New study suggests that you might be infecting your pets unknowingly

Pets that share close contact with their owners, engaging in activities such as co-sleeping, snuggling, and sharing eating spaces, may be more susceptible to contracting human illnesses, according to a study published in Zoonoses: Infections Affecting Humans and Animals. The research reveals that various diseases, ranging from swine flu, human norovirus, COVID-19, and tuberculosis to dengue, fungal infections, and parasites, can be transmitted between humans and pets. Dogs and cats were reported to be the primary recipients of such diseases, with sporadic cases found in horses, ferrets, and parrots.

Zoonoses, which are diseases transmissible between humans and other species, constitute over 60 percent of human pathogens. When diseases pass from humans to animals, it is termed reverse zoonosis. Benjamin Anderson, the study’s author and an assistant professor at the University of Florida’s College of Public Health and Health Professions, notes that pets might be more susceptible to diseases than previously believed, although certain viruses that infect humans typically do not align with the receptors found in dogs or cats.

Pathogens such as COVID-19 and the flu can mutate to acquire a structure that facilitates penetration of another species’ cells, allowing them to transfer between different species. Zoonosis and reverse zoonosis generally occur among closely related species, but pathogens sometimes mutate enough to traverse the gap and spread across mammals, birds, or reptiles.

Reverse zoonosis creates an additional pathway for disease dissemination, potentially amplifying an epidemic that poses risks to humans. For example, pigs infected with human flu and bird flu can serve as a breeding ground for new viruses. Anderson emphasizes that continuous exchange between humans, animals, and the environment increases the likelihood of mutations that enable pathogens to infect new hosts.

The study highlights the complexity of tracking human diseases in animals, as they often do not exhibit infections. The authors recommend that people with pets avoid close contact with their animals, particularly in cases of COVID-19 or the flu.