A new study suggested that more cats are likely infected by SARS-CoV-2 than previously considered. In screenings of several cats in Wuhan, many developed antibodies against it.
The prevalence of COVID-19 in cats was investigated by researchers at Huazhong Agricultural University. Their investigation showed that multiple cats developed antibodies to fight the coronavirus. However, none of the cats tested positive for COVID-19 or displayed the obvious symptoms of infection. Still, the number of cats examined in the study recommended maintaining the distance between COVID-19 patients and their pets. The distance could limit the possibility of SARS-CoV-2 spread in a community. They published their findings in the journal Emerging Microbes and Infections.
WHO-Led Assistance on Global COVID-19 Response
The COVID-19 pandemic has put a significant strain on the lives of millions of people and operations of various sectors. Many companies have been forced to suspend or permanently close their operations due to the economic impact of the pandemic. This resulted in millions of unemployed individuals worldwide. And because the economic impact is severe, some governments are unable to provide financial support to these displaced workers.
According to the World Health Organization (WHO) of the United Nations, 27,486,960 individuals have been infected and 894,983 people died from COVID-19 worldwide, as of September 9, 2020. In 150 countries, the organization shipped a total of 16,510,785 respirators, 127,150,743 medical masks, 7,892,479 face shields, 6,414,929 gowns, 10,653,650 gloves, and 1,053,178 goggles. The figures showed the estimated cost of the rampaging coronavirus.
As a zoonotic disease, COVID-19 is believed to be transmitted from bats to humans. While the animal acting as a go-between is yet to be confirmed, scientists know that the coronavirus was not directly brought by bats to people. Moreover, the coronavirus appears to be non-exclusive to humans due to reports of pets and zoo animals being carriers. This angle needs to be understood because if a COVID-19 patient owns a pet, they may interact with it and give the pathogen to their furry friend. That furry friend may spread the coronavirus to another person. But there is no scientific evidence yet to prove that angle.
Wuhan Cats Found with SARS-CoV-2
A group of Chinese researchers led an investigation of SARS-CoV-2 among cats. In some ways, their study acted as a continuation of previous research that discovered the coronavirus in some zoo animals and pets. The study aimed to prove that the coronavirus could be picked up by animals, whether or not they would become sick. The possibility hinted proper hygiene and quarantine protocols to separate COVID-19 patients from their pets, at least until their body is clear of the pathogen.
"Although the infection in stray cats could not be fully understood, it is reasonable to speculate that these infections are probably due to the contact with SARS-CoV-2 polluted environment, or COVID-19 patients who fed the cats. Therefore, measures should be considered to maintain a suitable distance between COVID-19 patients and companion animals such as cats and dogs, and hygiene and quarantine measures should also be established for those high-risk animals," explained Meilin Jin, the lead author of the study, quoted Taylor and Francis, an international publisher of books and journals.
In the study, researchers took blood samples from 102 cats between January and March 2020, the period of the first COVID-19 outbreak in China. Out of 102 cats, 46 were abandoned but from three animal shelters, 41 were from five pet hospitals, and 15 cats were from COVID-19 patient families. They made a follow-up and obtained nasal and anal swab samples from these cats. Tests they used on samples include the enzyme-linked immunosorbent assay or ELISA, the virus neutralization test or VNT, and the western blotting assay.
Results showed that 15 blood samples were positive for antibodies in the ELISA test. While 11 samples were confirmed by VNT with SARS-CoV-2 neutralizing antibodies. But none of the 102 cats were confirmed positive of COVID-19. None of the pets were found with obvious clinical symptoms of the disease. Also, none of the cats tested in the study died based on return visits.
Three of the cats showed the highest levels of antibodies. These cats were owned by patients clinically-diagnosed with COVID-19. Four abandoned cats and four cats from pet hospitals likely infected other cats with SARS-CoV-2. The transmission of SARS-CoV-2 between cats might be due to a contaminated environment, while the transmission from humans to cats might be supported by feeding the animals.
Researchers dug deeper to better interpret the antibodies among infected cats. Their analysis suggested a typical reaction from cats. Since other coronaviruses could infect felines, their bodies naturally responded to SARS-CoV-2. The antibody activity in studied cats was associated with a normal response to seasonal coronavirus infection. This could mean that cats might be at risk of being re-infected.
Jin added that there is no evidence at this time to support cat to human transmission of SARS-CoV-2. Though, people must consider precautions in case it is possible. Due to many unknowns, it is better to be extra careful to prevent human to cat transmission. The coronavirus can survive for hours or a few days on certain surfaces. Even if cats cannot spread the pathogen to humans, their contact with surfaces may pose some risk.
Researchers proposed their findings to be used in clinical treatment and prevention of COVID-19. Scientists could use cats as animal models for observing and studying the antibody activity against the coronavirus in humans. Epidemiologists might utilize cats as well in assessing factors of outbreaks in the future.
The study of cats was conducted during the Wuhan outbreak. But the number of tested animals was small. Results would require larger sample sizes to verify the findings. Future research must determine if cats could get the coronavirus from humans or from the environment. If from the environment, the source must be traced and investigated. Some research groups have been tracking wastewater and water treatment facilities, which are believed to harbor live SARS-CoV-2 in cities.