Bat rabies - Video

Behavioural observations in some rabid bats

by Zomer Bruijn, Amersfoort, Netherlands

Within a period of two months from February 25^th, 2003, I received three diseased male Serotine bats (Eptesicus serotinus) respectively found in the town of Putten, the city of Amersfoort and the village of Ochten (The Netherlands). The bats died after some days in captivity and were submitted to the Central Institute for Animal Disease Controle (CIDC-Lelystad) where rabies was diagnosed in all three specimens.

During captivity the behaviour of the bats was observed, and in one case also with a video camera. The bats were emaciated but refused any offered mealworm. Just one animal was drinking water occasionally, however with difficulty. All three bats appeared to be hypersensitive to sounds. Almost no reaction followed low frequency sounds, but higher frequency sounds immediately caused fierce reactions of prolonged loud screaming and uncontrolled wing beats (Figure). The intensity of wing beats, apparently unsuccessful attempts at take-off, was connected with the remaining vitality of the animals. One of the bats initially showed strong uncontrolled wing beats  and regularly ended up on its back.

After one week this animal was considerably enfeebled and only showed some weak wing beats and short screaming after high frequency sounds.

The bats showed a strong biting behaviour. A mealworm offered with forceps was repeatedly bitten, after which it was refused. The forceps were also often bitten viciously. One of the bats seriously attacked the forceps when they were moved along the snout. Sometimes the animal fastened its teeth to the forceps with such fierceness that the bat could be lifted up for about 20 seconds. When quiet, the bat was often seen biting on the piece of cloth on which it was lying, sometimes for several minutes. Sometimes it kept the cloth in it mouth while sleeping. Between the times with abnormal behaviour the bats also showed normal behaviour, such as grooming their wings and fur.

Summarizing, each of the bats demonstrated to a lesser or greater degree the following signs:

• inability to fly
• loss of weight
• hypersensitivity for high frequency sounds
• loud (prolonged) screaming and uncontrolled wing beats after high frequency sounds
• strong tendency to bite and aggressive reactions.

Rabid bats in the final stage of the disease may not show these symptoms.

Notes of the editor

The video sequence mentioned in this article has kindly been made available to the Rabies Bulletin Europe by Zomer Bruijn from Amersfoort, The Netherlands. It is available for viewing on the website of the Rabies Bulletin (www.who-rabies-bulletin.org).

This article was translated and edited by Peter Lina, Netherlands and Tony Hutson, UK from the original paper: Bruijn, Z. (2003). Het gedrag van hondsdolle vleermuizen. Zoogdier. 14(3), 27-28.