Abstract
Canine distemper is a fatal disease of canine animals including dogs which resulting in high rates of morbidity and mortality in unvaccinated domestic and other wildlife animals. Stray dogs represent a major reservoir in maintaining and spreading of infection to susceptible dogs. Hence, this study aims to serological screening of serological evidence of CDV exposure in stray dogs and estimating the relationship between seropositivity and some risk factors (inhabitance, age, and sex) with evaluation of immune status in positively seropositive dogs compared to negatives. For this purpose, Whole blood samples were collected from totally 43 stray dogs in Wasit province between January and December 2024 and then tested serologically by the canine enzyme linked immunosorbent assay kits to identify qualitatively anti-canine distemper IgG antibodies and quantitative measurement of immune markers including interleukins (IL-1, IL-6, IL-10, and IL-12) and tumor necrosis factor-alpha (TNF-α). Findings revealed that Sixteen (37.21%) of the 43 examined stray dogs were seropositive for anti-canine distemper virus (CDV) IgG antibodies, indicating previous exposure to the virus with an OD ranged 0.242 to 0.494 and being 0.328±0.022. In accordance to risk factors, seropositivity and risks of infection were increased significantly in stray dogs of suburban compared to urban areas; elderly ( 5 years) more than younger (1 and 2-4 years), and females more than males. Concerning immune markers, the results of all tested markers were elevated significantly in seropositive stray dogs compared to seronegatives. In conclusion, the notably higher seroprevalence of anti-CDV IgG antibodies detected in stray dogs in this study suggests previous exposure and the continuing circulation of canine distemper virus among these strays in Wasit Province. Since ELISA detects antibodies and not the virus itself, identification of an active infection is best accomplished using molecular techniques like RT-PCR suggesting the need to additional surveys to support our data. Also, this might represent the first study in Iraq insight the association of the disease to immune status.

Key words: Canine distemper virus; Seroprevalence; stray dogs; ELISA; Cytokines; IL-6; TNF-α; Iraq