Scientists are learning that diseases like avian influenza, also known as bird flu, can actually change the smell of an animal’s feces. And, they are using this knowledge to help them sniff out when birds, such as mallard ducks, are infected.
Of course, the research team from the Monell Chemical Senses Center and the U.S. Department of Agriculture (USDA) didn’t sit around in the lab sniffing duck poop themselves. They used specially-trained mice to do the job.
The mice were trained to differentiate between flu-infected and non-infected duck feces by having them run a maze. Each time they found the infected feces, they were rewarded with a drink of water. Eventually they learned to find the correct feces about 90 percent of the time.
The reason for learning whether animals could be trained to detect the smell is simple. Infected ducks and other waterfowl generally do not exhibit any obvious symptoms, making it necessary to identify infected birds by either capturing them and collecting swab samples or by locating dead birds to test. If a larger animal like a dog could be trained to detect the smell in bird droppings, this would make the process much faster and simpler.
The team didn’t stop here though. They also used feces from the infected ducks to do chemical analyses, finding that two chemicals – acetoin and 1-octen-3-ol – were responsible for the differences in odor.
Dr. Bruce Kimball, a research chemist with the USDA National Wildlife Research Center (NWRC), says that these unique odor-producing chemicals may be formed when products of the virus’ metabolism interact with bacteria found in the gastrointestinal tract of the ducks.
He also believes that their unique odor might serve the purpose of signaling other animals that they should avoid the sick birds. Or, alternatively, it might actually attract other birds, helping the virus to spread and survive.
And, these same chemical compounds found in the duck feces might also be used as markers for the disease in humans, Kimball says.
Avian flu is actually rare in humans; but, when it does occur, it may cause symptoms similar to the flu, such as fever, muscle aches, cough, sore throat, nausea, vomiting or diarrhea. Severe respiratory distress and pneumonia are also possible symptoms. Some of those with more severe cases of the illness have even died. However, in a few cases it has caused only mild eye infections, but no other symptoms. These signs and symptoms usually begin within about two to five days following exposure to the virus.
An antiviral medication called oseltamivir is recommended by the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) for both the treatment and prevention of avian flu.
The CDC maintains the most up-to-date information about avian flu, which can be found at the link below.
The full results of this study were released online on October 16, 2013 in the journal PLOS ONE.
Written by: Nancy Schimelpfening