Next-generation sequencing metabarcoding assays reveal diverse bacterial vector-borne pathogens of Mongolian dogs

Abstract

Bacterial vector-borne pathogens (BVBPs) negatively impact canine health worldwide, with several also being zoonotic, posing an additional disease risk to humans. To date, BVBPs have been reported in humans and various sylvatic and domestic animal hosts across multiple Mongolian aimags (provinces); however, there has been no published data on these pathogens within Mongolia's canine populations. Collection of such data is important given Mongolia's size, diverse number of climatic regions, and large population of dogs, most of which closely share their environment with humans and livestock. Therefore, a bacteria-targeting next-generation sequencing metabarcoding (mNGS) assay was used to test the feasibility of mNGS as a proof-of-concept study to ascertain the detection of BVBP in 100 Mongolian dogs. The majority of dogs (n = 74) were infected with at least one of six BVBPs identified; including three species of haemoplasmas (also known as haemotropic mycoplasmas, n = 71), Bartonella rochalimae (n = 3), Ehrlichia spp. (n = 2) and Anaplasma platys (n = 1). Univariable analysis found sex, housing, and role of the dog to be associated with BVBP infection. Male dogs had 4.33 (95% CI: 1.61-11.62, P = 0.003) times the odds of infection with BVBPs compared to females. The majority of dogs included in this study were kept outdoors and had regular direct contact with both livestock and humans, indicating that dogs may contribute to the transmission and dissemination of BVBPs in Mongolia and could act as epidemiological sentinels. This study underscores the importance of pathogen surveillance studies in under-researched regions, reinforces the efficacy of mNGS as an explorative diagnostic tool, and emphasises the need for further larger-scale seroprevalence studies of Mongolian dogs.

Keywords: Asia; Canine; One health; Parasitology; Zoonotic.

Graphical abstract

Fig. 1

Location of the 100 investigated Mongolian dogs that were sampled and tested using the present bacterial vector-borne pathogen next-generation sequencing metabarcoding assay.

Fig. 2

Example of the outdoor free-roaming habits of a herder Bankhar dog, in Tov aimag, one of the 100 ‘high-risk’ Mongolian dogs that was sampled and tested using the present bacterial vector-borne pathogen next-generation sequencing metabarcoding assay.

Fig. 3

Phylogenetic relationship of the novel Bartonella spp. obtained from the blood of three Mongolian dogs (bold) with representative sequences from across the genus Bartonella determined by the neighbour-joining distance method. Relationship was based on a 225-bp stretch of the ftsZ gene, with bootstrap percentages greater than 75% shown and Brucella abortus used as an outgroup. A range of Bartonella species are shown from numerous host species and countries.