In Brazil, 31% of dogs and 40% of cats tested positive for COVID-19

With more than 9 million confirmed cases of COVID-19, Brazil is one of the countries hardest hit by the novel coronavirus. Researchers therefore set out to assess the pandemic’s impact on pets in the country. A study reveals that 31% of dogs and 40% of cats whose owners are infected with SARS-CoV-2 also test positive for COVID-19, although half of them show no clinical signs.   The impact of the current SARS-CoV-2 pandemic on pet populations is still being assessed. Significant gaps remain regarding the existence of intermediate or accidental hosts, reservoirs, or amplifiers, as well as the role of vertebrates in viral transmission. Infection in animals, particularly those in close contact with humans, can have implications for human health and well-being, wildlife conservation, as well as biomedical research and global crisis management. The recent discovery of infection in mink, which could have public health implications, has, for example, led to the adoption of drastic public health measures. Pets live in the same environment as their owners and are therefore exposed to the same pathogens, including SARS-CoV-2. While cats and dogs are known to be susceptible to coronavirus infection—albeit to a lesser extent—the role of humans in this context remains unclear. A few studies seem to show that SARS-CoV-2 infection in dogs and cats primarily affects animals living in households with at least one confirmed human case. This research suggests that human-to-animal transmission is the cause. However, until now, epidemiological investigations and longitudinal studies have been limited and have involved only a small number of animals. In particular, they do not provide estimates of the frequency of infection or the onset of clinical signs. A Brazilian study sought to assess exposure to, infection with, and persistence of SARS-CoV-2 in dogs and cats in the country living in households with owners infected with the virus, while also examining clinical and physiological signs in the animals, and thus the risks associated with infection. Between May and October 2020, 39 pets (29 dogs and 10 cats) belonging to 21 patients were monitored. The presence and persistence of SARS-CoV-2 infection were identified in these animals, living in Rio de Janeiro with infected animal owners. Nine dogs (31%) and four cats (40%), from 10 households (47.6%), were found to be infected with or seropositive for SARS-CoV-2. The animals tested positive 11 to 51 days after the onset of clinical signs in their animal owners. Three dogs tested positive twice, at intervals of 14, 30, and 31 days. Neutralizing antibodies against SARS-CoV-2 were detected in one dog (3.4%) and two cats (20%). Among the 13 animals infected with or seropositive for SARS-CoV-2, 6 developed mild and reversible signs of the disease, primarily respiratory and gastrointestinal manifestations, but without significant associated laboratory abnormalities. Although the statistical power of this study is limited, the data presented suggest that close contact with human cases of COVID-19 is a major risk factor for SARS-CoV-2 infection in pets, especially cats, particularly in Brazil. The infection rate among animals is higher there compared to other regions of the world that have already been studied, likely due to the higher viral prevalence in the country’s population. A logistic regression analysis identified sterilization (and thus a more sedentary lifestyle) and the presence of the dog or cat in the owner’s bed as risk factors for infection in animals. Close contact between the animal and its infected owner therefore appears to increase viral transmission. Thus, it is important to maintain physical distancing—even from one’s own pet—when infected or identified as a close contact, to prevent transmission. Wearing a mask and following hygiene measures must also be observed, even around animals.