Animal Reservoir Hosts of Zoonotic Visceral Leishmaniasis in Iran: A Systematic Review and Meta-Analysis

Background: Zoonotic visceral leishmaniasis (ZVL), caused by Leishmania infantum, remains a veterinary and public health concern in Iran. Domestic and wild animal reservoirs play a critical role in maintaining transmission. This systematic review and meta-analysis aimed to estimate the prevalence of L. infantum infection among animal reservoir hosts in Iran and evaluate heterogeneity across Iran overall.

Methods: A systematic search of PubMed, Scopus, Web of Science, ScienceDirect, SID, Magiran, and IranMedex was conducted. Studies published between 2001 and 2024 reporting L. infantum infection in domestic and wild animal reservoirs were included. A random-effects meta-analysis estimated pooled prevalence with 94% confidence intervals (CI). Heterogeneity was assessed using Cochran’s Q test and the I² statistic. Subgroup analyses were performed according to reservoir host species, region, and diagnostic methods, including DAT, PCR, ELISA, IFAT, and parasitological assays. Publication bias was evaluated using funnel plot asymmetry and Egger’s regression test.

Results: A total of 63 eligible studies involving 24,872 animals were included. The pooled prevalence of L. infantum infection among reservoir hosts was 13.21% (94% CI: 11.3–15.12). Domestic dogs showed the epidemiological importance, with prevalence estimates ranging from 11% to 15%, followed by cats, jackals, foxes, wolves, and rodents. Significant between-study heterogeneity was observed (I² >74%, P <0.001), likely due to differences in endemicity, reservoir species, geographical location, and diagnostic techniques. Subgroup analyses revealed higher prevalence rates in northwestern endemic provinces and in studies using molecular diagnostic methods. PCR and DAT demonstrated the highest sensitivity and specificity. No significant publication bias was detected.

Conclusions: Animal reservoirs, particularly domestic dogs and wild canids, play a major role in ZVL persistence and transmission in Iran. The substantial heterogeneity among studies highlights the need for surveillance systems and diagnostic protocols. Integrated surveillance, molecular monitoring, and reservoir control strategies are essential for reducing zoonotic transmission in endemic areas.