Molecular and seroepidemiological study of Leishmania infantum infection among humans, dogs and wild canines from Azarshahr (new endemic focus), Iran

摘要

An epidemiological survey of visceral leishmaniosis among domestic and wild canines as well people was carried out in the new endemic focus of Azarshahr (northwest of Iran) to assess the distribution of the disease and the possible association between infection in dogs and people during 2008-2009. At first using direct agglutination test (DAT), an examination of visceral leishmaniosis was carried out among 1500 Azarshahr district residents children in the age from 6 month to 10 years old. Then, one hundred and twenty domestic dogs, ten jackals, ten foxes and ten wolves from the district were examined for clinical and serological signs of canine leishmaniosis. The sera were evaluated by DAT then parasitological study was performed for all seropositive animals. Human sera samples, the overall seropositive rate of disease was 1.3% (19/1500) (95% CI, 0.7 to 1.8) by DAT (1:3200 and above). Data analysis revealed that serological positivity was statistically associated with age groups (χ2?=7.46, P =0.023). Of the 120 serum sampled collected from 120 domestic and stray dogs, 19.2% (23/120) (95% CI, 12.1-26.2) were positive by DAT (1:320 and above). No statistically significant difference was found between male (17.9%) and female (37.5%) seroprevalence (P=0.172). Also, no statistically significant difference was found between serological positivity and age groups (P=0.107). Serology and parasitology tests that were performed in 30 wild canines showed 10% of these animals were infected by?Leishmania infantum. Amastigotes of Leishmania were observed in 14 seropositive dogs after dissection and parasitological examinations. A polymerase chain reaction (PCR) genotyping tool was developed and used to identification of species of the seropositive dog isolates. This isolates were identified as?L. infantum. The present study provides, for the first time, information on the distribution of the visceral leishmaniosis in Azarshahr county of Iran, as a new endemic focus of disease.