Zoonosis is any disease that can be transmitted from animals to humans and vice versa, either by consumption of animal products or by contact. Reptile zoonoses are mainly caused by bacteria or parasites (worms, fungi…). To date, no reptile virus is potentially transmissible to humans.
It is the disease most frequently transmitted from reptiles to humans: in the United States, 3 to 5% of salmonellosis diagnosed in humans is believed to be of reptilian origin.
The bacterium is present in the intestinal tract of the reptile naturally and sometimes even on the skin, but 85 to 90% of reptiles are carriers without being sick.
Transmission of the bacterium to humans occurs through direct contact, or accidental ingestion of food and/or water contaminated with fecal matter. Cases of salmonellosis are common in young children, who bring their fingers to their mouths after handling the animals. Not everyone infected with Salmonella will necessarily develop disease; however, children under 5 years of age, the elderly and immunocompromised people are more likely to have symptoms.
Symptoms of salmonellosis in humans can include gastroenteritis-like bowel problems, fever and even septicaemia.
Tuberculosis is transmitted to humans either by inhalation of oral or respiratory secretions of a reptile carrying the bacterium or by biting. Direct contact through an injury while handling the animal or cleaning the cage can also be a cause of transmission.
In reptiles, infection results in lung, skin, mouth, visceral or nerve damage.
In humans, the disease affects the lungs and causes coughing, spitting, respiratory distress, shortness of breath, fever, weight loss…
Aeromonas sp. is a bacterium present in the water of terrariums (bowls, ponds… .). Humans become contaminated by contact of contaminated water with a pre-existing skin wound. It can also be contaminated by reptile bites.
In reptiles, the infection can be asymptomatic or cause pneumonia, diarrhea, stomatitis or septicaemia.
In humans, the symptoms caused by this disease are varied, ranging from wound infection to lung infection to gastroenteritis.
Other bacteria are responsible for zoonoses but are much rarer. They are most often present in the digestive tract and in the mouths of reptiles that carry them without getting sick. They cause gastroenteritis in humans, especially in young children, with signs resembling appendicitis (Yersinia enterocolitica), septicemia (Yersinia pseudotuberculosis) or urogenital infections (Enterobacter cloacae and Klebsiella pneumoniae).
In Europe, it is rare for reptiles to transmit parasitic diseases to humans. These zoonoses are mainly encountered in Africa or Southeast Asia due to the consumption of reptile meat.
Various parasitic diseases are caused by fungi. The most common transmissible fungus of reptiles is called zygomycosis.
Transmission occurs through inhalation, ingestion or skin contamination by fungus spores contained on the skin or in the feces of the contaminated reptile.
Immunocompromised individuals are most at risk of contracting the disease.
Symptoms in humans are very varied and can range from skin damage with the appearance of granulomas, to damage to the oro-nasal sphere, and even more serious conditions such as meningitis.
Humans can be affected by two cestodoses, sparganosis and mesocestoidosis, after consumption of contaminated reptile meat or concoction of medicinal remedies based on contaminated snake venom. These worms are cousins of the “tapeworm” and therefore cause digestive disorders in most cases.
Pentastomids, or linguatules, are parasites resembling small worms. The disease is transmitted to humans by ingestion of eggs contained in respiratory secretions or snake droppings. Man then declares a hepatitis, pneumonia, meningitis, pericarditis or peritonitis, depending on the location of the larva from the ingested egg. To date, no drug treatment has been able to eradicate this parasite, neither in reptiles nor in humans. Only surgery is possible. This is why it is strongly advised to have your reptile undergo a parasitological examination of its stool to detect the presence of the parasite.
The contamination of humans by reptile mites is anecdotal. One can cite Ophionyssus, a mite present mainly on snakes, and likely to pass on the skin of humans in case of prolonged and close contact with this type of reptile.
There are many diseases transmissible from reptiles to humans, but fortunately, most of them remain rare. Simple gestures allow to protect oneself against the risks of transmission.
Simple rules to limit the risk of zoonosis in contact with your reptiles
- Hand cleaning is essential after handling a reptile or terrarium accessory. Use warm water with soap (and ideally bactericidal gel) for best results.
- Your terrarium should not be installed in your kitchen or any other room dedicated to food storage or preparation.
- Your terrarium and its accessories must be washed, disinfected and thoroughly rinsed. Bleach remains the most effective antiseptic for cleaning. The use of disposable gloves during this operation is strongly recommended, or even a protective mask. The use of food-related utensils for cleaning should be avoided.
- When designing your terrarium, remember that it must be easy to clean in order to keep it healthy for you and your reptile. The accessories must therefore be easy to remove and clean.
- Do not eat, drink or smoke while handling your reptile or cleaning its terrarium, to avoid contact between your hands and mouth. Do not allow the reptile to walk on food preparation surfaces (work surfaces).
- Avoid handling by young children and immunocompromised individuals. Teach children not to kiss the animal.
- Always disinfect and monitor a wound caused by a reptile, whether by bite or scratch.
These gestures are not very restrictive, but are essential to protect oneself against zoonoses. Prevention must focus on young children and people with weakened immune defences.
IMPORTANT: Do not hesitate to consult a doctor in case of injury caused by a reptile. The symptoms mentioned here are only indications and only the doctor can make a diagnosis.
It is also advisable to consult a veterinarian on a regular basis to verify the good health of your reptile.