Bird Diseases

Avian Influenza

Avian influenza is a disease caused by avian influenza Type A viruses which occur naturally in wild birds. There are many different strains of avian influenza which are categorized into two groups based on how they affect poultry. These categories are low pathogenic avian influenza (LPAI) and highly pathogenic avian influenza (HPAI). These viruses get transmitted through direct contact with infected individuals or surfaces contaminated with infected fecal matter, nasal secretions or saliva.

Read the most up-to-date information on HPAI.

Many bird species have been reported with avian influenza. Avian influenza viruses are primarily found in aquatic birds and poultry. Waterfowl and shorebirds are considered reservoirs for avian influenza meaning they can carry the virus with no health implications. Certain strains of the virus have been reported in mammals, including people.

Wild birds are primarily infected with LPAI and do not show any signs. Poultry with LPAI may go undetected but can have decreases in egg production and egg quality. 

HPAI viruses are mainly found in poultry. Signs of HPAI in poultry include: discoloration on the unfeather parts of the body (legs, wattles and combs), lethargy, nasal discharge, swelling of the head, diarrhea, and coughing and sneezing.  

LPAI viruses in wild birds generally do not cause any health problems. HPAI viruses can cause mortality. Poultry are very vulnerable HPAI viruses which spread rapidly when birds are in confined spaces and can cause up to 100% mortality. 

Three subtypes of avian influenza (H5, H7 and H9) are known to infect people with most infection coming from the HPAI Asian lineage H7H9 and H5N1 viruses. The CDC considers avian influenza to be low risk to public health in the United States. As a general precaution, people should avoid direct contact with birds that are dead or appear sick and any surfaces that are contaminated with feces. While rare, pets can be affected by certain strains of avian influenza. 

Avian Pox

Avian pox is a disease caused by various strains of the poxvirus. The disease is primarily transmitted by biting insects but can also be spread by consuming contaminated feed or water or by direct contact with other infected birds. Avian pox presents itself in two different ways. The most common is the dry form, which causes lesions to develop on the unfeathered areas of the body such as the feet, legs, eyelids, and beak. The wet form is more severe and causes mucus build up in the upper respiratory tract.

To keep from facilitating the spread of the disease, it is important to temporarily take down feeding stations if sick birds are present. It is good practice to regularly clean bird feeders with a 10% bleach solution. 

Many bird species can be affected by avian pox including eagles, songbirds, turkeys, and owls. Different strains of the poxvirus will target different species. 

The dry form of avian pox causes wart-like growths to develop on the unfeathered parts of the body.  This is very similar to squirrel fibromas and cutaneous fibromas on deer. The wet form will cause the bird to have labored breathing and difficulty eating. 

Mild cases of the dry form are often not lethal and can clear up on their own. In severe cases, the growths will impede the bird’s ability to see and will lead to death due to difficulty finding food and avoiding predators. The wet form is often lethal. 

Domestic bird species can be affected by avian pox. High densities of birds in small areas such as apiaries have greater transmission rates. There is no evidence that people and other pets can get avian pox. 

Conjunctivitis

Conjunctivitis in birds is caused by the bacterium Mycoplasma gallisepticum. Originally only found in domestic poultry and turkeys, the first reported case in a wild species was a house finch in 1994 and has since been reported in other songbird species. Conjunctivitis causes eyes to become swollen, watery, or crusty looking. In severe cases the bird can become blind due to the eyes swelling shut. Conjunctivitis is thought to be spread through direct contact with an infected individual or contaminated surfaces. Bird feeders may facilitate the spread of conjunctivitis as they attract large numbers of birds into close contact. To help keep from spreading the disease, it is important to regularly clean bird feeders with a 10% bleach solution.

Avian conjunctivitis mostly affects house finches, but other songbird species can contract it such as purple finches, American goldfinches, evening grosbeaks, and tufted titmice.

The infection causes a bird's eyes to become swollen, red, and watery or crusty looking. Conjunctivitis can lead to respiratory infection, so nasal discharge (liquid coming out of the mouth or nostrils) may also be noticeable. Birds with this infection will often become lethargic and have poor body condition, and can die suddenly.

Some birds can overcome a conjunctivitis infection, but many die from starvation or predation since it directly harms their ability to see, fly, and feed normally.

Domestic bird species (including domestic chickens, domestic turkey, and pen-raised game birds) may be susceptible to conjunctivitis. People and other pets cannot contract conjunctivitis from birds.

Conjunctivitis in birds is mostly caused by bacteria that spread when many birds congregate over time at a single location, especially at bird feeders. You can help protect birds from spreading contagious diseases by feeding birds naturally rather than using artificial feeders. Planting native trees, shrubs, and flowers in your yard is an excellent way to support and attract birds without spreading disease the way feeders can. Learn about native plants that attract birds safely.

Salmonella

Salmonella is a disease in birds caused by bacteria of the genus Salmonella. Infections can cause swelling of the lungs, spleen and liver as well as lesions on the esophagus.  The disease is spread by consuming contaminated fecal matter and is often associated with feeding stations. Birdfeeders facilitate the spread of the disease by attracting high densities of birds into close contact. Salmonellosis is often seen in the winter months when birds rely more heavily on feeders. It is important to regularly clean bird feeders in a 10% bleach solution and to temporality remove them if dead or sick birds are found in the area.

Many different animals can get sick from salmonella bacteria. Some species can carry and spread the bacteria without getting sick themselves, such as domestic chickens and many reptiles. Other species, such as humans, dogs, cats, and songbirds, can become sick if they get salmonella bacteria into their bodies (usually by ingestion). Salmonella poisoning in songbirds is usually fatal.

Birds with salmonellosis, or salmonella poisoning can appear to be lethargic or stressed. They will often pant with their mouth gaped open or have visible tremors or diarrhea. Birds with this condition can die suddenly and without warning.

While some birds do overcome the disease, it is usually lethal.