Pets are increasingly important in this and other developed countries.
Many pet owners are unaware of the diseases and parasites their pets may harbor that can cause illness to humans. This is one reason that proper veterinary care through routine visits to a veterinarian is so important.
The transmission of diseases between people and pets is the basis for the “One Health Initiative” whose goal is to “unite human and veterinary medicine.” Check out their website, where you will find information about the history of this organization and the important work they are undertaking to share information about the new or re-emerging diseases, 70% of which are zoonotic (spread between animals and humans) or vector-borne (transmitted by vectors, including insects).
As recently discussed here, cats, like other animals can harbor and transmit a number of diseases and parasites to humans. The Centers for Disease Control and Prevention, the leading public health institute in the United States, contains a plethora of scientific information and data on its website, including “[t]he most common diseases associated with cats that can cause human illness.”
The description of these diseases and parasitic disorders is republished below to demonstrate why it is so important for cat owners to take care of their pets, which, in turn will help keep all family members healthy.
Campylobacter is a type of bacteria that spreads through contaminated food (meat and eggs), water, or contact with stool (poop) of infected animals. Cats infected with Campylobacter may show no signs of illness at all or may have diarrhea.
Most people who become sick with campylobacteriosis will have diarrhea, cramping, abdominal pain, and fever within 2-5 days after exposure to the organism. Campylobacter bacteria can cause serious life-threatening infections in infants, older persons, and those with weakened immune systems.
Cat-scratch disease is a bacterial disease that people may get after being bitten or scratched by a cat. About 40% of cats carry the bacteria at some time in their lives, although kittens younger than 1 year of age are more likely to have it. Most cats with this infection show no signs of illness.
People who are bitten or scratched by an affected cat may develop a mild infection 3-14 days later at the site of the wound. The infection may worsen and cause fever, headache, poor appetite, and exhaustion. Later, the person’s lymph nodes closest to the original scratch or bite can become swollen, tender, or painful. Seek medical attention if you believe you have cat-scratch disease.
Cheyletiellosis is a mild, short-term skin inflammation caused by mites that feed on skin cells. Cheyletiella is spread through contact with infested animals. Pets such as rabbits and adult cats may not show signs of infestation. However, affected kittens may have patches of scaly skin with dandruff.
The most common symptoms of cheyletiellosis in people include itching, redness, and raised bumps on areas of the skin that touched the infested animal. Cheyletiellosis in people generally resolves on its own.
Cryptosporidiosis is a parasitic disease that is transmitted through contaminated food or water from an infected person or animal. Cryptosporidiosis in cats is rare, but they can carry the germ without showing any signs of illness.
Cryptosporidiosis can cause profuse, watery diarrhea with cramping, abdominal pain, and nausea in people and many types of animals. Illness in people is usually self-limiting and lasts only 2-4 days, but can become severe in people with weakened immune systems.
Echinococcosis is a disease caused by eating or drinking food and water contaminated with tapeworm eggs or through contact with an infected animal. Cats become infected by eating tissue of an infected animal. Cats rarely show any signs of disease, but can be infected with a large number of adult tapeworms.
Although Echinococcus invades many different organs of the body, most people who are infected with the disease will not have any signs of illness for years. Symptoms start when the slow-growing cysts become large enough to press on the organs they have invaded. The tapeworms grow slowly in several different organs of the body, most commonly the liver and lungs.
Giardia is a parasite that causes diarrhea in animals and people. Giardia is transmitted to animals and people through food or water contaminated with stool.
Symptoms for animals and people include diarrhea, greasy stools, and dehydration. People can also have abdominal cramps, nausea, and vomiting. Symptoms can last 1-2 weeks.
Cat hookworms are tiny worms that can spread through contact with contaminated soil or sand. Cats can also become infected with hookworms through accidentally ingesting the parasite from the environment or through their mother’s milk or colostrum. Hookworm infections can cause anemia and weight loss in kittens. Severe infections can be fatal.
People become infected with cat hookworms while walking barefoot, kneeling, or sitting on ground contaminated with stool (poop) of infected animals. Hookworm larvae enter the top layers of skin and cause an itchy reaction called cutaneous larva migrans. A red squiggly line may appear where the larvae have migrated under the skin. Symptoms usually resolve without medical treatment in 4-6 weeks.
Staphylococcus aureus is a common type of bacteria that is normally found on the skin of people and animals. Methicillin-resistant Staphylococcus aureus (MRSA) is the same bacterium that has become resistant to some antibiotics. Cats and other animals often can carry MRSA without being sick, but MRSA can cause a variety of infections, including of the skin, respiratory tract, and urinary tract.
MRSA can be transmitted back and forth between people and animals through direct contact. In people, MRSA most often causes skin infections that can range from mild to severe. If left untreated, MRSA can spread to the bloodstream or lungs and cause life-threatening infections.
Pasteurellosis is a bacterial disease associated with animal bites and scratches. Pasteurella is a normal bacterium that lives in the mouths of healthy cats. The bacteria do not typically make cats sick; however, cats can develop abscesses or skin infections in places where they were scratched or bitten by another animal.
In people, pasteurellosis causes painful wound and skin infections. In severe cases, it can cause widespread infection and might even affect the nervous system.
Plague is a bacterial disease in animals and people that can lead to serious illness or death if left untreated. Cats are highly susceptible to plague and their symptoms are similar to those experienced by humans. Cats that hunt wild rodents and rabbits in the western, particularly the southwestern, United States are at greatest risk of becoming infected.
People most often become infected through flea bites or from contact with body fluids of infected animals. Bubonic plague is the most common form; symptoms include sudden onset of high fever, chills, headache, malaise, and swollen lymph nodes. The other two forms of plague, septicemic and pneumonic, cause more severe disease. Cats infected with plague can infect people through bites, scratches, coughs, or sneezes.
Rabies, a fatal neurologic disease in animals and people, is caused by a virus. Animals and people are most commonly infected through bites from rabid animals. Infected cats may have a variety of signs, but most often have sudden behavioral changes and progressive paralysis. Cats may also appear restless, pant, and attack other animals, people, or objects. Animals with rabies typically die within a few days of appearing sick. Owners should vaccinate their cats against this deadly disease.
The first symptoms in people can start days to months after exposure; they include generalized weakness, fever, and headache. Within a few days, symptoms progress to confusion, anxiety, and behavioral changes. If you have been bitten by a cat or other animal and feel that there is a risk for rabies, contact your health care provider right away. Once symptoms appear, it is almost always too late for treatment.
Ringworm is a condition caused by a fungus that can infect skin, hair, and nails of both people and animals. Ringworm is passed from animals to people through direct contact with an infected animal’s skin or hair. Cats infected with ringworm typically have small areas of hair loss around their ears, face, or legs, with scaly or crusty skin. But some cats carrying ringworm have no signs of infection at all. Kittens are most commonly affected.
Ringworm infections in people can appear on almost any area of the body. These infections are usually itchy. Redness, scaling, cracking of the skin, or a ring-shaped rash may occur. If the infection involves the scalp or beard, hair may fall out. Infected nails become discolored or thick and may possibly crumble.
Toxocara roundworms cause a parasitic disease known as toxocariasis. Cats and people can become infected by swallowing roundworm eggs from the environment. Cats can also become infected as young kittens. Larval worms can come through the milk of a mother cat, passing the infection on to her kittens. Infected kittens usually do not seem sick. Those that do may have mild diarrhea, dehydration, rough coat, and a pot-bellied appearance.
In people, children are most often affected with roundworm. There are two forms of the disease in people: ocular larva migrans and visceral larva migrans. Ocular larva migrans happens when the larvae invade the retina (tissue in the eye) and cause inflammation, scarring, and possibly blindness. Visceral larva migrans occurs when the larvae invade parts of the body, such as the liver, lung, or central nervous system.
Salmonella spreads to people through contaminated food (eggs and meat) or contact with stool of certain animals, including cats. Cats can get salmonellosis through eating infected birds. While it usually does not make the cats sick, Salmonella infection can cause serious illness when it is passed to people.
People infected with Salmonella bacteria may have diarrhea, vomiting, fever, or abdominal cramps. Infants, elderly persons, and those with weakened immune systems are more likely than others to develop severe illness.
Sporotrichosis is a fungal disease that can affect both animals and people. It is usually acquired from the environment through a cut or scrape in the skin but can be acquired from contact with animals as well. Infection with sporotrichosis in cats can range from no signs of illness to very serious disease. Signs often begin with small draining wounds that become raised lumps with the surface eroded away. The disease can worsen.
Three forms of sporotrichosis can infect people.
The first form is the cutaneous or skin form, which can progress from small raised areas on the skin to infection invading the lymph nodes and forming nodules that eventually ulcerate.
The second is the disseminated form, which occurs when the infection affects the internal organs and bones.
In the third form, the pulmonary form, a person acquires the infection through inhalation the fungus into the lungs, which often leads to chronic disease similar to tuberculosis.
Most healthy people who become infected with Toxoplasma show no signs or symptoms. However, pregnant women and people who have weakened immune systems may be at risk for serious health complications.
Toxoplasmosis is a parasitic disease that can spread to people and animals through contaminated soil, water, or meat, and contact with stool from an infected cat. Cats are the main source of infection to other animals but rarely appear sick.
The latter two forms are potentially fatal.