By Helen Briggs
BBC News science reporter
The spread of bird flu poses serious risks to biodiversity, say scientists who have detailed an outbreak of the virus in Owston's civets.
The Owston's civet is prized by bushmeat restaurants
The mammal is a small, endangered carnivore that lives in the forests of Vietnam, Laos and southern China.
Three animals died at a conservation centre in northern Vietnam last summer. It is not known how they contracted the virus, as they do not eat poultry.
The scientists report the cases in a journal of the UK's Royal Society.
The team - from the UK, Vietnam and China - call for better monitoring of the H5N1 virus in wild animals.
"H5N1 could pose a risk to a variety of wild birds and mammals," lead author Diana Bell, of the Centre for Ecology, Evolution and Conservation at the University of East Anglia, Norwich, UK, told the BBC News website.
"We need to be screening wild birds and mammals in those countries where the virus has been present for some time.
"We mustn't be totally anthropocentric in our focus on H5N1. It doesn't only kill humans and poultry; it also kills a wide variety of wild birds and carnivorous mammals."
H5N1 has killed birds in at least 11 of the 27 avian orders, including gulls, storks, pigeons, eagles, cranes, pelicans, parrots and owls.
It has also infected tigers, leopards and domestic cats fed contaminated meat, and ferrets and mice in laboratory studies.
It's not known how the civets were infected
Dr Bell's team warns that the disease poses a threat to bird and mammal biodiversity in many Asian countries that are "global hotspots" for conservation.
"This report illustrates the ease with which this influenza A H5N1 virus can cross species barriers and reinforces the pandemic concern engendered by its progressively increasing geographic range," they write in the Proceedings of the Royal Society B: Biological Sciences.
The civets that died were part of a conservation scheme in Cuc Phuong National Park that coordinates an international breeding programme for the species.
Owston's civet (Chrotogale owstoni) is listed as globally threatened and is losing numbers to hunting and trapping.
Its meat is prized by bushmeat restaurants, its body parts by traditional medicine makers and its skin by taxidermists in Vietnam and China.