An illness transferred from animals to humans is called a zoonotic disease. COVID-19 is a zoonotic disease that may have passed from live animals in Wuhan, China, to humans in the Huanan Market — though the data on this is still new.
Examples of Zoonotic Diseases
However the virus was transmitted, this is hardly the first time humans have had to worry about a zoonotic disease. Here are four other diseases that were passed from animals to humans.
According to the Centers for Disease Control (CDC), rabies is a fatal but preventable virus. It is most often transmitted to humans or pets if bitten or scratched by a rabid animal. If left untreated, the virus will infect the central nervous system and spread until the brain and spinal cord are inflamed, resulting in death.
According to the World Health Organization (WHO), most rabies cases are spread through dog bites. However, in North and South America, bites from hematophagous bats are the leading cause of rabies transmissions.
Common animals that carry rabies are raccoons, foxes, skunks, jackals, mongooses, bats and unvaccinated dogs. If you are bitten or scratched by a wild animal you believe may have rabies, seek medical attention immediately.
2. Cat Scratch Disease
Cat scratch disease, according to the CDC, is a bacterial infection transmitted from cats. Infection can happen if a cat has licked a person's open wound, or the cat scratches or bites them hard enough to break the skin.
The bacteria can cause swelling and redness around the wound site, and round, raised lesions. The bacteria may also cause swollen lymph nodes near the wound and symptoms like fever, fatigue, headache and loss of appetite.
Cats can pick up the bacteria (Bartonella henselae) from scratching and biting fleas. According to the CDC, kittens are more likely to carry and spread the disease.
3. Bubonic Plague (Black Death)
While the bubonic plague may seem like something we only ever read about in history books, the bacterial infection is still around today. According to the Cleveland Clinic, the bubonic plague killed over 25 million people in Europe during the 14th century. The bacterium, Yersinia pestis, spread from fleas to humans — typically fleas on rodents, like rats. Symptoms of the bubonic plague often included large, swollen lymph nodes that oozed puss.
Today, humans can still contract bubonic plague via flea bites, but also from their cats, who may have eaten an infected rodent or scratched an infected flea. Bubonic plague, while severe, is treatable with common antibiotics.
4. Lyme Disease
Along with being zoonotic, Lyme disease is also the most common vector-borne disease — one spread by fleas, ticks or mosquitos — in the U.S., according to the CDC. The bacterium, Borrelia burgdorferi (or rarely Borrelia mayonii), is usually spread to humans via bites from certain ticks.
Symptoms can include fever, fatigue, headache and a bullseye-shaped rash. Lyme disease can spread to the heart, joints and even the central nervous system without treatment. However, if noticed right away, Lyme disease is easily treated with antibiotics.
Read More: What You Need to Know About Lyme Disease