EOHA ASM 2026

Abstract

Background

OH4Surveillance (One Health for Surveillance) is a 3-year EU4Health-funded initiative aimed at strengthening zoonotic disease surveillance under a One Health approach. Since 2024, Belgium has participated in the 11-country consortium, coordinated by Denmark. Objectives: To enhance surveillance, early warning, and coordinated responses to emerging zoonotic threats across Europe.

Methods

In Belgium, the project targets three zoonotic pathogens: Highly Pathogenic Avian Influenza (HPAI), West Nile Virus (WNV), and Q fever. Existing HPAI surveillance is expanded with serosurveillance in wild birds, rodents, and foxes, combined with active and environmental virosurveillance. WNV surveillance combines active and passive monitoring of wild birds. Q fever surveillance includes air and dust sampling and rodent investigations in nondairy farms.

Results

During the first two years, efforts focused on capacity building, protocol development, and implementation of surveillance. For HPAI, one virological infection was detected in 297 healthy wild birds. Serology indicated prior exposure in 1/4 actively sampled and 11/38 passively sampled birds. All 246 passive rodent samples tested viro-negative. In foxes, 33/164 were seropositive and 1/250 viro-positive. Environmental testing was positive in 3/226 fecal and 1/17 dust samples, while feathers, air and water were negative. In year one, all wild birds tested PCR-negative for WNV; however, Usutu virus was detected in 2/452 actively sampled and 44/201 passively sampled birds. In year two, the first autochthonous WNV cases ever reported in Belgium were detected (7/644), and 7/644 birds also tested positive for Usutu virus. For Q fever, 15/138 air and dust samples from 30 locations tested positive, identifying previously undetected positive farms. Rodent testing confirmed pathogen circulation, with 73/192 spleen samples and 104/319 serological samples testing positive.

Conclusions

The project strengthened zoonotic surveillance in Belgium and improved EU preparedness, demonstrating the value of a coordinated One Health approach for early detection and risk assessment of emerging threats.