Seroepidemiology of visceral leishmaniasis among free-roaming dogs and children in Zahedan city, southeast of Iran, 2018-2020

Background: Mediterranean visceral leishmaniasis (VL) or kala-azar is an endemic zoonotic disease in Iran. Domestic dogs are the primary reservoir host and source of VL infection. The high-risk populations are children and immune-deficient adults. Objective: Based on the lack of published reports about the VL in Sistan and Baluchestan province in the southeast of Iran, this study aimed to assess the seroprevalence of diseae in free-roaming dogs and children under 12 years old using indirect fluorescent antibody (IFA) test. Methods: This cross-sectional study was performed between 2018 and 2020 in Zahedan city, Sistan, and Balu-chestan province. Blood samples were taken from 400 children under 12 years old with a fever history accompanied by at least another specific clinical presentation. In the same period, blood samples were collected from 150 stray dogs. Demographic characteristics and clinical manifestations in both humans and dogs were recorded. The IFA test examined all blood samples for the detection of anti-Leishmania infantum antibodies. Results: Overall, the IFA test results were positive in 8 dogs (5.33%). Only two seropositive dogs (25%) showed obvious clinical symptoms. There was a significant correlation between the positive cases, clinical signs (P = 0.046), and age (P = 0.037) in infected dogs. None of the collected sera from 400 febrile children were positive. Conclusion: According to the present finding, it seems that VL is not endemic in Zahedan city, Sistan, and Baluchestan province, but the domestic cycle of L. infantum has been established in this area. Further investigations would be needed to estimate the status of VL infection in wild canines as a secondary potential reservoir host. Furthermore, periodic monitoring of disease must not be neglected.