 "A vector control team vehicle displays a sign warning of West Nile Virus before the early morning spraying of a neighborhood due to increasing numbers of mosquitoes having tested positive for West Nile virus in San Diego, California, U.S. May 18, 2016. (Representative Photo, Credit: Reuters)")
For the first time, the West Nile virus has been detected in the United Kingdom. Climate change is being considered as the culprit.
In a routine mosquito surveillance programme, the Animal and Plant Health Agency (APHA) found the West Nile virus in a batch of aedes vexans mosquitoes collected from marshlands on Idle river in Nottinghamshire. No case has been detected in the UK so far and experts say that the risk of an outbreak is very low.
While the West Nile virus has been endemic to Africa and West Asia for decades, the climate change-induced warming up of Europe has brought the virus to the continent as well. The UK is the latest European country to report the virus.
The West Nile virus is primarily found in birds. Mosquitoes that bite birds get the virus and occasionally transfer it to humans with their bites. As much as 80 per cent of human infections cause no symptoms and severe infections are rare. In severe cases, encephalitis can occur and can lead to brain damage and even death. While the virus is not contagious among humans, it can spread from an infected person via blood transfusion, organ transplants, pregnancy, or breastfeeding.
Climate change brings West Nile virus to UK
The confirmation of the West Nile virus in the UK follows warnings that carriers of vector-borne diseases, such as dengue and yellow fever, are moving northwards from their traditional areas due to climate change.
Dr Arran Folly, an arbovirologist at the APHA and head of the surveillance programme that found the virus in the UK told Guardian that the discovery is “part of a wider changing landscape where, in the wake of climate change, mosquito-borne diseases are expanding to new areas”.
Impact Shorts
More ShortsThe warming up of a place makes it likelier for the West Nile virus to grow. At 15*C, it takes many months for the virus to reach infectious level, which is much more than a mosquito’s average lifespan. At 30*C, however, the same process can happen in two-three weeks, which is within a mosquito’s average lifespan.
In an article for The Conversation, Dr Paul Hunter noted that while the exact route of West Nile virus to the UK is not clear, it is believed that the virus may have arrived via migratory birds infected elsewhere.
So far, conditions ripe for a West Nile virus outbreak in the UK have not been reached but that could change if temperatures keep rising.
“For a local outbreak to occur, there would need to be a critical mass of infected birds and mosquitoes, with enough warm weather to sustain multiple cycles of transmission. So far, that hasn’t happened in the UK. But climate change could alter the equation. With rising global temperatures and longer, hotter summers, the conditions that allow viruses such as West Nile to spread may become more common in the UK,” noted Hunter, a specialist in medical microbiology and virology.
As temperatures are rising across the world, diseases are being reported in places with no history of that disease. The West Nile virus in the UK is just one such example.