Species composition, seasonal abundance and distribution of potential anopheline vectors in a malaria endemic area of Iran: field assessment for malaria elimination

Abstract

Background Despite decreases in incidence, malaria remains a major public health challenge in south and southeast Iran, where vector control is considered one of the main strategies for elimination of the disease. The efficacy of this strategy depends on understanding malaria vector ecology, which varies by species. This study was conducted to determine the species composition, seasonal abundance and distribution of potential anopheline vectors in Bashagard County, one of the important malaria-endemic areas in south Iran. Methods In this cross-sectional study, four typical foothill and mountainous villages were selected by simple random sampling. Anopheline mosquitoes were collected by the standard dipping method for larvae and total catch for adults. Anopheline specimens were morphologically identified using taxonomic keys. Statistical analyses were performed using SPSS ver.20 software. Results In total, 1211 anopheline specimens, including 1055 (87.12%) larvae and 156 (12.88%) adults, were collected and identified. They consisted of 9 species: Anopheles moghulensis (27.89%), Anopheles dthali (18.91%), Anopheles culicifacies (16.60%), Anopheles stephensi (15.38%), Anopheles turkhudi (9.83%), Anopheles superpictus (9.66%), Anopheles apoci (1.40%), Anopheles fluviatilis (0.17%), and Anopheles sergentii (0.08%). The most prevalent species in adult catches were An. culicifacies (44.23%), An. dthali (21.15%) and An. stephensi (16.03%), and the most prevalent species caught as larvae were An. moghulensis (31.94%), An. dthali (18.85%) and An. stephensi (15.26%). Most of the anopheline species were distributed in different topographical areas and two proven malaria vectors, An. culicifacies and An. superpictus, were significantly associated with altitude and collected more frequently in the foothill regions. Most of the anopheline species were present almost throughout the year with a major peak in April and a smaller peak in October. Conclusion The results of this study revealed that there are five malaria vectors in Bashagard County and some of them are more abundant in areas with special topographic features and are reproductively active throughout the year. These findings can be applied to successful planning and providing effective control measures in problematic areas during the malaria elimination phase in Iran.

Vertical Distribution, Biodiversity, and Some Selective Aspects of the Physicochemical Characteristics of the Larval Habitats of Mosquitoes (Diptera: Culicidae) in Chaharmahal and Bakhtiari Province, Iran

“…Similarly, data are presented by the topography of collection sites in few studies that paid attention to the vertical distribution of mosquito larval habitats. 27,64 In these investigations, there is no reference level to understand what they mean by mountainous or foothill areas.…”

Prediction ability of vector species, environmental characteristics and socio-economic factors for malaria risk in Sub-Saharan African Countries

“…We propose that other investigations on the prediction ability of vector species for malaria risk be conducted in the future according to the quality of LLN used. Although major vector species are not the same in Africa and in Asia, a study by Soleimani-Ahmadi, conducted in Iran, found a substantial difference in the reduction of malaria risk between the use of non-treated nets and Olyset nets (Soleimani-Ahmadi et al 2012;Sanei-Dehkordi et al 2019).…”

“…It is crucial to combine vector factors, environmental characteristics and socio-economic factors to investigate malaria risk. According to a study by Sanei-Dehkordi et al (2019), combining several strategies according to malaria vector characteristics is the most effective way to fight malaria. The study of environmental characteristics and malaria vectors is important in strategic axes of humanvector interaction control which could lead to a reduction in malaria prevalence (Pages et al 2007).…”

An Epidemiological Assessment of Malaria Cases in Udalguri District of Assam with Special Emphasis on Intensified Malaria Control Project (2008 to 2017)

“…The rise of malaria cases in these months may be because of high vector density and increase in the biting rates of malaria vectors. The seasonal abundance pattern of these vectors in different habitats was signi cantly higher in monsoon season than that of pre-and post-monsoon season (Mohapatra et al, 2003;Sanei-Dehkordi et al, 2019). Higher number of malaria cases in this region may be because of the presence of many breeding habitats throughout the year with favorable temperature that led to constant risk of malaria transmission (Shil and Balasubramanian, 2020).…”