CDC Says Avian Flu May Infect the Gut, Though Risk is Low

By Lisa Schnirring

Given ongoing detections of H5N1 avian flu in poultry, dairy cows, and wildlife, the US Centers for Disease Control and Prevention (CDC) yesterday addressed the potential for the threat of contracting the virus by eating or drinking potentially contaminated food or beverages, such as raw milk, saying the risk is low but possible.

Over the past 2 years, a few H5N1 human illnesses have been reported with unexplained sources, and some cat illnesses and deaths have been linked to consuming contaminated raw food and raw milk. The assessment comes as H5N1 continues to circulate in birds and mammals in the United States.

CDC recommends avoiding raw milk, related products

The CDC said no human H5N1 infections have been linked to consuming contaminated raw (unpasteurized) cow's milk or products made with raw cow's milk. 

Based on its review of the medical literature, the agency said seasonal and novel influenza A viruses have the potential to cause infection through the gastrointestinal (GI) tract. CDC scientists examined scientific reports of how often people infected with seasonal or novel influenza A infections experience GI symptoms and lab studies of live animals, such as dogs and cats, that became infected with H5N1 after eating or drinking contaminated products.

The CDC experts said overall the studies show that influenza A may infect mammals through nonrespiratory routes. Though consuming H5N1-contaminated food or milk can lead to infections in animals, there are limitations to translating the findings to people.