Seroepidemiological evaluation of the frequency of Leptospira interrogans serum varieties in the stray dog population of Qazvin using microscopic agglutination test

Leptospirosis is an infectious and zoonotic disease with global spread, and its agent, which is a serovar of <em>Leptospira interrogans</em> bacterium, is transmitted by contact with the urine of infected animals. The dog, as one of the important reservoirs of the mentioned bacteria, causes contamination in humans and domestic animals. The aim of the present study was to evaluate seroepidemiological <em>Leptospira interrogans</em> serum varieties using microscopic agglutination test (MAT) in stray dogs of Qazvin. For this purpose, a total of 74 serum samples were examined for the detection of antibodies against the mentioned bacteria, of which 15 samples showed a positive reaction with one or two serovars of <em>Leptospira interrogans</em>. The results showed that most infected dogs had serum titers of 1:100 (47.1%) and 1:1600 (17.65%). The highest contamination was with <em>Canicula </em>serovars with 70.6% and <em>Harjo</em> 11.76%, and <em>Gripotyphosa</em>, <em>Pomona</em> and <em>Icterohemorrhagia</em> serovars were in the next positions. Among the positive samples, three samples were related to female dogs and 12 samples belonged to male dogs, and the result of Chi square test showed that there was a significant relationship between gender and serum contamination (<em>p</em>&lt;0.05). Also, 8 samples belonged to the age groups above 3 years and 7 samples belonged to the age groups less than 3 years, and there was no significant relationship between age groups and the positive results (<em>p</em>&gt;0.05). Presence of serum contamination among the population of stray dogs in Qazvin can lead to a high prevalence of clinical infection in pet dogs and domestic and wild animals especially sheep flocks, which may also affect public health due to the zoonotic nature of the disease.