Diseases that pass from animals to humans are called zoonotic diseases, and can be caused by viruses, bacteria, parasites and fungi. They are very common, and the Centers for Disease Control (CDC) estimates that 75 percent of emerging infectious diseases originate in animals, with about six in 10 considered zoonotic.
There are two ways diseases pass from animal to human, according to Dr. Gregory Warner, an infectious disease specialist at NorthBay Medical Center. Disease can spread directly through contact with the saliva, blood, urine or feces of an infected animal, or by being bitten by a tick or mosquito (often called a “vector”) that carries disease.
Zoonotic diseases can result from contact with infected live poultry, rodents, reptiles, amphibians, insects and other domestic and wild animals.
“Rabies is the most widely known zoonotic disease because it is fatal if not treated,” Dr. Warner says. “It is a virus spread by contact with an infected animal’s saliva, such as through a dog bite. In Solano County, bats are the main carrier of rabies.”
How to Avoid Animal-Borne Diseases
- Wash your hands often, especially after you touch, feed, or clean up after a pet.
- Wear gloves while cleaning animal cages or cat litter boxes.
- Avoid washing your pet in the kitchen sink or bathtub; if you do, always disinfect it with bleach immediately afterward.
- Don’t let pets lick your cuts, scrapes or healing wounds.
- Don’t let pets drink out of the toilet.
- Maintain the veterinary care recommended for your pet.
- Don’t handle wild animals or birds, especially if they appear sick.
- Use EPA-registered insect repellents that contain 20 percent or more DEET on any exposed skin for several hours of protection from insect bites.
Dogs and cats carry a variety of germs in their saliva and feces that can make people sick. For example, Campylobacter is a type of bacteria that can live in the digestive systems of animals. People who come into contact with these bacteria can experience unpleasant symptoms such as diarrhea, abdominal pain, and fever.
Bartonella henselae is a type of bacteria that causes what is known as cat scratch disease. A person who gets bitten or scratched by a cat that has been infected with the bacteria may develop swollen and tender lymph nodes, headache, abdominal pain, and fever.
Dogs who drink from stagnant water can pick up Giardia, a microscopic parasite that causes the diarrheal illness known as giardiasis.
“You can avoid most of these conditions with basic cleanliness,” Dr. Warner advises. “Avoid contact with animal saliva and feces, including letting your dog lick your face, is my best advice,” Dr. Warner says.
West Nile virus is a disease that has been carried to California by birds. There is active surveillance of the disease during the warm months, when it can spread to humans and horses by mosquito bite. Three human cases were reported in Solano County last year, according to Dr. Warner. In 2012, California saw 479 human West Nile virus cases, with
Ticks are responsible for passing along several diseases, depending on the area of the country you live in. If you hike outdoors, or take dogs outdoors, be sure to check for ticks when you return home. In Northern California, blacklegged ticks are responsible for passing along a form of Lyme disease.
Salmonellosis, a bacterial infection caused by salmonella infection, is common and can be contracted several ways, Dr. Warner says. Contact with animal feces and not washing your hands is one way it spreads. It is also associated with handling reptiles, such as turtles, lizards and snakes, and baby chicks and ducklings. Symptoms usually begin from 12 hours to three days after you are infected and can include diarrhea, fever, abdominal cramps and headache. These symptoms, along with nausea, loss of appetite and vomiting, usually last for four to seven days.
Toxoplasmosis is an infection caused by a parasite and carried by cats and passed in their stool. Pregnant women are advised to avoid cat litter boxes because the parasite can cause problems with pregnancy, including spontaneous abortion. However, people are more likely to get toxoplasmosis from eating undercooked meat or gardening than from contact with pet cats, according to the CDC.
A person’s age and health status may affect his or her immune system, increasing their chances of getting sick. Children younger than age 5, organ transplant patients, people with HIV/AIDS, and people with cancer can be more susceptible, as can the elderly and those with diabetes.
Ringworm is a Contagious Fungus
Ringworm is a Contagious FungusRingworm is the most commonly seen zoonotic disease, says Fairfield Veterinarian Kelly Palm. It’s a skin infection caused by a fungus called tinea, not a worm as the name suggests.
Ringworm is very contagious and spreads easily from person to person, pet to person and person to pet. It is also spread by contact with items contaminated by the fungus, such as combs, unwashed clothing, and shower or pool surfaces.
Ringworm is often associated with cats, especially kittens, but dogs can spread it too. In animals it shows up as irregular patches of hair loss, usually around the face or feet. In humans, it appears as circular, reddish-edged patches on the skin.
Ringworm is usually treated with an antifungal lotion or cream and takes about four weeks to cure. Your physician may prescribe antifungal pills for severe or reoccurring infections.
Tips to prevent ringworm:
- Don’t touch pets with bald spots.
- Don’t share personal items such as towels, hairbrushes, headgear or clothes.
- Wear sandals or shoes at gyms and public pools.
- Keep your skin and feet clean and dry.
- Shampoo regularly, especially after a haircut.
Don’t Blame Fido if You Get Head Lice
If your child has head lice, don’t blame the dog. Unlike fleas and ticks, head lice is “species specific.” This means that lice don’t jump from pets to humans and vice versa, according to Fairfield veterinarian Kelly Palm.
People get head lice by head-to-head contact with an already infested person. This is common during play at school, at home, or elsewhere (camp, sports activities, slumber parties). Lice don’t have wings, so they don’t fly, hop or jump. But they are fast!
The good news is that head lice are not known to spread disease. They can be an annoyance because their presence may cause itching and loss of sleep. Sometimes the itching can lead to excessive scratching that can sometimes increase the chance of a secondary skin infection.
If you are unsure whether someone has head lice, check with your health care provider.