AUGUSTA — The hooded mergansers, a type of duck, rescued at the end of January from the mill stream in downtown Winthrop tested positive for avian influenza, the first such case in Kennebec County.
Separately, the Division of Animal and Plant Health in the state Department of Agriculture, Conservation and Forestry confirmed the highly contagious disease was found in Kennebec County on Monday in a backyard flock of birds who are not being kept for meat or eggs.
Mark Latti, director of communications for the state Department of Inland Fisheries & Wildlife, said Friday the National Veterinary Services Laboratories has determined that the birds, both those found dead and the sick ones that later died were infected with highly pathogenic avian influenza.
“We haven’t had a lot outside of the coastal area,” Latti said.
While the Kennebec River in central Maine is not coastal, Latti said, it is home to a population of bald eagles that feed on coastal waterfowl that make use of the open stretches of water on the river during winter.
State agriculture officials have been tracking the status of the disease in Maine and have been reporting confirmed cases since February 2022.
Migrating wild birds carry the disease, agriculture officials say, and expose other birds when they mix with domestic birds in backyard or commercial flocks. Avian influenza is spread directly through contact wild bird droppings and indirectly through contact via feed and water sources as well as bedding that may have been exposed to droppings.
State wildlife officials said the disease can be carried from one location to another on clothing or boots that have come in contact with bird droppings.
A second backyard flock in Hancock County was also identified with the disease on Monday. In both cases, state animal health officials placed the properties under quarantine, and euthanized the flocks.
For a year, state officials have been urging owners of backyard flocks and commercial poultry operations to keep birds indoors to prevent the disease from spreading.
Signs of infection include sudden death without clinical signs; lack of energy and appetite; decreased egg production or soft-shelled or misshapen eggs; swelling of the head, comb, eyelid, wattles and hocks; and purple discoloration of wattles, comb and legs.
Sick birds or unusual bird deaths should be reported to the state veterinarian in the Division of Animal and Plant Health in the Department of Agriculture, Conservation and Forestry.
State wildlife officials recommend avoiding sick or dead wild birds, but if found, they should be reported to the regional wildlife biologist. Officials note they are concerned with reports of three or more dead birds in a local area.
Because the disease can be carried by clothing or gear, authorities recommend they should be cleaned thoroughly or sanitized.
Latti said wildlife officials found an additional dead duck in Winthrop, where the other dead and sick birds were found.
All of the ducks that rescued from the Winthrop mill stream died.
To date, no cases of this particular strain of avian influenza virus have been detected in humans in the United States, and it is believed to present a low risk to the public.
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