Animal agriculture is an important part of Ohio's economy. Livestock provide us with healthy and nutritious food as well as products we use every day, such as wool and leather.
However, livestock can carry diseases that can make people sick. Some diseases, such as campylobacteriosis and salmonellosis, are spread when animal products are contaminated with bacteria as well as by direct contact with animals and their environment. Other diseases, such as influenza A viruses and rabies, are only spread through contact with animals and not through contaminated animal products. Raw milk consumption carries special risks as it is more likely to be contaminated with bacteria such as Campylobacter, E. coli and C. burnetii (Q fever) than pasteurized milk.
What are livestock-related diseases of concern in Ohio?
Animal bites: livestock
Although bites from livestock are uncommon, they can become infected and pose a risk for transmission for rabies. In 2010, a cow that had been imported from a raccoon rabies-endemic area was positive for rabies in Ohio.
If you have been bitten by livestock, consult with your healthcare provider regarding the need for antimicrobial treatment, and report the bite to your local health department.
Bovine spongiform encephalopathy
Bovine spongiform encephalopathy (BSE), also known as "mad cow disease," is a prion disease that affects the brains of cattle and people. In people, the disease is called variant Creutzfeldt-Jakob disease (vCJD). It is caused by an abnormal protein called a prion.
BSE causes behavioral changes, muscle control problems and eventually death in cattle. People become infected by ingesting meat that has been contaminated with nervous tissue from infected cattle.
Worldwide, 95 percent of cases have occurred in the United Kingdom. In the United States, your risk of getting vCJD is extremely low. Regulations prevent certain tissues of cattle from being used in human foods. Import restrictions prevent BSE-positive cattle from entering the United States, and there is a monitoring program for this disease.
Brucellosis is caused by Brucella species bacteria. Different types of livestock will carry different species of Brucella:
- Cattle can carry B. abortus
- Pigs carry B. suis
- Sheep and goats can be infected with either B. melitensis or B. ovis
Occasionally, an animal can be infected with a Brucella species from a different type of livestock, particularly when different types of livestock are housed together. Horses can also become infected when exposed to infected livestock.
Brucellosis is a major cause of abortion in livestock. Brucellosis is rare in the United States, due in large part to the National Brucellosis Surveillance Strategy, which has all but eliminated B. abortus from the U.S. cattle population.
People can become infected through contact with birthing materials, aborted fetuses and tissues or through consumption of raw milk and cheeses from infected animals.
Campylobacteriosis is a gastrointestinal illness of humans and animals caused by Campylobacter bacteria. It causes diarrhea in calves and abortion in sheep. It can also cause infection of the udder in cattle leading to excretion of the bacteria in milk.
Campylobacter bacteria are commonly found in the feces of infected animals and in food products contaminated with the bacteria during processing or preparation. Raw or undercooked chicken is one of the most common sources of human infection, although outbreaks have been associated with consumption of raw milk and cheeses.
Hand washing and proper food handling techniques are important ways of prevent human infections.
Cryptosporidiosis is caused by a protozoan parasite called Cryptosporidium parvum. C. parvum can infect many different species of animals, but the primary source of infection for people is other infected people or cattle.
Calves are commonly infected, and it can cause diarrhea. People become infected when they eat food or water than has been contaminated with human or cattle feces or when they come into direct contact with feces.
C. parvum is resistant to most disinfectants, so prevention relies on avoiding contact with feces, properly cooking food and avoiding potentially contaminated water.
Dermatophytosis, also known as ringworm, is caused by several species of fungi. Trichophyton verrucosum is the most important species found in cattle and is rarely found in sheep and goats.
T. verrucosum causes scaly white lesions with hair loss that progress to thick light brown scabs in cattle. It is more common in calves than in adult animals.
People can develop dermatophytosis after contact with infected livestock or their environment. The disease in humans starts as a small bump in the skin, the hair becomes brittle and the lesion spreads peripherally, leaving scaly, bald patches. Treatment is with topical antimycotics.
E. coli, Shiga toxin-producing
Shiga toxin-producing E. coli (STEC) bacteria are part of the normal gastrointestinal flora of cattle. Healthy cattle shed E. coli in their feces.
When people are infected with STEC bacteria, they develop vomiting, diarrhea and stomach cramps. About 5 to 10 percent of people with STEC infections will develop hemolytic uremic syndrome (HUS). This is a serious complication involving decreased kidney function. Children under five years of age and the elderly are at increased risk of developing HUS.
Most people become infected by consuming contaminated food or water, unpasteurized milk, contact with cattle or their environment or contact with the feces of an infected person. Although STEC infections are commonly associated with eating undercooked beef, fresh fruits and vegetables can also become contaminated.
Hand washing and proper food handling techniques are important ways of preventing human infections.
Influenza A, novel virus
When an influenza virus that normally infects pigs is also able to cause infection in people, it is called a novel influenza A virus. Outbreaks of influenza A H3N2v associated with pigs at agricultural fairs in Ohio have occurred in recent years.
Transmission occurs through direct contact with pigs or their environment. People cannot get novel influenza A from eating pork or pork products.
Hand washing after contact with animals and not eating or drinking in areas where animals are housed or exhibited are important ways of reducing the risk of infection.
Leptospirosis is caused by Leptospira interrogans bacteria. It can infect people and a wide range of domestic and wild animals, including cattle, pigs and less commonly, sheep and goats.
Leptospira is shed in the urine of infected animals. Transmission usually occurs through exposure to water or soil that has been contaminated with Leptospira bacteria, although transmission can also occur through direct contact with the urine from an animal shedding the bacteria.
Orf is a common disease worldwide in goats and sheep. It is also called "sore mouth" or "scabby mouth."
It is caused by a virus (parapoxvirus) that causes blisters to form on the lips, muzzle and in the mouth. Later, the blisters become crusty scabs. It is especially common in young animals and may cause them to have difficulty nursing or feeding. Most animals recover completely within a month, but may get re-infected. Orf lesions may resemble foot-and-mouth disease, which is a very serious animal disease that has not occurred in the United States since 1929.
People can become infected via direct contact with an infected animal or by touching contaminated equipment such as halters, buckets or fences in the animal's environment. The virus penetrates through small lesions in the skin. People most often get infections on their fingers where blisters form in three to seven days. The sores may be painful and can last for two months.
A lab test to diagnose the infection is available at the Centers for Disease Control and Prevention (CDC). Your healthcare provider would need to contact your local health department for information about testing. There is no specific treatment, and people do not infect other people.
Activities that may put people at risk of infection include:
- Bottle feeding sheep or goats
- Shearing sheep or goats
- Petting infected animals
- Handling contaminated equipment
- Being bitten by an infected animal
Q fever is caused by Coxiella burnetii bacteria. It can cause abortion in cattle, sheep and goats, but many animals are asymptomatic carriers.
The bacteria are shed in large numbers in birthing materials and, to a lesser extent, in the feces. C. burnetii can live for long periods of time in the environment.
In most people, it causes a mild flu-like illness, although some people may develop atypical pneumonia. If untreated, about 10 percent of infected individuals will develop chronic infection, which can result in endocarditis and heart valve damage.
People can become infected through:
- Inhalation of contaminated dust
- Contact with birthing materials, aborted fetuses and tissues
- Consumption of raw milk and cheeses from infected animals
Rabies virus can infect any species of mammal. It causes encephalitis and is almost always fatal once symptoms develop. It is spread when a person or animal is bitten by an infected animal or, less commonly, when saliva from an infected animal gets into an open wound or onto a mucous membrane.
All bites should be reported to the local health department. A vaccination is available for cattle and sheep and should be considered for valuable animals living in rabies-endemic areas.
If you suspect your animal may have rabies, contact your veterinarian and the Ohio Department of Agriculture.
Salmonellosis is a gastrointestinal illness of humans and animals caused by Salmonella bacteria. The most common source of infection for humans is through ingestion of food contaminated with Salmonella bacteria.
Cattle, pigs and, less commonly, sheep and goats infected with Salmonella may develop diarrhea, although some animals can shed the bacteria in their feces without apparent signs of infection.
Hand washing and proper food handling techniques are important ways of preventing human infections.
Toxoplasmosis is a common disease found in birds and mammals across North America. The infection is caused by a protozoan parasite called Toxoplasma gondii and affects 10 to 20 out of every 100 people in North America by the time they are adults.
Most people do not even know that they have been infected with T. gondii. However, if a woman becomes infected for the first time while she is pregnant, the Toxoplasma parasite can infect the fetus. Infection in the unborn child early in pregnancy can result in miscarriage, poor growth, early delivery or stillbirth. If the child is born with toxoplasmosis, he/she can experience eye problems, hydrocephalus (water on the brain), convulsions or mental disabilities.
Goats, sheep and swine are among the domestic animals commonly infected with Toxoplasma parasites; cattle are relatively resistant to infection with Toxoplasma. Infected livestock do not shed eggs (oocysts) in their feces, but develop infective cysts in their muscles and other organs.
Preventing toxoplasmosis from livestock includes:
- Avoiding consumption of undercooked, contaminated meat by cooking meat to safe temperatures (using an internal thermometer)
- Diligently washing hands, cutting boards, utensils and surfaces in contact with raw meat
Yersiniosis refers to infections caused by two different bacteria. Yersinia enterocolitca and Yersinia pseudotuberculosis cause gastrointestinal illness characterized by diarrhea. In children and adolescents, it can cause symptoms that are often confused with acute appendicitis.
Pigs are the reservoir for Y. enterocolitica, and people become infected through direct contact with infected pigs or consuming contaminated pork products. Person-to-person transmission can also occur.
Y. pseudotuberculosis can be carried by wild mammals, birds and domestic animals such as swine. People usually become infected through contact with a contaminated environment or from eating contaminated food.