Comforting as it may be, snuggling with your beloved pet may end up making you ill. This is because some common house pets and farm animals can infect you with a zoonotic disease. Zoonotic diseases are diseases passed from animals to humans.

From mild to fatal, zoonotic diseases may have very little impact on animals but lead to death in humans.

1. Cat scratch disease (CSD)

Humans can contract this bacterial infection when an infected cat scratches or bites them. A cat can also transfer the disease if it licks an open wound on a human body.

The disease is caused by a bacterium called Bartonella henselae.

Symptoms of CSD, which include fatigue, headaches, swollen lymph nodes, may only appear 14 days after the initial infection and may result in brain disease or inflammation of the optic nerve.

2. Listeriosis

The disease, which recently led to the death of a pregnant South African woman, is mostly contracted through the ingestion of contaminated food. 

The bacterium, Listeria monocytogenes, is occurs in poultry and cattle and can be passed to humans through the ingestion of the meat of an infected animal, or dairy products made from the milk of infected cattle.

Symptoms of the disease range from headaches to confusion and seizures. Listeriosis can be fatal in some cases.

3. Rabies

Perhaps the most commonly known zoonotic disease, rabies causes more than 59 000 worldwide deaths annually. According to the South African National Travel Health Network (SaNTHNet), 95% of deaths as a result of rabies occur in Africa and Asia. 

Rabies can be transferred to humans through the bite of an infected animal. In South Africa, many reported cases are a result of dog bites.

Fever, intolerance of bright light, hyperactivity as well as fear of water are some of the symptoms of rabies.

Paralytic rabies, which accounts for 30% of human rabies cases, can result in gradual paralysis and eventually death.

4. Query Fever

Also called Q fever, this bacterial infection can be passed from animals to humans by simply breathing in dust that has been exposed to the faeces, urine or milk of an infected animal.

Likely to be found in goats, sheep and cattle, severe infection can lead to pneumonia and hepatitis.

Infected humans will experience fever, night sweats or chills, stomach pains, nausea and vomiting.

5. Plague

With most cases of the plague occurring in Africa, this zoonotic disease can be fatal if left untreated.

Often passed to humans through the bite of an infected rodent or fleas, symptoms of the plague begin to show within six days of the onset of infection. Infected people will experience chills, chest pain, body aches as well as a sudden fever. 

If left untreated, the bacteria could enter the bloodstream and cause septicemic plague. The bacteria can also enter the lungs and result in pneumonic plague – which is fatal if not treated early. 

^{Image credit: iStock}

Nyakallo Moleko