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Background and Objective: Visceral Leishmaniasis or Kala-azar is an important infectious disease in northwestern Iran. Members of the Leishmania donovani complex, L. donovani and L.infantum, are the two main parasites causing the disease in the world. In this study immunophenotype characters such as N-glycosylation, and T-cell and B-Cell epitopes of CPB gene was evaluated in the Leishmania parasites isolated from sandflies of the region. Materials and Methods: Partial of the CPB (702-741 bp) of Leishmania parasites was amplified and sequenced and used for bioinformatics analysis such as test three dimensional (3D) protein structure, N-glycosylation, and T-cell and B-Cell epitopes. Results: In 7 out of 3477 sand flies there was a positive PCR test for systeine protease B, gene. Also according to findings of this study, both agents of kala-azar L. donovani and L. infantum were bing transfered by sand flies of Phlbtomus perfiliewi transcaucasicus in North West Iran. DNA analysis of the CPB gene showed a cytosine insertion at 5’ end of the proofreading frame of the gene resulted in a stop codon (TGA) seven AA further down and hence translation is halted. This caused a short amino acid chain with only 76 AA much shorter than normal CPB peptide with 234-247 AA. This mutation has not been found in the L.infantum strain resulted in a normal CPB peptide. AA analysis showed no N-glycosylation site, T-cell and B-Cell epitopes on the short peptide of the L. donovani strain. Conclusion: This is the shortest CPB peptide chain reported for the L. donovani complex in the literature. This short peptide could have an effect on host-parasite and vector-parasite interactions. Since the CPBs genes have important implication on host–parasite and play key roles in infection and expression of the disease, further studies on the L. donovani parasite and its diminutive peptide necessitate to improve our understanding about the epidemiology of visceral leishmaniasis in Iran.

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Background and Objective: Epidemiology of Visceral Leishmaniasis is affected by combination quality and interaction of Parasite-Vector-Host and environmental conditions. So, disease cycle related and eco-social factors and environmental risk factors co-analyzing, help to understanding these interactions, prognosis and orientation in disease control and treatment. This study was done to determine the role of nomadic and non-nomadic lifestyle in transmission of Kala-Azar in the Northwest of Iran.

Materials and Methods: In this case-control study, firstly the prevalence of Kala-Azar among people living in selected villages were determined by both serological test (Direct Agglutination Test: DAT) and immunological test (Montenegro Skin Test: MST) in the Northwest of Iran, on the way of Shahsavan tribe travelling in summer/winter quarters villages. Then DAT was conducted on the dogs presenting in those villages during 2006. One year later Seroconversion rate was calculated through collection of the individual’s negative sera and re-analyzing them via DAT. Finally, occurrence of Visceral Leishmaniasis in relation with various involving factors like dog density/abundance and nomadic and non-nomadic lifestyle using Chi-Square test were determined.

Results: Both MST and DAT were significantly higher in the nomadic lifestyle than in the non-nomadic lifestyle (P<0.05). Three values of prevalence (5.5%), seropositivity (2.7%) and seroconversion (2.5%) were higher in nomads than non-nomads. The GIS studies and electronically prepared maps showed that the endemicity and the infection rate are higher in nomads than non-nomads. There were a negative correlation between general distribution of Visceral Leishmaniasis in relation with environmental conditions altitude, mean temperature and rainfall.

Conclusion: This study indicated that Nomadic lifestyle can play as a risk factor in transmission of Visceral Leishmaniasis due to nomads/dog contacting, their entering in the wild cycle of disease and travelling.