There are specific infections that can be transmitted from animals to humans which may cause disease; these are known as ‘zoonotic diseases’ or zoonoses. Any animal can potentially transmit a zoonotic infection, including companion animals, farm animals, and wildlife. Further information on specific zoonotic diseases can be found in the linked articles at the end of this page.
There are also specific infections that can be transmitted from humans to animals; these are known as ‘reverse zoonotic diseases’ or ‘reverse zoonoses’. Examples of reverse zoonoses include: dermatophytosis (commonly known as ringworm), tuberculosis, and antibiotic resistant bacterial infections (e.g. methicillin resistant Staphylococcus aureus or MRSA).
Zoonotic and reverse zoonotic diseases can be caused by viruses, bacteria, parasites, and fungi (also called infectious agents).
People should make sure that they are aware of the different types of zoonotic diseases potentially present in animals that they handle or work with, how these diseases can be transmitted, and how to reduce the risk of disease transmission. People should also make sure that they are aware of reverse zoonotic infections that they may transmit to the animals with which they are in contact.
How are zoonotic and reverse zoonotic diseases transmitted?
Infections that can affect both humans and animals can be transmitted in a number of ways including:
- Direct contact between a human and an animal.
- Indirect contact through interaction with an area or object that the infected individual has been in contact with and which has been contaminated by the infectious agent. This can include animal enclosures, bedding, equipment, clothes, and soil.
- Foodborne infections are transmitted through the consumption of animal products from an infected animal or consumption of food/water that has been contaminated by an infectious agent. Eating undercooked meat or unpasteurized milk, handling raw meat and eating without washing your hands thoroughly are all examples of how a foodborne infection can be transmitted.
- Vector-borne infections are transmitted through a second animal (known as the vector), most commonly an insect, that carries the disease usually from the animal to the human.
What increases the risk that a human will be infected by a zoonotic disease?
It is possible for any person to be affected by a zoonotic disease. However, there are certain people who are at greater risk of contracting infectious disease (including zoonotic disease) because their immune system is not functioning normally and is unable to effectively resist or fight infections. People who may not have a normally functioning immune system include young children (under five years of age), older people (over 65 years of age), people on medication that supresses their immune system (for example, chemotherapy drugs or steroids), and people with diseases that can suppress their immune system (for example, cancer or HIV infection).
People at greater risk of contracting infectious disease should be careful around animals and take the precautions explained below. They should also talk to their doctor about any particular precautions they should take related to their specific condition.
Minimising the risk of disease transmission from animals to humans, and from humans to animals
The risk of contracting a zoonotic disease is low. If you are healthy, use common sense and good hygiene, and keep your animals healthy.
The following steps will minimise the risk of a zoonotic disease being transmitted from an animal to a person:
- Hygiene: hands should be washed after being near animals, whether you touched them or not.
- Keep animals healthy: regular veterinary checks and good preventative health care (for example, regular effective parasite control) will help reduce the risk that an animal will carry a zoonotic infection.
- Avoid being licked on/in the mouth by animals.
- Teach children that they should not put their mouths on an animal and should not put any part of an animal’s body in their mouth.
- Prevent children from playing in soil which may be contaminated with animal faeces.
- Avoid animal bites and scratches. If you do get bitten or scratched by an animal, promptly contact and/or visit your doctor for assistance.
- Prevent bites from insects that may transmit infections such as mosquitoes, ticks, and fleas.
- Be aware of zoonoses that may be present in the species of animals with which you come into contact. Animals do not always show symptoms of disease so the simple precautions above should be always be taken.
People should also be aware of human infections that can be transmitted to animals. If you know that you have an infection that could be transmitted to an animal, take precautions to reduce the risk of infecting animals with which you come into contact (for example, your pets, wildlife, or farm animals). Specific details should be discussed with your doctor and a veterinarian.