Background and Aim: Babesia species are tick-borne protozoan parasites of apicomplexan type which infect the erythrocytes of dogs it ranges from subclinical to severe cases, depending on different factors such as immune status, age, and presence of other co-infections with the Babesia species. Hence, this study aimed to identify the protozoan parasites infecting police dogs of different breeds, ages, and both sexes in Egypt. Concerning molecular detection of Babesia vogeli using conventional polymerase chain reaction sequencing and phylogenetic analysis, followed by the assessment of immunological and biochemical status of infected dogs.

Materials and Methods: The blood of 242 police K9 dogs was collected. The age, breed, sex, and health status with clinical signs of dogs were recorded. Hematological, biochemical, and oxidative stress analyses of the blood were performed together with gene expression analysis using two genes (gamma interferon [IFN-γ] and tumor necrosis factor-alpha [TNF- α]). The identification of the causative agent was performed using molecular analysis of the 18S ribosomal RNA (rRNA). The 18S rRNA region of canine Babesia spp. was successfully amplified, and sequencing data were deposited in GenBank (accession number: MT565474.1), which resembled those of B. vogeli.

Results: The results of blood samples screening revealed that of the 242 blood samples, 62 were positive for B. vogeli infection. The infection rate in male dogs was higher than that in female dogs. The police dogs were classified into the following three groups of dogs: (1st group) healthy, (2nd infected with B. vogeli, and mixed infection of B. vogeli and Ehrlichia canis). The oxidative stress biomarkers levels in B. vogeli infected dogs were greater than that of healthy dogs. Likewise, IFN-γ and TNF-α level in B. vogeli infected dogs were elevated in infected dogs.

Conclusion: Our findings demonstrated that B. vogeli had completely adverse effects on the health condition of the police dogs that may lead to death in some dogs.

Keywords: Babesia vogeli, Egypt, Ehrlichia canis, police dogs, tumor necrosis factor-alpha.