What Types of Diseases Can Humans Get From Animals?

Animals can be source of diseases affecting humans.

The World Health Organization defines zoonoses as diseases or infections that humans can get from animals and vice versa. Diseases that people can get from animals are called zoonotic diseases. These involve infectious agents that humans can get directly from animals or from their environment. These diseases may be classified according to the types of the causative agents.

Viruses

Racoons can be a source of rabies.

Rabies is a common viral infection that attacks the central nervous system and the brain. The virus is typically transmitted through bites or scratches where open skin allows the virus to enter the body to affect the brain. The State of Missouri Department of Health and Senior Services reports that 7,000 to 8,000 rabid animals are found in the United States each year. Rabies is common in racoons, skunks, rodents, cats, dogs, and bats.

The West Nile virus is another common viral infection in humans that originates in birds and mosquitoes. The Arizona Department of Health Services indicated that 80 percent of infected people usually do not show symptoms, while flu-like symptoms are seen in 20 percent of infected individuals. Other viral diseases are avian influenza, Ebola virus, Crimean-Congo Hemorrhagic Fever, Herpes Fever, and Rift Valley Fever.

Bacteria

Foodborne diseases are commonly caused by bacterial agents. These include Salmonellosis and campylobateriosis, illnesses that can cause diarrhea, body malaise, fever, abdominal pain, and nausea. Anthrax, leptospirosis, Q fever, shigellosis, brucellosis, Escherichia coli, plague, and tularaemia are other bacterial zoonoses.

Many bacterial strains have become resistant to antibiotics, resulting in the uncontrolled spread of infection. The industrialization of food production also contributes to the risk of contamination.

Urogenital tract infections, gastroenteritis, arthritis, lymphadenitis, intestinal infection and meningitis are other symptoms that occur due to bacterial infection.

Parasite

Some parasites can penetrate the skin of a bare foot.

Parasitic infection can cause seizures, irritable bowel diseases, and headache. Common parasitic zoonoses include trichinellosis, echinococcosis, and trematodosis. Children are the most likely candidates for this type of disease. Adults with compromised immune systems and those with occupational exposure to the disease are also at risk.

Infection in humans is commonly acquired through ingestion of the parasite eggs on through an insect bite. Skin penetration on bare feet is also common. Other forms of parasitic infection include hookworms, roundworms, and tapeworms. A contaminated environment and poor hygiene may put anyone at risk of parasitic infection.

Fungi

Nail infection may be caused by fungal zoonoses.

Fungal zoonoses usually affect the skin, nails and hairs of human beings with resulting symptoms of itchiness, scaling, redness, and hair loss. Sporotrichosis is a common disease found in cats that causes mycotic infection affecting the skin in humans. The sites of infections for fungal zoonoses may be superficial, cutaneous, sub-cutaneous, and systemic. The outer layer of the skin and hair are involved with superficial infection while the nails, skin, and hairs are affected with the cutaneous type of infection. The fungi implant in the skin, producing lesions affecting deeper skin layers and muscles in sub-cutaneous infection, while systemic infection involves the spread of fungi to the lungs or other organs, leading to pulmonary and other infections.

References

• World Helath Organization: Zoonoses and Veterinary Public Health
• Missouri Department of Health and Senior Services: Rabies Surveillance
• Vetres.org: "Emerging and Re-emerging Bacterial Zoonoses"; Jean Blancou et al; 2004

Resources

• Westmount Animal Clinic: Parasitic Zoonoses
• Centers for Disease Control and Prevention: Animals