What Animals Carry Diseases?
Obviously, all animals have the potential for carrying diseases. Nearly all of us remember the warning we heard as children when we approached an unfamiliar animal or a small furry creature in the wild: "Don't touch that; you don't know where it's been!"
Although we probably didn't know it then, much of the concern of those concerned parents and guardians had to do with animal diseases, and most of that was based on the fact that one cannot tell by looking at an animal if it has the potential to pass a disease on to humans. This was also behind the admonition to always wash our hands when we were done interacting with an animal, especially unfamiliar ones—and especially prior to eating.
Can Animals Made Me Sick?
There are at least 39 important diseases people catch directly from animals. There are at least 48 important diseases people get from the bite of bugs that bit an infected animal. And there are at least 42 important diseases that people get by ingesting or handling food or water contaminated with animal feces.1 Some of these diseases may be familiar, such as rabies, ringworm, and bubonic plague. Others have only recently emerged, like monkeypox, Zika Virus, West Nile Virus and Legionnaires' disease; these diseases are likely to be less recognizable to those in developed nations.
Animal diseases that people can catch are called zoonoses. Many diseases affecting humans can be traced to animals or animal products.2
Farm animals and wild animals can carry bacterial, viral, fungal or parasitic diseases. Deer and deer mice carry ticks that cause Lyme disease and other infections. Some wild animals may carry rabies or pneumonic plague. Turtles, snakes and iguanas can transmit Salmonella bacteria to humans. Toxoplasmosis can be transmitted to humans via the handling of litter (feces) from an infected cat. Toxoplasmosis is especially dangerous for pregnant women, since it can severely damage the fetus.
What Does It Mean To "Carry" A Disease?
This is a very good question. We need to make a distinction between carrying a disease and being sick with (having an active case of) a disease. An animal with an active case (which can be noticed and readily diagnosed by a veterinarian) is definitely carrying the disease and has the potential to infect others, but it is not "carrying" the disease in a clinical sense. An animal carrying a disease in the clinical sense has been infected at some point in time, but may or may not have developed an active case.
Depending on the disease, such an animal may be able to spread the disease to others without having an active case itself.
Risk Factors and Reality
What makes animal-borne diseases significant? According to zoonosis expert Lawrence T. Glickman, DVM and professor of veterinary epidemiology and environmental health at Purdue University School of Veterinary Medicine, West Lafayette, Indiana, there are two factors.
"If you ask Americans in general what is the most important zoonosis, most would say rabies," Glickman tells WebMD. "It is something they fear, it is in the news. But in terms of risk, there are only zero to two human cases a year in the U.S. It's one of those zoonoses that are important because of their seriousness, but not their frequency: rabies, tularemia, plague, monkeypox, listeria, anthrax. These are diseases that are very serious if one gets them but which are relatively uncommon."
On the flip side, Glickman notes, are animal-borne diseases that are important because they are fairly common even if not often fatal. Cat-scratch fever, for example, infects as many as 20,000 Americans a year. And an estimated 4%-20% of U.S. kids get roundworm from dogs and cats.1
So, while avoiding direct contact with animals is impractical for humans and avoiding indirect contact (food products, dander, aerosols, etc.) is nearly impossible, the good news is that the age-old habits of good hygiene and caution are likely to prevent most people from ever contracting an animal-borne disease.
About NexGen Pharmaceuticals
NexGen Pharmaceuticals is an industry-leading veterinary compounding pharmacy, offering sterile and non-sterile compounding services Nationwide. Unlike other veterinary compounding pharmacies, NexGen focuses on drugs that are difficult to find or are no longer available due to manufacturer discontinuance or have yet to be offered commercially for veterinary applications, but which still serve a critical need for our customers. We also specialize in wildlife pharmaceuticals, including sedatives and their antagonists, offering many unique options to serve a wide array of zoo animal and wildlife immobilization and anesthesia requirements.
Our pharmacists are also encouraged to develop strong working relationships with our veterinarians in order to better care for veterinary patients. Such relationships foster an ever-increasing knowledge base upon which pharmacists and veterinarians can draw, making both significantly more effective in their professional roles.