While animals around the farm may appear healthy, they may be carrying a disease that can infect you and family members. These diseases can be transmitted through everyday contact with the animal, or through contact with their carcasses or other by-products. A person can also be infected by just entering a contaminated animal housing facility. Diseases that can be transmitted from animals to humans are referred to as zoonotic diseases or zoonoses.
It is important for farmers to know about zoonotic diseases because the symptoms are frequently similar to other types of illnesses. Symptoms of psittacosis (ornithosis) for example, range from a flu-like illness to acute pneumonia. For proper diagnosis and treatment, your healthcare professional must be also aware of any potential sources of the infection. While there are many zoonotic diseases, this factsheet will address those where there is some potential for infection in Michigan. This is only a partial list of zoonotic diseases in the state.
Some of the more obvious zoonotic diseases can be the result of being scratched or bitten by an animal or from milking. Symptoms of one of the most common zoonotic diseases, Cat-Scratch Fever, can include localized pain, swelling, redness and fever. Another common zoonotic disease is Milkers' Nodules, which frequently results in pustules on the hands and fingers after being infected. Ringworm is a common zoonotic disease that causes pustular nodules with hair loss in exposed areas of the body head or arms.
Zoonotic diseases are caused by bacteria, viruses, chlamydia, fungi and parasites. Animal sources for zoonosis include cattle, sheep, horses, pigs, chickens, turkeys, dogs, cats, rodents and some wild animals. Depending on the disease, all of these animals can be a source of infection (See Table 1).
Steps to minimize the risk of contacting a zoonotic disease include wearing gloves for certain activities, a well-managed vaccination program, and good sanitation and personal hygiene.
| Table 1. Animal Diseases that can infect humans | ||||
| Disease | Common Source | Clinical Effects | Mode of Acquisition | Prevention |
| Bacterial Diseases | ||||
|---|---|---|---|---|
| Campylobacter | Cattle, Sheep Pigs, Dogs Rodents Poultry | Acute gastroenteritis nausea headache, diarrhea | Direct contact food contaminated with animal feces | Avoid contact with infected animals and feces contaminated food |
| Cat-scratch diseases | Cats, Dogs Fomites | Fever, primary skin papule, regional lymphadenopathy | Direct contact with infected animals | Avoidance of animal scratches and puncture wounds |
| Salmoneliosis | Cattle, Cats Dogs, Horses Poultry, Turtles | Chills, fever, headache, diarrhea, vomiting | Direct contact with animal or its feces, food contamination from infected animals | Improved food processing and preparation |
| Viral Diseases | ||||
| Encephalitis | Horses Rodents | Lethargy, fever headache, disorientation | Mosquito or tick bite | Protective clothing, insect repellents |
| Rabies | Cats, Dogs Raccoons Skunks, Bats Foxes | Fever, headache, agitation, confusion, seizures, excessive salivation, death | Animal bite, contact with infected tissue, body fluids or feces | Avoid contact with suspected animals, local wound care, pre- and post- exposure immunization/ vaccination |
| Chlamydial Diseases | ||||
| Psittacosis (Ornithosis) | Pigeons Turkeys Parakeets Parrots | Fever, headache, pneumonia | Inhaled from infected birds, carcasses, secretions and contaminated facilities | Avoid contact with infected birds, control of disease with antibiotics |
| Fungal Diseases | ||||
| Ringworm | Cats, Cattle | Skin lesions | Direct contact | Avoid close contact with infected animals, Children and individuals with immune suppressed system are more susceptible |
| Parasitic Diseases | ||||
| Tosocariasis (Visceral larval migrans) | Dogs Raccoons Cats | Eye disease, brain disease | Ingestion and contact with infected ovum of parasites | Treat pets, avoid fecal contaminated soil and sandboxes |
| Toxoplasmosis | Cats, Sheep Undercooked meat | Fever, lymph- adenopathy, abortion, still- birth, mental retardation | Ingestion of infected meats, oocysts in fecal contaminated soil | Proper disposal of cat feces, cook meat well, avoid contaminated soil (especially pregnant women and immune compromised individuals) |
| Scabies | Dogs Raccoons | Itching skin Lesions | Direct contact with infected animals | Treat pets, avoid contact with infected animals |
Michigan State University.
Kenneth D. Rosenman, M.D., Occupational Medicine, Michigan
State University, 5/92. Funded by the National Institute of
Occupational Safety and Health - #UO5/CC-4506052-01.
Disclaimer and Reproduction Information: Information in NASD does not represent NIOSH policy. Information included in NASD appears by permission of the author and/or copyright holder. More
