Home Health A-Z Zoonotic Diseases: Causes, Prevention and More

Zoonotic Diseases: Causes, Prevention and More

Verified By Apollo Doctors July 2, 2022 4794 0
Zoonotic Diseases
Zoonotic Diseases


A Zoonotic disease is also commonly called Zoonosis. Zoonotic diseases pass from an animal or insect to a human. Some of these don’t make the animal sick but will cause health issues in a human.

These diseases range from minor short-term illnesses to significant life-threatening conditions. This article will cover everything one should know about zoonotic diseases and ways to prevent them. 

What are zoonotic diseases?

Animals do help in providing several benefits to humans. Many humans interact with animals in their daily lives, both at home and away from home. Animals provide food, fibre, livelihoods, travel, sport, companionship, and education for humans across the globe. We might encounter animals in rural or urban settings while travelling, visiting animal exhibits or enjoying outdoor activities.

However, animals may carry harmful germs that can spread to humans and cause illnesses which are called zoonotic diseases/zoonoses. Zoonotic diseases are caused by harmful germs like bacteria, fungi, viruses and parasites. These germs may cause many diseases in humans and animals, ranging from mild to severe illness and even death. Animals sometimes appear healthy even when carrying germs that might make humans sick, depending on the zoonotic disease.

How do germs spread between animals and humans?

It is because of the close connection between humans and animals, that it is essential to know the common ways people can get infected with germs, which can cause zoonotic diseases. These can include:

  • Foodborne: Eating or drinking something contaminated, such as unpasteurized milk, undercooked meat or eggs, or raw fruits and vegetables contaminated with faeces from an infected animal.
  • Vector-borne: Being bitten by an insect, like tick, mosquito or flea
  • Direct contact: Encountering the saliva, blood, urine, mucous, faeces, or other body fluids of an infected animal. This can happen while petting or touching animals and through bites or scratches .
  • Waterborne: Drinking or encountering water contaminated with faeces from an infected animal.
  • Indirect contact: Encountering areas where animals reside and roam or objects or surfaces that have been contaminated with germs of these animals. Examples are: aquarium tank water, pet habitats, chicken coops, barns, plants, and soil, as well as pet food and water dishes

Also Read About: Rocky Mountain Spotted Fever

What are the zoonotic diseases caused by a pet?

Listed below are a few of the more common diseases one may get from one’s pet. People with weak immune systems, especially HIV/AIDS, may be more vulnerable than healthy individuals.


It is caused by a protozoan organism, which may cause flu-like symptoms in some people. A woman is pregnant or getting ready to become pregnant must be aware of this disease, as it may infect the fetus and cause a miscarriage or even a severe congenital disability. 

A person is likely to get toxoplasmosis from consuming partially cooked meat or from contact with cat  faeces.

Psittacosis (Parrot Fever)

It’s a bacterial infection that one can get from breathing in dried faeces or respiratory tract fluids from infected birds. This includes birds like parakeets, parrots, macaws, and cockatoos. It may be hard to observe this infection in birds because they often do not show any symptoms. This makes prevention even more difficult.


Dogs and cats can get infested with tapeworms by eating fleas that have been infected. Most human tapeworm infections come from ingesting contaminated meats, but children may pick up tapeworm by accidentally swallowing tapeworm larvae-infected flea. Segments of the tapeworm can be seen in the stool or around the anal area of a pet or human. 

Hookworm and roundworm

These intestinal parasites are found in dogs and cats, particularly kittens and puppies. The eggs or larvae of the worms are passed from pets through stool. People can pick up hookworms through their skin from walking barefoot or playing outside. Hookworm infection can cause itchy or painful skin infections or abdominal symptoms. Roundworm infections may cause no symptoms but may cause nerve or eye damage in some people.


Rabies is caused by a virus and spreads through bites. Rabies is a disease that directly affects the nervous system and is fatal. Early signs of it may be fever or headache. This can rapidly develop into symptoms of sleepiness, confusion, or agitation. Although rabies can spread from pets such as unvaccinated dogs or cats, one is more likely to get it from a wild animal.

Cat scratch disease or bartonellosis

It is a bacterial disease that is spread from cat to cat through fleas, but humans usually become infected through a cat scratch or bite. If a person develops cat scratch disease, they may show a mild infection and flu-like symptoms or more severe problems such as damage to the valves in the heart.

Other Key Zoonotic Diseases include:

NameDescriptionAnimal carrier
Anthrax A very rare but potentially life-threatening disease caused by bacteria that can be transmitted to humans through infected animals/animal products.Cattle, Sheep, Pigs, Goats
Avian Influenza A disease of birds that may occur in individuals in close contact with infected birds or those working with materials/products from infected birds.Birds
Bovine Tuberculosis (bovine TB)A bacterial disease of animals and humans that has clinical symptoms similar to other forms of Tuberculosis  Cattle, Deer, Alpacas, Llamas 
Brucellosis Also called undulant or Mediterranean fever, Brucellosis is a highly transmissible bacterial infection but rare in humans. Transmitted most commonly through contact with infected animals/ingestion of unpasteurised milk/milk products.Cattle, Pigs, Sheep, Goats, Camels
CampylobacteriosisIt causes infectious diarrhoea and mostly affects very young children as well as the elderly.Cattle, Poultry
Creutzfeldt-Jakob disease (CJD)An extremely rare, fatal neurodegenerative disease said to be caused by a build-up of an abnormal form of the naturally occurring ‘prion’ protein in our brainCattle
CryptosporidiosisIt is an infectious diarrhoeal disease that can be transmitted through contact with infected animals.Cattle, Sheep, Deer, Goats
E. coli O157 The E. coli O157 bacterium lives in the gut of the animals and can be transmitted via contact with infected animals or their faeces. It can cause disease ranging from diarrhoea to kidney failure in humans. In certain cases, the infection can be fatal. Young children and the elderly are at the greatest risk.Cattle, Sheep, Deer, Goats, 
Verotoxigenic E. coli (VTEC) 
ErysipeloidThis is a rare bacterial skin infection that can be acquired from a wide variety of infected animalsFish, Pigs, Birds
Giardiasis A diarrhoeal disease caused by a parasite that can spread through ingestion of contaminated water/food, or via direct contact with infected humans/animals.Cats. Dogs, Pigs, Sheep, Horses
Hantavirus Disease Hantavirus infections are caused by a set of viruses carried by rodents. Generally, it is spread through contact with saliva, urine or faeces from infected rats/rodents.Rats/Rodents
Hydatid Disease Canine tapeworm (Echinococcus) causes hydatid disease. It is mainly transmitted to humans through infected dog faeces.Dogs
Leptospirosis (Weil’s Disease and Hardjo) It is a bacterial infection in two forms: Weil’s disease and Hardjo. While Weil’s disease is commonly acquired from water contaminated with rat urine, Hardjo, is generally caught from infected cattle.Rodents, Cattle
Louping ill A viral infection that affects grouse and sheep that causes disease in humans very rarelyBirds, Sheep,
Lyme Disease This is a potentially severe bacterial infection transmitted through tick bites.Ticks
Newcastle Disease This is a highly transmissible disease in birds, but very rare in humans. It may be transmitted to humans via infected birds or their products.Birds
Orf Viral skin disease of sheep and goats, Orf can spread to humans via close contact with infected animals. While it is not considered a serious disease, it causes localised lesionsGoats, Sheep
Ovine Chlamydiosis A bacterial disease acquired from infected goats or sheep,  Ovine Chlamydiosis causes a a mild flu-like disease in most humans. However, in pregnant women, it can cause severe life-threatening disease in the mother leading to miscarriage or stillbirth of an unborn childSheep
Q Fever This is a bacterial disease that causes mild flu-like illness in most people, but can lead to more severe disease, as well.Goats, Sheep,  Cattle
Ringworm It is a fungal skin disease in humans, including other animals that cause a ring-like red rash on the skinHorses, Cattle
Salmonella A bacteria that usually causes a mild, self-limiting diarrhoeal disease, which can occasionally be severe, Salmonella is transmitted most commonly through food, but may also be found in faecally-contaminated water or soil.Pigs, Poultry, Pigs, including many other animals
Streptococcus suis A bacterium that causes disease in pigs, streptococcus suis is spread generally from pigs to humans by direct contact.Pigs
Streptococcus zooepidemicusIt is a bacterium that infects horses and cattle and is extremely rare in humans. But it can be acquired by direct contact with infected animals.Cattle, Horses
West Nile Virus This virus infects the birds. It spread to humans and horses through a bite from an infected mosquito.Birds

What to do in case of a zoonotic disease? 

If a person is scratched/bitten by an animal, they should ensure that the animal is thoroughly checked by a veterinarian. This is to ensure that the animal is appropriately vaccinated and doesn’t have rabies or other zoonotic diseases.

Although zoonotic diseases are pretty common, some people are at higher risk of getting them. These individuals may also show more severe reactions and symptoms. High-risk individuals include:

  • Children five years old or younger
  • Pregnant women
  • Those with HIV
  • Cancer patients going through chemotherapy
  • Adults aged 65 or older
  • Others with weakened immune systems

The best thing to do is consult an expert immediately.

How to prevent zoonotic diseases?

Zoonotic diseases are pretty common around the world. And there are several ways to help prevent getting a zoonotic disease. These include the following:

  • Practice safe food handling. This includes washing off all produce before consuming it.
  • Wash your hands properly with water and soap
  • Don’t consume, drink, or touch your eyes or mouth while handling or in close contact with animals
  • Have the pets at home vaccinated and take them for regular annual visits to the veterinarian
  • Use an insect repellent or other methods to keep mosquitos, fleas, and ticks away
  • Talk to the veterinarian about appropriate flea and tick preventatives for your pets
  • Check for ticks when you’ve been outside
  • Don’t approach any animal in the wild that appears to be sick
  • Keep all areas where animals are kept  clean and sanitized
  • Beware of areas where animals or insects might be, when out in nature, especially when participating in activities like hunting and camping
  • Use gloves if needed to handle an animal that is or appears to be sick


The seriousness of zoonotic diseases varies depending on the type of disease one may have. Many of these are treatable, while others can cause severe long-term and even lifelong and fatal conditions. So, check with your doctor or a medical professional as soon as you think you might have a zoonotic disease. 

Verified By Apollo Doctors
At Apollo, we believe that easily accessible, reliable health information can make managing health conditions an empowering experience. AskApollo Online Health Library team consists of medical experts who create curated peer-reviewed medical content that is regularly updated and is easy-to-understand.

Quick Appointment



Book ProHealth Book Appointment
Request A Call Back X