Autochthonous Transmission of West Nile Virus by a New Vector in Iran, Vector-Host Interaction Modeling and Virulence Gene Determinants

Abstract

Using molecular techniques and bioinformatics tools, we studied the vector-host interactions and the molecular epidemiology of West Nile virus (WNV) in western Iran. Mosquitoes were collected during 2017 and 2018. DNA typing assays were used to study vector-host interactions. Mosquitoes were screened by RT-PCR for the genomes of five virus families. WNV-positive samples were fully sequenced and evolutionary tree and molecular architecture were constructed by Geneious software and SWISS-MODEL workspace, respectively. A total of 5028 mosquito specimens were collected and identified. The most prevalent species was Culex (Cx.) pipiens complex (57.3%). Analysis of the blood-feeding preferences of blood-fed mosquitoes revealed six mammalian and one bird species as hosts. One mosquito pool containing non-blood-fed Cx. theileri and one blood-fed Culex pipiens pipiens (Cpp.) biotype pipiens were positive for WNV. A phylogram indicated that the obtained WNV sequences belonged to lineage 2, subclade 2 g. Several amino acid substitutions suspected as virulence markers were observed in the Iranian WNV strains. The three-dimensional structural homology model of the E-protein identified hot spot domains known to facilitate virus invasion and neurotropism. The recent detection of WNV lineage 2 in mosquitoes from several regions of Iran in consecutive years suggests that the virus is established in the country.

First Field Evidence On Circulation and Vertical Transmission of West Nile Virus Lineage-1a in Mosquitoes of Southern Iran

“…Despite the nationwide serological evidence on the prevalence of WNV since 1976 [27] and the establishment of Arbovirus monitoring system since 2000, there is a paucity of information about WNV vectors in Iran [29]. Also, the distribution map of the globally spreading Lineage 1a of West Nile Virus as a serious public health problem still not clear at national level [34]. The present study aimed to contribute towards WNV vectors identi cation and surveillance.…”

West Nile, Sindbis and Usutu Viruses: Evidence of Circulation in Mosquitoes and Horses in Tunisia

“…pipiens pipiens and Cx. theileri in Iran [ 73 , 74 ] and 0.28% for Cx. nigripalpus in Chiapas, Mexico [ 75 ].…”

Medically Significant Vector-Borne Viral Diseases in Iran

“…In addition, Shahhosseini et al identified WNV in Cx. theileri, one of the most common mosquito species in Iran, which suggests this may be a new vector for WNV within the country [107]. Furthermore, a recent study in southern Iran provided evidence that WNV can be transmitted vertically between female Culex mosquitoes and their offspring, which may explain how the virus survives the winter months.…”

“…Figure 2. Evidence of West Nile virus[48,96,99,107,[119][120][121][122], Chikungunya virus[15,[46][47][48], Dengue virus[15,48,58,60,62], Sindbis virus[75] and Rift valley fever virus[109] in Iran in either humans, animals, or mosquitoes by indirect and direct evidence.…”