Enhanced West Nile virus surveillance in Luxembourg

Increased surveillance efforts in the country as West Nile virus is getting closer to the borders

• Clinical and Applied Virology
• Department of Infection and Immunity
• OH4Surveillance

In recent years, West Nile virus infections have become a growing public health concern in Europe. The virus is primarily transmitted between birds by mosquito species indigenous in Europe (mainly Culex sp.). So-called bridge mosquito species feeding on both birds and mammals may lead to transmission to a wider range of species, such as horses or humans. Infections may be asymptomatic, but may also lead to severe outcomes such as encephalitis or meningitis in rare cases. While vaccination helps protecting horses against clinical signs, no vaccines are licensed for humans; hence, surveillance in its reservoirs is a valuable early warning signal to initiate further preventive measures.

The LIH, in partnership with the Luxembourg Veterinary and Food Administration (ALVA), has initiated West Nile virus surveillance in wild birds in 2018, coinciding with its first detection in Germany. Surveillance activities are currently being enhanced in the framework of the EU co-funded OneHealth4Surveillance project (2024-2026), in particular through a fruitful collaboration with the Centre de Soins pour la Faune Sauvage in Dudelange. In 2024, 280 samples from birds were tested, a seven times increase compared to the year before.

While West Nile virus has not yet been detected in Luxembourg, Usutu virus – another Flavivirus sharing epidemiological features with West Nile virus such as vectors, hosts and modes of transmission – is already present in the country (link). The gradual geographic expansion of Usutu virus is considered by some experts as a showcase for the possible future distribution map of West Nile virus in Europe, which is influenced by bird migration patterns and climate change – in particular warmer temperatures and changes in rainfall patterns affecting mosquito life cycles. This, together with further northwards and westwards expansion of West Nile virus in Germany in 2024 (link), highlights the importance of enhanced surveillance activities in Luxembourg in the interest of human and animal health.

Disclaimer

This activity is supported by co-funding from the European Union’s EU4Health programme under Grant Agreement Nr 101132473 OH4Surveillance.

Views and opinions expressed do not necessarily reflect those of the European Union or HaDEA. Neither the European Union nor the granting authority can be held responsible for them.