Haemonchus contortus, an obligatory haematophagus worm infection in small ruminants: Population genetics and genetic diversity

Haemonchus contortus is one of the most pathogenic gastrointestinal parasites that infect small ruminants. The indiscriminate use of anthelmintics (i.e., benzimidazole class, BZ) to control infections has led to the reduction of drug efficacy in H. contortus populations worldwide. Resistance to BZ is associated with high frequencies of single nucleotide polymorphisms at F200Y, F167Y, and E198A positions of the β-tubulin isotype 1 gene. This study aimed to determine the frequency of single nucleotide polymorphisms associated with BZ resistance in H. contortus from 18 farms (545 sheep and 124 goats) in Paraná, Southern Brazil. Health management practices were identified as risk factors from individual farms. Genomic DNA was extracted from 20,000 larvae/farm and used in quantitative polymerase chain reaction assays for the three mutations. We ran a correlation analysis between flock health and quantitative polymerase chain reaction data. H. contortus was the most prevalent parasite in 67% (12/18) of the farms. Resistant allele frequencies were detected for F200Y (var. 46.4 to 72.0%) and F167Y (var. 15.7 to 23.8%). Only (100.0%) susceptible alleles were detected for the E198A. High treatment frequency (15/18), visual weight estimations for anthelmintic dose (15/18), no integration with other farm practices (14/18), treatment of all animals (14/18), and no quarantine period for newly acquired animals (10/18) were considered the most critical risk factors associated with BZ resistance. This is the first systematic prevalence study linking management practices on smallholder farms and the molecular data of BZ resistance of H. contortus in Southern Brazil.

show abstract

Peripheral Blood Mononuclear Cells Regulated Cytokines and Transcription Factors Reduce Haemonchus contortus Larval Establishment in Black Bengal Goat

Ahmed,

Roy,

Biswas

et al. 2024

Preprint

View full text Add to dashboard Cite

Black Bengal goat (BBG) is a native breed of Bangladesh and its ability in reducing the establishment of H. contortus infection through cellular and immune responses was unexplored. In vitro larval motility in response to PBMC, in vivo larval infectivity assay, differential blood cell counts, histopathology, cytokine and transcription expression have been investigated in BBG kids following H. contortus L3. In vitro motility experiment revealed that L3 exposed to PBMC from primed kids had significantly (P < 0.05) reduced speed and straight-line distance compared to L3 exposed to PBMC from naive kids. Kids with L3 exposed to PBMC in primed and naive kids, reduced H. contortus egg shed. Upon 10,000 L3 challenge, WBC count was higher in primed kids compared to naive and 35% of TC were neutrophils. Lymph nodes were increased in weight (P < 0.05) in primed kids except 1st day (D0). IL-4, IL-5, IL-13, IL-33, MCP1, CXCL1, TLR2 and GAL14 were expressed both naive and primed kids. Significant expression of IL-4, IL-5, IL-13, IL-33, MCP1 and CXCL1 at D3, D5 and D7, suggesting early TH2 differentiation in primed kids. These results suggest that BBG can much resist H. contortus infectivity. Role of transcriptome differences in other resistant breeds should be investigated.

show abstract

Haemonchus contortus, an obligatory haematophagus worm infection in small ruminants: Population genetics and genetic diversity

Cited by 3 publications

References 47 publications

Exploring alternative anthelmintic compounds: Impact of peruvin, hentriacontane/1-nonacosanol and their synergistic effect on the health of Meriones unguiculatus infected with Haemonchus contortus

Exploring alternative anthelmintic compounds: Impact of peruvin, hentriacontane/1-nonacosanol and their synergistic effect on the health of Meriones unguiculatus infected with Haemonchus contortus

Genotyping of benzimidazole resistance using β-tubulin isotype 1 marker in Haemonchus contortus of sheep and goats in Paraná, Southern Brazil

Peripheral Blood Mononuclear Cells Regulated Cytokines and Transcription Factors Reduce Haemonchus contortus Larval Establishment in Black Bengal Goat

Contact Info

Product

Resources

About