Seroprevalence study of Tick‐borne encephalitis, Borrelia burgdorferi, Dengue and Toscana virus in Turin Province

Abstract

Tick borne encephalitis virus (TBEV) is present in some European countries and it is transmitted by a tick bite. Ixodes ricinus is the main vector of the infection in Italy, where fortunately clinical neurological manifestations, typical of the more serious phase of the disease, are very rarely observed. This behaviour is different from other endemic Euroasiatic areas where numerous cases of encephalitis are described. However TBE transmission has not been widely investigated in Italy and available epidemiological data have been obtained only by studies performed in Central and Northern Regions of the country. In addition seroepidemiological researches were made prevalently on subjects at high risk of tick bite, such as hunters or forest guards from Trentin and Central Italy. No precise information about TBE virus diffusion was available in the Piedmont before our investigations. We found that hunters and wild boar breeders seem to be particularly exposed to the risk of TBE virus infection in Turin Province and in particular in the Susa valley, although no neurological involvement was observed in our population. In particular a seroprevalence of about 5% was detected by the use of purified antigens ELISA test, amongst the subjects at high risk of tick bite. Moreover low risk individuals showed a seroprevalence of below 2%. In addition a parallel seroepidemiological study was performed in Turin Province for Borrelia burgdorferi, the aetiological agent of Lyme disease, also transmitted by tick bite (e.g. Ixodes ricinus), for Dengue and Toscana (TOS) arboviruses, respectively transmitted by Aedes mosquitoes and phlebotomes. Data reported here demonstrate only a sporadic presence in our population of antibodies against Borrelia and Dengue infection. Moreover using an ELISA test performed with viral purified nucleoprotein, we reported a total percentage of about 3% of subjects positive for TOSV.