Publications by authors named "John Asekhaen Ohiolei"

19 Publications

  • Page 1 of 1

Hydatigera taeniaeformis in urban rats (Rattus rattus) in Faisalabad, Pakistan.

Infect Genet Evol 2021 Apr 24;92:104873. Epub 2021 Apr 24.

State Key Laboratory of Veterinary Etiological Biology, National Professional Laboratory for Echinococcosis, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu Province, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease, Yangzhou 225009, Jiangsu Province, PR China. Electronic address:

Hydatigera taeniaeformis formerly referred to as Taenia taeniaeformis is a cestode of cats (definitive hosts) and rodents (intermediate hosts). The prevalence of the metacestode larval stage has been reported in rodents in many parts of the world even though the genetic polymorphisms or intraspecies variation is still understudied. Here, we report a prevalence of 22.09% (38/172) from an urban rodent population in Pakistan and a nucleotide diversity (cox1) of 0.00463 among the population. Infection was higher in male (27.85%) and adult (32.29%) rats than female and sub-adult/young rats. Interestingly, The median-joining network and phylogenetic construction comprising isolates from China, Japan, Kenya, Laos, Malaysia, Senegal, the United Arab Emirates, and countries in Europe demonstrated that Pakistani H. taeniaeformis are closer to Asian and African population than those of European origin. The results of the study will add-in preliminary data for H. taeniaeformis and will also contribute to understand the global molecular epidemiology and population structure of H. taeniaeformis.
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http://dx.doi.org/10.1016/j.meegid.2021.104873DOI Listing
April 2021

Genetic Evolution and Implications of the Mitochondrial Genomes of Two Newly Identified spp. in Rodents From Qinghai-Tibet Plateau.

Front Microbiol 2021 23;12:647119. Epub 2021 Mar 23.

State Key Laboratory of Veterinary Etiological Biology, National Professional Laboratory for Animal Echinococcosis, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.

The larva of Taeniidae species can infect a wide range of mammals, causing major public health and food safety hazards worldwide. The Qinghai-Tibet Plateau (QTP), a biodiversity hotspot, is home to many species of rodents, which act as the critical intermediate hosts of many Taeniidae species. In this study, we identified two new larvae of spp., named and , collected from the plateau pika () and the Qinghai vole (), respectively, in QTP, and their mitochondrial genomes were sequenced and annotated. Phylogenetic trees based on the mitochondrial genome showed that has the closest genetic relationship with , while was contained in a monophyletic group with , , and . Biogeographic scenarios analysis based on split time speculated that the speciation of (∼5.49 Mya) is due to host switching caused by the evolution of its intermediate host. Although the reason for (∼13.11 Mya) speciation is not clear, the analysis suggests that it should be infective to a variety of other rodents following the evolutionary divergence time of its intermediate host and the range of intermediate hosts of its genetically close species. This study confirms the species diversity of Taeniidae in the QTP, and speculates that the uplift of the QTP has not only a profound impact on the biodiversity of plants and animals, but also that of parasites.
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http://dx.doi.org/10.3389/fmicb.2021.647119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8021716PMC
March 2021

in Qinghai-Tibet plateau: population structure and confirmation of additional endemic areas.

Parasitology 2021 Mar 24:1-8. Epub 2021 Mar 24.

State Key Laboratory of Veterinary Etiological Biology/National Professional Laboratory for Animal Echinococcosis/Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou730046, Gansu Province, People's Republic of China.

Echinococcus shiquicus is currently limited to the Qinghai–Tibet plateau, a large mountainous region in China. Although the zoonotic potential remains unknown, progress is being made on the distribution and intermediate host range. In this study, we report E. shiquicus within Gansu and Qinghai provinces in regions located not only around the central areas but also the southeast edge of the plateau and describe their genetic relationship with previous isolates from the plateau. From 1879 plateau pikas examined, 2.39% (95% CI 1.79–3.18) were infected with E. shiquicus. The highest prevalence of 10.26% (4.06–23.58) was recorded in Makehe town, Qinghai province. Overall the prevalence was marginally higher in Qinghai (2.5%, CI 1.82–3.43) than in Gansu (2%, CI 1.02–3.89). The cox1 and nad1 genes demonstrated high and low haplotype and nucleotide diversities, respectively. The median-joining network constructed by the cox1–nad1 gene sequences demonstrated a star-like configuration with a median vector (unsampled haplotype) occupying the centre of the network. No peculiar distinction or common haplotype was observed in isolates originating from the different provinces. The presence of E. shiquicus in regions of the southeast and northeast edges of the Qinghai–Tibet plateau and high genetic variation warrants more investigation into the haplotype distribution and genetic polymorphism by exploring more informative DNA regions of the mitochondrial genome to provide epidemiologically useful insight into the population structure of E. shiquicus across the plateau and its axis.
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http://dx.doi.org/10.1017/S0031182021000512DOI Listing
March 2021

First Report on Molecular Characterization of Isolates From Sheep and Goats in Faisalabad, Pakistan.

Front Vet Sci 2020 10;7:594599. Epub 2020 Nov 10.

State Key Laboratory of Veterinary Etiological Biology, National Professional Laboratory for Animal Echinococcosis, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.

is the larval stage of commonly found in the brain (cerebral form), intramuscular and subcutaneous tissues (non-cerebral form) of ungulates. Globally, few reports exist on the molecular characterization and genetic diversity of . with none available for Pakistan. The current study molecularly characterized 12 . isolates surgically recovered from sheep ( = 4) and goats ( = 8) from a total of 3,040 small ruminants using a portion of the cytochrome oxidase subunit 1 (1) mitochondrial () gene. NCBI BLAST search confirmed the identity of each isolate. A high haplotype and a low nucleotide diversity with three haplotypes from the 12 isolates were observed. The findings suggest the existence of unique haplotypes of in Pakistan. The negative value of Tajima's and the positive value of Fu's Fs were inconsistent with population expansion, however, the sample size was small. Bayesian phylogeny revealed that all Pakistani isolates alongside the Chinese sequences (obtained from GenBank) constituted a cluster while sequences from other regions constituted another cluster. This is the first molecular study to determine the genetic diversity of . in Pakistan and serves as a foundation for prospective studies on the prevalence and population structure of in the country. Furthermore, in this study, we amplified only a partial segment of the 1 gene from a limited sample size. This could have implications on the interpretation of the actual population structure in reality. Thus, we recommend future studies to consider a larger sample size in a massive epidemiological survey for further insights.
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http://dx.doi.org/10.3389/fvets.2020.594599DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7683608PMC
November 2020

First report on the phylogenetic relationship, genetic variation of Echinococcus shiquicus isolates in Tibet Autonomous Region, China.

Parasit Vectors 2020 Nov 23;13(1):590. Epub 2020 Nov 23.

State Key Laboratory of Veterinary Etiological Biology/National Professional Laboratory for Animal Echinococcosis/Key Laboratory of Veterinary Parasitology of Gansu Province/Key Laboratory of Zoonoses of Agriculture Ministry, Lanzhou Veterinary Research Institute (CAAS), Lanzhou, 730046, Gansu, People's Republic of China.

Background: Cystic or alveolar echinococcosis caused by the larval stages of Echinococcus spp. is a very severe zoonotic helminth infection. Echinococcus shiquicus is a newly discovered species that has only been reported in the Qinghai and Sichuan provinces of the Qinghai-Tibet plateau, China where, to date, it has only been confirmed in Tibetan foxes and wild small mammal populations of the Tibetan plateau. Information on its genetic and evolutionary diversity is scanty. The aim of this study was to investigate the prevalence of E. shiquicus in plateau pikas (Ochotona curzoniae), a known intermediate host, and to determine the genetic variation and phylogenetic relationship of the E. shiquicus population in the Tibet region of China based on mitochondrial DNA.

Methods: Echinococcus shiquicus samples were collected from Damxung and Nyêmo counties (located in Tibet Autonomous Region, China). The mitochondrial cox1 and nad1 gene sequences were analyzed, and the genetic diversity and epidemiology of E. shiquicus in the region were discussed based on the results.

Results: The prevalence of E. shiquicus in pikas in Damxung and Nyêmo counties was 3.95% (6/152) and 6.98% (9/129), respectively. In combination with previous public sequence data, the haplotype analysis revealed 12 haplotypes (H) characterized by two distinct clusters (I and II), and a sequence distance of 99.1-99.9% from the reference haplotype (H1). The diversity and neutrality indices for the entire E. shiquicus populations were: haplotype diversity (Hd) ± standard deviation (SD) 0.862 ± 0.035; nucleotide diversity (Hd ± SD) 0.0056 ± 0.0003; Tajima's D 0.876 (P > 0.05); and Fu's F 6.000 (P > 0.05).

Conclusions: This was the first analysis of the newly discovered E. shiquicus in plateau pikas in the Tibet Autonomous Region of China. The neutrality indices suggest a deficiency of alleles, indicative of a recent population bottleneck.
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http://dx.doi.org/10.1186/s13071-020-04456-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7686673PMC
November 2020

In-House Developed ELISA Indicates High Prevalence of Anti- IgG in Sheep Population-An Update from Pakistan.

Pathogens 2020 Oct 29;9(11). Epub 2020 Oct 29.

State Key Laboratory of Veterinary Etiological Biology, National Professional Laboratory of Animal Hydatidosis, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China.

Cystic echinococcosis (CE) is a World Health Organization (WHO)-listed neglected tropical farm economy jeopardizing and public health concern disease. This study was aimed at furnishing sero-epidemiological baseline data of CE in sheep in Pakistan, where data are non-existent. For this purpose, two sheep-rich provinces of Pakistan were selected, and 728 sheep sera were collected using probability proportional to size (PPS) statistical technique. Epidemiological information was recorded on a questionnaire for the estimation of potential risk factors. The serum samples were analyzed for IgG antibodies against using an in-house-developed EgAgB-based ELISA kit. The overall seroprevalence recorded was 21.98% (160/728) in the tested sheep, suggesting higher seropositivity in sheep from Punjab (23.73%) as compared to Khyber Pakhtunkhwa (KPK) (19.04%). The overall apparent prevalence observed by this ELISA method was almost similar to the calculated true prevalence (21.77%). Prevalence was significantly different ( < 0.05) among sheep from different districts. Higher prevalence was found in females (22.54%, OR 1.41), age group > 5 years (29.66%, OR 1.64), crossbreeds (42.85%, OR 2.70), and sheep with pasture access (25.96%, OR 3.06). Being in age group > 5 years and having pasture access were the factors significantly associated with seropositivity ( < 0.05). This study provides serological evidence of . infection in sheep and can be used as a model for screening of the sheep globally.
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http://dx.doi.org/10.3390/pathogens9110905DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693474PMC
October 2020

A new molecular nomenclature for : mitochondrial DNA sequences reveal sufficient diversity suggesting the assignment of major haplotype divisions.

Parasitology 2021 Mar 23;148(3):311-326. Epub 2020 Oct 23.

State Key Laboratory of Veterinary Etiological Biology/National Professional Laboratory for Animal Echinococcosis/Key Laboratory of Veterinary Parasitology of Gansu Province/Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou730046, Gansu Province, P. R. China.

Cysticercosis caused by the metacestode larval stage of Taenia hydatigena formerly referred to as Cysticercus tenuicollis is a disease of veterinary importance that constitutes a significant threat to livestock production worldwide, especially in endemic regions due to condemnation of visceral organs and mortality rate of infected young animals. While the genetic diversity among parasites is found to be potentially useful in many areas of research including molecular diagnostics, epidemiology and control, that of T. hydatigena across the globe remains poorly understood. In this study, analysis of the mitochondrial DNA (mtDNA) of adult worms and larval stages of T. hydatigena isolated from dogs, sheep and a wild boar in China showed that the population structure consists of two major haplogroups with very high nucleotide substitutions involving synonymous and non-synonymous changes. Compared with other cestodes such as Echinococcus spp., the genetic variation observed between the haplogroups is sufficient for the assignment of major haplotype or genotype division as both groups showed a total of 166 point-mutation differences between the 12 mitochondrial protein-coding gene sequences. Preliminary analysis of a nuclear protein-coding gene (pepck) did not reveal any peculiar changes between both groups which suggests that these variants may only differ in their mitochondrial makeup.
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http://dx.doi.org/10.1017/S003118202000205XDOI Listing
March 2021

Thioredoxin Peroxidase 2 Regulates Protective Th2 Immune Response in Mice by Directly Inducing Alternatively Activated Macrophages.

Front Immunol 2020 25;11:2015. Epub 2020 Sep 25.

State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.

infection can induce macrophages into the alternatively activated phenotype, which is primarily associated with the development of a polarized Th2 immune response. In the present study, we examined the immunomodulatory effect of thioredoxin peroxidase-2 (TsTPX2), a protein derived from ES products, in the regulation of Th2 response through direct activation of macrophages. The location of TsTPX2 was detected by immunohistochemistry and immunofluorescence analyses. The immune response induced by rTsTPX2 was characterized by analyzing the Th2 cytokines and Th1 cytokines in the peripheral blood. The rTsTPX2-activated macrophages (M) were tested for polarization, their ability to evoke naïve CD4 T cells, and resistance to the larval infection after adoptive transfer in BALB/c mice. The immunolocalization analysis showed TsTPX2 in cuticles and stichosome of ML. The immunostaining was detected in cuticles and stichosome of Ad3 and ML, as well as in tissue-dwellings around ML after the intestines and muscle tissues of infected mice were incubated with anti-rTsTPX2 antibody. Immunization of BALB/c mice with rTsTPX2 could induce a Th1-suppressing mixed immune response given the increased levels of Th2 cytokines (IL-4 and IL-10) production along with the decreased levels of Th1 cytokines (IFN-γ, IL-12, and TNF-α). studies showed that rTsTPX2 could directly drive RAW264.7 and peritoneal macrophages to the M2 phenotype. Moreover, M could promote CD4 T cells polarized into Th2 type . Adoptive transfer of M into mice suppressed Th1 responses by enhancing Th2 responses and exhibited a 44.7% reduction in adult worm burden following challenge with infective larval, suggesting that the TsTPX2 is a potential vaccine candidate against trichinosis. Our study showed that TsTPX2 would be at least one of the molecules to switch macrophages into the M2 phenotype during infection, which provides a new therapeutic approach to various inflammatory disorders like allergies or autoimmune diseases.
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http://dx.doi.org/10.3389/fimmu.2020.02015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7544948PMC
September 2020

Morphological, Molecular Identification and Distribution of Trypanosome-Transmitting Dipterans from Cattle Settlements in Southwest Nigeria.

Acta Parasitol 2021 Mar 11;66(1):116-128. Epub 2020 Aug 11.

Infection Medicine, Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9JZ, UK.

Introduction: Glossina spp. (Glossinidae), Tabanus spp. (Tabanidae), Ancala spp. (Tabanidae), Atylotus spp. (Tabanidae) and Stomoxys spp. (Muscidae) are important transmitting vectors of African animal trypanosomosis in sub-Saharan Africa. There is paucity of information on the distribution and identification of these flies in cattle settlements in southwest Nigeria.

Methods: The distribution patterns, genetic variations and diversities of dipteran flies in southwest Nigeria were described and identified using morphological and molecular analysis of the 28S rDNA gene.

Results: Of the 13,895 flies examined morphologically between April 2016 and March 2017, tabanids were identified [Tabanus (0.34%), Ancala (0.03%), Atylotus (0.01%), Haematopota (0.014%) and Chrysops (0.11%)]. Two stomoxyine species were identified; Stomoxys niger niger Macquart (45.30%) and Stomoxys calcitrans Linnaeus (17.29%) and two Glossina spp. namely; Glossina p. gambiense Vanderplank, 1911 (0.46%) and Glossina tachinoides Westwood (0.51%) were identified. The identities were further confirmed in a BLAST search using their nucleotide sequences. The median-joining network of the 28S rDNA gene sequences indicated that fly species examined were genetically distinct. The apparent density of all the trapped flies was highest at a mean temperature of 26-28 ℃, humidity > 80% and rainfall of 150-220 mm/month. The distribution of flies was observed to increase as vegetation increased in density and decreased in areas with relatively high human population density (> 100/km).

Conclusions: The population indices of the 28S rDNA gene of the flies suggest that analysis of nuclear DNA fragments may provide more information on the molecular ecology of these flies. Characterising fly species and assessing their impact are essential in distribution and monitoring AAT spread.
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http://dx.doi.org/10.1007/s11686-020-00260-9DOI Listing
March 2021

Preliminary information on the prevalence and molecular description of Taenia hydatigena isolates in Pakistan based on mitochondrial cox1 gene.

Infect Genet Evol 2020 11 28;85:104481. Epub 2020 Jul 28.

State Key Laboratory of Veterinary Etiological Biology, National Professional Laboratory for Echinococcosis, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu Province, PR China. Electronic address:

Taenia hydatigena is a cestode of veterinary importance. Infection with the metacestode larval stage results in cysticercosis, which poses a serious challenge to the livestock industry worldwide. Globally, there are numerous reports on cysticercosis caused by T. hydatigena in sheep and goat but a lack of data on the prevalence and genetic diversity exists for Pakistan. We designed this study to provide an insight into the disease status as well as investigate the genetic variation among the recovered isolates based on the mitochondrial cox1 gene. In this study, we examined small ruminants (sheep and goats) slaughtered in Faisalabad in eastern Punjab province of Pakistan for T. hydatigena metacestodes and described the population structure and genetic variation using the cytochrome c oxidase subunit 1 (cox1) mitochondrial gene. Overall, a prevalence of 4.40% (goat =4.67% sheep = 4.07%) from a total of 2225 small ruminant carcasses (sheep = 983, goats = 1242) was observed. Based on the NCBI BLAST search and Bayesian phylogeny, the identity of all isolates was confirmed via their nucleotide sequences. The diversity indices indicated a high haplotype and a low nucleotide diversity with 43 haplotypes from 98 isolates. The results also show the existence of unique haplotypes of T. hydatigena in Pakistan as demonstrated by the significant negative values of Tajima's D and Fu's Fs neutrality test suggesting a recent population expansion. The median-joining network of the partial cox1 sequence dataset showed the existence of two main haplotypes detected in both sheep and goat populations. This study shows that the prevalence of cycticercosis due to T. hydatigena is below 5% in sheep and goats in Faisalabad, Punjab, Pakistan. The molecular analysis of the partial cox1 gene also indicates a high degree of genetic variation with the existence of rare haplotypes. These findings represent a preliminary report on the prevalence and genetic variation of T. hydatigena in Pakistan and serve as baseline information for future studies on the prevalence and population structure of T. hydatigena in the country.
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http://dx.doi.org/10.1016/j.meegid.2020.104481DOI Listing
November 2020

Echinococcus granulosus (sensu stricto) (G1, G3) and E. ortleppi (G5) in Pakistan: phylogeny, genetic diversity and population structural analysis based on mitochondrial DNA.

Parasit Vectors 2020 Jul 13;13(1):347. Epub 2020 Jul 13.

State Key Laboratory of Veterinary Etiological Biology, National Professional Laboratory of Animal Hydatidosis, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, Gansu, People's Republic of China.

Background: Cystic echinococcosis (CE) is a serious tapeworm infection caused by Echinococcus granulosus (sensu lato) which infects a wide range of animals and humans worldwide. Despite the millions of livestock heads reared in Pakistan, only a few reports on CE prevalence and even fewer on the genetic diversity are available for the country. Meanwhile, the available reports on the genetic diversity are predominantly based on short sequences of the cox1 gene.

Methods: To close this knowledge gap, this study was designed to investigate the genetic diversity and population structure of Echinococcus spp. in Pakistan using the complete mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes.

Results: Based on BLAST searches of the generated cox1 and nad1 gene sequences from a total of 60 hydatid cysts collected from cattle (n = 40) and buffalo (n = 20), 52 isolates were identified as E. granulosus (s.s.) (G1, G3) and 8 as E. ortleppi (G5). The detection of the G5 genotype represents the first in Pakistan. The phylogeny inferred by the Bayesian method using nucleotide sequences of cox1-nad1 further confirmed their identity. The diversity indices indicated a high haplotype diversity and a low nucleotide diversity. The negative values of Tajima's D and Fu's Fs test demonstrated deviation from neutrality suggesting a recent population expansion.

Conclusions: To the best of our knowledge, this report described the genetic variation of E. granulosus population for the first time in Pakistan using the complete cox1 and nad1 mitochondrial genes and confirms E. ortleppi as one of the causative agents of CE among livestock in Pakistan. While this report will contribute to baseline information for CE control, more studies considering species diversity and distribution in different hosts across unstudied regions of Pakistan are highly needed.
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http://dx.doi.org/10.1186/s13071-020-04199-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359271PMC
July 2020

Complete mitochondrial genome analysis confirms the presence of Echinococcus granulosus sensu lato genotype G6 in Nigeria.

Infect Genet Evol 2020 10 26;84:104377. Epub 2020 May 26.

State Key Laboratory of Veterinary Etiological Biology/National Professional Laboratory of Animal Hydatidosis/Key Laboratory of Veterinary Parasitology of Gansu Province/Lanzhou Veterinary Research Institute, CAAS, Lanzhou 730046, PR China. Electronic address:

Cystic echinococcosis (CE) is common in Africa especially in northern and eastern countries where it is highly prevalent and mainly caused by Echinococcus granulosus sensu stricto and Echinococcus granulosus sensu lato (G6/7). In a recent epidemiological survey in Nigeria, the G6/7 genotype was reportedly responsible for the majority of CE infection. In this study, considering the taxonomic challenges of the G6/7 genotype and the limitation of the cox1/nad1 genes in resolving the differences, we sequenced the complete mitochondrial (mt) genome of seven larval isolates of E. granulosus s.l. G6/7 haplotypes recently reported in Nigeria to correctly assign them to either (G6/7) genotype and to understand the mt genome variation with isolates from other geographical regions. On analysis, a total of 13,731 bp in a covalently closed circular molecule were realized. The total mt length was ≥10 bp than previously reported G6 and G7 mt genome sequences. Also, the median-joining network and phylogeny based on the 12 protein-coding sequences correctly identified them as G6 genotype. Since longer mt genome sequences have shown some advantage over individual genes in resolving taxonomic challenges, we confirm that the genotype responsible for the majority of CE infection in livestock in Nigeria is the G6 genotype and the availability of the complete mt genome from different Nigerian intermediate hosts will prove useful in future genetic population studies across the country and the West African sub-region.
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http://dx.doi.org/10.1016/j.meegid.2020.104377DOI Listing
October 2020

Molecular Identification of Taenia hydatigena from Sheep in Khartoum, Sudan.

Korean J Parasitol 2020 Feb 29;58(1):93-97. Epub 2020 Feb 29.

State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, P.R. China.

The cestode Taenia hydatigena uses canids, primarily dogs, as definitive hosts, while the metacestode larval stage cysticercus infects a range of intermediate hosts, including domestic animals such as goats, sheep, and pigs. Cysticercosis due to T. hydatigena has large veterinary and economic drawbacks. Like other taeniids, e.g., Echinococcus, intraspecific variation is found among the members of the genus Taenia. In Africa, few studies are available on the epidemiology and distribution of T. hydatigena, and even fewer studies are available on its genetic variation. In this study, we molecularly identified 11 cysticerci from sheep in Sudan and demonstrated the genetic variation based on the NADH dehydrogenase subunit 1 (nad1) and cytochrome c oxidase subunit 1 (cox1) mitochondrial genes. The isolates were correctly identified as T. hydatigena with more than 99% similarity to those in the GenBank database. Low diversity indices and insignificant neutrality indices were observed, with 3 and 2 haplotypes for the nad1 and cox1 genes, respectively. The results suggest the presence of unique T. hydatigena haplotypes in Sudan, as haplotypes with 100% similarity were not found in the GenBank database. With few available studies on the genetic variation of T. hydatigena in Africa, this report represents the first insights into the genetic variation of T. hydatigena in Sudan and constitutes useful data.
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http://dx.doi.org/10.3347/kjp.2020.58.1.93DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7066435PMC
February 2020

Genetic variation of Echinococcus spp. in yaks and sheep in the Tibet Autonomous Region of China based on mitochondrial DNA.

Parasit Vectors 2019 Dec 27;12(1):608. Epub 2019 Dec 27.

State Key Laboratory of Veterinary Etiological Biology/National Professional Laboratory of Animal Hydatidosis, Key Laboratory of Veterinary Parasitology of Gansu Province/Lanzhou Veterinary Research Institute, CAAS, Lanzhou, 730046, Gansu, People's Republic of China.

Background: Cystic echinococcosis (CE) in humans and livestock is caused by Echinococcus granulosus (sensu lato). In China where CE is endemic, a number of studies have shown that Echinococcus granulosus (sensu stricto) is majorly responsible for CE. However, E. canadensis (G6) which is the second leading cause of CE is now being detected in most parts of the country. In this study, the species diversity and genetic variation of Echinococcus granulosus (s.l.) in four counties in Tibet Autonomous Region of China were investigated.

Methods: Infection with Echinococcus granulosus (s.s.) in yaks and sheep was identified using NADH dehydrogenase subunit 1 and 5 (nad1 and nad5) mitochondrial genes while the genotype G6 of E. canadensis initially diagnosed with NADH dehydrogenase subunit 1 (nad1) was further confirmed by analysis of the complete mitochondrial genome and a phylogenetic network constructed based on the nad2 and nad5 genes.

Results: Out of 85 hydatid cyst samples collected from slaughtered sheep (n = 54) and yaks (n = 31), 83 were identified as E. granulosus (s.s.) G1 (n = 77), G3 (n = 6) and 2 were identified as E. canadensis G6. Analysis of the nad1/nad5 genes revealed 16/17 mutations with 9/14 parsimony informative sites resulting in 15/14 haplotypes, respectively. Haplotype diversity (Hd) and nucleotide diversity (π) of E. granulosus (s.s.) population were 0.650 and 0.00127 for nad1 and 0.782 and 0.00306 for nad5, respectively, with an overall negative Tajima's D and Fu's Fs. A low F indicated no genetic difference between isolates from sheep and yaks.

Conclusion: Pockets of infection with E. canadensis (G6, G7, G8 and G10) have been previously reported in sheep, goats, yaks and/or humans in different parts of China. While the G6 genotype has been previously reported in sheep in the Tibet Autonomous Region, the detection in a yak in the present study represents the first to the best of our knowledge. Therefore, we recommend future surveys and control efforts to comprehensively investigate other potential intermediate hosts for the prevalence and genetic diversity of the E. canadensis group (G6, G7, G8 and G10) across the country and their inclusion into the existing CE control programme.
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http://dx.doi.org/10.1186/s13071-019-3857-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6935104PMC
December 2019

A multiplex PCR assay for the simultaneous detection of Taenia hydatigena, T. multiceps, T. pisiformis, and Dipylidium caninum infections.

BMC Infect Dis 2019 Oct 16;19(1):854. Epub 2019 Oct 16.

State Key Laboratory of Veterinary Etiological Biology/ Key Laboratory of Veterinary Parasitology of Gansu Province/ Lanzhou Veterinary Research Institute, CAAS, Lanzhou, 730046, Gansu Province, People's Republic of China.

Background: Taenia hydatigena, T. multiceps, T. pisiformis, and Dipylidium caninum are four common large and medium-sized tapeworms parasitizing the small intestine of dogs and other canids. These parasites cause serious impact on the health and development of livestock. However, there are, so far, no commercially available molecular diagnostic kits capable of simultaneously detecting all four parasites in dogs. The aim of the study was therefore to develop a multiplex PCR assay that will accurately detect all four cestode infections in one reaction.

Methods: Specific primers for a multiplex PCR were designed based on corresponding mitochondrial genome sequences, and its detection limit was assessed by serial dilutions of the genomic DNAs of tapeworms examined. Furthermore, field samples of dog feces were tested using the developed assay.

Results: A multiplex polymerase chain reaction (PCR) assay was developed based on mitochondrial DNA (mtDNA) that accurately and simultaneously identify four cestode species in one reaction using specific fragment sizes of 592, 385, 283, and 190 bp for T. hydatigena, T. multiceps, T. pisiformis, and D. caninum, respectively. The lowest DNA concentration detected was 1 ng for T. hydatigena, T. multiceps and T. pisiformis, and 0.1 ng for D. caninum in a 25 μl reaction system. This assay offers high potential for the rapid detection of these four tapeworms in host feces simultaneously.

Conclusions: This study provides an efficient tool for the simultaneous detection of T. hydatigena, T. multiceps, T. pisiformis, and D. caninum. The assay will be potentially useful in epidemiological studies, diagnosis, and treatment of these four cestodes infections during prevention and control program.
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http://dx.doi.org/10.1186/s12879-019-4512-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6796438PMC
October 2019

Review of Cystic Echinococcosis in Nigeria: A Story of Neglect.

Acta Parasitol 2020 Mar 24;65(1):1-10. Epub 2019 Sep 24.

State Key Laboratory of Veterinary Etiological Biology/Key Laboratory of Veterinary Parasitology of Gansu Province/Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, Gansu Province, People's Republic of China.

Purpose: Cystic echinococcosis (CE) caused by Echinococcus granulosus sensu lato is a widespread zoonotic disease of global concern. In Nigeria, the exact picture/status of CE is unclear, as most of the states are largely uninvestigated. Yet, as with every parasitic zoonosis, the first step towards planning a comprehensive management and control programme involves assessment of available national/regional prevalence data, host range, and risk factors at play in the transmission dynamics.

Methods: Published articles on echinococcosis were searched on PubMed and Africa Journal Online (AJOL) databases. Inclusion criteria were based on studies reporting prevalence of echinococcosis in animals and humans (including case reports) from 1970 to 2018.

Results: In this study, we evaluated and summarized cystic echinococcosis reports in Nigeria and found that post 1970-80s, studies on cystic echinococcosis have remained sparse regardless of the high prevalence recorded in the early years of CE investigation. In addition, information on the genetic population structure and the role of wildlife in CE transmission is still lacking.

Conclusions: This study appraises the prevalence and distribution of CE in Nigeria and identified areas where surveillance and control efforts should be focused and intensified.
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http://dx.doi.org/10.2478/s11686-019-00124-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7223537PMC
March 2020

Cystic echinococcosis in Nigeria: first insight into the genotypes of Echinococcus granulosus in animals.

Parasit Vectors 2019 Aug 7;12(1):392. Epub 2019 Aug 7.

State Key Laboratory of Veterinary Etiological Biology/National Professional Laboratory of Animal Hydatidosis, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, 730046, Gansu, P. R. China.

Background: Cystic echinococcosis (CE) is a zoonosis caused by cestodes of Echinococcus granulosus (sensu lato) complex. In Nigeria, reports on the prevalence of CE, although limited, have been found to vary with location and host with higher prevalence and fertility rate observed in camels than other livestock. Until now, information regarding the molecular characteristics, genetic population structure, and genotypes of Echinococcus is lacking. Therefore, this study was aimed at addressing these gaps in knowledge.

Methods: We describe the genetic status of 31 Echinococcus isolates collected from slaughtered livestock (camels, cattle and goats) based on the full-length mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes.

Results: The resulting nucleotide sequences via the NCBI BLAST algorithm and Bayesian phylogeny of cox1 and cox1-nad1 genes using MrBayes v.3.1.2 showed that all isolates were clearly E. canadensis (G6/G7) and were 99-100% identical to previously reported G6/G7 haplotypes across Europe, Asia, North and East Africa.

Conclusions: Although, the G1 genotype is believed to be responsible for the majority of global CE burden, reports from a number of West African countries including Nigeria suggest that E. canadensis G6/G7 genotype could be the major causative agent of CE in the subregion. This study provides for the first time insight into the genetic population structure of Echinococcus species as well as implications for CE control in Nigeria.
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http://dx.doi.org/10.1186/s13071-019-3644-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6686243PMC
August 2019

Endoparasites of Small Mammals in Edo State, Nigeria: Public Health Implications.

Korean J Parasitol 2018 Feb 28;56(1):93-100. Epub 2018 Feb 28.

Department of Zoology, Ambrose Alli University, Ekpoma, Nigeria.

Some small mammals occur as household pests and harbour a number of parasites that could be of public health importance. This study profiled the helminth and protozoan parasites in trapped small mammals within and around human dwelling places (houses) located across 4 major towns (Auchi, Benin, Ekpoma, and Uromi) and environs in Edo state, Nigeria. Six genera ( sp., sp., , , sp., and sp.) were identified from 502 trapped small mammals. Overall, (71.9%) and (20.1%) were the most frequently trapped. In total, on examination of blood, gastrointestinal contents, and brain tissues, 12 helminth taxa ( sp., sp., sp., sp., sp., sp., and sp.), and 6 protozoan parasites ( sp., sp., sp., sp., and ) were isolated. Most prevalent helminths with relatively heavy mean intensity were sp. and , while , and were the most prevalent protozoan parasites. Generally, intrinsic factors like sex and age had marginal influence on the rate and burden of infection in and . Although the infection rate and prevalence of zoonotic parasites were low, they were largely recovered in rodents from Ekpoma. This study elucidates the public health implication of the presence of zoonotic parasites in these small mammals.
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http://dx.doi.org/10.3347/kjp.2018.56.1.93DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5858659PMC
February 2018

Toxoplasmosis in Nigeria: the story so far (1950-2016): a review.

Folia Parasitol (Praha) 2016 Aug 22;63. Epub 2016 Aug 22.

Department of Zoology, Ambrose Alli University, Ekpoma, Nigeria.

Toxoplasmosis is caused by intracellular protozoan parasite, Toxoplasma gondii (Nicolle et Manceaux, 1908). Cats and other felids are the definitive hosts. It could be transmitted to man and animals by consumption of infected undercooked meat and contaminated food items including drinking water. Results of toxoplasmosis epidemiological surveys in animals and humans in South-West, North-West, North-East and North-Central Zones of Nigeria have been reported with greater impact on the health of pregnant women and HIV-infected individuals. Meanwhile, studies in states within the South-South and South-East Zones are relatively scanty or non-existent. Overall, the seroprevalence of human toxoplasmosis in Nigeria is estimated at 32% with the following reports for North-West (32%), North-East (22%), North-Central (24%) and South-West (37%). Information on the genetic diversity of isolates of T. gondii in humans and animals including the role of the environment in transmission and maintenance of the disease are highly needed.
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http://dx.doi.org/10.14411/fp.2016.030DOI Listing
August 2016