Bird Flu Symptoms in Chickens, How to Protect Your Backyard Flock Explained

Avian flu has now been found in backyard or commercial birds in seven states, following the detection of bird flu in Kalamazoo County, Michigan.

In a statement on Thursday, the USDA said that samples from a backyard flock in the state were tested at the Michigan State University Veterinary Diagnostic Laboratory, part of the National Animal Health Laboratory Network, and the presence of avian influenza was confirmed by the Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories (NVSL) in Ames, Iowa.

The Kalamazoo County case brings the total number of states in which the virus has been found in backyard birds to four—Michigan, Maine, Virginia, and New York. Avian flu has also been detected in commercial flocks in Kentucky, Delaware and Indiana

In response to the outbreak, the USDA is offering advice to keepers of backyard birds. On Its website, it advises that biosecurity is the key to keeping poultry and backyard birds healthy.

Tips offered by USDA for bird keepers include restricting visitors to a minimum and keeping track of people who visit your property. Hygiene measures like the washing of hands can stop spread to humans and between birds.

Tools and equipment should be disinfected after coming in contact with birds or with bird feces. Items like cardboard egg trays that can't be cleaned shouldn't be reused.

In addition to protecting their flocks, backyard bird keepers need to protect themselves while handling their flocks.

The CDC adds that the best way to avoid avian flu is to avoid contact with affected poultry and especially avoid unprotected direct physical contact with sick birds, poultry carcasses, and poultry feces or litter.

For handlers who have to come in contact with birds, it advises that personal protective equipment is worn. The CDC says this should be removed carefully in sequence and thoroughly cleaned.

It adds that people who come into contact with infected birds should wear properly fitted N95 or higher respirators.

One of the most important aspects of biosecurity recommended by the USDA is the monitoring of birds for signs of sickness. These include; open mouth breathing, swelling of combs and wattles, swelling of legs, swelling around the eyelids, and purple coloration in any of these regions.

The USDA says any of these signs should be reported to USDA APHIS at 1–866–536–7593 or to a local or state veterinarian. But what are the signs of avian infection in humans?

What are the Symptoms of Bird Flu in Humans?

While cases of avian flu in humans are rare, and the CDC says that there is little risk to humans from this latest outbreak, which began in January, it is people who come into contact with birds who are at the greatest risk.

Assistant Professor of Molecular Biology at Princeton, A.J.W. te Velthuis told Newsweek: "Avian flu can 'jump' over to humans when we inhale dust containing bird feces or come into close contact with birds that carry the virus. This typically happens on poultry farms or poultry markets.

"In humans, the virus uses the same receptor that it uses to bind to bird cells to enter our cells. In birds this receptor is present on cells in the gut—in us it is present on cells in the lower respiratory tract."

"Moreover, since we don't have any good antivirals against flu and no pre-existing immunity against avian flu, it would have the ability to cause a pandemic."

The CDC says that symptoms of bird flu in humans are similar to forms of influenza that more commonly affect us. Avian flu virus infections in humans have ranged from mild to severe, it adds.

Reported symptoms have included conjunctivitis, fever, coughs, sore throats, and muscle aches. The CDC says that it has sometimes been accompanied by nausea, abdominal pain, diarrhea, and vomiting.

More severe symptoms are possible, however. Te Velthuis says: "Avian flu can, when it mutates and gains the ability to spread from human to human, cause severe respiratory disease with a high mortality rate."

The CDC adds that serious symptoms can also include neurologic changes including altered mental status and seizures, and can affect other organs.

The transmission of bird flu from person to person, even when those people live in the same home, is rare, and when it does occur, the CDC describes it as "limited, inefficient and not sustained."

Te Velthuis explains why this is the case. He told Newsweek: "Avian flu does not efficiently transmit from human to human because it needs to either exchange genetic information with a flu strain that can transmit from human to human, or acquire 4 to 5 amino acid changes in the viral hemagglutinin protein."

Professor Munir Iqbal, head of the avian influenza virus group at the U.K.'s Pirbright Institute, previously told Newsweek that another reason avian flu struggles to spread through human populations is due to our behavior compared to that of birds.

He said: "In addition, the behavior of humans and birds means the transmission routes are different.

"Water carrying fecal matter plays a large role in the transmission of avian influenza between birds, whilst between humans, transmission via droplets in the air is the common transmission mechanism."

Backyard Chickens
A stock image of some chickens in a backyard coup. Bird flu has been detected in backyard birds in four states with the USDA offering advice to bird keepers. Ksenia Shestakova/GETTY