An infection with West Nile virus (WNV) has been officially confirmed in a horse in the Netherlands. Wageningen Bioveterinary Research (part of Wageningen University & Research) has detected antibodies against WNV in a second horse in the province of Zuid-Holland. The sample was collected by the Netherlands Food and Consumer Product Safety Authority (NVWA). The Ministry of Agriculture, Fisheries, Food Security and Nature has informed the World Organisation for Animal Health (WOAH) of this finding.
Last week, antibodies against WNV were already found in another horse in the same province. That finding was based on a non-official sample, as the NVWA was not able to collect an official sample at the time. This horse showed neurological symptoms but is now recovering.
The second horse that has now tested positive is located elsewhere. Because this is officially the first confirmed case of WNV in horses in the Netherlands, the sample from this animal has been sent to the European Reference Laboratory for confirmatory testing. They have confirmed the WNV infection.
Symptoms in horses
In most horses, infection with WNV causes no visible signs of illness. When symptoms do occur, they are often mild, such as fever, lethargy or loss of appetite. In some cases, neurological signs may develop, such as coordination problems. In rare instances, these symptoms can be so severe that the animal has to be euthanised.
West Nile virus is a notifiable disease (category E). Reporting has no direct consequences for the horse or its owner. Horses can be protected through annual vaccination.
Virus transmission
West Nile virus spreads via birds, in which the virus can multiply. Mosquitoes can then transmit the virus from birds to horses and humans. Horses and humans are so-called 'dead-end hosts': they cannot transmit the virus further. Therefore, horses and humans cannot infect each other with WNV.
