Birds can carry a variety of infectious diseases that can be transmitted to humans. Some of the most common infections that humans can get from birds include psittacosis, avian influenza, histoplasmosis, and cryptococcosis. Understanding the potential risks and taking proper precautions can help prevent transmission of bird-related infections to humans.
Psittacosis
Psittacosis, also known as parrot fever or ornithosis, is a bacterial infection caused by Chlamydia psittaci. Humans can contract psittacosis through inhalation of aerosols from infected bird droppings, feathers, or respiratory secretions. Birds that most commonly transmit psittacosis include parrots, parakeets, macaws, cockatiels and turkeys.
The symptoms of psittacosis in humans include fever, chills, headache, rash, muscle aches, and respiratory problems like cough and pneumonia. Without treatment, psittacosis can lead to severe pneumonia, endocarditis, hepatitis, and other complications. Psittacosis is treated with antibiotics like doxycycline or tetracycline.
To prevent psittacosis, it is important to avoid exposure to bird droppings and respiratory secretions. Wearing a face mask when cleaning bird cages can help reduce risk. Quarantining and testing new birds before introducing them to an aviary can also minimize spread of Chlamydia bacteria. Routine disinfection of cages, feeders and waterers is recommended.
Who is at risk for psittacosis?
People who have frequent, close contact with infected birds are at highest risk of contracting psittacosis. This includes:
- Bird owners
- Pet store employees
- Zookeepers
- Veterinarians
- Poultry farmers
Rare cases have occurred from exposure to dead, infected birds. Wearing gloves and masks when handling dead birds can reduce psittacosis risk.
Avian Influenza
Avian influenza refers to infection with bird flu Type A viruses. These flu viruses occur naturally in wild aquatic birds but can infect domestic poultry and other bird species. When passed to humans, the virus is termed “avian influenza A virus.”
Human cases of avian flu most often cause mild conjunctivitis and influenza-like illness. But certain strains like H5N1 and H7N9 can lead to severe pneumonia, acute respiratory distress, multi-organ failure, and even death.
Transmission to humans occurs through direct contact with infected birds or contaminated environments. Proper handling and cooking of poultry products also eliminates avian flu risk.
Using personal protective equipment when working with birds can help prevent avian influenza infection. There are also avian influenza vaccines available for certain strains to immunize poultry flocks. Monitoring and containment of outbreaks in domestic birds are key public health strategies for controlling avian influenza spread.
Avian influenza pandemics
Strains of avian influenza have caused four major influenza pandemics in the past century:
- 1918 Spanish flu (H1N1)
- 1957 Asian flu (H2N2)
- 1968 Hong Kong flu (H3N2)
- 2009 swine flu (H1N1)
The natural reservoirs of influenza A viruses are wild aquatic birds. Novel strains can emerge when avian and human flu mix and swap genes in intermediate animals like pigs. Monitoring circulating strains in bird populations can help predict and prepare for future pandemics.
Histoplasmosis
Histoplasmosis is a fungal infection caused by breathing in spores of the fungus Histoplasma capsulatum. This fungus thrives in soils enriched with bird or bat droppings. Disturbing contaminated sites can aerosolize the fungal spores and lead to histoplasmosis infection if inhaled.
Most infected people have no symptoms or experience mild flu-like illness. In a small percentage, histoplasmosis can cause severe respiratory infections like pneumonia and even disseminated disease in immunocompromised individuals.
There is no vaccine for histoplasmosis. Treatment involves antifungal medications like itraconazole. Preventing exposure is the main way to avoid histoplasmosis. Using protective equipment when working in areas contaminated with bird or bat droppings can reduce risk.
Histoplasmosis risk factors
People at increased risk of contracting histoplasmosis include:
- Construction workers
- Roofers
- Demolition crews
- Cavers
- Archeologists
- Farm workers
- Laboratory personnel
Any activity that generates dust in settings with accumulated bird or bat droppings raises histoplasmosis risk. Prompt cleanup and disposal of guano following roosting or nesting lowers contamination levels.
Cryptococcosis
Cryptococcosis is an infection caused by the fungus Cryptococcus neoformans or Cryptococcus gattii. Bird droppings can be a source of exposure to these fungi.
Cryptococcus often causes pneumonia or meningitis in infected individuals. Those with compromised immunity are at increased risk of disseminated, severe illness. Fluconazole and other antifungals are used to treat cryptococcosis.
Avoiding areas contaminated by bird droppings can lower cryptococcosis risk. For those handling bird excrement, protective equipment like gloves, goggles, masks and coveralls is recommended.
Cryptococcosis in birds
Infected birds often show no signs of illness from Cryptococcus. Some species can develop pulmonary or central nervous system infections, however. Transmission between birds occurs through inhalation of fungi shed in droppings.
Routine disinfection and proper ventilation in aviaries helps control cryptococcosis spread. Infected birds can be treated with antifungal medications. Isolating sick birds and testing newcomers prevents introduction into an aviary.
Other infections
Some other less common infections that can be acquired from birds include:
- Campylobacteriosis – Bacterial disease that can cause gastroenteritis
- Chlamydiosis – Bacterial infection that can cause pneumonia
- Salmonellosis – Common bacterial cause of foodborne illness
- Toxoplasmosis – Parasitic disease that rarely causes illness
- Newcastle disease – Viral infection of poultry that can cause conjunctivitis in humans
- Pasteurellosis – Bacterial zoonotic disease associated with respiratory infection
Proper handling and preparation of poultry products prevents transfer of many foodborne pathogens like Salmonella from birds to humans. Avoiding contact with bird feces, secretions and ingesta is also protective against a wide range of infectious diseases.
Protecting backyard flocks from infection
There are several steps backyard chicken and waterfowl owners can take to protect their flocks and prevent disease transmission:
- Source birds only from reputable farms or hatcheries
- Quarantine and test new birds before adding to flock
- Isolate any sick or injured birds promptly
- Avoid mixing species
- Utilize good biosecurity measures
- Restrict access to enclosures
- Change clothes/shoes when entering pen
- Clean and disinfect equipment regularly
- Remove standing water sources
- Secure enclosures from wild birds
- Vaccinate when recommended
Consulting a veterinarian experienced in avian health can provide guidance on infectious disease prevention for backyard flocks. Strong biosecurity helps exclude pathogens and keep birds healthy.
Conclusion
Birds can transmit a variety of infectious diseases to humans, especially those who have regular close contact. These include psittacosis, avian influenza, histoplasmosis, cryptococcosis and various gastrointestinal infections. Practicing good hygiene and protective behaviors around birds reduces infection risk. Owners should monitor backyard flocks for signs of illness and implement biosecurity protocols. Although human infections originating from birds occur, the risk can be minimized through proper precautions and awareness.
Key Points
- Psittacosis, avian flu, histoplasmosis and cryptococcosis are some of the most common infections passed from birds to humans
- People who work closely with birds, like bird owners, veterinarians and poultry workers, have the highest risk of contracting a bird-associated infection
- Avoiding exposure to bird droppings, secretions and dust from roosting sites protects against numerous illnesses
- Cooking poultry products thoroughly, using protective equipment around birds and disinfecting cages helps reduce transmission
- Isolating sick birds, restricting contact with wild birds and quarantining new additions are key biosecurity measures for backyard flocks