Equine seroprevalence rates as an additional indicator for a more accurate risk assessment of the West Nile virus transmission.

The research paper discusses the use of equine seroprevalence rates as a potential indicator for risk assessment of West Nile Virus transmission, particularly in eastern Croatia.

Background and Purpose

• The study was undertaken in connection with the West Nile Virus (WNV), a zoonotic arbovirus that has been causing outbreaks in several countries in southern and Central Europe.
• In 2012, the virus caused its first outbreak in eastern Croatia with 7 human clinical cases reported.
• The aim of this research was to aid public health officials in improving their survey methods and vector control strategies by identifying and mapping out the high-risk areas for WNV transmission.

Research Methodology

• The research was conducted in the cities of Osijek and Slavonski Brod, as well as 8 municipalities within the Vukovarsko-Srijemska County.
• Risk assessment was performed based on the seroprevalence of WNV infections in horses, to indicate the presence of the virus, and on the presence of potential WNV mosquito vectors along with their corresponding vector competences.
• Four mosquito species, namely Aedes vexans, Culex modestus, Culex pipiens, and Ochlerotatus caspius, were considered as potential WNV vectors and included in the study.
• Mosquito sampling was executed using the dry-ice baited CDC trap twice a month from May to October.

Findings

• The study found that two mosquito species, Culex pipiens and Aedes vexans, posed the main risk of WNV transmission in eastern Croatia.
• The risk from Culex pipiens arises from their high vector competence, meaning their ability to transmit the virus, while Aedes vexans pose a risk due to their very high abundances.
• Therefore, the research recommends that future mosquito surveillance and vector control management ought to focus on these two species.