Molecular-based survey of Rickettsia spp. and Coxiella burnetii in mosquitoes (Diptera: Culicidae) from Fars province, southern Iran, during 2017-18

Abstract

Background Mosquito-borne diseases are main problems of public health worldwide, especially in tropical and subtropical regions. Mosquitoes can transmit human filariasis, arboviruses, malaria, and dirofilariasis. It has been recently found that Anopheles gambiae is a vector of Rickettsia felis. Both cells of Anopheles gambiae and Aedes albopictus help developing of R. felis. These studies indicated that mosquitoes could be vector of Rickettsia spp., especially R. Felis. Since there was no study on roles of the Iranian mosquitoes in transmission of Rickettsia spp. and Coxiella burnetii, the present study for the first time investigated roles of mosquitoes in the transmission of these pathogens using the PCR technique in Iran.Methods The present study was conducted in Fars province, and mosquitoes were manually caught (hand-catch, total catch etc.) in Qir and Karzin Counties from four different geographical regions during the activity seasons of mosquitoes in 2017-18. The primers design were done to investigate the probability of mosquito’s contamination with Rickettsia spp. and Coxiella burnetii from gltA genes (Rickettsia sp. citrate synthase kinase) for Rickettsia spp. and IS111 A Transposase gene for Coxiella burnetii. The conventional PCR was used after the extraction of DNA from mosquitoes to study the contamination.Results A total of 1103 adult mosquitoes were collected and identified from four regions of the County. Among them, 3 genera and 11 species were identified including Anopheles (25.74%) (An. dthali, An. stephensi, An. superpictus), Culex (51.84%) (Cx pipiens, Cx sinaiticus, Cx bitaeniorhynchus, Cx theilers, Cx laticinctus, Cx tritaeniorhynchus, and Cx torrentium) and Culiseta (22.39%) (Cu. longiareolata) genera. All tested mosquitoes were negative in terms of contamination to Rickettsia spp. and Coxiella burnetii.Conclusions Based on the results, mosquitoes in this part of the country are not considered as vectors of Rickettsia spp. and Coxiella burnetii currently. In general, limited studies have been conducted on Rickettsial diseases in Iran and since Rickettsia spp. has been reported from different vectors in Iran and other neighboring countries, there is a need for further studies on this field in tropical areas of Iran especially in mosquitoes as a possible vector with high abundance and mobility.