Four more people in the Netherlands have died after contracting West Nile virus. This brings the country’s death toll this year to nine, with 56 confirmed infections in total. The first cases after a six-year lull were reported in August.
Number of Infections on the Rise in the Netherlands
The latest fatalities were announced by the National Institute for Public Health and the Environment (RIVM). According to RIVM data, the virus has reappeared significantly this year; since 2020, the Netherlands hasn’t seen this many local human infections.
Since August, confirmed cases have increased to 56. However, RIVM reports that the virus’s spread likely peaked recently, as the number of new cases has declined in recent weeks.
Virus Transmitted Mainly by Infected Mosquitoes
West Nile virus primarily circulates among birds and mosquitoes. Humans can become infected after being bitten by a mosquito that previously fed on an infected bird.
RIVM notes that the virus is mainly spread by mosquitoes of the Culex genus, which includes the common house mosquito. Neither humans nor horses are considered sources of further transmission to others through normal contact.
Most People Show No Severe Symptoms After Infection
Infection does not automatically result in serious illness. According to RIVM, roughly 80 percent of those infected do not develop any symptoms at all.
About one in five may experience mild flu-like symptoms, such as fever, headaches, or muscle aches. In approximately one percent of cases, the virus can lead to severe neurological illness, including encephalitis or meningitis.
The Dutch health institute says older adults and individuals with weakened immune systems are at higher risk of severe outcomes.
Virus Detected in Animals in the Netherlands
West Nile virus has also been confirmed in animals in the Netherlands. In September, RIVM recorded a growing number of positive cases among horses and wild birds.
As of September 23, there were 136 reports of infected horses and 171 infected birds in the country. The virus has also been detected in groups of tested mosquitoes.
Birds are especially important for the spread of West Nile virus. Mosquitoes become infected after feeding on infected birds, and then may transmit the virus to other animals or humans.
Did High Temperatures Contribute to the Spread?
The World Health Organization notes that higher temperatures can create more favorable conditions for mosquitoes and extend the period in which they can transmit the virus.
Other European countries have reported increased West Nile virus cases this year as well. Available data point to infections in Greece and Italy, among others.
This marks a major shift for the Netherlands. As recently as August, RIVM stated that the risk of catching the virus in-country was very low. The current season, however, shows that the virus can once again spread among the local mosquito population.
Experts Continue to Monitor the Situation
Doctors, veterinarians, virologists, epidemiologists, and ecologists are jointly monitoring the presence of the virus in the Netherlands. They are tracking cases among people, horses, birds, and even mosquitoes themselves.
Although RIVM says the number of new infections is now declining, the current toll of nine deaths highlights that West Nile virus can have serious consequences in rare cases.
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This article was translated from the original Slovak version with the assistance of AI.
