Molecular Investigation of Francisella-Like Endosymbiont in Ticks and Francisella tularensis in Ixodid Ticks and Mosquitoes in Turkey

Abstract

This study was carried out to investigate the molecular prevalence of Francisella-like endosymbionts (FLEs) and Francisella tularensis in ticks (Acari: Ixodidae) and mosquitoes in Turkey. Genomic DNA pools were constructed from a total of 1477 adult hard ticks of Rhipicephalus (Rh.) annulatus, Rh. turanicus, Rh. sanguineus, Rh. bursa, Haemaphysalis (Hae.) parva, Hae. sulcata, Hyalomma marginatum marginatum, H. anatolicum anatolicum, H. anatolicum excavatum, H. detritum detritum, H. dromedarii, Dermacentor marginatus, and Ixodes ricinus species, which were collected from several barns, cattle, and people. Genomic DNA was also extracted from pools consisting of 6203 adult female mosquito species belonging to Aedes vexans, Culex (Cx.) pipiens, Cx. hortensis, Cx. theileri, Culiseta annulata, and Anopheles maculipennis species. Conventional PCR and TaqMan probe-based real- time PCR targeting the 16S rRNA gene for FLEs and the lpnA gene for F. tularensis, respectively, were performed on the DNA isolates obtained. FLEs and F. tularensis were not found in any genomic DNA pools constructed from ixodid ticks and mosquitos. This study represents the first investigation of F. tularensis and FLEs in potential vector ticks and mosquitoes by molecular methods in Turkey. The present study provides useful insights into the molecular epidemiology of F. tularensis and FLEs. One of the major conclusions of the study is that tularemia outbreaks may be essentially due to direct transmission from the environment (especially from water) in Turkey and not to vector-borne transmission.

Keywords: Francisella tularensis; Francisella-like endosymbiont; Ixodid tick; Molecular investigation; Mosquito.