While there is a vaccine for Covid-19, hopes of eradicating the virus should be curbed. Covid has achieved what is termed an animal reservoir, a non-human source.
Animal reservoirs, such as insects, provide chances for pathogens to spill back into people. These include yellow fever, Ebola and chikungunya virus.
SARS-CoV-2 probably originated in bats, but it might have passed to people through an intermediate host. The virus can readily infect many animals, including cats, rabbits and hamsters. It is particularly infectious in mink, and mass outbreaks on mink farms in Denmark and the Netherlands have led to huge animal culls.
Minks farmed for their fur are acquiring SARS-CoV-2 from humans and transmitting it back, a classic scenario for a possible genetic mutation that could create a mismatch with some vaccines under development, the World Health Organization (WHO) reported.
The SARS-CoV-2 pandemic has brought many questions over the origin of the virus, the threat it poses to animals both in the wild and captivity, and the risks of a permanent viral reservoir developing in animals. Animal experiments have shown that a variety of animals can become infected with the virus. The ability of Covid-19 to infect different animal species poses the threat of animal to human transmission and reverse zoonosis.
Coronaviruses, such as the one that caused COVID-19, are enveloped, single-stranded, positive-sense RNA viruses. They possess the largest genome of the RNA viruses with four open reading frames (ORFs) that code for the main structural proteins: the Spike (S), Membrane (M), Envelope (E), and Nucleocapsid (N).
The SARS-CoV-2 virus sequence is 96% identical to the bat coronavirus RaTG13, detected in Rhinopholus affinis in Yunnan Province in China . Another bat coronavirus, RmYN02, has shown 97.2% similarity in the longest gene-encoding region, 1ab-this has led experts to believe that, at some point, SARS-CoV-2 likely emerged as a result of a recombination event between a bat coronavirus and an unknown coronavirus, possibly in an unknown intermediate host.
Cats and Dogs
Much like their larger counterparts, domestic cats are also susceptible to SARS-CoV-2 infection. Cats have their own feline coronaviruses, FCoV I and II, which are only distantly related to SARS-CoV-2. In addition, SARS-CoV RNA was detected in cats from a live animal market in Guangzhou in 2004. Like cats, dogs have their own distantly related coronaviruses, including canine enteric coronavirus and canine respiratory coronavirus.
Since the SARS-CoV-2 outbreak has spread globally, the threat of a reverse zoonosis from humans to animals has become a distinct possibility. Currently, the best proof of transmission from humans to animals has been in farmed minks and domestic cats and dogs.