Wednesday 17th May 2023Combating West Nile Virus (WNV)- The NEJM leads with a perspective that WNV
As the article is from authors based in the US then naturally the references refer to the increases in reported infections and deaths in humas in southern states as well as the impact on farming through bovine cases. This is another arbovirus, vectored by mosquitoes of both night and daytime flying species (Culex and Aedes). WNV is widely distributed across other continents such as Africa, Middle East, West Asia, SE Asia and Europe.
In Europe the European Center for Disease Control (ECDC) has a specialist surveillance unit for WNV, and subsequent vectors. The latest seasonal surveillance from 2021 showed 159 cases acquired within EU member states. Although this number is small and not of any epidemic size the first reported case was in 2015 and constantly reported at over 100 cases per year.
These reported cases are geographically reported include southern France, Northern Italy, Greece, and Eastern Europe. With reported outbreaks of Dengue (France 2022) and Tick-Borne Encephalitis (UK 2023) the vector patterns are extending due to a variety of reasons that include climate warming, increased traffic movement post Covid and changes in wild bird distribution patterns. When comparing this with animal and veterinary reports a clear geographical overlap in areas becomes apparent.
This raises the question currently should the EK and also EU states be concerned about WNV to the extent of the USA. Probably not as the infection rates are not comparable. Therefore, do we need to support the development of a WNV vaccine? Probably yes as climate warming continues the seasons in Europe will become warmer and move further north in latitude, indicating at some time in the future the need of a vaccine will be required. When will this be needed is reflected in the recording of data, the ECDC only started with data collection in 2015; whilst the Americans first recorded this is 1999. However, the impact and cost is shown with the 3000+ hospitalisations in California between 2004 and 2017, the average hospital cost was $59.9 million per year.
The argument then rises which new arbovirus takes precedent for development funding. Currently we have on trial malaria vaccines in Africa and new licences for dengue and chikungunya vaccines by US, UK, and EU authorities, does WNV need to be added to the equation?