If the dog is man's best friend, it can also carry diseases that can be transmitted to humans. We then speak of a zoonosis. This term, which does not only concern dogs but all animals, refers to diseases and conditions transmitted to humans by dogs, but also the reverse, from humans to dogs, through bacteria. or viruses.
The modes of contamination can be direct contact (bite, caress, etc.), ingestion (eating food contaminated by the animal), inhalation or transmission by a third vector, often an insect. Children and the elderly, who have a more fragile immune system, are the people most at risk of being affected by these diseases transmitted by dogs. Even if this animal represents a risk for humans in terms of disease transmission, the latter remains minimal in our country. Examples of three diseases that dogs can transmit to humans.
Leptospirosis is a little known disease, yet it is widespread and even increasing in France. It is an infectious disease caused by a bacterium (leptospira) studied by the Institut Pasteur in France. This bacterium is present in damp places where animals such as rats, nutria, hedgehogs, wild boars or farm animals have deposited it while urinating. These animals are indeed carriers of these bacteria but without being sick. It is the dogs, by frequenting puddles, ditches or ponds soiled by these bacteria that are then contaminated. The bacteria enter the dog's body through their skin, lips or pads.
For a week after its contamination, the dog does not show any particular symptoms. Fatigue, lack of appetite and sometimes vomiting may occur afterwards. As soon as the first symptoms appear, it is advisable to consult a veterinarian quickly because leptospires attack the liver and kidneys and can quickly lead to the death of the dog.
In humans, leptospirosis is a mild disease but it can lead to kidney failure and even death in rare cases. The incubation of the disease is of the order of 4 to 14 days. Symptoms are those of a flu-like state for moderate forms of leptospirosis and can progress to kidney, liver, meningeal or lung damage. The serious forms of this disease in humans combine acute renal failure, neurological damage and more or less severe bleeding. The administration of antibiotics is the main treatment for leptospirosis. Although the healing time is often long, the disease does not leave any sequelae.
Toxocariasis is a parasitic infection transmitted to humans by dogs, but also by cats. It is a widespread disease in industrialized countries. Dogs are infected with this parasite, which is a roundworm called "Toxocara canis", by ingesting it directly or by their mother, in utero, already affected by toxocariasis. In animals, the adult form of the parasite lives in its small intestine but goes from one organ to another while causing damage to them and their tissues. This worm lays thousands of eggs every day that the dog rejects with its excrement.
It is by eating poorly washed vegetables or by the contact of his hands with materials soiled by these parasites that man is contaminated if he then brings them to his mouth. Given the specific mode of transmission of toxocariasis, children are the most affected. They are indeed more inclined to play with their hands in an environment contaminated by worms, such as sandboxes for example, and put them in their mouths without washing them first. Most often, toxocariasis does not cause any particular symptoms in humans except for slight fatigue, minimal respiratory problems or even digestive disorders. There are, however, more severe, but rare, cases of this parasitic disease, which cause inflammation of the retina of the eye.
The best way to protect yourself from toxocariasis is to deworm your dog regularly and to apply hygiene rules by washing your hands often, for example.
Salmonellosis is a disease caused by the "Salmonella" bacteria in dogs. This infection causes fever, fatigue, vomiting, diarrhea, weight loss, skin problems and increased heart rate in the animal. Sometimes no symptoms occur. Salmonellosis particularly affects dogs with an immune protection deficiency and those who have received antibiotic treatment. Dogs can be contaminated by stools that are already infected or by eating raw meat that is itself contaminated.
In humans, salmonellosis causes gastroenteritis. It is manifested by fever, diarrhea, vomiting and abdominal pain. Transmission of the disease from dogs to humans can occur by simply touching an object that has been in contact with the infected animal. Antibiotic treatment, combined with the isolation for a few days of the person infected with salmonellosis, contribute to the effective treatment of this disease.
