Predicting the potential distribution of Amblyomma americanum (Acari: Ixodidae) infestation in New Zealand, using maximum entropy-based ecological niche modelling

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The unique resistance and resilience of the Nigerian West African Dwarf goat to gastrointestinal nematode infections

<p>Abstract</p> <p>Background</p> <p>West African Dwarf (WAD) goats serve an important role in the rural village economy of West Africa, especially among small-holder livestock owners. They have been shown to be trypanotolerant and to resist infections with <it>Haemonchus contortus </it>more effectively than any other known breed of goat.</p> <p>Methods</p> <p>In this paper we review what is known about the origins of this goat breed, explain its economic importance in rural West Africa and review the current status of our knowledge about its ability to resist parasitic infections.</p> <p>Conclusions</p> <p>We suggest that its unique capacity to show both trypanotolerance and resistance to gastrointestinal (GI) nematode infections is immunologically based and genetically endowed, and that knowledge of the underlying genes could be exploited to improve the capacity of more productive wool and milk producing, but GI nematode susceptible, breeds of goats to resist infection, without recourse to anthelmintics. Either conventional breeding allowing introgression of resistance alleles into susceptible breeds, or transgenesis could be exploited for this purpose. Appropriate legal protection of the resistance alleles of WAD goats might provide a much needed source of revenue for the countries in West Africa where the WAD goats exist and where currently living standards among rural populations are among the lowest in the world.</p

Introgression of Ivermectin Resistance Genes into a Susceptible Haemonchus contortus Strain by Multiple Backcrossing

Anthelmintic drug resistance in livestock parasites is already widespread and in recent years there has been an increasing level of anthelmintic drug selection pressure applied to parasitic nematode populations in humans leading to concerns regarding the emergence of resistance. However, most parasitic nematodes, particularly those of humans, are difficult experimental subjects making mechanistic studies of drug resistance extremely difficult. The small ruminant parasitic nematode Haemonchus contortus is a more amenable model system to study many aspects of parasite biology and investigate the basic mechanisms and genetics of anthelmintic drug resistance. Here we report the successful introgression of ivermectin resistance genes from two independent ivermectin resistant strains, MHco4(WRS) and MHco10(CAVR), into the susceptible genome reference strain MHco3(ISE) using a backcrossing approach. A panel of microsatellite markers were used to monitor the procedure. We demonstrated that after four rounds of backcrossing, worms that were phenotypically resistant to ivermectin had a similar genetic background to the susceptible reference strain based on the bulk genotyping with 18 microsatellite loci and individual genotyping with a sub-panel of 9 microsatellite loci. In addition, a single marker, Hcms8a20, showed evidence of genetic linkage to an ivermectin resistance-conferring locus providing a starting point for more detailed studies of this genomic region to identify the causal mutation(s). This work presents a novel genetic approach to study anthelmintic resistance and provides a “proof-of-concept” of the use of forward genetics in an important model strongylid parasite of relevance to human hookworms. The resulting strains provide valuable resources for candidate gene studies, whole genome approaches and for further genetic analysis to identify ivermectin resistance loci

Hammondia heydorni oocysts in the faeces of a greyhound in New Zealand

AIMS: To identify oocysts found in faecal material of a greyhound. METHODS: Polymerase chain reaction (PCR) and DNA sequencing were used to study genomic DNA isolated from oocysts purified from faeces of a greyhound. RESULTS: Database searches with the DNA sequences obtained showed they were derived from Hammondia heydorni. A species-specific PCR was developed to detect H. heydorni DNA. CONCLUSIONS: Light microscopy in conjunction with PCR and DNA sequencing definitively identified the presence of H. heydorni oocysts in faeces of a greyhound. CLINICAL RELEVANCE: This study confirms the presence of H. heydorni in New Zealand and indicates the need to correctly identify similar oocysts from dogs, rather than assume they are Neospora caninum. © 2003 Taylor and Francis Group, LLC

A growing degree-day model for determination of Fasciola hepatica infection risk in New Zealand with future predictions using climate change models

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