Investigation of SARS-CoV-2 indications for zoonotic diseases and transmission of zoonotic diseases

human coronavirus (HCoV) supports the emergence of new coronaviruses such as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the virus responsible for the current epidemic of coronavirus disease (COVID-19). It has evolved through changes in the environment and adversity. .. In addition to COVID-19, currently known HCoVs that can infect humans include α-CoV such as HCoV-229E and HCoV-NL63, or HCoV-HKU1, HCoV-OC43, SARS-CoV, There are β-CoV such as Middle East Respiratory Syndrome. Coronavirus (MERS-CoV), and SARS-CoV-2.

SARS-CoV, MERS-CoV, and SARS-CoV-2 are known to cause asymptomatic, mild, or severe respiratory syndrome with case fatality rates of 10%, 35%, and 6%, respectively. SARS-CoV and MERS-CoV are zoonotic diseases and are known to infect civets and camels, respectively.

study: SARS-CoV-2 in human-animal interphase: review. Image Credit: Magic Photo / Shutterstock.com

The first reported case of COVID-19 was found to have occurred in 2019 due to SARS-CoV-2 transmission from animals to humans in the fresh market in Wuhan, China. Since then, SARS-CoV-2 has been infected in excess of 264. One million people have died worldwide and more than 5.2 million have died.

recently Helion In a review, researchers summarize possible causes and routes of SARS-CoV-2 infection between humans and animals. In addition, the researchers in this article are investigating the causes of direct animal-to-human transmission and vice versa.

Mode of SARS-CoV-2 infection

SARS-CoV-2 is considered a zoonotic virus in which animals function as their reservoirs and intermediate hosts. Few studies have investigated the role of animals in the cause of SARS-CoV-2 infection.

The first of these theories suggests that the virus has crossed the species barrier and invaded human populations from animal sources in the Wuhan market. Another theory suggests that the virus was first introduced to the market by infected humans who infected amplified animals with the virus. This animal later spread it to more humans. None of these theories have been proven, even after collecting and testing animal samples from the Wuhan fresh market.

An animal reservoir of coronavirus was first reported in China in 2019 from a virus sample isolated from Sunda pangolin, which was found to be 99% genetically identical to SARS-CoV-2. According to another study, SARS-CoV-2 was highly similar to betacoronavirus / bat / Yunnan / RaTG13 / 2013 virus, with only 92.4% similarity to pangorin coronavirus. Despite these discrepancies, these findings underscore the origin of zoonotic diseases and the background of the common ancestor of SARS-CoV-2.

Jacoles are known as intermediate hosts for SARS-CoV, and camels are known as intermediate hosts for MERS-CoV. These findings also add credibility to the fact that animals can serve as a reservoir for SARS-CoV-2. Due to the genetic similarity between SARS-CoV-2 and SARS-CoV, researchers focus not only on the origin of the virus itself, but on the importance of intermediate hosts at the human-animal interface. I considered it.

In order for the virus to cross the species barrier, it requires close contact with infected animals, infectious secretions, and animals, and perhaps repeated contact with the source of infection. Since China has been involved in the consumption and illegal trade of wildlife, including the Chinese pangolin (Manis Penta Dactilla) And the tiger (Panthera tigris), Hunters, traders, and consumers tend to come into direct or indirect contact with wildlife.

In addition, both wildlife and livestock are in contact at the market. Studies show that more than a billion cases of direct and indirect contact between wildlife and livestock and wildlife humans are traded each year.

Bates have been shown as evolutionary carriers of both alpha and beta coronaviruses, and birds have been shown as evolutionary carriers of gamma coronavirus and delta coronavirus. Of the four identified strains of beta coronavirus, humans, bats, pigs, horses, rabbits, camels, cattle, and antelopes are known to support strain A replication, but humans, bats, And palm civet support line B replication. , Camels and bats support strain C replication, and only bats support strain D replication.

To date, only 11 species of animals are known to be infected with SARS-CoV-2. Spontaneous infection of SARS-CoV-2 susceptible animals requires close contact with COVID-19-infected humans.

In the setting of domesticated animals, cats (cat),dog(Canis lupus is familiar), And ferrets (Musteraptorius Flo) It was first reported that SARS-CoV-2 infection was acquired spontaneously. Cats and ferrets have been reported to be very susceptible to SARS-CoV-2, but dogs have only experienced mild infections.

Among the fascinated zoo animals, the lion (Panthera Leo),Tiger(Panthera tigris),mink(Neo Bison Bison), Snow leopard (Uncle Panther) Puma (Same color as puma),gorilla(Gorilla Gorilla), And otters (Lutra canadensis) It was also found that SARS-CoV-2 was naturally infected.

Infections induced in laboratory-controlled environments include domestic cats (Felis catus) and dogs (Felis catus).Canislupus familiaris),ferret(Musteraptorius Flo),mink(Neo Bison Bison), Syrian hamster (Mesocricetus auratus), Egyptian fruit bat (Rousettus aegyptiacus), Roborovski hamster (Phodopus roborovskii), Deer Mouse (Peromyscus maniculatus), Bushy-tailed wood rat (Neotoma cinerea), striped skunk (Mephitis mephitis), bank vole (Myodes glareolus), Rhesus monkey (Rhesus monkey), Cynomolgus monkey (M. fascicularis), African Green Monkey (Chlorocebus sp.. ), Treeshrew in China (Tupaia belangeri chinensis), Common marmoset (Callithrix jacchus), Tanuki (Nyctereutes procyonoides), raccoon(Raccoon lotor), White-tailed deer (Odocoileus virginianus), Experimental rabbit (Oryctolagus cuniculus), And transgenic mice (Mouse muscle) Shows the characteristics of infection and viral shedding.

In addition, examples of natural exposure of various livestock and zoo animals to SARS-CoV-2 continue to grow. However, cattle are included in livestock that have shown resistance to SARS-CoV-2 infection (Taurus boss), Chicken, ducks, pigs, cottontail rabbits (Cottontail rabbit sp. ), Fox squirrel (Chloris), Wyoming Ground Squirrel (Urocitellus elegans), Black-tailed prairie dog (Cynomys ludovicianus), Mouse (Mouse muscle), And a large brown bat (Eptesicus fuscus).

Contrary to popular belief, interspecific transmission of SARS-CoV-2 does not always cause clinical disease. By comparison, most human COVID-19 cases cause asymptomatic or mild infections.

Mutual contamination from wildlife carcasses, especially body fluids, as well as digestive, reproductive and respiratory parts of food animals has also been investigated. However, the exact link between animal and human infections remains unresolved.

Implications

More research is needed to track the development of SARS-CoV-2 in animal and human hosts. These studies will also help study the effects of mutations in vaccinated individuals and help prescribe improved vaccines.

SARS-CoV-2 continues to mutate, and the world’s medical community is rushing to catch up with the emergence of new variants. It may take longer to find the exact link between SARS-CoV-2 animal and human infections. However, to remain safe in the current COVID-19 pandemic, it is imperative that humans continue to adhere to physical distance, masking, and vaccination standards.