West Nile virus (WNV) is an arbovirus belonging to the genus Flavivirus (an antigenic complex of Japanese encephalitis). Discovered in 1937 in Uganda, its circulation in the living world has been documented on almost every continent in Africa, America, Asia, Australia, Europe and the Middle East.
WNV infection is transmitted by vectors – vector-transmitted infection, which most often affects wild birds. The infection between them is transmitted through different types of mosquitoes. Humans and mammals, and especially horses, are random hosts and have a limited role in the natural cycle.
People are most often infected with an infectious mosquito bite. Human-to-human disease is not transmitted unless the possibility of transfusion and organ transplantation is excluded.
The incubation period usually lasts from 3 to 14 days.
About 80% of human infections are without any symptoms. The remaining 20% of symptomatic infections are most often manifested as fever on its own, and less than 1% of WNV infections in humans develop in severe forms, with severe clinical picture and are potentially fatal (eg, inflammation of the brain, inflammation). of the cord or paralysis).
There is no specific therapy, and the treatment is mainly aimed at treating the symptoms. Appropriate intensive care provides the chance for survivors of severe forms to survive. In severe cases, the mortality rate is 3-15% and increases in the elderly.
For those who survive, recovery is long-lasting, with fatigue, muscle weakness, difficulty walking, memory loss, depression and so on.
There is no vaccine for humans (only for horses).
The best way to prevent it is to avoid mosquito bites that are transmitters of the disease.
Seasonal surveillance of this disease in Europe is carried out from June to November, that is, in the season of possible transmission, amid the mosquito’s massive presence as a vector for the disease.
In 2019, during the second week of July, the first human cases of West Nile fever in the EU were reported for the current season, from Greece and Romania. Since the start of the transfer season in 2019 and as of August 15, there have been 68 human cases reported in EU / EEA member states, including 6 deaths.
Greece 48 infected (4 deaths)
Romania 8 infected (2 deaths)
Cyprus 5 infected
Italy 3 infected
Hungary 2 infected
Bulgaria 1 infected
France 1 infected
In the neighboring EU countries (non-EU countries), only one case has been reported this year in Serbia.
In terms of animal disease, 7 outbreaks of WNF in horses have been reported in the current season in Greece (6) and Italy (1).
In the Republic of North Macedonia, in the period from 2011 – when the first cases of West Nile Fever were registered – to 2018, a total of 22 cases of the disease have been reported, 3 of them have resulted in death. In the period 2016-2018 there are no registered cases of WNV infection in humans.
During 2019, as of 21.08.2019, in our country there was one case of West-Nile virus reported in August.
Europe is prone to autochthonous transmission of arboviruses. The risk of further transmission within Europe is linked to the importation of viruses from persons infected with areas where these vectors are present (in continental Europe, primarily around the Mediterranean, on the island of Madeira).
The epidemic potential of different vectors, including mosquitoes, is conditioned by their mass – which allows human health to be compromised in a short time, but this feature also allows for the effective destruction of vectors, breaking the chain of transmission of the disease.
Such measures, unfortunately, have a temporary and incomplete effect, and therefore repeated actions are needed to destroy the vectors.
PREVENTION OF DISEASES THROUGH COMMUNITIES
Environmental measures (reducing mosquito populations and their habitat in humans)
Prevent mosquito breeding in your environment:
- Do not leave open barrels, bins, boats (boats, canoes) and old tires in yards where rainwater can be collected!
- Regularly clean gutters to allow water to leak!
- Keep your swimming pools clean, decorative pools, fountains clean!
- Do not create ponds in the yards.
Reduce the chance of being exposed to mosquito bites:
- Use scented candles, spirals, as protective repellents while staying outdoors (garden, patio).
- Use special bulbs, lanterns, mosquito repellents!
- Install safety nets on doors and windows in your home!
- Avoid going out and staying at dawn or dusk when the mosquitoes are most active!
Personal protective measures against mosquito bites
- Wear appropriate clothing, best in bright colors, which will leave less exposed parts of your body / skin (long sleeves, long pants, socks, hats …)!
- Apply lotions, stick, aerosol spray or skin and clothing creams that repel mosquitoes in the form of lotions!
- Do not use any protective equipment if you have cuts, open sores, under clothing, around the eyes and mouth on the hands! Attention especially to young children !!!
- Travelers traveling to / from countries or areas where mosquito-borne illnesses are recorded must make use of repellents during their stay, and sleeping windows and beds should be closed with safety nets impregnated with adequate insecticide !!!
- Upon returning home, these people should be aware of their possible contagion while staying in such areas, and monitor their health! If symptoms occur, seek medical attention immediately and tell your doctor about a recent outbreak in mosquito-borne diseases! Early diagnosis and timely treatment can prevent the onset of a severe form of the disease, which can result in serious health impairment and severe consequences or death.