Indeed, such cases do occur, but extremely rarely. They are associated with a bacterium with the complex name Capnocytophaga canimorsus. According to a study by Japanese scientists, it is found in the saliva of 69% of dogs and 54% of cats. But why, if it is so widespread, are there not very many cases of the disease?
“Such cases are not excluded in immunocompromised people,” says . Candidate of Biological Sciences, Microbiologist, Senior Researcher, Laboratory of Microorganism Viruses, Institute of Microbiology named after A.I. S. N. Vinogradsky RAS Evgeny Kulikov. “They can be the elderly, patients receiving chemotherapy, glucocorticoid hormones or immunosuppressive drugs after organ transplants, patients with HIV or other diseases that depress the immune system. In such cases, it is best to take reasonable precautions, most notably not kissing the animal and avoiding biting. And in no case should you go into a psychosis, as it sometimes happens. It must be understood that the primary role in such conditions is played by the state of immunity, and not by the Capnocytophaga canimorsus bacteria that a pet has in saliva. Sepsis is not only from them, it often develops from a small focus of chronic infection, to which a person does not even particularly pay attention. That is, in people who develop sepsis, it could also come from many other more common bacteria. Again, this is more of an immune problem than any bacteria. And to avoid it, you need to keep the immune system in good condition and I emphasize again, reasonable precautions are especially important in case of immunosuppression.
Infection can occur not only with “kissing” with a dog or cat, but also with bites or scratches, when saliva enters the wound. How does all this look in the mirror of statistics? For example, a new study was recently published in France with more than ten years of observations. There were 44 cases of infection caused by capnocytophages in the country, and in 15% of cases dogs were the culprits. According to American statistics, over the past 10 years, at least 6 people have suffered from these bacteria, and in the UK, 13 such cases have been registered over 26 years (a quarter of patients died – this usually happens with sepsis, which means it develops extremely rarely). Nevertheless, it happens, and many stories end very tragically, even for those who survived. Patients often undergo various amputations due to tissue death.
In very rare cases, people without immunosuppression get sick. Scientists from Harvard Medical School studied the genomes of 5 patients who were healthy and immune, but who developed sepsis due to capnocytophages. All had a specific variant of the gene involved in the immune system. Most likely, they suffered because of this.
Here are typical manifestations of such an infection. Near the site where bacteria enter the body, there may be bullous eruptions (bubbles or blisters with fluid) on the skin. There is also swelling and redness, and pus may be released. A person has a fever, vomiting and diarrhea, abdominal cramps, headaches, muscle and joint pain. Usually all this begins 1-2 days after infection, but sometimes it happens later – up to 2 weeks. With such symptoms, you should immediately consult a doctor. The disease is treated with antibiotics, which must be taken very strictly and for at least 3 weeks.