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Rabies antibodies found in Swedish bats

2016-12-19

A new study has found rabies antibodies in the blood of bats in southern Sweden belonging to a certain species. The study is published by researchers at the Swedish Public Health Agency, the National Veterinary Institute, the Swedish University of Agricultural Sciences and the Zoonosis Centre at Uppsala University.

The study demonstrates the existence of antibodies against rabies of the type European Bat Lyssa Virus (EBLV) in the blood of bats sampled in southern and central Sweden over a six-year period. Using genetic engineering, the animals’ saliva was checked for genetic material from rabies viruses.

The findings are not a big surprise given that the same type of rabies has been found in bats in several neighbouring countries. Even if the risk of humans becoming infected is very small, it cannot be entirely ruled out.

None of the 452 examined bats could be shown to have rabies virus RNA in their saliva. However, 14 of the bats had antibodies in their blood specifically targeting rabies virus, which shows that they were or recently had been infected with rabies.

All bats with rabies-specific antibodies belonged to the species Daubenton’s bat (Myotis daubentonii) and had been caught in the Skåne and Småland regions of Sweden. However, none of the 246 bats caught in the Uppland region showed any signs of rabies infection. In other species no infections were found at all.

The rabies virus is one of the world’s most feared viruses. For people who have started developing symptoms after being infected, the infection is always fatal. If the infected person is treated with a combination of vaccine and antibodies (before developing any symptoms) the infection is nearly always halted and does not result in any permanent harm.

Today we know that rabies virus exists in bats in many European countries, including Denmark, Norway, Finland and now also Sweden. In 1985 a bat researcher died from rabies, likely infected with EBLV-2 from a bite by a bat in Finland, and in 2003 a bat researcher in England died from a bite by the same species of bat now found to be infected in Sweden.

The study is published in the journal Infection Ecology & Epidemiology.

See also: The Public Health Agency of Sweden’s article about the study (in Swedish).