Ohio is home to 200 different species of wild birds, and approximately 3 percent of households in the United States own one or more birds as pets.
Although uncommon, birds can carry diseases that can be spread to humans by touching them or their environments. The types of diseases carried by birds vary by species. Chicks, ducklings, and other baby and adult poultry often carry Salmonella bacteria, while parakeets and parrots can carry the bacteria that cause psittacosis. Bird droppings can also carry germs that can cause human illness.
What bird-related diseases are of concern in Ohio?
Cryptococcosis is caused by Cryptococcus neoformans or Cryptococcus gattii fungi.
Most people exposed to cryptococcal fungi do not become ill from it; however, people who are immunocompromised are more likely to become ill with headache, fever, cough, shortness of breath, and night sweats.
Cryptococcus neoformans is found in the droppings of wild birds, such as pigeons. Dried bird droppings can be stirred up, creating a dust that can be inhaled by humans when they work, play, or walk in areas where birds have been. Pets, such as dogs and cats, can also become ill from dust containing cryptococcal fungi, but they cannot spread it to other animals or humans.
The best way to avoid being infected with cryptococcal fungi is to avoid areas contaminated with bird droppings and to avoid exposure to birds, especially for people with immunocompromising conditions.
Eastern equine encephalitis
Eastern equine encephalitis (EEE) is caused by a virus that is transmitted through the bite of an infected mosquito; however, birds are amplifying hosts for the virus. Mosquitoes that feed on infected birds and then bite humans can pass eastern equine encephalitis virus on to humans. While there have been no reports of human cases who contracted eastern equine encephalitis in Ohio, the virus has been detected in Ohio mosquitoes, birds, and horses.
Symptoms of eastern equine encephalitis in humans include a sudden onset of headache, high fever, chills, and vomiting which can progress to disorientation, seizures, and coma. Approximately one-third of people who develop severe disease with encephalitis (an inflammation of the brain) die, and many of those who survive will have mild to severe permanent neurologic damage.
There is no vaccine or drug to prevent eastern equine encephalitis, so the best way to avoid infection is to avoid mosquito bites.
Histoplasmosis is caused by a fungus called Histoplasma capsulatum. The fungus is present in the environment and grows in soil and material contaminated with large amounts of bird or bat droppings. When disturbed, the fungi can become airborne and can be inhaled by humans and animals. Histoplasmosis cannot be transmitted by infected people or animals.
Most people infected with Histoplasma fungi do not become ill, but those who do may experience fever, chest pains, a dry cough, and joint pains. Histoplasmosis can spread from the lungs to other organs if not treated. Infants, young children, people who are immunocompromised, and older adults, particularly those with chronic lung disease, are more at risk for developing severe disease from Histoplasma.
H. capsulatum is present throughout the world, but is commonly found in the Mississippi and Ohio River Valleys.
Avoiding contact with areas containing bird and bat droppings is import to prevent histoplasmosis, particularly for people at higher risk for severe disease. Additional information is available for protecting workers at risk for histoplasmosis.
Influenza A, novel virus
Novel influenza A viruses that infect birds are also known as avian influenza viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species.
Wild aquatic birds can be infected with avian influenza A viruses without showing signs of disease. However, avian influenza A viruses are very contagious among birds, and some of these viruses can sicken and even kill certain domesticated bird species including chickens, ducks, and turkeys.
Outbreaks of avian influenza in North American poultry and wild birds have occurred in recent years, but the risk to people in the United States is considered low. Avian influenza mainly affects birds and only rarely infects humans. There are currently two avian influenza viruses with limited circulation in humans: one emerged in Southeast Asia in 2013 (H7N9), and the other first emerged in humans in 2003 (H5N1). Both are found primarily in Asia, and H7N9 has been associated with exposure at live bird markets.
People are unlikely to catch avian influenza from a wild bird. However, those who handle sick or dead birds or hunters who process bird carcasses could be at higher risk.
Psittacosis is a rare bacterial infection caused by Chlamydia psittaci. Although all birds are capable of being infected with and transmitting C. psittaci, infection to humans is most often associated with pet birds (parrots, parakeets, macaws, cockatiels) and poultry (ducks, turkeys). People become infected with psittacosis when they breathe in dried secretions from infected birds.
Birds can carry C. psittaci without showing symptoms, but they do not shed the bacteria in their secretions unless they appear sick. Symptoms in birds may be subtle and can include lethargy, decreased appetite, and ruffled feathers. Other signs include watery to thick whitish/greenish eye or nose drainage, eye redness, diarrhea, and green to yellow-green droppings. Severely affected birds may stop eating and produce sparse, dark green droppings followed by death.
Symptoms of psittacosis in humans include fever, chills, headache, muscle aches, and a dry cough; pneumonia commonly occurs. Severe complications sometimes occur requiring intensive care hospitalization, and fatal cases have been reported. Psittacosis can be treated with antibiotics.
Bird owners, pet shop employees, veterinarians, and poultry processing plant employees are at increased risk for psittacosis. Precautions should be taken when handling pet birds and cleaning their environment and include:
- Washing hands diligently.
- Wearing respiratory protection.
- Dampening bedding or litter before cleaning to prevent aerosolizing contaminated dust.
Salmonellosis is a bacterial infection caused by Salmonella. Salmonella is most commonly transmitted through contaminated food, but animals, including wild and pet birds and poultry, can also carry the bacteria and shed it in their feces, infecting humans and other animals.
The bacteria easily contaminate anything in the bird's environment as well as the bodies of birds, getting trapped in feathers. Birds that carry Salmonella bacteria often appear healthy and clean.
Humans who become sick with salmonellosis experience diarrhea, fever, and abdominal pain that usually goes away after one week; severe diarrhea and bloodstream infections can occur.
Infants and children less than 5 years of age, the elderly, and people who are immunocompromised are more likely to become ill if infected with Salmonella.
Important ways to avoid Salmonella infection from birds include:
- Thorough hand washing.
- Keeping birds and live poultry out of homes and facilities with young children.
- Preventing people at risk for severe infection from handling or touching birds.
- Keeping food and drinks away from birds and their environment.
- Carefully cleaning bird habitats.
West Nile virus
Birds are the natural source for West Nile virus. West Nile virus has been detected in more than 300 species of birds in the United States. Although most bird species survive West Nile virus infection, some species, such as crows and blue jays, can become ill and die from West Nile virus infection.
Humans become infected from mosquitoes that have fed on infected birds; humans cannot become infected from handling live or dead infected birds or through consuming infected birds or other animals.
Most people (80 percent) infected with West Nile virus do not become ill, but some people will experience a febrile illness characterized by fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. Less than 1 percent of people infected with West Nile virus will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain and surrounding tissues).
Avoiding mosquito bites is the best way to prevent West Nile virus. Although there is no evidence people can get West Nile virus directly from infected birds, avoiding sick birds and bare hand contact with dead birds are good precautions to take.