Molecular-Based Detection of Vector-Borne Diseases in Shelter Dogs in Northern of Vietnam

Canine vector-borne pathogens (CVBPs) pose a major challenge in shelter medicine, yet data from shelter populations in Vietnam remain unknown. This study determined the prevalence, and risk factors of CVBPs in shelter dogs in northern Vietnam. Blood samples from 300 apparently healthy dogs from three shelters in Hanoi were screened by PCR for Babesia vogeli, Hepatozoon canis, Rickettsia spp., and Mycoplasma spp. Representative positive amplicons underwent Sanger sequencing and BLAST analysis. Sequence analysis showed 96.07-100% identity with reference strains, with phylogenetic trees confirming clustering within B. vogeli, H. canis, M. haemocanis and R. felis clades. Overall, 43.7% (131/300) of dogs were infected with at least one pathogen, with shelter-level prevalence ranging from 38.0 to 52.0%. Single infections accounted for 35.0%, dominated by R. felis (25.7%) and M. haemocanis (24.0%), B. vogeli and H. canis were low (1.3% each). Co-infections were found in 8.7% of dogs, primarily R. felis and M. haemocanis (8.3%). No evaluated host factors (age, sex, breed, body size, housing style) significantly associated with infection (p > 0.05). This study provides the first molecular evidence of canine vector-borne pathogen circulation in Vietnamese shelter dogs, emphasizing the need of ectoparasite control and One Health-oriented surveillance.