphenicol, a banned substance; two feed, two liver, and one pork samples were positive for β-agonists but did not exceed current MRL; 28% of pooled samples had lead, but all were below MRL; and all samples were negative for cadmium and arsenic. Thus, the health risks due to chemical hazards in pork in Hung Yen and Nghe An seemed not as serious as what were recently communicated to the public on the mass media.

Conclusions: There is potential exposure to sulphonamide, chloramphenicol, and β-agonists from pork. Risk communication needs to focus on banned chemicals, while informing the public about the minimal risks associated with heavy metals.
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http://dx.doi.org/10.1007/s00038-016-0912-yDOI Listing
February 2017

Assessing potential health impacts of waste recovery and reuse business models in Hanoi, Vietnam.

Int J Public Health 2017 Feb 30;62(Suppl 1):7-16. Epub 2016 Aug 30.

Center for Public Health and Ecosystem Research, Hanoi School of Public Health, Hanoi, Vietnam.

Objectives: In resource-constrained settings, the recovery of nutrients and the production of energy from liquid and solid waste are important. We determined the range and magnitude of potential community health impacts of six solid and liquid waste recovery and reuse business models in Hanoi, Vietnam.

Methods: We employed a health impact assessment (HIA) approach using secondary data obtained from various sources supplemented with primary data collection. For determining the direction (positive or negative) and magnitude of potential health impacts in the population, a semiquantitative impact assessment was pursued.

Results: From a public health perspective, wastewater reuse for inland fish farming, coupled with on-site water treatment has considerable potential for individual and community-level health benefits. One of the business models investigated (i.e. dry fuel manufacturing with agro-waste) resulted in net negative health impacts.

Conclusions: In Hanoi, the reuse of liquid and solid waste-as a mean to recover water and nutrients and to produce energy-has considerable potential for health benefits if appropriately managed and tailored to local contexts. Our HIA methodology provides an evidence-based decision-support tool for identification and promotion of business models for implementation in Hanoi.
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http://dx.doi.org/10.1007/s00038-016-0877-xDOI Listing
February 2017

Intestinal parasite infections and associated risk factors in communities exposed to wastewater in urban and peri-urban transition zones in Hanoi, Vietnam.

Parasit Vectors 2016 10 10;9(1):537. Epub 2016 Oct 10.

Swiss Tropical and Public Health Institute, Basel, Switzerland.

Background: Infections with intestinal parasites (helminths and intestinal protozoa) are endemic in Southeast Asia and inappropriate management and reuse of wastewater might exacerbate the risk of human infections. In rapidly growing urban settings, little is known about the extent of intestinal parasite infections. We assessed the point-prevalence and risk factors of intestinal parasite infections in population groups differently exposed to wastewater in urban and peri-urban transition zones in Hanoi, the capital of Vietnam.

Methods: A cross-sectional survey was carried out between April and June 2014 in people aged ≥ 18 years at risk of wastewater exposure from To Lich River: workers maintaining wastewater treatment facilities; urban farmers reusing wastewater; and urban dwellers at risk of flooding events. For comparison, two peri-urban population groups living in close proximity to the Red River were chosen: farmers using river water for irrigation purposes; and people living in the same communities. A single stool sample was subjected to Kato-Katz and formalin-ether concentration methods for the diagnosis of helminth and intestinal protozoa infections. A questionnaire was administered to determine risk factors and self-reported signs and symptoms.

Results: A total of 681 individuals had complete data records. Highest point-prevalence rates of intestinal parasite infections were observed for peri-urban farmers (30 %). Hookworm and Trichuris trichiura were the predominant helminth species (25 % and 5 %, respectively). Peri-urban farmers were at higher odds of infection with intestinal parasites than any other groups (adjusted odds ratio 5.8, 95 % confidence interval 2.5 to 13.7). Lack of access to improved sanitation and not receiving deworming within the past 12 months were associated with higher infection risk, while higher educational attainment and socioeconomic status were negatively associated with intestinal parasite infections.

Conclusions: Our results suggest that exposure to wastewater was not directly associated with infection with helminths and intestinal protozoa in different population groups in Hanoi. These findings might be explained by a high level of awareness of health risks and access to safe sanitary infrastructure in urban areas. The high prevalence rates observed in peri-urban farmers call for specific interventions targeting this population group.
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http://dx.doi.org/10.1186/s13071-016-1809-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5057403PMC
October 2016

Microbial contamination along the main open wastewater and storm water channel of Hanoi, Vietnam, and potential health risks for urban farmers.

Sci Total Environ 2016 Oct 17;566-567:1014-1022. Epub 2016 Jun 17.

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

The use of wastewater in agriculture and aquaculture has a long tradition throughout Asia. For example, in Hanoi, it creates important livelihood opportunities for >500,000 farmers in peri-urban communities. Discharge of domestic effluents pollute the water streams with potential pathogenic organisms posing a public health threat to farmers and consumers of wastewater-fed foodstuff. We determined the effectiveness of Hanoi's wastewater conveyance system, placing particular emphasis on the quality of wastewater used in agriculture and aquaculture. Between April and June 2014, a total of 216 water samples were obtained from 24 sampling points and the concentrations of total coliforms (TC), Escherichia coli, Salmonella spp. and helminth eggs determined. Despite applied wastewater treatment, agricultural field irrigation water was heavily contaminated with TC (1.3×10(7)colony forming unit (CFU)/100mL), E. coli (1.1×10(6)CFU/100mL) and Salmonella spp. (108 most probable number (MPN)/100mL). These values are 110-fold above Vietnamese discharge limits for restricted agriculture and 260-fold above the World Health Organization (WHO)'s tolerable safety limits for unrestricted agriculture. Mean helminth egg concentrations were below WHO tolerable levels in all study systems (<1egg/L). Hence, elevated levels of bacterial contamination, but not helminth infections, pose a major health risk for farmers and consumers of wastewater fed-products. We propose a set of control measures that might protect the health of exposed population groups without compromising current urban farming activities. This study presents an important example for sanitation safety planning in a rapidly expanding Asian city and can guide public and private entities working towards Sustainable Development Goal target 6.3, that is to improve water quality by reducing pollution, halving the proportion of untreated wastewater and increasing recycling and safe reuse globally.
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http://dx.doi.org/10.1016/j.scitotenv.2016.05.080DOI Listing
October 2016

Identifying the impediments and enablers of ecohealth for a case study on health and environmental sanitation in Hà Nam, Vietnam.

Infect Dis Poverty 2014 1;3(1):36. Epub 2014 Oct 1.

Department of Population Medicine, Ontario Veterinary College, University of Guelph, 2509 Stewart Building (#45), Guelph, N1G 2W1 ON Canada.

Background: To date, research has shown an increasing use of the term "ecohealth" in literature, but few researchers have explicitly described how it has been used. We investigated a project on health and environmental sanitation (the conceptual framework of which included the pillars of ecohealth) to identify the impediments and enablers of ecohealth and investigate how it can move from concept to practice.

Methods: A case study approach was used. The interview questions were centred on the nature of interactions and the sharing of information between stakeholders.

Results: The analysis identified nine impediments and 15 enablers of ecohealth. Three themes relating to impediments, in particular-integration is not clear, don't understand, and limited participation-related more directly to the challenges in applying the ecohealth pillars of transdisciplinarity and participation. The themes relating to enablers-awareness and understanding, capacity development, and interactions-facilitated usage of the research results. By extracting information on the environmental, social, economic, and health aspects of environmental sanitation, we found that the issue spanned multiple scales and sectors.

Conclusion: The challenge of how to integrate these aspects should be considered at the design stage and throughout the research process. We recommend that ecohealth research teams include a self-investigation of their processes in order to facilitate a comparison of moving from concept to practice, which may offer insights into how to evaluate the process.
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http://dx.doi.org/10.1186/2049-9957-3-36DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4194379PMC
October 2014

Diarrhoeal diseases among adult population in an agricultural community Hanam province, Vietnam, with high wastewater and excreta re-use.

BMC Public Health 2014 Sep 20;14:978. Epub 2014 Sep 20.

Center for Public Health and Ecosystem Research (CENPHER), Hanoi School of Public Health (HSPH), 138 Giang Vo, Hanoi, Vietnam.

Background: Despite the potential health risks of wastewater and excreta use as fertiliser in agriculture, it is still widespread in Vietnam. However, the importance of diarrheal risk in adults' associated with the combined exposures to both excreta and wastewater use in agriculture is largely unknown. This study was carried out to determine diarrhoeal incidence and associated risk factors among the adult population exposed to wastewater and excreta used in agriculture in Hanam province, Vietnam.

Methods: An open cohort of 867 adults, aged 16-65 years, was followed weekly for 12 months to determine the incidence of diarrhoea. A nested case-control study was used to assess the risk factors of diarrhoeal episodes. Two hundred and thirty-two pairs of cases and controls were identified and exposure information related to wastewater, human and animal excreta, personal hygiene practices, and food and water consumption was collected.

Results: The incidence rate of reported diarrhoea was 0.28 episodes per person-years at risk. The risk factors for diarrhoeal diseases included direct contact with the Nhue River water (odds ratio [OR] = 2.4, attributable fraction [AF] 27%), local pond water (OR = 2.3, AF 14%), composting of human excreta for a duration less than 3 months (OR = 2.4, AF 51%), handling human excreta in field work (OR = 5.4, AF 7%), handling animal excreta in field work (OR = 3.3, AF 36%), lack of protective measures while working (OR = 6.9, AF 78%), never or rarely washing hands with soap (OR = 3.3, AF 51%), use of rainwater for drinking (OR = 5.4, AF 77%) and eating raw vegetables the day before (OR = 2.4, AF 12%).

Conclusions: Our study shows that professional exposure to wastewater and excreta during agricultural activities are significantly contributing to the risk of diarrhoea in adults. The highest attributable fractions were obtained for direct contact with Nhue River and local ponds, handling practices of human and animal excreta as fertilisers, lack of protective measures while working and poor personal hygiene practices, and unsafe food and water consumption were associated with the risk of diarrhoeal episodes in adults. Improve personal hygiene practices and use of relevant treated wastewater and excreta as the public health measures to reduce these exposures will be most effective and are urgently warranted.
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http://dx.doi.org/10.1186/1471-2458-14-978DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4180152PMC
September 2014

Scenario planning for community development in Vietnam: a new tool for integrated health approaches?

Glob Health Action 2014 18;7:24482. Epub 2014 Aug 18.

Infrastructure Department, Embassy of the European Union in Chad/European Union Delegation in Chad, N'Djamena, Chad.

Background: Like many countries in Southeast Asia, Vietnam's rapid population and economic growth has met challenges in infrastructure development, especially sanitation in rural areas.

Objective: As an entry point, we developed scenario planning as an action-research tool in a peri-urban community to identify first steps towards improving their complex sanitation problem and to, systemically, address emerging/re-emerging infectious diseases, as these are commonly linked to unsafe water and inadequate sanitation conditions. As an integrated approach, the process of constructing scenarios allowed us to work across sectors and stakeholders to incorporate this knowledge into a common vision.

Design: We conducted focus group discussions to identify and rank driving forces, orally constructed scenarios for the most uncertain drivers, discussed scenario implications and options, and examined the overall process for usefulness and sustainability. During a one-month scoping phase and in between focus group meetings, we carried out household visits which helped us understand the context of data and gather feedback from participants outside of the formal data collection process. Recorded results from these activities were used to develop subsequent tools.

Results And Conclusions: The research process gave us insights into how to adapt the scenario planning tool to identify alternative options. This involved choosing boundary partners, negotiating priorities, drawing out participant learning through self-assessment of our process (a prerequisite for changing mental models and thus achieving outcomes), and understanding how conveyed messages may reinforce the status quo. These insights showed the importance of examining research results beyond outputs and outcomes, namely through process.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4138499PMC
http://dx.doi.org/10.3402/gha.v7.24482DOI Listing
April 2015

Ascaris lumbricoides and Trichuris trichiura infections associated with wastewater and human excreta use in agriculture in Vietnam.

Parasitol Int 2013 Apr 8;62(2):172-80. Epub 2013 Jan 8.

Center for Public Health and Ecosystem Research, Hanoi School of Public Health, 138 Giang Vo, Hanoi, Vietnam.

Background: We assessed the risk of helminth infections in association with the use of wastewater and excreta in agriculture in Hanam province, northern Vietnam. In two cross-sectional surveys, we obtained samples from 1,425 individuals from 453 randomly selected households. Kato-Katz thick smear and formalin-ether concentration techniques were used for helminth diagnosis in two stool samples per person. Socio-demographic and water, sanitation and hygiene related characteristics, including exposure to human and animal excreta and household wastewater management, were assessed with a questionnaire.

Results: Overall 47% of study participants were infected with any helminth (Ascaris lumbricoides 24%, Trichuris trichiura 40% and hookworm 2%). Infections with intestinal protozoa were rare (i.e. Entamoeba histolytica 6%, Entamoeba coli 2%, Giardia lamblia 2%, Cryptosporidium parvum 5% and Cyclospora cayetanensis 1%). People having close contact with polluted Nhue River water had a higher risk of helminth infections (odds ratio [OR]=1.5, 95% confidence interval [CI] 1.1-2.2) and A. lumbricoides (OR=2.1, 95% CI 1.4-3.2), compared with those without contact. The use of human excreta for application in the field had an increased risk for a T. trichiura infection (OR=1.5, 95% CI 1.0-2.3). In contrast, tap water use in households was a protective factor against any helminth infection (i.e. T. trichiura OR=0.6, 95% CI 0.4-0.9). Prevalences increased with age and males had generally lower prevalences (OR=0.8, 95% CI 0.6-1.0), participants performing agricultural (OR=1.5, 95% CI 1.1-2.1) and having a low educational level (OR=1.7, 95% CI 1.2-2.4) were significantly associated with helminth infections. None of the factors related to household's sanitary condition, type of latrine, household's SES, use of animal excreta, and personal hygiene practices were statistically significant associated with helminth infection.

Conclusions: Our study suggests that in agricultural settings, direct contact with water from Nhue River and the use of human excreta as fertiliser in the fields are important risk factors for helminth infection. Daily use of clean water is likely to reduce the risk of worm infection. Deworming policies and national programs should give more attention to these agricultural at risk populations.
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http://dx.doi.org/10.1016/j.parint.2012.12.007DOI Listing
April 2013

Risk factors for Entamoeba histolytica infection in an agricultural community in Hanam province, Vietnam.

Parasit Vectors 2011 Jun 10;4:102. Epub 2011 Jun 10.

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

Background: Entamoeba histolytica is an important protozoan intestinal infection in resource-poor settings, including Vietnam. The study objective was to assess risk factors of E. histolytica infection in a community in Vietnam, where wastewater and human excreta are used in agriculture. A case-control study was conducted among residents of Hanam province, Northern Vietnam. Cases (n = 46) infected with E. histolytica and non-infected controls (n = 138) were identified in a cross-sectional survey among 794 randomly selected individuals and matched for age, sex and place of residence. Potential risk factors including exposure to human and animal excreta and household wastewater were assessed with a questionnaire.

Results: People from households with an average socio-economic status had a much higher risk of E. histolytica infection (odds ratio [OR]=4.3, 95% confidence interval [CI]: 1.3-14.0) compared with those from households with a good socioeconomic status. Those individuals who never or rarely used soap for hand washing had a 3.4 times higher risk for infection (OR=3.4, 95% CI: 1.1-10.0), compared to those who used always soap. In contrast, none of the factors related to use of human or animal excreta was statistically significant associated with E. histolytica infection. People having close contact with domestic animals presented a greater risk of E. histolytica infection (OR = 5.9, 95% CI: 1.8-19.0) than those without animal contact. E. histolytica infection was not associated with direct contact with Nhue river water, pond water and household's sanitary conditions, type of latrine or water source used.

Conclusions: Our study suggests that in settings where human and animal excreta and Nhue River water are intensively used in agriculture, socio-economic and personal hygiene factors determine infection with E. histolytica, rather than exposure to human and animal excreta in agricultural activities.
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http://dx.doi.org/10.1186/1756-3305-4-102DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3141740PMC
June 2011

How do we sell the hygiene message? With dollars, dong or excreta?

Environ Health 2010 Jun 18;9:27. Epub 2010 Jun 18.

Department of International Health, Immunology and Microbiology, Faculty of Health, University of Copenhagen, Øster Farimagsgade 5 PO Box 2099,1014 Copenhagen K, Denmark.

In North and Central Vietnam it is common among farmers to use excreta from the family double vault composting latrine (DVC) as fertilizer in the fields. The official Vietnamese health guidelines stipulate a six-month period of composting before applying excreta to two of their three annual crops. However, farmers in this region cannot afford to follow these guidelines and this paper presents the reasons why.In their efforts to ensure optimal hygienic conditions, by providing a guideline, the Vietnamese health authorities have not put sufficient attention to the 'excreta economy' in relation to farmers' livelihoods. The free fertilizer in the household DVC represents a value of approximately US$ 15.5 per year--or the equivalent of 15 percent of the annual household income for the poorest 20 percent of farmers. For this reason, the economic benefits derived from free fertilizer outweigh the hygiene message for most Vietnamese farmers. Even at national level the excreta economy has an impact. If Vietnam were to replace human excreta with imported fertilizer, it would involve an extra national expenditure of at least US$ 83 million a year.In order to convince Vietnamese farmers to adopt different fertilizing methods when reusing human excreta, it is necessary for the Vietnamese health authorities to change their hygiene message. They need to replace their current health sector-specific approach with a holistic one that takes the premises of farmers' livelihoods into account. If they do not the hygiene message will simply be lost.
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http://dx.doi.org/10.1186/1476-069X-9-27DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910668PMC
June 2010

Hygiene versus fertiliser: the use of human excreta in agriculture--a Vietnamese example.

Int J Hyg Environ Health 2008 Jul 4;211(3-4):432-9. Epub 2008 Feb 4.

Department of International Health, Immunology and Microbiology, University of Copenhagen, Øster Farimagsgade 5, Building 16, Entrance I, P.O. Box 2099, 1014 Copenhagen K, Denmark.

The use of human excreta as fertiliser in agriculture is a common practice in parts of South East Asia benefiting production but at the same time a risk factor for increased helminth infections. This paper describes the hygienic handling of human excreta for use in agriculture in Central Vietnam from a practical farming perspective presenting the farmers perceived health risks and benefits of its use. Further, in the study findings are discussed relating to the new Vietnamese guidelines for the use of human excreta in agriculture to their implications on an on-farm context. A total of 471 households in five communes responded to a structured questionnaire. This survey was supplemented by focus group discussions, key informant interviews and participant observations. More than 90% of the surveyed households used their own excreta as fertiliser and a total of 94% composted the excreta before use, either inside or outside the latrine. However, due to the prevailing design of the latrine and the three annual cropping seasons, it was found that for a minimum of one cultivation season per year 74% of the households will have only 3-4 months for composting before the input is needed in production, which is short of the 6 months stipulated in the national guidelines. The community associated great benefits from using human excreta in agriculture, especially if composted, and did not associate risks with the use of composted excreta if it was dry and lacked odour. It is recommended that the guidelines be revised and attempts made to identify ways of reducing the time needed to ensure the die-off of helminth eggs, including the use of pH regulators, such as an increased use of lime in the latrines.
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http://dx.doi.org/10.1016/j.ijheh.2007.08.011DOI Listing
July 2008

Successful sanitation promotion must recognize the use of latrine wastes in agriculture--the example of Viet Nam.

Bull World Health Organ 2005 Nov 10;83(11):873-4. Epub 2005 Nov 10.

Institute of Public Health, Department of International Health, University of Copenhagen, Øster Farimagsgade 5, Building 16, PO Box 2099, 1014 Copenhagen K, Denmark.

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http://dx.doi.org//S0042-96862005001100019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2626463PMC
November 2005