Zoonoses Associated with Swine
This document provides information on various diseases that can be passed from swine to humans. Often these diseases do not make the animal appear sick but can cause serious illness in humans. Persons with specific medical conditions such as a chronic illness, immunodeficiency and pregnancy may be at higher risk of developing disease or complications from a zoonotic disease and should consult with their physician before working with animals. Additional information on zoonotic diseases can be found on the Center for Disease Control and Prevention Website, Healthy Pets, Healthy People.
The diseases associated with swine include ringworm, erysipelas, leptospirosis, streptococcosis, campylobacterosis, salmonellosis, cryptosporidiosis, giardiasis, balantidiasis, influenza, infection with pathogenic E. coli, and brucellosis. The majority of swine housed at WSU are bred and raised under controlled conditions and are unlikely to carry pathogens that could be transferred to people.
Diseases associated with direct contact or bites:
Dermatophytosis is a fungal skin infection commonly known as “ringworm” and is seen in both animals and people as scaly round areas of hair loss. Transmission of ringworm is by direct skin-to-skin contact with an infected animal.
Diseases associated with vectors or contaminated materials:
Erysipelas, leptospirosis and streptococcosis are bacterial infections that occasionally infect pigs. Erysipelas is transmitted through direct contact with animals, tissues and droppings. The risk of infection increases if persons have unprotected cuts or abrasions on their hands. In pigs, erysipelas cause fever, skin lesions, arthritis, or sudden death. Disease in humans may present as cellulitis, bacteremia, endocarditis, encephalitis, and arthritis. Leptospirosis causes reproductive problems, and liver and kidney failure in pigs. The bacteria are typically shed in the urine of infected animals. People acquire the infection by accidental ingestion and contact with contaminated urine, placenta, and fetal tissues. The organism can infect through abraded skin. Pigs affected by leptospirosis can have fever, kidney or liver failure, and reproductive problems like abortions and stillbirths. In people, the disease causes fever, headache, abdominal and muscle pain, vomiting, diarrhea, jaundice, and rash. In more severe cases, it can cause hemorrhagic pneumonia, liver and kidney failure and can lead to death. Streptococcosis can be acquired by people via contact with infected animals or their body fluids and tissues, and by consumption of undercooked pork meat. Streptococcosis in pigs may present as inflammation in several organs, septicemia and sudden death. The causative agent can cause serious illness in people, including meningitis and endocarditis.
Swine influenza is caused by influenza viral strains, which primarily infect swine but can be transmitted to people in close contact with infected pigs. Animals with the virus may not have any signs of illness but if they do, these include fever, nose or eye discharge, depression, lack of appetite, coughing, sneezing, and difficulty breathing. Symptoms in people are also typical flu-like ones, such as fever, coughing, lack of appetite, and fatigue, but can also have gastrointestinal ones like nausea, vomiting, abdominal pain, and diarrhea. The disease can progress to more serious complications, including inflammation of organs like the heart and brain as well as organ failure.
Salmonellosis, campylobacterosis, cryptosporidiosis, giardiasis, balantidiasis and infections with pathogenic E. coli are acquired by contact and accidental ingestion of fecal material from infected animals. Pigs infected with these bacterial and protozoal diseases typically have diarrhea, but some animals may show no symptoms of disease. Avoid direct contact with feces and urine and use gloves and handwashing to avoid accidental ingestion of animal waste. Any animal with diarrhea should be suspect of having a zoonotic disease. Symptoms in people include abdominal pain, diarrhea, and fever.
Brucellosis is a potential bacterial zoonoses in several farm animals, including pigs. Animals affected by Brucellosis usually do not present any signs of illness but are suspected of having the disease when reproductive problems are evidenced as infection in the reproductive organs, abortions and stillbirth, or weakened offspring. The disease can spread from pigs to people via direct contact with infected animals or animal tissues and fluids, such as blood. The bacteria can penetrate damaged skin and mucous membranes. Infected people typically have flu-like symptoms and the disease can affect the reproductive organs and cause miscarriages.
Individuals with exposure to animals and animal environments may develop allergic reactions to animal proteins (allergens). Approximately 20-30 percent of individuals working with laboratory animals will develop an allergic reaction to animal proteins and 5-10 percent of individuals will develop asthma. Personnel may be exposed to allergens through inhalation and contact with skin, eyes and mucous membranes. Animal allergens may be present in animal dander, hair, skin, urine, saliva, serum and any contaminated feed or bedding materials. Risk factors for developing an allergic reaction include history of previous allergies to animals. The signs and symptoms of an allergic reaction are nasal discharge and congestion, conjunctivitis, tearing and eye itching, skin redness, rash or hives and lower airway symptoms (coughing, wheezing and shortness of breath). Individuals with symptoms suggestive of an allergic reaction related to a workplace allergen should report their concerns to their supervisor and consult a physician.
Transmission of zoonotic diseases from animals is primarily by direct contact, ingestion, indirect contact with insect vectors and contaminated inanimate objects, or inhalation of aerosolized materials. We can protect ourselves from most diseases by using the following procedures:
- Handle animals appropriately and safely to avoid bites and injuries.
- Thoroughly wash any bite wounds and report injuries.
- Do not eat, drink, apply cosmetics or use tobacco products while handling animals or in animal housing areas.
- Wear gloves when handling ill animals, animal tissues, body fluids and waste and wash hands after contact.
- Wear dedicated protective clothing such as a lab coat or coveralls and boots or shoe covers when handling animals. Launder the soiled clothing separate from your personal clothes and preferably at the animal facility.
- Keep animal areas clean and disinfect equipment after using it on animals or in animal areas.
Most importantly, familiarize yourself about the animals that you will be working with and the potential zoonotic diseases associated with each species. If at any time, you suspect that you have acquired a zoonotic disease, inform your supervisor and seek medical care.
**Prepared by Office of the Campus Veterinarian and the Office of Research Assurances January 2021
- Centers for Disease Control and Prevention. Healthy Pets, Healthy People. (Farm Animals | Healthy Pets, Healthy People | CDC)