A Geomedical Survey: Is There an Association Between Climatic Conditions and Leishmania Species Distribution in Iran During the Years 1999-2021?

PURPOSE: Iran is among the high-risk leishmaniasis regions in the world. WHO recommends the use of GIS as an ideal tool for healthcare authorities to predict the evolution of a disease, delimit the risk of outbreaks and identify critical areas. The aim of this research is to find the association between the main species of Leishmania (L. major, L. tropica, L. infantum) dispersion and climatic variables in Iran. METHODS: All molecular-based reports of leishmaniasis from Iran between 1999 and 2021 were gathered from reliable medical sources. Meteorological data (air and soil temperatures, annual rainfall and humidity) of the country along the study period were obtained from the Iranian Climatological Research Centre. The data concerning species distribution and climatic conditions during this period were moved to a base-map through raster layers using ArcGIS 10.4.1 software. The relationship between parasitological and climatic models was examined using ANOVA. RESULTS: High risk area maps, based on the cut-off thresholds, were generated for Leishmania major, L. tropica and L. infantum. According to the molecular-based reports, the L. major distribution was significantly related to all climatic variables, while L. tropica was merely related to rainfall and humidity, and the L. infantum distribution was significantly associated with rainfall, soil and air temperatures. CONCLUSION: The association between climatic conditions and Leishmania species distribution in Iran has been confirmed. Consequently, both, the relationship between climatic conditions and the geographical distribution of Leishmania species, and the use of GIS to better understand the spatial epidemiology of leishmaniasis, have been reaffirmed.

Spatio-temporal Prediction of the Malaria Transmission Risk in Minab District (Hormozgan Province, Southern Iran).

INTRODUCTION: Malaria is the most important parasitic disease in tropical and subtropical regions, with more than 240 million cases reported annually. In Iran, indigenous cases occur in its south-eastern region. The aim of this study is to assess the environmental risk of malaria transmission in an endemic area of southern Iran. METHODS: The study was carried out in Minab district (Hormozgan province, southern Iran), with the aim to assess the environmental risk of malaria, based on a spatio-temporal study, using Growing Degree Days (GDD)-based predictions, larval habitat ecology, MaxEnt spatial predictions and malaria transmission data. RESULTS: The Gradient Model Risk index showed the highest malaria transmission risk period to be during January-April and October-December. The ecological conditions of water bodies of larval habitats of the four vector species (Anopheles culicifacies, A. dthali, A. fluviatilis and A. stephensi) were assessed, with A. stephensi being the most prevalent and the most widely distributed species. CONCLUSION: These findings, together with the MaxEnt Anopheles predictive distribution models, allowed identifying villages in danger of malaria transmission in Minab district. This spatio-temporal prediction of malaria transmission risk should be incorporated in the design of malaria control initiatives towards a local malaria early warning system. Moreover, the proposed transmission risk model can be extrapolated, at local scale, to other malaria endemic areas of tropical and subtropical regions.

Molecular, Morphological, and Spatial Study of Galba schirazensis (Pulmonata, Lymnaeidae) from Southeastern Iran.

BACKGROUND: Snails of the genus Galba are the intermediate hosts of Fasciola species, the etiological agents of liver fluke disease, fascioliasis. A genetically different but morphologically very similar species in the genus, G. schirazensis, is sympatrically distributed with G. truncatula in some regions of the world. We aimed to investigate the occurrence of G. schirazensis in Kerman province, Iran and to characterize genetically G. schirazensis specimens from southeast Iran. METHODS: Field-collected snails from four localities in Jiroft, Bam and Faryab, Kerman province, southeastern Iran were studied. Hydrological variables including temperature and pH were recorded for each habitat. Each specimen was identified using morphological as well as conchological characteristics. Genetic characterization was performed using PCR-sequencing followed by phylogenetic analyses on nuclear ITS2 as well as mitochondrial cox1 gene fragments. MaxEnt software was used to predict the most appropriate ecological niches for the targeted species. RESULTS: G. schirazensis was found in 4 out of 28 locations. One ITS2 and two cox1 haplotypes were detected among G. schirazensis populations from the four localities. Habitat study showed that G. schirazensis thrives in habitats with alkaline pH. G.schirazensis from South America were clustered with specimens from Bam, Kerman, Iran; however, north Iranian isolates of G. schirazensis were strongly correlated with specimens from Jiroft and Faryab. MaxEnt model for the most appropriate ecological niches of the targeted species predicted environmental suitability for this species in western Africa as well as coastal areas in north and southwestern Africa. CONCLUSION: G. schirazensis is frequently present in southern areas of Kerman Province. At least two genetically different haplotypes are present in southeastern Iran.