One Health: Zoonotic Diseases

Zoonotic diseases are infections that can be naturally transmitted between animals and humans.

These diseases are caused by a variety of organisms, including bacteria, viruses, fungi, and parasites.

Some zoonotic diseases, such as rabies and cowpox, are transmitted directly from animals to people through contact with saliva, blood, urine, or feces. Others may spread through the air or through bites and scratches. In other diseases, transmission occurs through the bite of insects such as mosquitoes, ticks or fleas.

In Lyme disease, for example, deer ticks transmit the bacteria from infected carrier animals, such as mice, to humans or other animals. Insects that carry and transmit germs that cause diseases in people are called vectors.

Other zoonotic diseases, like Salmonella infection, are contracted by consuming food, water, or milk that has been contaminated by an infected animal, by consuming food that has been washed or grown in contaminated water, or by eating undercooked meat from an animal with Salmonella.

Zoonotic diseases make up more than half of all emerging infectious diseases (those that are rapidly increasing in incidence worldwide).

Zoonotic diseases not only cause illness and death in people, but also impact animal health, leading to illness in pets, zoo animals, wild animals and livestock, and reduced food availability. These diseases can have devastating effects on economies because of trade restrictions, health care expenditures, and negative effects on tourism.

Rabies is a viral zoonotic disease that is primarily spread through the bites or scratches of animals that are infected, called reservoirs. Common animal reservoirs for rabies include bats, skunks, raccoons, and foxes. Rabies spreads to the brain and spinal cord and can be fatal if not treated promptly.

Anthrax is a bacterial zoonotic disease commonly found in animals exposed to food, air, or water that is contaminated with anthrax spores. These spores can live in the environment and infect both people and animals when they are ingested, inhaled, or absorbed through open wounds. Humans may become infected through contact with infected animals or animal products that are contaminated with spores. Once inside the body, the spores develop into bacteria. The bacteria release toxins that can cause inflammation, bleeding, tissue death, and potentially sepsis.

Lyme disease is a bacterial zoonotic disease that is spread when a deer tick bites an infected carrier animal, such as a mouse, and ingests the bacteria that causes Lyme disease. The tick then bites animals or people, spreading the bacteria to them. Symptoms include fever, headache, fatigue, and a distinctive bull’s eye-shaped rash. If untreated, Lyme disease can affect the joints, heart, and nervous system

The best way to prevent zoonotic disease is to limit your exposure to infected animals and vectors.

When contact with infected animals is necessary, it is important that you wear protective clothing and equipment like hats, gloves and glasses to avoid bites and scratches, and that you wash your hands thoroughly after handling animals.

To protect against insect vectors such as mosquitoes, ticks, and fleas, you can wear long pants and long-sleeve clothing, use mosquito netting, use insect repellents, and check for ticks after being outside in areas where they live.

It is also important to handle food safely and to avoid food that might be contaminated.

To protect animal health, keep healthy animals separate from infected animals and also protect them from exposure to insect vectors and contaminated food sources.