First microscopic detection of Cystoisospora protozoan infecting dogs in Babylon province

Cystoisospora species are protozoa parasites belonging to the phylum of Apicomplexa that live in the small intestine of hosts, such as dogs. Cystoisospora infection in dogs has not been investigated in Babylon province. Therefore, this study aimed to diagnose the disease by this protozoan macroscopically and microscopically in stray and domestic dogs using a direct smear, flotation methods based on Sheathers solution, and staining by modified Ziehl Neelsen stain. In the current study, a total of 150 fecal samples of dogs (different in sex and age) were collected from other areas of Babylon City during the period from December 2024 to February 2025. The results of macroscopic observation showed that the infected dogs exhibited various clinical symptoms, including dehydration, diarrhea, fever, weight loss, vomiting, and even death in extreme cases. These observations also noticed that watery diarrhea of positive samples 15/40 (37.5) recorded the highest rate among other consistency of fecal samples with significant differences (p≤0.05). In addition, the microscopic results demonstrated that 26 out of 150 dogs (17.33%) were microscopically infected in both stray and domestic dogs. According to sex, no significant difference (p = 0.688) was found in the infection, where it was 18.60% (16 out of 86) in males, while 15.62% (10 out of 64) in females. For the age groups, there was a significant difference (p≤0.01), which has a high incidence of illness in canines less than 6 months 15/45(33.33%) compared to other age groups. Current data also revealed that the infection rate in rural areas was slightly lower than in urban areas, where it recorded 11/75 (14.66%) and 15/75 (20%), respectively, without significant differences (P = 0.469). Overall, these findings provide baseline data and valuable information to the owners and the veterinary community regarding this canine coccidian's presence and risk factors. It is suggested that this is the first study recording the infection of Cystoisospora in dogs living in Babylon province. Further molecular investigation has been carried out to confirm the presence of this protozoan and its species in dogs.