Modelling the number of dermal lesions in anthroponotic cutaneous leishmaniasis and its associated factors in Herat province, western Afghanistan, during 2012-2013.

Cutaneous leishmaniasis (CL), caused by Leishmania tropica, is the main causative agent of CL in the Herat province, western Afghanistan. In CL patients, one of the most important indicators for reducing the amount of body damage and the choice of treatment is the number of dermal lesions, but there is no strong evidence in this regard. Therefore, using count regression models, the main objective of this historical cohort study was to identify the distribution of the number of dermal lesions and determine the associated factors among CL patients referring to leishmaniasis reference laboratory in Herat province, from January 2012 to December 2013. In a total of 4,127 clinically suspected CL cases, 50.20% were female and 49.80% male. Based on the results of ZINB model, which is the best model suggested by goodness-of-fit criteria, age variables (IRR = 1.007), duration of lesion (6-12 weeks compared to < 6 weeks with IRR = 1.36 and >12 weeks with IRR = 1.39 compared to <6 weeks), type of lesion(both nodule and ulcer compared to papule with IRR = 2.03), location of lesion (trunk with IRR = 1.90, upper with IRR = 1.66, lower with IRR = 1.61 and mix with IRR = 10.35 compared to head/neck/ears) and type of lesion (ulcer compared to papule with IRR = 0.50, nodule and lupoid, respectively, as IRR = 0.72 and IRR = 0.51 compared to papule) had a significant effect on the mean number of dermal lesions (p < .05). Also, our results showed that among four models used, the ZINB model represented a better performance to determine the associated probable factors about the number of dermal lesions in ACL patients. Moreover, there was a direct association between age and number of dermal lesions; in addition, duration of lesion, type of lesion and location of lesion had a significant effect on the number of dermal lesions. Therefore, a comprehensive planning is necessary for controlling and reducing the number of dermal lesions.

Distribution pattern of anthroponotic cutaneous leishmaniasis caused by Leishmania tropica in Western Afghanistan during 2013-2014.

Anthroponotic cutaneous leishmaniasis (ACL), caused by Leishmania tropica, is the main cause of cutaneous leishmaniasis (CL) in the Herat province, Western Afghanistan. We investigated the role of environmental factors on ACL distribution in Herat. Epidemiological data from 2457 patients were retrieved from the local WHO sub-office. Shapefile layers of districts, cities, villages, land cover, soil type and digital elevation model (DEM) of the Herat province were used to assess, by logistic regression modelling, the effects of land cover, soil types, elevation, and proximity to the Harirud river on the distribution of ACL. The key determinants of distribution were: (i) close proximity to the Harirud river, (ii) elevation between 700 and 1200m, (iii) intensive and intermittent irrigated cultivated land, and (iv) Haplocalcids with Torriorthents and Torrifluvents soil types. No ACL cases were found below 700m, and a few cases were present at >1200m in irrigated areas around the Harirud river. These findings suggest that moist soil and the humidity from irrigated areas found between 700 and 1200m provide suitable breeding sites of Phlebotomus sergenti, the main sandfly vector of L. tropica in Afghanistan. The effect of elevation also explains the predominance of ACL over ZCL in this region. The present study showed that distribution of ACL is strongly associated with environmental factors in West Afghanistan where the political and socio-economic conditions may also affect the epidemiology of CL.

Genetic diversity of Leishmania tropica strains isolated from clinical forms of cutaneous leishmaniasis in rural districts of Herat province, Western Afghanistan, based on ITS1-rDNA.

Despite the high incidence of cutaneous leishmaniasis (CL) in Afghanistan, there is a little information concerning epidemiological status of the disease and phylogenetic relationship and population structure of causative agents. This study was conducted to determine the prevalence and distribution of CL cases and investigate the Leishmania tropica population structure in rural districts of Heart province in the West of Afghanistan in comparison to neighboring foci. Overall, 4189 clinically suspected CL cases from 177 villages (including 12 districts) in Herat province were enrolled in the referral laboratory of WHO sub-office in Herat city from January 2012 to December 2013. 3861 cases were confirmed as CL by microscopic examination of Giemsa-stained slides. ITS1 PCR-RFLP analysis showed dominance of L. tropica (more than 98%) among 127 randomly chosen samples. Analysis of the ITS1 sequences revealed 4 sequence types among the 21 L. tropica isolates. Comparison of sequence types from Herat rural districts with the representatives of L. tropica from Iran, India, and Herat city showed two main population groups (cluster A and B). All isolates from Herat province, India and Southeast, East, and Central Iran were found exclusively in cluster A. The close proximity of West Afghanistan focus and Birjand county as the capital of Southern Khorasan province in East Iran can explain relatively equal to the genetic composition of L. tropica in these two neighboring regions. In addition, two populations were found among L. tropica isolates from Herat rural districts. Main population showed more similarity to some isolates from Birjand county in East Iran while minor population probably originated from the Southeast and East Iranian L. tropica. Recent study provided valuable information concerning the population structure of L. tropica and epidemiology of ACL in the West of Afghanistan, which could be the basis for molecular epidemiology studies in other regions of Afghanistan.