2024-07-11 10:12:33
When summer comes, some cases of West Nile virus appear again. Although 80% are asymptomatic, it can be fatal in some patients by affecting the central nervous system. Mosquito bites are behind West Nile virus disease, which is summarized in eight keys.
Information campaign against Nile virus and mosquitoes in Puebla del Río (Seville) in summer 2023. EFE/ David Arjona
This summer this infection has reappeared in Andalusia with two cases recorded in the Sevillian city of Dos Hermanas, one of them killed. It holds the keys to understanding the future of West Nile virus.
1. Most are asymptomatic cases
West Nile virus is a disease spread by mosquito bites that occurs in 80% of cases without symptoms, while another 20% of those affected develop severe viral disease, according to the World Health Organization. .
Mild in humans, West Nile fever is a combination of symptoms: fever, headache, joint pain, vomiting, rash, and swollen liver; symptoms that last between 3 and 6 days, and then disappear without major consequences.
2. Results in critical events
However, approximately one in every 150 infected people develops the disease in its most severe form, leading to encephalitis or meningitis (inflammation of the brain or surrounding tissues), which can lead to brain damage and death. .
Headache, high fever, stiff neck, numbness, coma, seizures, muscle weakness and paralysis are some of the symptoms of the serious condition.
People who are most at risk of suffering from the aggressive version of the disease are those over 50 years old and those who have suffered from severe illnesses.
3. Summer, the time of maximum occurrence
The incubation period of the virus is between 3 and 14 days; and the highest incidence is recorded in late August and early September. The risk then decreases as the weather cools and mosquitoes begin to disappear.
Belonging to the genus of flaviviruses, West Nile virus is primarily waterborne in birds, so it spreads when a mosquito – generally of the genus Culex – bites an infected bird and then transmits the water to humans.
4. We do not spread between people
Both humans and horses are terminally ill, meaning they are infected but not contagious.
In serious cases, the disease can be spread by movement and movement, but not by direct contact.
5. The best prevention: avoid mosquito bites
There is no vaccine for humans (there is one for the equine condition), so the best prevention method is to avoid mosquito bites, for which it is recommended to protect yourself, use disinfectants and empty containers with standing water to avoid for mosquitoes to correct.
6 He isolated himself for the first time in Uganda
West Nile virus is found in Africa, parts of Europe, Middle East, West Asia, America and Australia, this is another key.
It was isolated for the first time in 1937 in Uganda, specifically in a female from the West Nile region (from which it takes its name) and in 1953 it was identified in birds from the Nile River, according to OMS.
7. It also rose in the 90s due to drought in Africa
In the 1990s it reappeared as a result of drought in Africa, from where it spread to the United States in 1999, the year we saw the first cases in New York.
Since then, the virus has been limited in the United States, where cases are recorded every year.
8. The worst outbreaks, in 2002 and 2003
The worst outbreaks to date occurred in 2002, with 4,156 cases and 284 deaths, and 2003, a year in which 9,862 cases and 264 deaths were recorded, according to the Centers for Disease Control and Prevention. (CDC) from the United States.
In Europe, Greece recorded 306 cases of infection in 2018, of which 41 people died, all over the age of 63.
In the same year, Romania recorded its first three cases, and in Spain it was that the presence of the Asian “Aedes japonicus” was recognized for the first time, capable of spreading, among other diseases, the West Nile virus.
Precisely in Spain, another of the keys, the West Nile virus claimed seven deaths in 2020 (four in Seville and three in Cádiz), in the largest outbreak recorded in Andalusia to that date, in which the cases 76 reported 36 possible).
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