Zoonotic diseases

Zoonosis is another name for a zoonotic disease. This type of disease passes from an animal or insect to a human. Some don’t make the animal sick but will sicken a human.

Zoonotic diseases range from minor short-term illness to a major life-changing illness. Certain ones can even cause death.


The types of zoonosis include those caused by:

  • viruses
  • bacteria
  • fungi
  • parasites

Zoonotic diseases spread by mosquitoes and ticks are some of the most serious of these diseases.

List of known zoonotic diseases

Disease Main reservoirs Usual mode of transmission to humans
Anthrax livestock, wild animals, environment direct contact, ingestion
Animal influenza livestock, humans may be reverse zoonosis
Avian influenza poultry, ducks direct contact
Bovine tuberculosis Cattle Milk
Brucellosis cattle, goats, sheep, pigs dairy products, milk
Cat scratch fever Cats bite, scratch
Cysticercosis cattle, pigs Meat
Cryptosporidiosis cattle, sheep, pets water, direct contact
Enzootic abortion farm animals, sheep direct contact, aerosol
Erysipeloid pigs, fish, environment direct contact
Fish tank granuloma Fish direct contact, water
Campylobacter poultry, farm animals raw meat, milk
Salmonella poultry, cattle, sheep, pigs foodborne
Giardiasis humans, wildlife waterborne, person to person
Glanders horse, donkey, mule direct contact
Haemorrhagic colitis Ruminants direct contact (and foodborne)
Hantavirus syndromes Rodents aerosol
Hepatitis E not yet known not yet known
Hydatid disease dogs, sheep ingestion of eggs excreted by dog
Leptospirosis rodents, ruminants infected urine, water
Listeriosis cattle, sheep, soil dairy produce, meat products
Louping ill sheep, grouse direct contact, tick bite
Lyme disease ticks, rodents, sheep, deer, small mammals tick bite
Disease Main reservoirs Usual mode of transmission to humans
Lymphocytic choriomeningitis Rodents direct contact
Orf Sheep direct contact
Pasteurellosis dogs, cats, many mammals bite/scratch, direct contact
Plague rats and their fleas flea bite
Psittacosis birds, poultry, ducks aerosol, direct contact
Q fever cattle, sheep, goats, cats aerosol, direct contact, milk, fomites
Rabies dogs, foxes, bats, cats animal bite
Rat bite fever (Haverhill fever) Rats bite/scratch, milk, water
Rift Valley fever cattle, goats, sheep direct contact, mosquito bite
Ringworm cats, dogs, cattle, many animal species direct contact
Streptococcal sepsis Pigs direct contact, meat
Streptococcal sepsis horses, cattle direct contact, milk
Tickborne encephalitis rodents, small mammals, livestock tickbite, unpasteurised milk products
Toxocariasis dogs, cats direct contact
Toxoplasmosis cats, ruminants ingestion of faecal oocysts, meat
Trichinellosis pigs, wild boar pork products
Tularemia rabbits, wild animals, environment, ticks direct contact, aerosol, ticks, inoculation
Ebola, Crimean-Congo HF, Lassa and Marburg viruses variously: rodents, ticks, livestock, primates, bats direct contact, inoculation, ticks
West Nile fever wild birds, mosquitoes mosquito bite
Zoonotic diphtheria cattle, farm animals, dogs direct contact, milk


How they are transmitted

Zoonoses can be transmitted in various ways:

  • through the air
  • by eating contaminated meat or produce
  • through close contact with an infected animal
  • by touching an area or surface that an infected animal touched
  • through insect bites like mosquitoes or ticks

Many transmissions occur when people hike, bike, boat, or enjoy other activities in the great outdoors.

Petting zoos are also common places for a zoonotic disease to be transmitted.

Those who live and work on farms are in close contact with many types of livestock. Livestock is a common carrier of many zoonoses.

Your family pet can carry ticks and fleas indoors that can then move onto you and your family.


What to do if you have a zoonotic disease

If you have or think you have a zoonotic disease, you should contact a medical professional as soon as possible.

If you’re scratched or bitten by an animal, be sure to have the animal thoroughly checked by a veterinarian. This is to make sure that they’re appropriately vaccinated and don’t have rabies or other zoonotic diseases.

If you’ve been bitten by a tick, try to preserve the tick after removal in a safe container. This way it can be identified to narrow down the possible diseases that it might transmit and tested for any of those diseases.

Although zoonotic diseases are common, some people are at higher risk of getting them. These individuals may also have more severe reactions and symptoms. If you’re one of these individuals at risk, you should seek medical attention immediately if you think you may have a zoonotic disease. High-risk individuals include:

  • pregnant women
  • adults aged 65 or older
  • children 5 years old or younger
  • those with HIV
  • those with cancer who are going through chemotherapy
  • others with weakened immune systems


Zoonotic diseases are common everywhere in the world. However, the United States and other countries work constantly to reduce the number of illnesses caused by animals and insects. One way they do this is through creating food safety regulations. These regulations reduce the chances of getting a zoonotic disease from something you eat in a developed country.

There are also ways to help prevent getting a zoonotic disease. These include the following:

  • Wash your hands diligently.
  • Use insect repellent or other methods to keep mosquitoes, fleas, and ticks away.
  • Practice safe food handling. This includes washing off all produce before eating it.
  • Avoid being bitten or scratched by an animal.
  • Have your pets vaccinated and take them for regular annual visits to the veterinarian.
  • Talk to your veterinarian about appropriate flea and tick preventatives for your pets.
  • Check for ticks when you’ve been outside.
  • Don’t eat, drink, or touch your eyes or mouth while you’re handling or in close contact with animals.
  • Use gloves if you need to handle an animal that is or appears to be sick.
  • Keep any areas where animals are kept clean and sanitary.
  • Be aware of areas where animals or insects might be when you’re out in nature, especially when you participate in activities like hunting and camping.
  • Don’t handle or approach any animal in the wild that appears sick. Be sure to contact animal control or the local government to have the sick animal removed.


The seriousness and outlook of zoonotic diseases vary depending on the type of disease you have. Many are treatable, while others can cause serious long-term and even lifelong and fatal conditions. So it’s important that you check with your doctor or a medical professional as soon as you think you might have a zoonotic disease. It’s also an important reason to practice prevention around any animals, wild or domestic.