The Potential Role of Humans in the Transmission Cycle of Leishmania major (Kinetoplastida: Trypanosomatidae), the Causative Agent of the Old World Zoonotic Cutaneous Leishmaniasis.

Zoonotic cutaneous leishmaniasis (ZCL) due to Leishmania major (Yakimoff and Schokhor, 1914) is known as a neglected tropical disease, transmitted by Phlebotomus papatasi (Scopoli, 1786) in North Africa and the Middle East. The main reservoirs of ZCL are desert gerbils and the role of humans as a reservoir host of the disease is not clearly defined and is therefore investigated in this study. In order to achieve this objective, Ph. papatasi sand flies were allowed to take blood through indirect blood sources (human, Rhombomys opimus (Lichtenstein, 1823) (great gerbil), and BALB/c mice) using artificial feeding or direct xenodiagnoses from ZCL patients. To detect Leishmania promastigotes inside digestive canal, blood-fed sand flies were dissected and examined under light microscope and then confirmed by nested-PCR. In indirect xenodiagnoses, promastigote forms of Leishmania parasite were observed in 7.1%, 12%, and 13.6% of sand flies which fed on Rh. opimus, BALB/c mice, or human blood sources, respectively. In direct xenodiagnoses, among 93 female lab-reared sand flies which fed on active L. major lesion(s), 2.1% Leishmania infection was subsequently observed in the sand flies. No infection was detected in those sand flies that fed on nonlesioned skin of CL patients. Humans can serve as a reservoir of ZCL since the data indicate that Ph. papatasi is able to acquire L. major parasites from an active lesion of ZCL patients and the parasites can complete metacyclogenesis in the sand fly.

Serological Survey and Associated Risk Factors of Visceral Leish-maniasis in Qom Province, Central Iran.

BACKGROUND: Visceral leishmaniasis (VL) or kala-azar is considered as a parasitic disease caused by the species of Leishmania donovani complex which is intracellular parasites. This systemic disease is endemic in some parts of provinc-es of Iran. The aim of this study was to determine the seroprevalence of VL in Qom Province, central Iran using di-rect agglutination test (DAT). METHODS: Overall, 1564 serum samples (800 males and 764 females) were collected from selected subjects by random-ized cluster sampling in 2011-2012. Sera were tested and analyzed by DAT. Before sampling; a questionnaire was filled out for each case. Data were analyzed using Chi-square test and multivariate logistic regression for risk factors analysis. RESULTS: Of 1564 individuals, 53 cases (3.38%) showed Leishmania specific antibodies as follows: with 1:400 titer 16 cases (1.02%), with 1:800 titer 20 cases (1.27%), with 1:1600 titer 16 cases (1.02%) whereas only one subject (0.06%) showed titers of ≥ 1:3200. There was no significant association between VL seropositivity and gender, age group and occupation. Binary logistic regression showed that rural areas was 0.44 times at higher risk of infection than urban areas (OR= 0.44; %95 CI= 0.25- 0.78). CONCLUSION: Although the seroprevalence of VL is relatively low in Qom Province, yet due to the importance of the disease, the surveillance system should be monitored by health authorities.