J Arthropod-Borne Dis, December 2017, 11(4): 482–496 E Moradi-Asl et al.: Situational Analysis of … Original Article Situational Analysis of Visceral Leishmaniasis in the Most Important Endemic Area of the Disease in Iran Eslam Moradi-Asl 1,2, *Ahmad Ali Hanafi-Bojd 1, *Yavar Rassi 1, Hassan Vatandoost 1,3, Mehdi Mohebali 4, Mohammad Reza Yaghoobi-Ershadi 1, Shahram Habibzadeh 5, Sadegh Hazrati 5, Sayena Rafizadeh 6 1Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2Department of Public Health, School of Public Health, Ardabil University of Medical Sciences, Ardabil, Iran 3Department of Chemical Pollutants and Pesticides, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran 4Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 5Department of Infection Disease, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran 6Ministry of Health and Medical Education, National Institute for Medical Research Development, Tehran, Iran (Received 26 Sep 2017; accepted 9 Dec 2017) Abstract Background: Visceral leishmaniasis is one of the most important vector borne diseases in the world, transmitted by sand flies. Despite efforts to prevent the spread of the disease, cases continue worldwide. In Iran, the disease usually occurs in children under 10 years. In the absence of timely diagnosis and treatment, the mortality rate is 95–100%. The main objective of this study was to determine the spatial and temporal distribution of visceral leishmaniasis as well as its correlation with climatic factors for determining high-risk areas in an endemic focus in northwestern Iran. Methods: In this cross-sectional study, data on VL cases were collected from local health centers in Ardabil Province, Iran during 2001–2015 to establish a geodatabase using ArcGIS10.3. Data analysis was conducted using SPSS23 and ArcMap Spatial Analyst. MaxEnt model was used to determine ecologically suitable nichesfor the disease. Results: Two hotspots were found in Meshkinshahr and Germi counties with 59% and 23% of total cases, respec- tively. There was an increase in the incidence rate of VL in Ardabil County from 2.9 in 2009 to 9.2/100,000 popula- tion in 2015. There was no spatial autocorrelation between county and total number of cases (P> 0.05). Higher NDVI, lower altitude and southern aspects had positive effects on the presence probability of VL. Conclusion: The number of cases of this disease have been rising since 2013 and doubled in 2015. According to the derived distribution maps, the disease is spreading to new locations such as Ardabil and Namin counties. Keywords: Visceral leishmaniasis, Seroepidemiology, GIS, Iran Introduction Arthropod-Borne diseases are among the with a wide spectrum of clinical manifesta- most important public health problems, with tions ranging from self-healing skin lesions over one-third of the infectious diseases be- to lethal (visceral) forms, has been reported ing transmitted by insect vectors (1). Leish- from 101 countries in the world (4). Over 350 maniasis is a complex vector-borne disease million people are at risk of contracting the caused by Leishmania spp (2–3). The disease, disease (5). The most important vector of leish- *Corresponding authors: Dr Ahmad Ali Hanafi- 482 http://jad.tums.ac.ir Bojd, E-mail: [email protected], Prof Yavar Published Online: December 30, 2017 Rassi, E-mail: [email protected] J Arthropod-Borne Dis, December 2017, 11(4): 482–496 E Moradi-Asl et al.: Situational Analysis of … maniasis in the old world is sand flies of the in terms of geographical distribution (17). genus Phlebotomus whilst in the new world, Using space technologies provides new op- is Lutzomyia spp. Clinically, leishmaniasis is portunities for rapid assessment of endemic divided into cutaneous leishmaniasis (CL), diseases, accurate and reliable estimation of visceral leishmaniasis (VL) and mucocutane- the population at risk, prediction of disease ous leishmaniasis (MCL) (6). Visceral leish- distribution in areas where information is not maniasis or kala-azar is the most lethal form available, and determination of appropriate of this group of diseases, and has a very high strategy for the control and prevention of the mortality rate in the absence of timely diag- disease in these areas (18). Previous studies nosis and treatment (7). It has an annual preva- that used GIS and RS techniques to examine lence of 0.2–0.4 million cases leading to more the spatial distribution of VL found a corre- than 40,000 deaths (8). lation between the disease and environmen- Since the first report of visceral leishman- tal variables. These techniques were also used iasis in 1949 in Iran, at least four main endem- to describe host and vector ecology as well ic foci of the disease in Ardabil, Fars, East as the population at risk of contracting the Azerbaijan, and Bushehr provinces have been disease. For example, land use was positive- reviewed and approved (9). Mediterranean ly affected sand fly population and thus, a leishmaniasis due to L. infantum is the most risk factor for VL transmission in Brazil, In- common form of disease in Iran (10), and do- dia and Iran (19–23). mestic dogs and other wild canines have been In Iran, sand flies from genus Phlebotomus identified as the main reservoirs. Although (P. kandelakii, P. neglectus, P. keshishiani, P. about 100–300 new cases are reported every perfiliewi transcaucasicus, P. alexandri and year in Iran across the country, the main foci P. tobbi) mainly transmit L. infantum, the caus- are in northwestern part, especially Ardabil ative agent of VL, from the infected canines Province (11–12). Children under 5yr old con- to humans (24–31). This parasite usually in- stitute over 89% of patients in the endemic fects children under the age of 10 years. Ardabil areas of VL in Iran (13). The symptoms of Province is the most important endemic focus VL include fever, hepatosplenomegaly (14) of VL in Iran, and in recent years, 25–50% of and anemia (15). visceral leishmaniasis cases have been found Geographic Information System (GIS) is a to occur in this province (12, 32, 33). new technology which is now widely used in One of the most important serologic tests the study of diseases transmitted by arthropods used for the diagnosis of visceral leishmania- (VBDs) such as the different forms of leish- sis is Direct Agglutination Test (DAT) (2, 34). maniasis. Its application has caused significant This test has been used for the diagnosis of VL changes in data interpretation and decision- patients in Ardabil Province since 1996 (15). making on disease control (16). GIS technique Like other vector-borne diseases, different en- is useful in understanding the spatial distribu- vironmental variables as well as demographics tion of the diseases, which provides valuable and human activities seem to affect the dis- information on the correlation between infec- tribution and incidence of VL. These varia- tion occurrences, climate and environmental bles should thus be taken into account during variables. It is also able to identify and predict disease prediction and management investi- high-risk areas of the diseases. Data derived gations. from this technique will facilitate the imple- The objectives of this study were to deter- mentation of environmental interventions at the mine the geographical distribution of viscer- right time and place. There is a high correla- al leishmaniasis in Ardabil Province using tion between the life cycle of VL and the en- GIS in order to identify high-risk zones in the vironmental factors involved in its life cycle province, and to evaluate the role of environ- 483 http://jad.tums.ac.ir Published Online: December 30, 2017 J Arthropod-Borne Dis, December 2017, 11(4): 482–496 E Moradi-Asl et al.: Situational Analysis of … mental and geographical variables on the dis- then imported into ArcMap 10.3 and stored ease distribution. as a shapefile for mapping and statistical/ spatial analysis. The impact of factors such as Materials and Methods age, gender and residence of patients on the prevalence of VL was assessed by SPSS ver- sion 23 (Chicago, IL, USA) and chi-square Study area analysis (CI= 95%). Ardabil Province is located in the north- Meteorological data were obtained from the west of Iran (37.45–39.42o N, 47.30–48.55o Ardabil Meteorological Center during the study E). The province has an area of 17,953km2 and period. The data included annual precipitation a population of 1,249,000 people, according (mm), average monthly temperature (oC), av- to the last census conducted in 2011. The cap- erage minimum temperature (oC), average max- ital of this province is Ardabil County and ac- imum temperature (oC), and relative humidity cording to the latest provincial demarcations, (%). the province consists of 10 counties, 21 dis- tricts, 26 cities, 71 rural districts and 1477 per- Spatial analysis manent villages (35). Topographically, 477 vil- ArcGIS 10.3 (http://www.esri.com/arcgis) lages (32.3%) are located in plain areas, 975 was used for spatial analysis and mapping. villages (66%) in mountain valleys, 17 villages Inverse Distance Weighted (IDW) interpola- (1.17%) in foothill areas and 8 villages (0.54%) tion analysis was used to prepare raster maps in forested areas. Climate is variable in Ar- of the climatic variables and NDVI (Normal- dabil Province. About 2/3 of the extent of the ized difference in vegetation index) (Fig. 1), study area has mountainous areas and the re- and was also used to determine high risk ar- maining is covered by plains. Overall, the north eas of the disease across the study area. This of the province is situated at lower altitude method assumes that the variable being with relatively warmer weather, whereas the mapped decreases in influence with distance central and southern regions have cool and from its sampled location.