Recent findings indicate a link between Babesia canis infection and acquired infertility in male dogs, prompting further investigation into how Babesia gibsoni affects male reproductive health. Blood samples of 100 male dogs suspected of having babesiosis were collected for PCR, hematological, biochemical, and serological analyses to verify B. gibsoni infection and assess possible co-infections with Anaplasma spp., Ehrlichia canis, Leishmania infantum, and Mycoplasma spp. Out of the 37 B. gibsoni-positive dogs, semen samples were collected and analyzed before treatment and six months later from six American Staffordshire Terriers (ASTs), and compared to eight sexually mature, reproductively healthy dogs. At initial examination, Babesia spp. was detected in the semen of one dog, while two others tested positive six months posttreatment. Sperm analysis revealed no changes in sperm concentration between initial presentation and six months posttreatment. However, significantly lower percentages of progressively motile spermatozoa (PMOT, median range 26.5%) were observed alongside decreased velocity (VCL – curvilinear velocity, median range 51µm/s; VSL – straight-line velocity, median range 23µm/s; VAP – average path velocity, median range 27µm/s) and viability parameters (Dead, median range, 53.5%; Total defects median range, 37%) compared to healthy dogs (PMOT median range 80.5%; VCL median range 131µm/s; VSL median range 67µm/s; VAP median range 78µm/s; Dead,  median range, 6.5%; Total defects, median range, 19.5%). The presence of Babesia spp. in semen may adversely affect sperm quality, causing acquired male sterility even six months posttreatment. Further research is essential to improve prevention efforts, resolve legal concerns about parasite transmission through semen, and enhance treatment strategies and reproductive results.

To Cite This Article: Strahinja M, Jelena FA, Slobodanka V, Svetlana N, Milica KF, Miloš D, Dimitrije G and Vladimir M 2025. Male fertility impairment associated with Babesia gibsoni infection in dogs. Pak Vet J. http://dx.doi.org/10.29261/pakvetj/2025.262