Stanford University

Working Safely with Farm Animals and Hooved Mammals

Zoonoses are diseases that animals can transmit to humans. This guide details the occupational hazards of farm animals and hooved mammals, as well the precautions you should take to minimize the risk of animal-to-human disease transmission. Contacts are provided for further assistance.

How Can I Protect Myself?
  1. When working with farm animals or hooved mammals, 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 animal use area, do not eat, drink, or apply cosmetics.
    • After handling farm animals or hooved mammals, always wash your hands.

    Unfixed tissues, body fluids, and other materials derived from animals may also pose a risk. Bedding, hay, dust, and hair can also exacerbate allergies.

    If you have any concerns or questions about working with farm animals and hooved mammals, contact EH&S at (650) 723-0448. For help with training personnel, contact the Veterinary Service Center at (650) 723-3876

    All personnel working with farm animals or hooved mammals are eligible to enroll in the Laboratory Animal Occupational Health Program (LAOHP). Contact EH&S for more information.


If You Work with Farm Animals or Hooved Mammals
  1. Farm animals and hooved mammals may harbor a range of bacteria, pathogens, and parasites. Sheep can shed a rickettsia called Coxiella burnetii, the causative agent for Q fever. Ruminants and pigs may harbor SalmonellaCampylobacter, and Cryptosporidium. Contact with pigs, sheep, and goats can lead to skin conditions such as erysipelas and orf. Many of these animals may carry biting insects that are vectors for disease.

    The physical size and strength of hooved mammals can create additional hazards for researchers. Hooved mammals may resist handling and often require multiple workers to administer medication and perform other functions.

    The following page details some of the causative agents and potential illnesses associated with farm animals and hooved mammals, along with protective measures, signs of illness, and what to do if an exposure or injury occurs.

    Coxiella burnetii (Q fever)

    What is Q fever?

    Q fever is a zoonotic bacterial infection caused by the bacteria Coxiella burnetii. It is primarily associated with parturient ruminants, although domestic and wild animals may also infect humans. Q fever is characterized by a sudden onset of fever, chills, headache, weakness, malaise, and severe sweats.

    How is Q fever spread?

    It is spread to humans primarily through airborne dissemination of contaminated dust. Dust becomes contaminated with Coxiella burnetii bacteria present in the (usually reproductive) tissues or body fluids of infected animals. This contaminated dust can spread up to half a mile.

    Direct contact with infected animals (especially pregnant sheep at delivery) or contaminated materials (such as straw or other bedding materials) may also lead to infections. Ingestion of unpasteurized milk products from infected cows, sheep, or goats can also be a source of infections. Direct person-to-person transmission is very uncommon, but possible. Arthropods (usually ticks) can serve as reservoirs for infections among domestic and wild animal hosts, but are not thought to play a role in human transmission.

    Who is at risk for infection?

    People who work with the agent in the laboratory or with infected animals are at the highest risk.

    Is a Q fever infection serious?

    Q fever can be treated with antibiotics and recovery is usually quick. However, complications may occur, particularly in people at increased risk, such as pregnant women or those with valvular heart disease or altered immune systems. Complications may include chronic endocarditis (inflammation of the heart), pneumonitis (inflammation of the lungs), abnormal liver function tests, and neurological problems.

    How can I protect myself?

    If you work with animals that may be infected, learn the signs and symptoms of Q fever. If you feel you may be infected, seek treatment immediately. A vaccine may be available through the Department of Defense for some individuals at high risk of exposure.

    To minimize the risk of infection, take the following precautions:

    • Learn about the sources of infection and the possible modes of transmission.
    • When handling pregnant animals, hides, wool, straw, or other potentially contaminated material, follow strict hygienic practices. Avoid inhaling contaminated dust or fluid droplets, adequately disinfect and dispose of the material, and promptly treat cuts and abrasions.
    • When working with sheep or other hoofed mammals, wear gloves, shoe covers, and long-sleeved apparel at all times.
    • When working with pregnant sheep, wear N95 respirators.
    • After handling animals, thoroughly wash your hands.
    • After animal work, sanitize lab and surgical areas.
    • Use disposable supplies whenever possible.

    What are the signs of a Q fever infection?

    Q fever is characterized by a sudden fever and may also cause chills, headaches, weakness, malaise (a general sick feeling), and severe sweats. Symptoms often appear two to three weeks after exposure.

    What do I do if an exposure or injury occurs?

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

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

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

    Salmonellosis

    What is salmonellosis?

    Salmonellosis is an infection with the bacteria Salmonella. Most people infected with Salmonella develop diarrhea, fever, and abdominal cramps within 72 hours after infection. The illness usually lasts four to seven days, and most people recover without treatment. In severe cases, hospitalization may be necessary.

    How is Salmonella spread?

    Salmonella live in the intestinal tracts of humans and other animals, including birds. Salmonella is usually transmitted to humans by eating foods contaminated with animal feces. Although contaminated foods are often of animal origin (e.g. beef, poultry, milk, or eggs), all foods, including vegetables, can become contaminated.

    Food may be contaminated by food handlers neglecting to wash their hands with soap after using the bathroom. Salmonella may also be found in the feces of some pets, especially those with diarrhea, and people can become infected if they do not wash their hands following contact with pet feces. Reptiles are particularly likely to harbor Salmonella; you should always wash your hands immediately after handling a reptile, even if the reptile is healthy.

    Who is at risk for infection?

    Healthy people are less likely to become sick from Salmonella because normal stomach acidity prevents the growth of bacteria. The elderly, infants, and people with impaired immune systems are more likely to develop severe illness from it.

    Is Salmonella infection serious?

    People with diarrhea usually recover completely, although it may take several months for their bowel habits to return to normal. In some cases, diarrhea may be so severe that the patient needs to be hospitalized. In these patients, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites. Death can occur if the person is not promptly treated with antibiotics. A small number of people may develop chronic symptoms due to reactive arthritis.

    How can I protect myself?

    • Always wash hands thoroughly with soap and water before eating or preparing food, after using the toilet, after changing diapers, and after touching pets or other animals (particularly reptiles or birds).
    • Cook poultry, ground beef, and eggs thoroughly before eating. Do not eat or drink foods containing raw eggs or raw unpasteurized milk. Refrigerate leftover foods promptly.
    • Clean and disinfect hard surfaces that have been in contact with raw animal products or infected animals.
    • If you develop persistent or severe diarrhea (with or without a fever), contact your doctor or health care center.

    What are the signs of Salmonella infection?

    The most common symptoms of Salmonella infection are:

    • stomach cramps and abdominal pain
    • headache
    • diarrhea
    • fever
    • nausea
    • vomiting

    Symptoms most often begin 12 to 36 hours after the bacteria are swallowed, but may not occur for up to three days. Symptoms generally last for several days.

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

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

    Orf (Contagious Ecthyma)

    What is orf?

    Orf (also known as contagious ecthyma, sore mouth, contagious pustular dermatitis, or scabby mouth) is a pox-like viral disease carried by sheep and goats characterized by scabs and pustules on the face (i.e. on the muzzle, lips, inside the mouth, and around the eyes), on the feet, and occasionally on the udder. Orf can occasionally be transmitted to humans.

    How is orf spread?

    The virus enters the sheep and establishes infection through a break in the skin. Outbreaks are normally associated with abrasions. Ear tagging has also been associated with orf infection. The virus is spread from animal to animal and from animal to human by direct contact with the infected animal, or by contact with contaminated items, such as wool, pens, feeders, waterers, and equipment. Humans are also susceptible to infection from contact with the sores or saliva of infected sheep or goats.

    Who is at risk for infection?

    Any person who comes into contact with the virus from an infected animal or contaminated equipment (such as a harnass that has rubbed against the animal’s sores) can potentially be infected, especially if there are open cuts or abrasions on the skin. Exposure to the virus may also occur from the bite of an infected animal. The virus is not transmitted from human to human.

    Is orf infection serious?

    Human infection commonly consists of painful sores on the hands or fingers, which can last up to two months. People with weakened immune systems can develop a more serious infection.

    How can I protect myself?

    To minimize the risk of infection, the following preventive measures should be taken:

    • Use good personal hygiene:
      • Always wash your hands after all animal contact and before you leave the lab or animal facility.
      • Do not eat, drink, smoke, take or apply medicine, store human food, handle contact lenses, or apply cosmetics in animal facilities and laboratories. Wash your hands before engaging in any of these activities.
    • Wear personal protective equipment:
      • Wear protective clothing in the animal facility and lab. In addition to lab coats or coveralls, some facilities may require shoe coverings and gloves.
      • Do not wear soiled protective clothing outside of the lab or animal facility. Do not launder soiled protective clothing at home. All soiled nondisposable clothing must be institutionally laundered.
      • Wear protective garments, gloves, and disposable shoe coverings (or sanitizable boots) when handling live vaccine or animals with skin lesions.
    • Isolate animals with skin lesions whenever possible. Handle and care for contagious animals last whenever possible.
    • Cleaning and disinfection:
      • Disinfect lab work surfaces daily (and after any spills) with a disinfectant approved by the facility supervisor.
      • Clean contaminated animal pens and cages to mechanically remove the agent.
      • Disinfect animal areas and equipment with a disinfectant approved by the facility supervisor.
    • Dispose of laboratory waste, contaminated bedding, animals, their products, and items contaminated by their products properly (as directed by the facility supervisor).

    What are the signs of orf infection?

    The following are signs of orf infection in animals:

    • Pox-like skin lesions in sheep and goats are usually found on the lips, but may also be found on the nose, eyelids, ears, oral cavity, udder, wounds, the skin at the top of the hoof, and the skin between the hoof claws.
    • The disease takes two to 14 days to develop after exposure.

    The following are signs of orf infection in humans:

    • The disease in humans is similar to the disease in animals, with a “chicken pox” lesion usually developing on the fingers, hands, face, or forearms. The sores are red and swollen with a grayish center, are usually one inch in diameter, and produce minor discomfort.
    • The disease takes two to 10 days to develop after exposure, and lasts for one to six weeks.

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

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

    Pasteurellosis

    What is pasteurellosis?

    Pasteurellosis is a bacterial infection caused by Pasteurella bacteria. Pasteurella multocida is the species that most commonly infects humans, and can also infect cattle, rabbits, cats, and dogs. It is especially opportunistic in cattle. Although the bacteria are commonly found in the upper respiratory tract, disease occurs when the animal’s normal defenses are compromised.

    How is pasteurellosis spread?

    Pasteurella infections are spread by inhalation of aerosol droplets, by direct nose to nose contact, or by ingestion of food or water that has been contaminated by nasal and oral discharges from infected animals. Humans can also acquire the organism through dog or cat bites.

    Who is at risk for infection?

    Pasteurellosis is relatively uncommon in humans. However, people with weakened immune systems are at higher risk.

    Is pasteurellosis infection serious?

    The most common symptom of pasteurellosis in humans is a local wound infection, usually following an animal bite or scratch. Complications may include abscesses, cellulitis (an area of spreading inflammation), and joint infections.

    The organism can also infect the respiratory tract, causing sinusitis and ear infections. More severe symptoms, including pneumonia or lung abscesses, may occur in those with underlying pulmonary disease, though this is rare. Other uncommon presentations include septicaemia (blood poisoning), eye infections, meningitis, and gastrointestinal problems.

    How can I protect myself?

    Pasteurellosis can be treated with antibiotics.

    If someone has been bitten or scratched by an animal, they should gently cleanse the area around the bite wound then seek medical attention as soon as possible. This advice applies to all animal bites. People at high risk (including those with a weakened immune system, rheumatoid arthritis, or a prosthetic joint) should seek medical attention immediately after any significant animal bite or scratch.

    What are the signs of pasteurellosis infection?

    Patients tend to have swelling, cellulitis, and some bloody drainage at the wound site within 24 hours after the animal bite. Infection may also move to nearby joints, where it can cause swelling and arthritis.

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

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

    Campylobacteriosis

    What is campylobacteriosis?

    Commonly found in untreated water and 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 jejuniC. jejuni is the leading cause of bacterial diarrhea in the United States.

    How is campylobacteriosis spread?

    People most typically 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 (e.g. AIDS patients or cancer patients on immunosuppressive therapy) are thought to be 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?

    • Wear gloves, shoe covers, and long-sleeved apparel at all times when working with animals.
    • Thoroughly wash hands after handling animals.
    • Sanitize lab and surgical areas after animal work.
    • Use disposable supplies whenever possible.

    What are the signs of campylobacteriosis?

    Symptoms of campylobacteriosis include fever, headache, and muscle pain, followed by diarrhea, stomach pain, and nausea. Symptoms usually occur within two 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 the hours of 8 am and 5 pm, proceed to Stanford Occupational Health Clinic at 480 Oak Road, Room B15, 5-5308.

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


Who Is at Risk for Infection?
  1. Bites or scratches involving farm animals or hooved mammals, or injuries from objects contaminated with body fluids from these animals, require immediate medical attention. Always notify your supervisor in these cases.

    Between the hours of 8 am and 5 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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