Investigation of multiple infections with zoonotic pathogens of rodents in northern Vietnam

Background & objectives: Rodents are important reservoir hosts for several zoonotic pathogens such as Rickettsia, Leptospira and Bartonella. Studies on the prevalence of zoonotic pathogens in Vietnam are data deficient, and there is a scarcity of data on multiple co-infections of zoonotic pathogens to date. This study examined the prevalence of Rickettsia spp., Leptospira spp., and Bartonella spp. and the co-infection of these pathogens in rodents captured in three provinces of northern Vietnam - Ha Giang, Lao Cai and Cao Bang.Methods: In total, 133 rodents of 25 species were screened for pathogen prevalence by real-time PCR.Results: Very high infection rates were found for each pathogen, with 42 of 133 rodents (31.6%) positive for Bartonella and 33 of 133 (24.8%) positive for Rickettsia (5.3% were positive for Rickettsia typhi, and 19.5% were infected with Rickettsia spotted fever group). Additionally, 24 rodents (18%) were positive for Leptospira. Double infection among these three pathogens was found in 26 of 133 rodents (18.8%), with the highest dual infection rates for Rickettsia and Bartonella co-infection (40%) and Leptospira and Bartonella co-infection (up to 40%), followed by Rickettsia and Leptospira co-infection (20% of animals investigated). One case of triple infection was documented for a house rat (Rattus cf. rattus species group) trapped in Ha Giang province.Interpretation & conclusion: Our survey indicates that rodents in northern Vietnam may host multiple zoonotic pathogens simultaneously; thus, rodents contribute significantly to the increased risk of transmission of multiple zoonotic infections from animals to humans.