Stanford University

Working Safely with Birds

Zoonoses are diseases that animals can transmit to humans. The following guide details the occupational hazards associated with birds, as well as the precautions necessary for minimizing the risk of animal-to-human disease transmission. Contacts are provided for further assistance.

How Can I Protect Myself?
  1. When working with birds, take the following protective measures:

    • Always wear gloves and a laboratory coat, or other dedicated protective clothing, such as a scrub suit. In some cases, masks or protective eye wear is also indicated.
    • While working in an aviary, do not eat, drink, or apply cosmetics.
    • After handling birds, always wash your hands.
    • Unfixed tissues, body fluids, and other materials derived from birds may also pose a risk. Guano (feces), hair, and feathers may exacerbate allergies.

    Contact EH&S at (650) 723-0448 for any concerns or questions you have about working with birds (or for any concerns or questions regarding vertebrate animals and occupational risks). Contact the Veterinary Service Center at (650) 723-3876 for help with training personnel.

    Note that all personnel working with birds or vertebrate animals are eligible to enroll in the Laboratory Animal Occupational Health Program (LAOHP). Contact EH&S at (650) 723-0448 for additional information.


If You Work with Birds
  1. Birds can carry disease, including psittacosis and an avian form of tuberculosis. Mycological fecal contamination is also possible when handling birds.

    In research studies or teaching demonstrations, use only inspected, properly quarantined birds. The following describes some of the causative agents and potential illnesses associated with birds, along with protective measures, signs of illness, and what to do if an exposure or injury occurs.

    Campylobacteriosis

    What is campylobacteriosis?

    Commonly found in the intestines of poultry, cattle, swine, rodents, wild birds, and household pets (e.g. cats and dogs), campylobacteriosis is a bacterial illness caused by Campylobacter jejuni. It is also found in untreated water. C. jejuni is the leading cause of bacterial diarrhea in the United States.

    How is campylobacteriosis spread?

    People most commonly develop campylobacteriosis after consuming undercooked poultry, raw milk, or non-chlorinated water that has been contaminated. C. jejuni may also be transmitted through ingestion after petting infected cats and dogs, whose coats may contain infected fecal matter. In the absence of adequate hygiene, person to person transmission may also occur through human fecal matter.

    Who is at risk for infection?

    Although anyone can develop a C. jejuni infection, children under 5 years and young adults (15-29) are more frequently affected than other age groups. Immunocompromised people (such as AIDS patients, or cancer patients on immunosuppressive therapy) are likely more susceptible to health complications following infection. The elderly may also be more susceptible.

    Is campylobacteriosis infection serious?

    Complications are relatively rare, but infections have been associated with reactive arthritis, hemolytic uremic syndrome, and septicemia.

    How can I protect myself?

    • When working with animals, wear gloves, shoe covers, and long sleeved apparel at all times.
    • After handling animals, thoroughly wash hands.
    • After animal work, sanitize lab and surgical areas.
    • Whenever possible, use disposable supplies.

    What are the signs of campylobacteriosis?

    Symptoms include fever, headache, and muscle pain, followed by diarrhea, stomach pain, and nausea. Symptoms usually occur within 2 to 10 days of ingestion. It may take anywhere from a few days to a few weeks to recover.

    What do I do if an exposure or injury occurs?

    Exposure to aerosols, bites, or scratches involving animals, or injuries from objects contaminated with body fluids from animals, require immediate first aid and medical attention. Always notify your supervisor immediately.

    Between 8:00 am and 5:00 pm., proceed to Stanford Occupational Health Clinic at 480 Oak Road, Room B15, 5-5308.

    After 5:00 pm and before 8:00 am., call (650) 723-2670 or proceed to the Stanford Emergency Room, H126 (in the hospital, next to the cafeteria).

    Chlamydophila Psittaci (Avian Psittacosis)

    What is Chlamydophila psittaci?

    Chlamydia psittaci is a bacterium that can be transmitted from birds to humans. In humans, the resulting infection is referred to as psittacosis (also known as parrot disease, parrot fever, and ornithosis). Psittacosis often causes influenza-like symptoms and can lead to severe pneumonia and nonrespiratory health problems.

    How is Chlamydophila psittaci spread?

    Infection with C. psittaci usually occurs when a person inhales the organism, which has been aerosolized from respiratory secretions or the dried feces of infected birds. Other possible means of exposure include bird bites, mouth-to-beak contact, and the handling of infected birds’ plumage and tissues. Even brief exposures can lead to symptomatic infection.

    Who is at risk for infection?

    The following groups have the greatest risk of infection:

    • Bird fanciers and owners of pet birds
    • Those whose occupation places them at risk for exposure, including pet shop employees, employees in poultry processing plants, veterinarians and veterinary technicians, laboratory workers, farmers, and zoo workers

    However, because infection can result from brief, passing exposure to infected birds or their droppings, those with no identified risk can also become infected.

    Is Chlamydophila psittaci infection serious?

    Infection often causes flu-like symptoms and can lead to severe pneumonia and nonrespiratory health problems. Pregnant women may be at greater risk for serious infection. Antibiotics can successfully treat most infections.

    How can I protect myself?

    • Take measures to protect high risk people from becoming infected:
      • Inform anyone in contact with infected birds about this risk.
      • If an exposed person develops respiratory illness, a physician should initiate early and specific treatment for psittacosis.
      • Always wear protective clothing, gloves, a paper surgical cap, and a respirator with an N95 rating (or a higher-efficiency respirator) when cleaning cages or handling infected birds. Surgical masks may not be effective in preventing transmission of C. psittaci.
    • Maintain records of all bird-related transactions to aid in identifying sources of infected birds and potentially exposed people.
    • Do not purchase or sell birds that show signs of infection (e.g. ocular or nasal discharge, diarrhea, or low body weight).
    • Whenever possible, perform procedures in a class II biosafety cabinet.
    • Do not stack cages. Use solid-sided cages, or barriers if cages are adjoining. Make sure the bottom of the cage is made of wire mesh; place non dust-producing litter (e.g., newspapers) underneath the mesh.
    • Clean all cages and food/water bowls daily. Soiled bowls should be emptied, cleaned with soap and water, rinsed, placed in a disinfectant solution, and rinsed again before reuse.
    • Use disinfection measures.
    • C. psittaci is susceptible to most disinfectants and detergents. In the clinic or laboratory, use a 1:1000 dilution of quaternary ammonium compounds, or 70% isopropyl alcohol, 1% Lysol, 1:100 dilution of household bleach, or chlorophenols.

    What are the signs of Chlamydophila psittaci infection?

    The onset of illness follows an incubation period of 5 to 14 days. Persons with symptomatic infection typically have abrupt onset of fever, chills, headache, malaise, and myalgia. They usually develop a nonproductive cough that can be accompanied by breathing difficulty and chest tightness. Other symptoms may include loss of appetite, nausea, vomiting, diarrhea, and abnormal intolerance to light.

    What do I do if an exposure or injury occurs?

    Exposure to aerosols, bites, or scratches involving animals, or injuries from objects contaminated with body fluids from animals, require immediate first aid and medical attention. Always notify your supervisor immediately.

    Between 8:00 am and 5:00 pm., proceed to Stanford Occupational Health Clinic at 480 Oak Road, Room B15, 5-5308.

    After 5:00 pm and before 8:00 am., call (650) 723-2670 or proceed to the Stanford Emergency Room, H126 (in the hospital, next to the cafeteria).

    Histoplasmosis

    What is histoplasmosis?

    Caused by the fungus Histoplasma capsulatum, this is an infectious disease that starts in the lungs and may spread to other parts of the body. The fungus grows in contact with droppings from chickens, pigeons, starlings, blackbirds, and bats. These birds carry the fungus on their feathers, but due to high body temperatures, they are themselves immune to infection. The fungus also appears in soil, particularly when enriched with bird or bat droppings.

    How is it spread?

    People get this fungus by breathing air containing small spore forms of it. When contaminated soil is disturbed, spores get airborne. Commonly, these people are around environmental sites where birds had roosted, or partake in hobbies or professions that expose them to bird roosts or bat habitats. The infection can spread through the bloodstream. Dissemination of disease is most frequently seen in immunocompromised individuals.

    Who is at risk for infection?

    People whose occupations involve contact with the soil (and particularly soil enriched with bird and bat droppings) are at high risk of being infected. These occupations include:

    • farmers and poultry keepers, especially when cleaning silos, chicken coops, and pigeon roosts
    • gardeners and horticulturists using poultry manure as fertilizer
    • construction and other workers in earth-moving operations
    • workers who monitor bird populations
    • workers who have contact with bats or bat caves

    Others at risk include archaeologists, geologists, and medical laboratory technicians who handle cultures of the organism.

    Is histoplasmosis infection serious?

    Most histoplasmosis infections either produce mild symptoms or none at all.

    However, histoplasmosis can be severe, and may produce an illness similar to tuberculosis. More severe disease usually occurs in patients with diseases which impair their body’s ability to fight infections. In such cases, histoplasmosis may spread from the lungs to involve other parts of the body. If left untreated, the infection is progressive and usually fatal.

    How can I protect myself?

    Prevention of histoplasmosis relies on avoiding exposure to dust in a contaminated environment. Before cleaning chicken coops or other contaminated soil, spray with water to reduce dust. Decontamination with 3% formaldehyde has been shown to be effective. However, such solutions should be used with caution, since the chemical may cause adverse health effects following inhalation, ingestion, or skin or eye contact.

    If you work in a contaminated area, wear protective clothing, such as gloves and coveralls. Also, use a respirator equipped with a high efficiency particulate air (HEPA) filter that is capable of filtering particles down to two microns. For major clean-up operations of prolonged exposure, a powered air purifying or supplied air respirator may be necessary.

    What are the signs of histoplasmosis infection?

    Histoplasmosis causes a spectrum of illness, and the symptoms vary depending on the type of infection, the underlying health of the patient, and the extent of exposure. Symptoms of the infection appear within 5 to 18 days after exposure, most commonly in 10 days. In the healthy individual, H. capsulatum may cause no symptoms or may cause a flu-like illness with fever, cough, chest pain, and fatigue. In some healthy individuals histoplasmosis may cause joint pain, muscle pain, and painful red lumps on the arms or legs. In patients with pre-existing lung disease, or those who are immunocompromised, histoplasmosis may lead to more severe symptoms or lung infection.

    What do I do if an exposure or injury occurs?

    Exposure to aerosols, bites, or scratches involving animals, or injuries from objects contaminated with body fluids from animals, require immediate first aid and medical attention. Always notify your supervisor immediately.

    Between 8:00 am and 5:00 pm., proceed to Stanford Occupational Health Clinic at 480 Oak Road, Room B15, 5-5308.

    After 5:00 pm and before 8:00 am., call (650) 723-2670 or proceed to the Stanford Emergency Room, H126 (in the hospital, next to the cafeteria).

    Cryptococcus Neoformans

    What is Cryptococcus neoformans?

    This is a fungal organism that can cause disease in immunocompromised people, and (more rarely) others. Its main habitats include debris around pigeon roosts and soil contaminated with decaying pigeon or chicken droppings.

    How is it spread?

    The organism likely enters the host via the respiratory route in the form of a dehydrated haploid yeast or as basidiospores. After some time in the lungs, the organism hematogenously spreads to extrapulmonary tissues. Since it has a predilection for the brain, infected persons may contract meningoencephalitis. Cryptococcus neoformans does not spread from person to person.

    Who is at risk for infection?

    Human hosts with impaired immune responses are at higher risk for acquiring most of these fungal infections, and for extrapulmonary dissemination of the disease.

    Is Cryptococcus neoformans infection serious?

    If untreated, cryptococcal meningoencephalitis is 100% fatal, and even when treated with the most effective antifungal drugs, cryptococcal infections can be fatal for immunocompromised people.

    How can I protect myself?

    Accidental parenteral inoculation of cultures or other infectious materials represents a potential hazard to laboratory personnel, particularly to those that may be immunocompromised. Bites by experimentally infected mice and manipulations of infectious environmental materials (e.g. pigeon droppings) may also represent a potential hazard.

    Biosafety Level 2 practices and facilities are recommended for activities with known or potentially infectious clinical, environmental, or culture materials.

    Animal Biosafety Level 2 practices and facilities are recommended for activities with experimentally infected animals.

    The processing of soil or other environmental materials known or likely to contain infectious yeast cells should be conducted in a Class I or II biological safety cabinet. This precaution is also indicated for culture of the perfect (or sexual) state of the agent.

    What are the signs of Cryptococcus neoformans infection?

    Cryptococcal infection may cause a pneumonia-like illness, with symptoms including shortness of breath, coughing, and fever. Skin lesions may also occur.

    Another common form of cryptococcosis is central nervous system infection, such as meningoencephalitis. People with cryptococcal meningoencephalitis are usually immunocompromised. Symptoms may include fever, headache, or change in mental status.

    What do I do if an exposure or injury occurs?

    Exposure to aerosols, bites, or scratches involving animals, or injuries from objects contaminated with body fluids from animals, require immediate first aid and medical attention. Always notify your supervisor immediately.

    Between 8:00 am and 5:00 pm., proceed to Stanford Occupational Health Clinic at 480 Oak Road, Room B15, 5-5308.

    After 5:00 pm and before 8:00 am., call (650) 723-2670 or proceed to the Stanford Emergency Room, H126 (in the hospital, next to the cafeteria).

    Mycobacterium Avium Complex

    What is Mycobacterium avium complex?

    Mycobacterium avium complex (MAC) is caused by a group of organisms with over 30 serovars, including Mycobacterium avium. The organisms may cause disease not only in birds, but in other warm and cold-blooded vertebrate species as well.

    In humans, MAC tends to be an opportunistic infection that is primarily found in immunocompromised individuals. MAC organisms are common in water, water mists or vapors, dust, soil, and bird droppings.

    How is MAC spread?

    MAC organisms usually enter the body through contaminated food and water. However, transmission can also occur through inhalation of infective aerosols. MAC is probably not passed from person to person.

    Who is at risk for infection?

    MAC occurs most often in people with AIDS and other immunocompromised individuals. Most people who get MAC have fewer than 50 T-cells. MAC almost never occurs in people with over 100 T-cells. Individuals who are anemic are also at higher risk for MAC.

    Is MAC infection serious?

    Infections with MAC can lead to disseminated disease, including blood infections, hepatitis, skin lesions, and pneumonia.

    How can I protect myself?

    • Take measures to protect persons at high risk from being infected, including:
      • All persons in contact with infected birds should be informed about the nature of the disease.
      • Minimize animal contact, especially with birds and bird droppings. Pigeons, common in most urban areas, can also transmit organisms that cause infection.
      • Always wear protective clothing, gloves, a paper surgical cap, and a respirator with an N95 rating (or a higher-efficiency respirator) when cleaning cages or handling infected birds. Surgical masks may not be effective in preventing transmission of MAC.
    • Practice preventative husbandry:
      • Position cages to prevent the transfer of fecal matter feathers and other materials from one cage to another.
      • Perform procedures in a laminar flow hood whenever possible.

    What are the signs of MAC infection?

    The most common symptoms of MAC are persistent fevers which may be accompanied by night sweats, weight loss, a loss of appetite, fatigue, or progressively severe diarrhea. Symptoms of early MAC disease often involve the gastrointestinal tract. Painful joints, bone, brain, and skin infections can result from MAC bacteria spreading throughout the body. Some physical signs of MAC may include swollen or enlarged abdominal lymph nodes, usually on only one side of the body, and an enlarged liver and spleen. Respiratory symptoms (e.g. coughing and difficulty breathing) are relatively uncommon.

    What do I do if an exposure or injury occurs?

    Exposure to aerosols, bites, or scratches involving animals, or injuries from objects contaminated with body fluids from animals, require immediate first aid and medical attention. Always notify your supervisor immediately.

    Between 8:00 am and 5:00 pm., proceed to Stanford Occupational Health Clinic at 480 Oak Road, Room B15, 5-5308.

    After 5:00 pm and before 8:00 am., call (650) 723-2670 or proceed to the Stanford Emergency Room, H126 (in the hospital, next to the cafeteria).


How Are Avian Diseases Spread?
  1. People acquire fungal infections (e.g. histoplasma and cryptococcus) that produce avian diseases by inhaling spores.

    Another route of exposure may be surface contact while handling avian fecal specimens. Contact with tissues through cuts or scratches may also pose a risk.


Who Is at Risk for Infection?
  1. Investigators, animal technicians, laboratory personnel, and others who routinely handle birds, their tissues, and/or feces are all at risk for infection. Scratches or cuts involving birds, as well as injuries from objects contaminated with body fluids or feces from birds, require immediate first aid and medical attention. Always notify your supervisor in these cases.

    Between 8:00 am to 5:00 pm, Monday through Friday, contact the Stanford University Occupational Health Center (SUOHC) at (650) 725-5111 for immediate phone triage and to schedule an urgent drop-in appointment time.

    For immediate, life-threatening injuries, or when SUOHC is closed, go directly to the Stanford University Medical Center Emergency Department.



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