Zooanthroponosis – the Canine Diseases Transmissible to Humans

The terms zoonosis and zooanthroponosis should be known to all animal owners. The words stem from ancient Greek. Zōon means “animal” and nósos “illness” and anthrop “human”. So it is about diseases than can go back and forth between animals and humans. One speaks of zooanthroponosis when it concerns disease that can be transmitted by animals in general, and dogs in particular, to humans.

The transmission of the diseases happens through viruses, bacteria, fungi, or parasites. However, the onset of the disease in dogs and humans is not necessarily identical. Dogs can act as temporary hosts while being asymptomatic. Some pathogens attack humans and use them as so-called false hosts. Some diseases are transmitted to humans through the consumption of animal products. The BSE pathogen of the cattle disease is a good example of this.

You should bear in mind that the possibility of an infection is basically always present. However, this should not stop you from playing and carefree contact with your dog. Additionally, the opposite also holds true: we can also infect our dog (anthropozoonosis).

One of the worst diseases that can be transmitted by zooanthroponosis is rabies. This is a viral infection that is transmitted via blood and is therefore usually onset by a bite from an infected dog. But, even small injuries suffice for the virus to get into our bloodstream. Rabies is almost always fatal to animals and humans.

In dogs the first symptoms occur after approx. three weeks – like barking without reason, aggressive behaviour, and increased salivation (“frothing at the mouth”), problems swallowing and later paralysis.

The incubation time for the virus is longer with humans. The first symptoms appear only after one to three months. The disease starts like a flu, then causes meningitis or spinal meningitis and paralysis. It is also accompanied by typical fits of anger. Germany is officially “rabies-free” since 2008. You should still get your dog vaccinated and, especially if you travel a lot, consider getting vaccinated yourself. Find out more in the Maxi Zoo guide Dog vaccination.

Leptospirosis belongs to the dog diseases that can be transmitted to humans through contact with the blood or urine of the animal. These are bacterial pathogens that result in symptoms like vomiting, loss of appetite, fever, and a bloody stool in serious cases for the dog. The disease is fatal in approx. 10 percent of dogs.

In human’s leptospirosis has similar symptoms to the flu and can be treated with antibiotics. Dog vaccinations against leptospirosis only cover four pathogen strains (serovariants) currently and last for between six months to one year.

Mange or scabies is a highly infectious mite infection. The mites migrate from host to host. Simple skin contact with the animal is enough to catch the pests. Humans act as false hosts to the mites. The good news: if we live in accordingly good hygienic conditions with our dogs there are generally no symptoms, as the immune system contains the plague and keeps the parasites to a minimum.

In dogs, symptoms such as red, scaly, calloused skin, severe itching and hair loss can be seen. With humans, the skin also reddens and starts to itch. Personal hygiene and a clean environment are the best preventative measures against mites of all types. The treatment is through special medication, medical partial baths / lotions and proper disinfection of the entire living environment. Treatment should be started as soon as possible.

An infestation with tapeworms can also be transmitted from dogs to humans. Infection with tapeworms happens through oral ingestion of the eggs. Normally the danger of infection is low in Europe. While deworming is normally sufficient to prevent further spread in dogs, the nesting of tapeworms in humans can become dangerous.

Infections with fox and dog tapeworms must be reported as it can lead to extremely dangerous illnesses. The tapeworm larvae nest in various human organs and, if necessary, must be removed surgically. When cutting the cysts out, there is a risk of bursting and thus spreading throughout the body.

Toxocariasis is transmitted orally to humans through dog (or cat) faeces. Dogs only show symptoms when there is a massive infestation. Veterinarians therefore recommend regular deworming of dogs. Humans act as false hosts for roundworms. The infection can only be detected by an antibody test. Hygiene is the best precautionary measure with roundworms as well, clean playing areas for children are especially important.

The roundworm larvae reach the organs through the bloodstream and, in humans, mainly nest in the liver and lungs, as well as in the brain and in the eyes. Currently there are different medical treatments but surgical removal is not recommended.