Background
Transmission of malaria, filariasis, Japanese encephalitis, dengue fever, and other arboviral diseases by mosquitoes has turned mosquitoes into the most important group of arthropods in medicine and health [
1]. In Iran, mosquitoes are vectors of two protozoan, two bacterial, four filarial, and seven arboviral diseases [
2,
3]. There are 70 species and eight (or 12) genera of Iranian mosquitoes depending on the classification of the tribe Aedini [
4].
Anopheles species are responsible for the transmission of malaria, but the majority of mosquito species from the genera of
Culex and
Aedes are responsible for the transmission of arboviruses to humans [
5,
6].
Globally, in 2019, there were an estimated 229 million malaria cases in 87 malaria-endemic countries. The disease is a major endemic infectious disease in Iran, especially in the south and southeastern provinces, including the Sistan-Baluchistan, Hormozgan and Kerman Provinces [
7‐
12].
Anopheles species are responsible for the transmission of malaria. So far, seven malaria vectors have been recognized and reported in Iran, including
Anopheles stephensi,
Anopheles culicifacies,
Anopheles dthali,
Anopheles fluviatilis,
Anopheles superpictus,
Anopheles maculipennis, and
Anopheles sacharovi [
13]. The first five of these vectors can be found in the southeast of the country, together with the majority of malaria cases. Also,
Anopheles pulcherrimus has been considered as a potential malaria vector in this area based on immunological parasite detection [two-site immunoradiometric assay (IRMA)] [
14].
Anopheles maculipennis sensu lato (
s.l.) is distributed in Eurasia and North America and comprises nine Palearctic members [
15,
16]. Some research indicated the occurrence of this malaria vector in Central Iran, the Caspian coast in the north, and North-West Iran [
17‐
19].
Anopheles superpictus s.l. is distributed in Europe, Asia and North Africa [
20‐
24]. This species is one of the seven species of malaria vectors and reported in the Iranian Plateau, the slopes of the Alborz Mountains and southern Zagros, as well as the coastal plains of the Caspian Sea and the Persian Gulf in both malaria-endemic and non-endemic areas [
8,
21]. Oshaghi et al
. in 2008 reported three genotypes X, Y and Z in Iran. Interestingly, while the sympatric Y and Z genotypes appear to be exclusive to the populations from the southeastern part of the country, genotype X is geographically separated, and present in the North, the West, the South and the Central territories [
22].
One of the goals of control methods is to reduce the size of vector populations. There is a risk of insecticide resistance and off-target effects on other arthropod species in chemical control [
25]. Biological control is biodegradable and ecologically friendly [
26]. Entomopathogenic fungi were first used on
Anopheles gambiae with a fungus from the genus of
Coelomomyces [
27]. Weiser et al
. reported
Coelomomyces irani from
An. maculipennis in Iran [
28]. Azari-Hamidian and Abaei reported
Coelomomyces sp. from the larvae of
An. culicifacies s.l. in Sistan and Baluchistan Province, southeast Iran, where 5.8% of larvae were infected with the fungus [
29].
The use of pathogenic insect fungi against mosquito larvae has been reported in many studies, and fungi are proven an effective way of killing mosquito larvae [
30‐
34]. The use of
Beauveria bassiana for control of
Aedes aegypti [
31] and
Lagenidium giganteum in California targeted to control
Culex tarsalis [
32] reduced the survival rate, blood-feeding, fecundity, and disease transmission power of targeted mosquitoes. Some insect pathogenic fungi have been used effectively in the laboratory, small-, and large-scale field studies to control vector mosquitoes especially in
Culex [
35,
36],
Mansonia [
37], and
Anopheles species [
32] and have a wide range of species diversity. This group of pathogens is found among all phyla of fungi. The Ascomycota is the largest group of fungi. This group is extremely ecologically diverse, just like the pathogenesis pathogen of plants, animals and humans. Pathogenic insect ascomycetes include a large group of fungi that attack a wide range of insects and are the most common insect pathogens [
38]. The entomopathogenic ascomycete fungi, including
Metarhizium anisopliae and
Beauveria bassiana have been reported as insecticides [
39]. In many studies, spores and secondary metabolites of insect pathogenic fungi have been reported as biocontrol agents against mosquitoes [
34,
40‐
42]. The fungal hyphae produce endotoxins and penetrate through the larval body. These toxins cause larval damage and toxicity in the haemocoel and larval mosquito guts [
43]. Metabolites of
Beauveria bassiana caused changes in the body and tissues of treated
Culex pipiens larvae, especially in the cuticle and midgut [
44].
The present study was to isolate and identify entomopathogenic fungi associated with mosquito larvae in Kashan County, Central Iran, and their infection and effects on mosquito larvae.
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