A state veterinarian says a duck shot by a hunter in Johnston last month has tested positive for avian flu.

The state Department of Environmental Management says the H5 strain of the avian influenza virus detected in the mallard cannot be transmitted to humans, but it can infect other birds.

Officials are asking hunters and poultry farmers to keep an eye out for birds that appear ill. Poultry farmers may notice some of their fowl with respiratory illnesses or a drop in egg production

Veterinarian Scott Marshall tells The Providence Journal the H5 strain appears to be nonfatal, but there is concern it could mutate into fatal form for birds.