Researchers have discovered that avian flu can be detected in infected birds based on smell.
Following on from recent findings that diseases could modify animal odours in subtle ways, the team of scientists then examined how bird flu changed faecal odours in mallard ducks using behavioural and chemical methods.
“The fact that a distinctive faecal odour is emitted from infected ducks suggests that avian influenza infection in mallards may be ‘advertised’ to other members of the population,” said Dr Bruce Kimball, a US Department of Agriculture (USDA) research chemist working at the US Monell Chemical Senses Centre.
“Whether this chemical communication benefits non-infected birds by warning them to stay away from sick ducks or if it benefits the pathogen by increasing the attractiveness of the infected individual to other birds is unknown.”
Laboratory mice were trained to discriminate between faeces from infected and non-infected ducks, indicating a change in smell. Chemical analysis then identified the chemical compounds associated with the odour changes as acetoin and 1-octen-3-ol.
These compounds have been identified as biomarkers for diagnosing gastrointestinal diseases in humans. Dr Kimball and his team believe that metabolites resulting from bird flu infection interact with bacteria in the gastrointestinal system of ducks to produce “odour signatures” indicating the presence of the avian flu virus.
“Infection in ducks and waterfowl can only be diagnosed by directly detecting the virus, requiring capture of birds and collection of swab samples,” said Monell behavioural biologist Dr Gary Beauchamp, another author of the research paper.
“Our results suggest that rapid and simple detection of influenzas in waterfowl populations may be possible through exploiting this odour change phenomenon.”
The research was carried out by the USDA and Monell Centre, and was published in the journal PLOS ONE.