Genetic variation of Haemonchus contortus (Trichostrongylidae) in sheep and goats from Malaysia and Yemen

This study investigated the overall prevalence of Haemonchus contortus infection in sheep and goats from five purposively selected subdivisions (sectors) of Nyagatare district from January to December 2014, after a high prevalence of gastrointestinal parasites and generalized poor productivity was reported in small ruminants in some districts of Rwanda. Faecal egg counts (FEC) were performed using the Modified Wisconsin Sugar Floatation method and the Fluorescent-labeled peanut-lectin agglutination test while enumerations, as log (FEC), were done using the modified McMaster method. The overall prevalence of H. contortus infection in sheep and goats was 75.7% (n=949). The overall prevalence of H. contortus infection in sheep (83.4%, n=314) was higher than in goats (71.8%, n=635) (Odds Ratio [OR] 1.98, 95% Confidence Interval [CI]: 1.40-2.79, and p≤0.001). The prevalence of H. contortus infection in female goats (74.2%) was higher than in male goats (64.3%) (OR 1.60, 95% CI: 1.09-2.36, and p=0.01). The prevalence of H. contortus infection in goats from Nyagatare was higher than in goats from Matimba (OR 3.25, 95% CI: 1.76-5.99, and p≤0.001) and from Katabagemu (OR 3.67, 95% CI: 2.04-6.59, and p≤0.001). The prevalence of H. contortus infection in goats from Karangazi was higher than in goats from Matimba (OR 4.72, 95% CI: 2.40-9.28, and p≤0.001). The overall mean monthly log (FEC) for H. contortus in sheep and goats were highest in April (18.9±0.2 and 14.05±0.1, respectively) and October (19.25± 0.2 and 13.75±0.1, respectively). Though, overall, sheep in Nyagatare district were at greater risk of H. contortus infection and goats from Nyagatare and Karangazi sectors were paradoxically at greater risk of H. contortus infection. It was also apparent that young female goats were at greater risk of H. contortus infection than young male goats. H. contortus infection is endemic in small ruminants in Nyagatare district and possibly other districts in Rwanda. Targeted selective treatment (TST) using FAMACHA with emphasis on low-lying swampy pastures and appropriate anthelmintic drugs may be the most economically viable solution in the short term. In the long term breeding of H. contortus resistant small ruminants and strategic grazing using the concept of refugia may bring about considerable relief from H. contortus infection in Nyagatare district, in particular, and Rwanda at large.

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THE DETECTION OF PROTEINS OF THE NEMATODE, HAEMONCHUS CONTORTUS, IN THE SERA OF INFECTED SHEEP AND GOATS*

American Journal of Epidemiology ◽

10.1093/oxfordjournals.aje.a117951 ◽

1933 ◽

Vol 18 (2) ◽

pp. 247-265

Author(s):

JOHN E. STUMBERG

Keyword(s):

Haemonchus Contortus ◽

Infected Sheep ◽

Sheep And Goats

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Signatures of selection for resistance to Haemonchus contortus in sheep and goats

10.21203/rs.2.9164/v2 ◽

2019 ◽

Author(s):

Zaira Magdalena Estrada-Reyes ◽

Yoko Tsukahara ◽

Rodrigo R. Amadeu ◽

Arthur L. Goetsch ◽

Terry A. Gipson ◽

...

Keyword(s):

Candidate Gene ◽

Haemonchus Contortus ◽

Selection Process ◽

Gastrointestinal Nematode ◽

Gene Panel ◽

Bayesian Approaches ◽

Sheep And Goats ◽

Host Genetic ◽

Study Support ◽

Signatures Of Selection

Abstract Background Gastrointestinal nematode infection (GNI) is the most important disease affecting the small ruminant industry in U.S. The environmental conditions in the southern United States are ideal for the survival of the most pathogenic gastrointestinal nematode, Haemonchus contortus. Host genetic variation for resistance to H. contortus allows selective breeding for increased resistance of animals. This selection process increases the prevalence of particular alleles in sheep and goats and creates unique genetic patterns in the genome of these species. The aim of this study was to identify loci with divergent allelic frequencies in a candidate gene panel of 100 genes using two different approaches (frequentist and Bayesian) to estimate Fst outliers in three different breeds of sheep and goats exposed to H. contortus. Results Our results for sheep populations showed SNPs under selection in C3AR1, CSF3, SOCS2, NOS2, STAT5B, TGFB2 and IL2RA genes using frequentist and Bayesian approaches. For goats, SNPs in CD1D, ITGA9, IL12A, IL13RA1, CD86 and TGFB2 genes were under selection. Common signatures of selection in both species were observed in NOS2, TGFB2 and TLR4 genes. Directional selection was present in all SNPs evaluated in the present study. Conclusions A total of 13 SNPs within 10 genes of our candidate gene panel related to H. contortus exposure were identified under selection in sheep populations. For goats, 11 SNPs within 7 genes were identified under selection. Results from this study support the hypothesis that resistance to H. contortus is likely to be controlled by many loci. Shared signatures of selection related to mechanisms of immune protection against H. contortus infection in sheep and goats could be useful targets in breeding programs aimed to produce resistant animals with low FEC.

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Survival and infectivity studies of in-vitro cultivated larvae of Haemonchus contortus in Sheep and Goats in Nigeria

Veterinary World ◽

10.5455/vetworld.2011.533-536 ◽

2011 ◽

pp. 533

Author(s):

A Sonibare ◽

H Kumshe ◽

E Okewole ◽

A Talabi ◽

O Alaka ◽

...

Keyword(s):

Haemonchus Contortus ◽

Sheep And Goats

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Signatures of selection for resistance to Haemonchus contortus in sheep and goats

10.21203/rs.2.9164/v5 ◽

2019 ◽

Author(s):

Zaira Magdalena Estrada-Reyes ◽

Yoko Tsukahara ◽

Rodrigo R. Amadeu ◽

Arthur L. Goetsch ◽

Terry A. Gipson ◽

...

Keyword(s):

Candidate Gene ◽

Haemonchus Contortus ◽

Selection Process ◽

Gastrointestinal Nematode ◽

Gene Panel ◽

Bayesian Approaches ◽

Sheep And Goats ◽

Host Genetic ◽

Study Support ◽

Signatures Of Selection

Abstract Background: Gastrointestinal nematode infection (GNI) is the most important disease affecting the small ruminant industry in U.S. The environmental conditions in the southern United States are ideal for the survival of the most pathogenic gastrointestinal nematode, Haemonchus contortus . Host genetic variation for resistance to H. contortus allows selective breeding for increased resistance of animals. This selection process increases the prevalence of particular alleles in sheep and goats and creates unique genetic patterns in the genome of these species. The aim of this study was to identify loci with divergent allelic frequencies in a candidate gene panel of 100 genes using two different approaches (frequentist and Bayesian) to estimate F st outliers in three different breeds of sheep and goats exposed to H. contortus . Results: Our results for sheep populations showed SNPs under selection in C3AR1 , CSF3 , SOCS2 , NOS2 , STAT5B , TGFB2 and IL2RA genes using frequentist and Bayesian approaches. For goats, SNPs in CD1D , ITGA9 , IL12A , IL13RA1, CD86 and TGFB2 genes were under selection. Common signatures of selection in both species were observed in NOS2 , TGFB2 and TLR4 genes. Directional selection was present in all SNPs evaluated in the present study. Conclusions: A total of 13 SNPs within 10 genes of our candidate gene panel related to H. contortus exposure were identified under selection in sheep populations. For goats, 11 SNPs within 7 genes were identified under selection. Results from this study support the hypothesis that resistance to H. contortus is likely to be controlled by many loci. Shared signatures of selection related to mechanisms of immune protection against H. contortus infection in sheep and goats could be useful targets in breeding programs aimed to produce resistant animals with low FEC.

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Signatures of selection for resistance to Haemonchus contortus in sheep and goats

BMC Genomics ◽

10.1186/s12864-019-6150-y ◽

2019 ◽

Vol 20 (1) ◽

Cited By ~ 4

Author(s):

Zaira M. Estrada-Reyes ◽

Yoko Tsukahara ◽

Rodrigo R. Amadeu ◽

Arthur L. Goetsch ◽

Terry A. Gipson ◽

...

Keyword(s):

Candidate Gene ◽

Haemonchus Contortus ◽

Selection Process ◽

Gastrointestinal Nematode ◽

Gene Panel ◽

Bayesian Approaches ◽

Sheep And Goats ◽

Host Genetic ◽

Study Support ◽

Signatures Of Selection

Abstract Background Gastrointestinal nematode infection (GNI) is the most important disease affecting the small ruminant industry in U.S. The environmental conditions in the southern United States are ideal for the survival of the most pathogenic gastrointestinal nematode, Haemonchus contortus. Host genetic variation for resistance to H. contortus allows selective breeding for increased resistance of animals. This selection process increases the prevalence of particular alleles in sheep and goats and creates unique genetic patterns in the genome of these species. The aim of this study was to identify loci with divergent allelic frequencies in a candidate gene panel of 100 genes using two different approaches (frequentist and Bayesian) to estimate Fst outliers in three different breeds of sheep and goats exposed to H. contortus. Results Our results for sheep populations showed SNPs under selection in C3AR1, CSF3, SOCS2, NOS2, STAT5B, TGFB2 and IL2RA genes using frequentist and Bayesian approaches. For goats, SNPs in CD1D, ITGA9, IL12A, IL13RA1, CD86 and TGFB2 genes were under selection. Common signatures of selection in both species were observed in NOS2, TGFB2 and TLR4 genes. Directional selection was present in all SNPs evaluated in the present study. Conclusions A total of 13 SNPs within 7 genes of our candidate gene panel related to H. contortus exposure were identified under selection in sheep populations. For goats, 11 SNPs within 7 genes were identified under selection. Results from this study support the hypothesis that resistance to H. contortus is likely to be controlled by many loci. Shared signatures of selection related to mechanisms of immune protection against H. contortus infection in sheep and goats could be useful targets in breeding programs aimed to produce resistant animals with low FEC.

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Morphological variation between isolates of the nematode Haemonchus contortus from sheep and goat populations in Malaysia and Yemen

Journal of Helminthology ◽

10.1017/s0022149x12000776 ◽

2012 ◽

Vol 88 (1) ◽

pp. 82-88 ◽

Cited By ~ 4

Author(s):

A.A. Gharamah ◽

W.A. Rahman ◽

M.N. Siti Azizah

Keyword(s):

Morphological Variation ◽

Haemonchus Contortus ◽

Total Body Length ◽

Morphological Characters ◽

Minor Variation ◽

Highly Pathogenic ◽

Sheep And Goats ◽

Cuticular Ridge ◽

Left Spicule ◽

Total Body

AbstractHaemonchus contortus is a highly pathogenic nematode parasite of sheep and goats. This work was conducted to investigate the population and host variations of the parasitic nematode H. contortus of sheep and goats from Malaysia and Yemen. Eight morphological characters were investigated, namely the total body length, cervical papillae, right spicule, left spicule, right barb, left barb, gubernaculum and cuticular ridge (synlophe) pattern. Statistical analysis showed the presence of morphological variation between populations of H. contortus from Malaysia and Yemen, with minor variation in the synlophe pattern of these isolates. Isolates from each country were grouped together in the scatterplots with no host isolation. Body, cervical papillae and spicule lengths were the most important characters that distinguished between populations of the two countries. This variation between Malaysia and Yemen may be attributed to geographical isolation and the possible presence of a different isolate of this worm in each country.

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