Zoonotic diseases (zoonoses) are infectious diseases that are transmitted from animals to humans.
Over 60 per cent of infectious diseases that we get are zoonotic, and 75 per cent of new, "emerging" infectious diseases are zoonotic.Causes
These diseases range from mild, gastro-intestinal (stomach) illnesses like Giardiasis (beaver fever) to deadly rabies. Many of the foodborne illnesses are zoonotic, coming from raw foods of animal origin, such as meats.
Influenza, like the H1N1 pandemic flu strain is zoonotic as well. Many of these diseases may start with animals, but can be transmitted between people.
Diseases from animals can make people sick in different ways. Stomach upset is common, respiratory disease can occur (like influenza), nervous system disease occurs with rabies and variant Creutzfeldt-Jacob disease (vCJD, or mad cow disease in humans) and sometimes the whole body - many organs - can be involved as with leptospirosis.
Infectious disease from animals is transmitted in various ways:
- through vectors, such as mosquitoes (which can transmit West Nile Virus)
- directly, as with the bite of a rabid animal causing rabies
- indirectly, when cattle contaminate drinking water with their feces and cause shiga toxin producing E. coli infection
- through contaminated food we eat, such as Salmonella infections caused by undercooking poultry.
- through the air (for example, breathing in the bacteria that cause Q fever)
- through contact with our skin: an example being cutaneous anthrax caused by contaminated animal hides
There are a number of ways to determine if someone has a zoonosis:
- looking at a clinical specimen, such as a stool or blood sample under a microscope to see if the pathogen (disease causing germ or microorganism) is present
- culturing a clinical specimen to see if the pathogen will grow
- antigen tests to see if there are antibodies to the pathogen in the person's blood
- molecular biology testing of the person's blood to see if the DNA or RNA of the pathogen is present
Fortunately, prevention is fairly easy in most situations:
- protect against insect bites by using repellents and window/door screens
- keep the numbers of insects that spread disease down by reducing their habitat, and where necessary, using pesticides
- get appropriate vaccinations and antibiotics before traveling to areas where zoonoses occur
- avoid contact with wildlife (e.g. feed your pets indoors to avoid attracting wild animals)
- treat drinking water with many barriers such as filtration and disinfection
- handle food properly, using the principles of Clean, Separate (Don't Cross-Contaminate), Cook and Chill
Veterinarians and others who work with animals can protect themselves from specific diseases of wild and domestic animals by using personal protective equipment.