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WBVR study shows European Bat Lyssavirus type 1 in Dutch cat
An infection with European Bat Lyssavirus type 1 (EBLV-1, lyssavirus Hamburg) has been demonstrated in a Dutch cat. The animal suddenly changed its character and became aggressive. Research by Wageningen Bioveterinary Research showed that the animal was infected with EBLV-1. It is the first time this virus has been found in a cat in the Netherlands. Only three previous cases of EBLV-1 in cats are known in Europe, all detected in France in 2003, 2007 and 2020.
On Friday 25 October, analysis by Wageningen Bioveterinary Research (WBVR, part of Wageningen University & Research) showed that a cat (2.5 years old) tested positive for the presence of European Bat Lyssavirus type 1 (EBLV-1). EBLV-1 is a lyssa virus related to classical rabies virus, which is occasionally detected in the Netherlands in one specific species of bat (Eptesicus serotinus, serotine bat).
Investigation
From Tuesday 22 October, the cat showed abnormal behavior. A dead bat was found in the house and discarded without additional investigation three-and-a-half weeks before the cat showed symptoms. The cat had not been vaccinated against rabies. The veterinarian initially prescribed sedatives and painkillers. Due to its aggressive behavior, the cat was isolated. As rabies could not be ruled out clinically, the Netherlands Food and Consumer Product Safety Authority (NVWA) was contacted a day after the vet's visit. On Friday, the cat was euthanised and collected on behalf of the NVWA for examination at WBVR, the National Reference Laboratory for Veterinary Rabies. Brain material tested positive in the immunofluorescence test (IFT) and a PCR test specific for EBLV-1. Later, additional testing also showed EBLV-1 virus in a mouth swab and the salivary gland of the cat.
Environment
In the vicinity of the cat, risk contacts in humans and animals were inventoried by the public health service (GGD) and NVWA. This involved nine people. These persons received Post Exposure Prophylaxis.
Two dogs which resided in the same house as the cat were quarantined for six months. These dogs will be monitored during this period for signs of rabies. Two horses that stayed in a stable at the same address are required to remain on site for six months. The animals are cared for by vaccinated people and are not allowed to have contact with other kept animals.
Nearby pet owners are informed and advised to keep a close eye on the animals and consult the vet especially in case of incipient behavioural changes.
Bats
This is the first time EBLV-1 has been detected in a cat in the Netherlands. It has been observed three times before in Europe, all three times involving France. So far, there are no known cases of people infected by pets after being infected by bats. However, six human cases have been reported in Europe in recent decades. These people died from infection with EBLV after likely intensive contact with bats.
In the Netherlands, EBLV-1 is found with some regularity in bats scattered across the country. The prevalence of EBLV-1 among the Dutch surveyed population of bats is 23.6 per cent (WBVR data from 1987-2017). The surveyed population concerns a selection of sick or dead animals. The actual prevalence of EBLV-1 in the late kite bat population is most likely much lower. The risk of infecting a pet or human with EBLV-1 is very small.
Advice
Rabies is a notifiable animal disease. If you see an animal with symptoms that could indicate rabies, contact the NVWA immediately.
If a dog or cat has been in direct contact with a bat, the advice is to vaccinate the animal. Classical rabies virus and EBLV-1 belong to the same phylogroup (I) of Lyssaviruses. Cross-immunity is known to occur when vaccinated with a classical rabies vaccine.
If a person is bitten, licked or scratched by a bat or clinically suspect animal, the Public Health Service should be contacted immediately.