Kotze, A. | Search bioRxiv

bioRxiv2024

Widespread occurrence of benzimidazole resistance SNPs in the canine hookworm, Ancylostoma caninum, in Australia

Canine hookworm (Ancylostoma caninum), a gastrointestinal nematode of domestic dogs, principally infects the small intestine of dogs and has the potential to cause zoonotic disease. In greyhounds and pet dogs in the USA, A. caninum has been shown to be resistant to multiple anthelmintics. We conducted a molecular survey of benzimidazole resistance in A. caninum from dogs at veterinary diagnostic centers in Australia and New Zealand. First, we implemented an internal transcribed spacer (ITS)-2 rDNA deep amplicon metabarcoding sequencing approach to ascertain the species of hookworms infecting dogs in the region. Then, we evaluated the frequency of the canonical F167Y and Q134H isotype-1 {beta}-tubulin mutations, which confer benzimidazole resistance, using the same sequencing approach. The most detected hookworm species in diagnostic samples was A. caninum (90%; 83/92); the related Northern hookworm (Uncinaria stenocephala) was identified in 11% (10/92) of the diagnostic samples. There was a single sample with coinfection by A. caninum and U. stenocephala. Both isotype-1 {beta}-tubulin mutations were present in A. caninum, 49% and 67% for Q134H and F167Y, respectively. Mutation F167Y in the isotype-1 {beta}-tubulin mutation was recorded in U. stenocephala for the first known time. Canonical benzimidazole resistance codons 198 and 200 mutations were absent. Egg hatch assays performed on a subset of the A. caninum samples showed significant correlation between 50% inhibitory concentration (IC50) to thiabendazole and F167Y, with an increased IC50 for samples with >75% F167Y mutation. We detected 14% of dogs with >75% F167Y mutation in A. caninum. Given that these samples were collected from dogs across various regions of Australia, the present study suggests that benzimidazole resistance in A. caninum is widespread. Therefore, to mitigate the risk of resistance selection and further spread, adoption of a risk assessment-based approach to limit unnecessary anthelmintic use should be a key consideration for future parasite control.

microbiology↗

bioRxiv2020

Conservation Genomic Analyses of African and Asiatic Cheetahs (Acinonyx jubatus) Across Their Current and Historic Species Range.

Cheetahs (Acinonyx jubatus) are majestic carnivores and the fastest land animals; yet, they are quickly heading towards an uncertain future. Threatened by habitat loss, human-interactions and illegal trafficking, there are only approximately 7,100 individuals remaining in the wild. Cheetahs used to roam large parts of Africa, and Western and Southern Asia. Today they are confined to about 9% of their original distribution. To investigate their genetic diversity and conservation status, we generated genome-wide data from historical and modern samples of all four currently recognized subspecies, along with mitochondrial DNA (mtDNA) and major histo-compatibility complex (MHC) data. We found clear genetic differentiation between the sub-species, thus refuting earlier assumptions that cheetahs show only little population differentiation. Our genome-wide nuclear data indicate that cheetahs from East Africa may be more closely related to A. j. soemmeringii than they are to A. j. jubatus. This supports the need for further research on the classification of cheetah subspecies, as East African cheetahs are currently included in the Southern Africa subspecies, A. j. jubatus. We detected stronger inbreeding in individuals of the Critically Endangered A. j. venaticus (Iran) and A. j. hecki (Northwest Africa), and show that overall genome-wide heterozygosity in cheetah is lower than that reported for other threatened and endangered felids, such as tigers and lions. Furthermore, we show that MHC class II diversity in cheetahs is generally higher than previously reported, but still lower than in other felids. Our results provide new and important information for efficient genetic monitoring, subspecies assignments and evidence-based conservation policy decisions.

evolutionary biology↗