Zoonotic diseases are contagious diseases that spread between animals and humans. It is estimated that approximately 75% of recently emerging infectious diseases affecting humans are diseases of animal origin; approximately 60% of all human pathogens are zoonotic. Humans can contract zoonotic diseases through direct contact with infected animals, and also by consumption of contaminated food or water, inhalation, arthropod vectors (such as flies, ticks, and mosquitoes) and pests.
Below is a condensed list of sheep and goat diseases that can be transmitted to humans. The diseases are grouped in alphabetical order within groups of common routes for human infection. Many of these diseases, whether in animals or humans, are reportable to State and Federal Authorities. Contact your State Veterinarian or your State/Local Health Department for information about State disease reporting requirements in animals and humans, respectively.
Sheep and Goat Diseases that can be Transmitted to Humans
Crimean-Congo Hemorrhagic Fever
**Crimean-Congo hemorrhagic fever (CCHF) is a viral disease that shows no evidence of disease in infected animals, but is a serious threat to humans. Humans can become infected through the skin or by ingestion. Aerosol transmission has been suspected put not proved. Although the virus is often transmitted by ticks, animal-to-human and human-to-human transmission also occurs. Human infections begin with a fever, but progress to a serious hemorrhagic syndrome (a rash followed by severe bleeding). Cardiovascular, gastrointestinal, and neurological symptoms may also occur. The CCHF virus is a potential bioterrorist agent; it has been listed in the U.S. as a CDC/NIAID Category C priority pathogen. This is a foreign animal disease, so State and Federal veterinarians should be notified immediately of any suspected cases of CCHF.
Rabies is a severe, viral disease that can affect all mammals, including sheep and goats. People most often get rabies from the bite (direct contact) of an infected animal, but can also be exposed to the virus by entry of saliva, brain or spinal cord fluid of an infected animal into cuts or breaks in the skin or mucous membranes. Early human symptoms include fever, headache, confusion and abnormal behavior (neurological signs). Once signs begin, recovery is very rare. If you are bitten by an animal, immediately contact local animal control so the animal may be tested or quarantined, and contact your physician immediately to determine whether post-exposure treatment is indicated.
Anthrax is caused by the spore-forming bacterium, Bacillus anthracis. Spores can infect people through a break or abrasion in the skin after direct contact with infected animals or their products, such as blood, wool or hides. Anthrax can also be inhaled (aerosol) in contaminated dust from the environment or animal products (e.g., hides, wool). skin infections may occur after handling hides or unprocessed wool from areas were anthrax occurs; redness, and swelling will occur followed by a black scab at the site of infection.
**Brucellosis (Undulant fever, Malta fever, Mediterranean fever, Contagious Abortion, Bang’s disease)
Brucellosis is a contagious bacterial disease caused by members of the Brucella genus. In sheep or goats it is usually caused by B. melitensis or B. ovis and rarely B. abortus (in goats exposed to infected cattle). However, only B. melitensis and B. abortus are considered to be a human health threat. People can become infected by direct contact with infected animal fluids, but there are additional ways to be infected. People who work with animals (e.g., livestock producers, veterinarians) may be at higher risk of exposure to Brucella. Infection in people may cause re-occurring fever, night sweats, headaches, back pain, and joint pain. Brucella melitensis is a foreign animal disease, so State and Federal veterinarians should be notified immediately of any suspected cases.
Contagious Ecthyma (Soremouth)
Caused by the orf virus, contagious ecthyma in people is called Orf. People become infected by direct contact with skin lesions or scabs usually on the face and mouth of infected animals. In people, usually only one single lesion (local sore/wound) develops.
**Mange, Scabies (Acariasis)
Mites such as Sarcoptes scabiei (sarcoptic mange) and Psoroptes ovis (psoroptic mange) are easily spread to other animals or people by direct contact with infested animals. Some mites can survive for several days on objects such as clothes, towels, or bedding (indirect/fomite). Infestations of sheep and goats can cause debilitation and damage to the hides and wool. Sarcoptic mange is highly contagious to dogs and humans, and between humans. People infested with mites from animals will typically experience reddening of the skin, irritation and intense itching (allergic reaction in the skin). Sarcoptic mange is a foreign animal disease, so State and Federal veterinarians should be notified immediately of any suspected cases.
Ringworm is a common fungal disease caused by dermatophytes. People can become infected by direct contact with the spores on an infected animal. The spores may be on the animal’s hair/wool or skin, and can even be on fomites such as brushes or clippers. Dermatophytosis tends to be more common in show lambs than production flocks. Itchiness is the most common symptom, and the spots are generally inflamed at the edge with redness, scaling, and occasionally blistering.
Tularemia is a disease caused by the bacteria Francisella tularensis. Humans can become infected by direct contact with infected animals, in addition to other methods. In people, tularemia causes flu-like signs (fever, chills, nausea, headache), and joint pain occur. Glands (or lymph nodes) may become swollen and painful.
Vesicular stomatitis is a viral disease of animals and can infect humans, who can become infected when handling infected animals (direct contact). In people, vesicular stomatitis causes flu-like symptoms (fever, muscle aches, headache and weakness). Rarely, people can get oral blisters similar to cold sores. Although it occurs sporadically in the US it is treated as a foreign animal disease, so State and Federal veterinarians should be notified immediately of any suspected cases of vesicular stomatitis.
Handling Contaminated Tissues during Lambing or Kidding
Chlamydiosis is a bacterial disease in sheep and goats is caused by Chlamydophila abortus. Pregnant animals can shed large numbers of C. abortus in the placenta and uterine discharges when they abort or give birth. Although rare, people can be infected by direct contact with birthing tissues, but there are additional ways to be infected. In people, animal-associated chlamydiosis causes flu-like signs (fever, body aches, headache), reddened eyes, and pneumonia. Pregnant women should avoid contact with pregnant or aborting animals.
**Brucellosis (see above, Direct Contact: Directly Handling Sheep and Goats)
B. abortus and B. melitensis can be also transmitted to people by milk, contact with the placenta, fetus, fetal fluids, blood, and vaginal discharges from an infected animal. Pregnant women should avoid contact with pregnant or aborting animals.
Contact with infected urine or water
Leptospirosis is a bacterial disease that affects many animal species, as well as humans. People usually become ill after contact with infected urine, or through contact with water, but can be infected in additional ways, such as direct contact with infected animals. In people, leptospirosis can cause flu-like symptoms (fever, body aches, headache), weakness, vomiting, mental confusion, jaundice (orange/yellow skin color), and stiff neck.
People will often orally contract zoonotic diseases after eating contaminated sheep and goat products, or by ingesting contaminated material on unwashed hands following contact with an ill animal
Anthrax (see above, Direct Contact: Directly Handling Sheep and Goats)
People can become infected orally by eating undercooked meat of infected animals. Nausea, vomiting, abdominal pain and severe, bloody diarrhea may occur.
**Brucellosis (see above, Direct Contact)
The most common way people can become infected is by eating or drinking (oral) contaminated, unpasteurized milk products. There is no danger from eating cooked meat or pasteurized milk products.
A major cause of enteritis in humans, Campylobacter spp. (e.g., C. jejuni and C. coli) often infects people by the consumption of contaminated or undercooked meat and unpasteurized milk or dairy products (oral). People can also be infected by untreated water or contact with infected animals or feces. People infected with campylobacteriosis can have diarrhea, fever, nausea, vomiting, abdominal pain, headache and muscle pain. People with compromised immune systems are at higher risk for severe or recurrent infections.
Chlamydiosis (see above, Direct Contact: Handling Contaminated Tissues during Lambing or Kidding)
People are most often exposed by ingesting bacteria by way of unwashed hands after contact with an ill animal.
Cryptosporidiosis results from infection by Cryptosporidium parvum, a coccidian parasite common in the environment and carried by many animals without symptoms. People often become infected by ingestion following contact with objects contaminated with feces or unwashed hands after contact with ill animals. Infections in people can cause stomach cramps, watery diarrhea, nausea and a poor appetite. Vomiting, fever, and muscle aches may also occur.
Escherichia coli (E. coli)
Although most Escherichia coli are harmless bacteria and part of the normal intestinal flora, some serotypes such as E. coli O157:H7 can cause intestinal disease (food poisoning) in humans, resulting in bloody diarrhea, kidney failure, and death. People can become infected by ingestion following contact with feces of infected animals (and humans) in contaminated food, and water.
Listeria monocytogenes causes listeriosis, a bacterial disease in ruminants and humans. Most infections in people occur by eating raw meat or unpasteurized dairy products (oral), but there are additional ways to be infected. Animals can shed L. monocytogenes in the feces, milk and uterine discharges. Pregnant women or immunocompromised people should take special care to avoid unpasteurized dairy products. Unlike other bacteria, L. monocytogenes can grow in cold temperature, including in the refrigerator. A skin infection form of the disease can occur in people who handle sick animals.
Q Fever (see below, Inhalation)
Transmission can also occur by the ingestion of unpasteurized milk.
People most commonly get salmonellosis from eating (oral) improperly cooked food, such as meat, eggs or unpasteurized milk/dairy products. People can also get salmonellosis by direct contact with feces/diarrhea from infected animals. People with salmonellosis may have diarrhea, fever and abdominal cramping.
Sarcocystosis is a disease caused by a group of parasitic protozoan species, Sarcocytis. People can get sarcocystosis by ingesting (oral) the protozoan, most commonly through undercooked meat products. Symptoms in people with muscular disease caused by sarcocystosis may include muscle tenderness or painful swelling, muscle weakness, headache, cough, transient itchy rashes. Symptoms in people with intestinal disease caused by sarcocystosis may include fever, chills, sweating, abdominal pain, diarrhea, nausea, vomiting.
Toxoplasmosis is a disease caused by a microscopic protozoal parasite called Toxoplasma gondii. People can get toxoplasmosis by ingesting (oral) Toxoplasma gondii from undercooked meat. Infections in people cause flu-like signs (fever, body aches, headache, sore throat). Toxoplasmosis can cause abortion or birth defects in pregnant women. Pregnant women or immunocompromised people should avoid contact with pregnant or aborting animals.
Anthrax (see above, Direct Contact: Directly Handling Sheep and Goats, and Oral)
People can become infected after inhaling spores from animal products, but natural cases of inhalational anthrax are rare. *Weaponized anthrax can readily form aerosols. Symptoms of respiratory infection in humans include fever, coughing, severe chest pain and difficulty breathing may occur.
Q Fever (Query Fever, Coxiellosis)
Q fever results from infection by the bacterium, Coxiella burnetii, which can infect people who inhale aerosolized organisms, or by additional routes. Most human infections are associated with cattle, sheep and goats, and often occur when the animal gives birth. Symptoms of Q fever include fever, chills, night sweats, headache, fatigue and chest pains. Q fever can cause abortion or premature delivery in pregnant women, so pregnant women should avoid contact with pregnant or aborting animals.
Sheep are the most important hosts for louping ill virus. Humans can be infected via tick bites (vector) or by contact with the virus in tissues or laboratory cultures. Infection in people causes non-specific flu-like signs (night sweats, fever, headaches, back pain) and joint pain. This is a foreign animal disease State and Federal veterinarians should be notified immediately of any suspected cases of louping ill.
**Rift Valley Fever
Mosquitoes transmitRift Valley fever, a viral disease, to cattle, sheep, and goats. In addition to mosquitoes (vector), the virus may also be spread through aerosol from infected animal tissues or fluids (blood, urine, fetal fluids). People often become infected during slaughter or when assisting the delivery of newborn animals. Symptoms may include dizziness, weakness, fever, stiffness of the neck, headache, and sensitivity to light. This is a foreign animal disease State and Federal veterinarians should be notified immediately of any suspected cases of Rift Valley Fever.
Screwworms are the larvae (maggots) of a certain fly species that most often feed on living tissue of mammals. Humans can get screwworm (by flies depositing larvae on an open wound, just as in animals. The disease can quickly become debilitating if it affects the eyes, mouth, nasal or frontal sinuses or the ears. This is a foreign animal pest State and Federal veterinarians should be notified immediately of any suspected cases of New World or Old World Screwworm.
**This symbol indicates that the disease is foreign to the United States (FAD: Foreign Animal Disease), so State and Federal animal health authorities must be notified immediately of any suspected cases.
Signs and symptoms will vary depending on the particular disease involved, and the individual affected. Only your doctor can provide an adequate diagnosis of a zoonotic disease, based on the signs or symptoms and laboratory results. Contact your physician immediately if you are exhibiting signs of illness after being in contact with infected or potentially infected animals.
Reduce your risk of contracting a zoonotic disease by washing your hands thoroughly and frequently. Also, wear protective equipment such as gloves, coveralls and boots when working with sheep and goats, and other susceptible species. Practice good sanitation and personal hygiene. Anyone who has contact with animals has some risk of getting zoonotic diseases, but some groups of people may be more at risk than others, such as pregnant women, children, the elderly, people with a genetic predisposition and immunocompromised individuals.