Identification of climatic and environmental factors associated with incidence of cutaneous leishmaniasis in Central Iran using satellite imagery

Objective: To determine the effect of climatic and environmental factors on the incidence of cutaneous leishmaniasis in Qom province in 2018. Methods: In this cross-sectional study, the data on cutaneous leishmaniasis incidence were collected from the Disease Control and Prevention Center in Qom province. Climatic and environmental data including Normalized Difference Vegetation Index (NDVI), Land Surface Temperature (LST), and soil moisture were extracted using satellite images. Data of altitude and sunny hours were provided based on shuttle radar topography mission digital elevation model and hemispherical viewshed algorithm, respectively. The associations of climatic and environmental variables with the incidence of the disease were analyzed by Pearson correlation method. The ArcGIS 10.3 software was used to determine the geographical distribution of these factors. Results: There were positive correlations between cutaneous leishmaniasis incidence and the two climatic factors: LST and sunny hours per day (P=0.041, P=0.016), and it had weak negative correlations with the digital elevation model (P=0.27), soil moisture (P=0.54), and NDVI (P=0.62). The time delay analysis showed that in one-, two-, and three month periods, the correlations increased with a 95％ confidence interval. Accordingly, the correlation with the three-month time delay was positive and relatively strong between the cutaneous leishmaniasis incidence and LST and sunny hours (P=0.027, P=0.02); nevertheless, there were negative correlations between the cutaneous leishmaniasis incidence and the soil moisture (P=0.27) and NDVI (P=0.62). Conclusions: As Qom is located in one of the semi-arid climate zones, topography and solar energy are important factors affecting the incidence of cutaneous leishmaniasis in autumn. Therefore, appropriate disease control programs are recommended.

Spatial distribution and infection rate of leishmaniasis vectors (Diptera: Psychodidae) in Ardabil Province, Northwest of Iran

Objective: To determine the spatial distribution and infection rate of sand flies as vectors of Leishmania parasite in Ardabil province, northwest of Iran. Methods: This was a descriptive cross-sectional study. The sand flies were collected from 30 areas in all 10 districts of Ardabil province during 2017. The specimens were caught using the sticky traps. The head and genitalia of sand flies were separated and mounted in Berlese solution for microscopic identification. The Geographical Information System ArcMap10.4.1 software was used to provide the spatial maps. Results: A total of 2794 sand flies specimens were collected and 22 species of sand flies were identified from the two genera: Phlebotomus and Sergentomyia from Ardabil province. The highest frequency was found in Phlebotomus papatasi (23.7％) followed by Phlebotomus kandelakii (13.0％). The promastigote form of Leishmania infantum parasite has been reported from the three main vectors of visceral leishmaniasis (Phlebotomus kandelakii, Phlebotomus perfiliewi and Phlebotomus tobbi) from Ardabil province, where the spatial distribution map of these visceral leishmaniasis vectors was prepared. Some important species of sand flies such as Phlebotomus kandelakii, Phlebotomus perfiliewi and Phlebotomus tobbi were reported and identified as main and probable vectors of visceral leishmaniasis in Ardabil. Conclusions: According to the Geographic Information System based maps, the frequency of the sand flies as leishmaniasis vectors, the leishmania parasite infection rate and the prevalence of the disease in the central areas of Ardabil province are higher than in other areas in Ardabil province.

Spatial distribution of sand flies (Diptera: Psychodidae; Larroussius group), the vectors of visceral leishmaniasis in Northwest of Iran

Objective: To determine spatial distribution of sand flies (Diptera: Psychodidae; Larroussius group), the vectors of visceral leishmaniasis in Ardabil province, Northwest of Iran. Methods:Sand flies were collected using sticky traps from the 30 selected points in Ardabil province, during May-November 2017. The MaxEnt model in GIS software was used for modeling. Results: A total of 2794 specimens of sand flies were collected, of which 33％ were Larroussius subgenus sand flies. Phlebotomus kandelakii and Phlebotomus wenyoni were the highest and lowest collected species respectively. Based on the modeling, four areas in the province were identified with more than 70％ probability of the presence of Larroussius group vectors which were at risk of visceral leishmaniasis disease transmission. Conclusions: The distribution of Larroussius subgenus sand flies was observed in all parts of Ardabil. But the northern parts of the province (Germi and Bilesavar counties) as well as central part (Ardabil and Meshkinshahr counties) were of great importance in terms of the presence of Larroussius subgenus sand flies and the possibility of transmission of the visceral leishmaniasis.

[Estimating the cost of healthcare services delivered to cutaneous leishmaniasis patients in Qom province]

Cutaneous leishmaniasis [CL] is prevalent in most tropical and subtropical countries of the world and leads to adverse economic consequences. This study was performed to estimate the cost of healthcare services delivered to CL patients in Qom Province. Based on the data from 638 CL patients, this cross-sectional study was performed in Qom during 2009-2011. First, using researcher-made forms and based on the accounting documents, the direct and overhead costs of health services in the studied areas were calculated. Then, the out-of-pocket costs per patient were obtained. Finally, the gathered data were calculated using the excel software. In total, more than 1,600 million rials was spent on providing health services to 638 patients with cutaneous leishmaniasis in endemic foci of Qom. The direct healthcare cost was estimated to be about a thousand million and the overhead cost about 600 million rials. Besides, the state cost per patient was estimated to be over 2,520 thousand and the out-of-pocket cost per patient about 240 thousand rials. Moreover, the average total cost per patient was calculated to be 2,760,772 in the studied period. Based on results, considerable costs are spent for CL diagnosis and treatment in Qom. Therefore, health planners should give priority to the prevention of this disease in their programs

Phlebotomus papatasi and Meriones libycus as the vector and reservoir host of cutaneous leishmaniasis in Qomrood District, Qom Province, central Iran

OBJECTIVE@#To determine the sand flies species responsible for most transmission of Leishmania major (L. major) to human, as well as to determine the main reservoir hosts of the disease.@*METHODS@#Sand flies were collected using sticky papers and mounted in Puri's medium for species identification. Rodents were trapped by live Sherman traps. Both sand flies and rodents were subjected to molecular methods for detection of leishmanial parasite.@*RESULTS@#Phlebotomus papatasi (P. papatasi) was the common species in outdoor and indoor resting places. Employing PCR technique only three specimens of 150 P. papatasi (2%) were found naturally infected by parasites with a band of 350 bp which is equal to the L. major parasite. Forty six rodents were captured by Sherman traps and identified. Microscopic investigation on blood smear of the animals for amastigote parasites revealed 1 (3.22%) infected Meriones libycus (M. libycus). Infection of this animal to L. major was confirmed by PCR against rDNA loci of the parasite.@*CONCLUSIONS@#This is the first molecular report of parasite infection of both vector (P. papatasi) and reservoir (M. libycus) to L. major in the region. The results indicated that P. papatasi was the primary vector of the disease and circulating the parasite between human and reservoirs and M. libycus was the most important host reservoir for maintenance of the parasite source in the area.