Serological detection of Anaplasma spp., Ehrlichia spp., Borrelia burgdorferi s.l. antibodies, and Dirofilaria immitis antigen in stray dogs in Bosnia and Herzegovina.

Stray dogs may be highly exposed to vector-borne pathogens (VBP), including zoonotic agents, and therefore may pose a high risk of spreading infection to other animals and humans. Our study is the first large-scale prevalence study of VBP in stray dogs in Canton Sarajevo, Bosnia and Herzegovina. During the period 2016-2018, a total of 3720 blood samples of stray dogs were screened by the SNAP 4Dx plus test for antibodies against Anaplasma spp., Ehrlichia spp., B. burgdorferi s.l., and D. immitis. The 910 dogs (910/3720, 24.46%) were seropositive for one or more CVBPs. The proportion of seropositive dogs against one, two, or three pathogens was 864 (23.23%), 43 (1.15%), and 3 (0.08%), respectively. The most prevalent canine VBP was Anaplasma spp. (21.59%), followed by B. burgdorferi s.l. (2.47%) and Ehrlichia spp. (1.13%). The lowest prevalence was recorded for D. immitis (0.5%). The number of seropositive dogs older than 1 year was 704 (704/2497, 28.19%), while the number of dogs younger than 1 year was 206 (206/1223, 16.84%). The most common dual coinfection detected was with Anaplasma spp. and B. burgdorferi s.l. (26/3720, 0.7%). The results show that stray dogs are exposed to at least one of these four CVBD pathogens. Since some of these pathogens cause zoonoses, controlling these infections is crucial for both veterinary and public health. These findings highlight the need for continuous serological monitoring of CVBD pathogens in stray dogs due to their risks to animal and human health.