ARCHIVED - First case of West Nile virus of the year confirmed in Seville

The virus, which can be caught from mosquito bites, caused 77 severe cases and seven fatalities in Andalusia in 2020. 

The Andalusian health department has reported the first case of West Nile virus so far this year in Seville.

The patient, whose age and gender have not been disclosed, also has Covid and has been admitted to intensive care at Virgen del Rocio hospital in the regional capital city and medical sources have said their condition is “worrying”.

The virus led to 77 severe cases and seven deaths in Andalusia last summer, four in Seville and three in Cádiz.

The health services informed the Andalusian Epidemiological Surveillance System when tests, which are now run in all suspicious cases of meningoencephalitis, came back positive for West Nile virus. 

Public health protocols were activated as soon as the results came back, the authorities have said, and samples have been sent to the reference laboratory in Granada and the National Microbiology Centre.

The West Nile Virus (WNV) is commonly found in Africa, Europe, the Middle East, North America and West Asia and is a member of the “Flavivirus”family, which also contains the Zika virus, dengue virus, and yellow fever virus.

West Nile virus is contracted when a mosquito bites an infected bird and then a human. It cannot be spread from one human to another. Horses can also be affected by the virus. However, the health services have said that there have been no reports of the virus in horses or birds to date, and adult mosquito levels are currently low. 

The best way to avoid catching the virus is to avoid being bitten by mosquitos by fitting nets over doors and windows, leaving lights off and trying not to spend much time outdoors between dusk and dawn.

Those living in areas where mosquitos are present are also advised to avoid strong perfumes and scents, cover up as much as possible, shake clothes out well if they have been hung outside, and use insect repellents, carefully following instructions.

In a similar manner to Covid-19, the West Nile virus can be asymptomatic.  According to WHO, 80 per cent of infected patients do not show symptoms, but those who do may experience a wide range of symptoms from a mild headache or slight nausea to encephalitis or meningitis, high fevers, seizures and even comas. Anyone who feels unwell a few days after being bitten by mosquitos in high-risk areas is advised to seek medical attention just in case.

Last year the unusually wet spring caused a proliferation in the number of common Culex mosquitos breeding in the wetlands of the Andalusian region, particularly in the area around the national park of Doñana, and on the banks of the Guadalquivir river, where mosquitoes are commonly found, co-inciding with the appearance of the Asian Bush mosquito (Aedes Japonicus), the combination of which is believed to have been the cause of an outbreak which started in Seville province and spread to Cádiz.

Town halls in the areas where the deaths occurred last year have been engaged in preventative mosquito spraying for several months already in an effort to limit the populations of mosquitos, a task made difficult by the wet spring which has provided perfect conditions for breeding.

Image: Puebla del Río in Seville town hall engaged in preventative spraying. The town is typical of those bordering wetlands and rivers which provide ideal conditions for mosquitos to breed. Ayto-Puebla del Río.