The prevalence and risk factors of Spirocerca lupi in domestic dogs in the Mekong Delta of Vietnam

Spirocercosis is caused by Spirocerca spp., which is a chronic disease and might cause life-threatening due to forming cancer in oesophagus in canid carnivores. There are limited studies involving spirocercosis in domestic dogs. Thus, this study aims to investigate the prevalence and analyse risk factors involved in the S. lupi infection in Mekong Delta in Vietnam. In total, 400 fecal samples from domestic dogs were collected from May 2020 to May 2021. The overall prevalence of spirocercosis in domestic dogs in the Mekong Delta was 10.50% by copromicroscope and PCR methods. PCR targeted to the housekeeping gene cytochrome c oxidase I (cox-1) was applied to identify species of Spirocerca spp. and analyse the phylogenetic tree. Outdoor dogs had 5.48 times (CI 95% = 2.45-11.690, p < 0.001) higher risks of S. lupi infection compared to indoor dogs. Besides, seasons and age showed a correlation to the increase the risk of S. lupi infection, while neither dog breeds nor gender influenced the prevalence of this species. The cytochrome c oxidase I (cox-1) gene sequence of S. lupi in the Mekong Delta showed the high homologues to the S. lupi isolates in India, Israel, and the North of Vietnam and belonged to the S. lupi genotype 2.