Dataset Information

Genetic characterizations of Giardia duodenalis in sheep and goats in Heilongjiang Province, China and possibility of zoonotic transmission.

ABSTRACT: BACKGROUND: Giardia duodenalis is a widespread intestinal protozoan of both humans and mammals. To date, few epidemiological studies have assessed the potential and importance of zoonotic transmission; and the human giardiasis burden attributable to G. duodenalis of animal origin is unclear. No information about occurrence and genotyping data of sheep and goat giardiasis is available in China. The aim of the present study was to determine prevalence and distribution of G. duodenalis in sheep and goats in Heilongjiang Province, China, and to characterize G. duodenalis isolates and assess the possibility of zoonotic transmission. METHODOLOGY/PRINCIPAL FINDINGS: A total of 678 fecal specimens were collected from sheep and goats on six farms ranging in age from one month to four years in Heilongjiang Province, China. The average prevalence of G. duodenalis infection was 5.0% (34/678) by microscopy after Lugol's iodine staining, with 5.6% (30/539) for the sheep versus 2.9% (4/139) for the goats. Molecular analysis was conducted on 34 G. duodenalis isolates based on the triosephosphate isomerase (tpi) gene. 29 tpi gene sequences were successfully obtained and identified as assemblages A (n = 4), B (n = 2) and E (n = 23). High heterogeneity was observed within assemblage E at the tpi locus, with five novel subtypes found out of seven subtypes. Two subtypes of assemblage A were detected, including subtype AI (n = 3) and a novel subtype (designated as subtype AIV) (n = 1). Two assemblage B isolates were identical to each other in the tpi gene sequences. CONCLUSIONS/SIGNIFICANCE: This is the first report of G. duodenalis infections in sheep and goats in China. The present data revealed the unique endemicity on prevalence, distribution and genetic characterization of G. duodenalis in sheep and goats in Heilongjiang Province. The findings of assemblages A and B in sheep and goats implied the potential of zoonotic transmission.

SUBMITTER: Zhang W

PROVIDER: S-EPMC3447956 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Genetic characterizations of Giardia duodenalis in sheep and goats in Heilongjiang Province, China and possibility of zoonotic transmission.

Zhang Weizhe W Zhang Xiaoli X Wang Rongjun R Liu Aiqin A Shen Yujuan Y Ling Hong H Cao Jianping J Yang Fengkun F Zhang Xiaoyun X Zhang Longxian L

PLoS neglected tropical diseases 20120920 9

<h4>Background</h4>Giardia duodenalis is a widespread intestinal protozoan of both humans and mammals. To date, few epidemiological studies have assessed the potential and importance of zoonotic transmission; and the human giardiasis burden attributable to G. duodenalis of animal origin is unclear. No information about occurrence and genotyping data of sheep and goat giardiasis is available in China. The aim of the present study was to determine prevalence and distribution of G. duodenalis in sh ...[more]

PMID: 23029587

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Project description:BackgroundCryptosporidiosis and giardiasis are significant parasitic diseases shared between humans and domestic animals. Due to the close contact between humans and domestic animals in rural areas, it is important to consider the potential transmission of zoonotic parasites from infected domestic animals to humans. This investigation aimed to determine the prevalence and molecular characteristics of Cryptosporidium spp. and Giardia duodenalis in domestic animals and villagers.MethodsA total of 116 fecal samples from villagers and 686 fecal samples from domestic animals in Heilongjiang Province, China, were analyzed for two parasites using nested polymerase chain reaction (PCR) targeting various genetic loci and DNA sequence analysis of the PCR products.ResultsBy sequence analysis of the SSU rRNA gene, the prevalence of Cryptosporidium in humans was 0.9% (1/116), with one species of C. parvum (n = 1) detected; among domestic animals, the prevalence was 2.6% (18/686), with five species identified: C. suis (n = 7) and C. scrofarum (n = 7) in pigs, C. meleagridis (n = 1) in chickens, C. andersoni (n = 1) in cattle, and C. canis (n = 2) in foxes. C. parvum and C. canis were further subtyped as IIdA19G1 and XXa4 on the basis of gp60 gene. Regarding G. duodenalis, based on the SSU rRNA, bg, gdh, and tpi genes, the prevalence in domestic animals was 5.1% (31/608), with three assemblages identified: A (n = 1) in pigs, D (n = 1) in foxes, and E (n = 27) in geese, cattle, pigs, ducks, and sheep, along with mixed infection of A + E (n = 1) in one pig and B + E (n = 1) in one sheep. No G. duodenalis was detected in humans (0/116).ConclusionsThe present results show that no overlap of subtypes between animals and villagers was found in Cryptosporidium spp. and G. duodenalis, indicating a minor role of domestic animals in infecting humans in this population. However, the presence of zoonotic protozoa in domestic animals highlights the need for special attention to high-risk individuals during close contact with domestic animals.

Project description:Giardia duodenalis, originally regarded as a commensal organism, is the etiologic agent of giardiasis, a gastrointestinal disease of humans and animals. Giardiasis causes major public and veterinary health concerns worldwide. Transmission is either direct, through the faecal-oral route, or indirect, through ingestion of contaminated water or food. Genetic characterization of G. duodenalis isolates has revealed the existence of seven groups (assemblages A to G) which differ in their host distribution. Assemblages A and B are found in humans and in many other mammals, but the role of animals in the epidemiology of human infection is still unclear, despite the fact that the zoonotic potential of Giardia was recognised by the WHO some 30 years ago. Here, we performed an extensive genetic characterization of 978 human and 1440 animal isolates, which together comprise 3886 sequences from 4 genetic loci. The data were assembled into a molecular epidemiological database developed by a European network of public and veterinary health Institutions. Genotyping was performed at different levels of resolution (single and multiple loci on the same dataset). The zoonotic potential of both assemblages A and B is evident when studied at the level of assemblages, sub-assemblages, and even at each single locus. However, when genotypes are defined using a multi-locus sequence typing scheme, only 2 multi-locus genotypes (MLG) of assemblage A and none of assemblage B appear to have a zoonotic potential. Surprisingly, mixtures of genotypes in individual isolates were repeatedly observed. Possible explanations are the uptake of genetically different Giardia cysts by a host, or subsequent infection of an already infected host, likely without overt symptoms, with a different Giardia species, which may cause disease. Other explanations for mixed genotypes, particularly for assemblage B, are substantial allelic sequence heterogeneity and/or genetic recombination. Although the zoonotic potential of G. duodenalis is evident, evidence on the contribution and frequency is (still) lacking. This newly developed molecular database has the potential to tackle intricate epidemiological questions concerning protozoan diseases.

Project description:BackgroundGiardia duodenalis is an important intestinal protozoan infecting both humans and animals, causing significant public health concern and immeasurable economic losses to animal husbandry. Sheep and goats have been reported as common reservoirs of G. duodenalis, but only a limited amount of information is available for native breeds of these small ruminants in China. The present study investigated the prevalence and multilocus genotypes of G. duodenalis in black-boned sheep and goats, two important native breeds in Yunnan Province, southwestern China.MethodsFecal samples were collected from 336 black-boned goats and 325 black-boned sheep from five counties (Meishui, Shanshu, Shilin, Yongsheng and Nanping) of Yunnan Province and the genomic DNA was extracted from these feces. The prevalence of G. duodenalis was determined by the nested PCR targeting the β-giardin (bg) gene. The assemblages and multilocus genotypes (MLGs) were investigated based on analyses of three genetic loci, i.e. bg, glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi).ResultsGiardia duodenalis infection was detected in both black-boned sheep and goats, and the prevalence of G. duodenalis in black-boned sheep (21.8%, 71/325) was significantly higher (χ2 = 36.63, df = 1, P < 0.001) than that in black-boned goats (4.8%, 16/336). Significant differences in prevalence were also observed in goats and sheep from different counties (χ2 = 39.83, df = 4, P < 0.001) and age groups (χ2 = 97.33, df = 3, P < 0.001). Zoonotic assemblage A and animal-specific assemblage E were identified in both black-boned sheep and goats with the latter as the predominant assemblage. Based on sequences obtained from the three genetic loci (bg, gdh and tpi), 16 MLGs were obtained in black-boned sheep and goats, including 15 MLGs in assemblage E and one MLG in assemblage A.ConclusionsOur results not only extended the host range of G. duodenalis, but also revealed high genetic variations in G. duodenalis assemblages. The findings of the present study also provide baseline data for preventing and controlling G. duodenalis infection in black-boned sheep and goats in Yunnan Province.

Dataset Information

Genetic characterizations of Giardia duodenalis in sheep and goats in Heilongjiang Province, China and possibility of zoonotic transmission.

Publications

Genetic characterizations of Giardia duodenalis in sheep and goats in Heilongjiang Province, China and possibility of zoonotic transmission.

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