West Nile Virus Circulation in Mosquitoes in Greece (2010-2013)

Area of Science:

• Medical Entomology
• Infectious Disease Epidemiology
• Public Health Surveillance

Background:

• A significant West Nile virus (WNV) epidemic in Northern Greece in 2010 necessitated enhanced WNV surveillance.
• An active mosquito surveillance program was established for three years (2011-2013) to monitor WNV activity.

Purpose of the Study:

• To evaluate the effectiveness of a mosquito-based surveillance system for early detection of West Nile virus (WNV) transmission.
• To inform public health authorities about WNV presence in mosquito populations for timely intervention.

Main Methods:

• Mosquito collections were conducted using primarily CO2 mosquito traps across Greece.
• Collected mosquito samples were pooled by date, location, and species for WNV testing.
• WNV presence was quantified using Minimum Infection Rate (MIR) and Minimum Live Equivalent (MLE) values.

Main Results:

• West Nile virus (WNV) positive mosquito pools were identified in various regions of Greece throughout the study period.
• In 2013, the Attica region, an outbreak epicenter, showed significantly elevated WNV levels in Culex pipiens (MIR: 10.75, MLE: 15.76).
• Positive mosquito pools were frequently detected before the onset of human WNV cases.

Conclusions:

• The implemented mosquito surveillance system proved valuable for tracking WNV transmission dynamics.
• Early detection of WNV in mosquito vectors facilitated the implementation of targeted public health interventions.
• This approach highlights the critical role of entomological surveillance in WNV prevention and control strategies.