Seropositivity Among Human Subjects for Both TBEV and Borrelia burgdorferi s.l. During a TBE Outbreak in Sibiu County, Romania

Abstract

Background: The tick Ixodes ricinus is the main vector of both tick-borne encephalitis (TBE) virus and Borrelia burgdorferi sensu lato in Eurasia. Borrelia burgdorferi is the cause of Lyme borreliosis, and TBE is a biphasic meningoencephalitis induced by an arbovirus belonging to the flavivirus family. The principal aim of the current investigation is to estimate the TBEV-Borrelia burgdorferi s.l. coinfection in human subjects from a TBE outbreak in Sibiu County, Romania. Methods: Sera and cerebrospinal fluid from 51 patients hospitalized during the TBE outbreak were examined with hemagglutination-inhibition and ELISA techniques for TBEV, and with ELISA test for Borrelia burgdorferi s.l. Results: Among the 51 TBE suspect patients, 38 had antibodies against TBEV. Patients that came out positive showed different symptoms: meningoencephalitis, flu-like syndrome and meningitis. Two of these patients had IgG antibodies against Borrelia burgdorferi too. So there was only 5% of the TBE sick patients that came in contact with B. burgdorferi also. Conclusion: Considering the results, our assessment is that the two pathogens antibodies coexistence in such a low number of patients is not consistent with coinfection following tick bite. Also, considering the fact that the overall incidence of TBEV in ticks is 0.5–2% and that of B. burgdorferi s.l. can reach values as high as 36%, the investigated TBE outbreak is more likely to have occurred from unpasteurized dairy products’ comsumption, conclusion which is sustained also by the observation that in the outbreak area intensive shepherding is practised.