Molecular Detection and Serological Evidence of Tick-Borne Encephalitis Virus in Serbia.

This research centers around detecting tick-borne encephalitis virus (TBEV) in ticks in Serbia and examining the presence of TBEV antibodies in humans and animals. It reestablishes TBEV presence after several decades and for the first time shows TBEV seroprevalence in animal species such as dogs, horses, wild boars, cattle, and roe deer in Serbia.

Research Motivation & Objectives

• The study was conducted in response to the increasing public health concerns about tick-borne encephalitis (TBE) throughout Europe. TBE is a zoonotic flavivirus infection that can cause serious illnesses in humans.
• The overarching goal was to detect and describe the presence and variety of TBEV in Ixodes ricinus ticks, thought to be natural hosts of the virus, in Serbia.
• The researchers investigated the prevalence of TBEV antibodies in humans and different animal species to gauge the extent of spread and possible reservoirs of the infection.

Methodology

• The researchers collected and analyzed 500 I. ricinus ticks using real-time RT-PCR, and conventional nested PCR, and sequencing techniques to detect TBEV.
• To determine the TBEV seroprevalence, they also collected serum samples from 267 humans and 200 animals of diverse species. These samples were tested using ELISA to check for the presence of TBEV antibodies.
• To avoid any crossed results, the researchers also checked for the presence of antibodies for related flaviviruses like West Nile Virus and Usutu virus.

Results

• The study confirmed the presence of TBEV in Serbia. Two microfoci (small concentrated areas) were identified where TBEV was detected in I. ricinus nymphs, with the rate of prevalence being 2% and 6.6% respectively at both locations.
• Human seroprevalence (the frequency of individuals in a population carrying TBEV antibodies) was found to be 0.37%, indicating exposure to the virus.
• The study for the first time showed TBEV seroprevalence in several animal species in Serbia: 17.5% in dogs, 5% in horses, 12.5% in wild boars, 2.5% in cattle, and 2.5% in roe deer. TBEV antibodies were not detected in the tested goat samples.
• The TBEV variety discovered from the I. ricinus tick in this study was related to the Western European subtype.

Implications

• This study brings attention to the reemergence of TBEV in Serbia and the risk it poses to public health.
• Through unveiling TBEV seroprevalence in various animal species, it also prompts the need to investigate the role these animals play in the virus’s transmission cycle.
• Given these findings, more detailed and comprehensive research regarding the epidemiology, clinical aspects, virology, and tick habitats in Serbia is needed.
• This could help formulate effective strategies to control and reduce the incidence of TBE in Serbia.