In a recent study released on the bioRxiv * preprint server, researchers from the US and Australia show that several common peridomestic species (including deer mice, striped sgunks and bushy tail bushes) are susceptible to infection with the severe respiratory coronavirus syndrome 2 (SARS). -CoV-2). The study reports on how these mammals are able to shed the virus in respiratory tracts – borrowing evidence that human wildlife interactions could lead to continued viral spread.
Coronavirus 2019 (COVID19) disease has had a widespread impact on the global human population; yet, so far little is known about how its causative agent, SARS-CoV-2, affects wildlife. Domestic dogs and cats can be infected with the virus, but they are asymptomatic or present with mild clinical infection (with very few exceptions).
On the other hand, cultivated mink are not only susceptible to the disease, but the infected animals can progress to a deadly disease (10,26). In contrast, ferrets (closely related to mink) are known to shed the virus after infection, but the course of the disease is bylaws.
However, key species for evaluating the epidemiology of SARS-CoV-2 are peridomestic animals, represented by wild and feral animals living close to humans. As a group, they have the ability to maintain the virus and spread it back to humans.
For this reason, a research group from Colorado State University in the U.S., the U.S. Department of Agriculture, the Animal and Plant Health Research Service, and the University of Queensland in Australia aimed to determine the prevalence of common peridomestic carnivores and assess their likelihood of spreading the infection.
Viral challenge for peridomestic animals
In this study, the researchers evaluated six common peridomestic rodent species for susceptibility to SARS-CoV-2: wild house mice, deer mice, shrub tail bushes, fox squirrels, Wyoming ground squirrels and prairie dogs with tails black. They have also evaluated three common peridomestic mammals: raccoons, cotyledons and striped sgunks.
The obtained snoring of the SARS-CoV-2 (WA1 / 2020WY96) was given twice in Vero E6 cells (kidney epithelial cell line from African green monkey) and stocks were frozen at 8080 ° C in Medium. Dulbecco Modified Eagle with 5% fetal bovine serum and antibiotics.
Three animals from each species (and two for ground squirrels) were selected for preliminary assessment of viral shedding and major pathology changes. In addition, all animals were clinically monitored daily, which included an assessment for their temperament and the presence of any clinical signs of the disease.
Viral isolation was performed on all oral swabs, nasal swabs and tissue samples three days after infection with a double-coated plaque assay on Vero cells. Plaque reduction neutralization assays were also performed, with records selected from culture plates to confirm SARS-CoV-2 viral excretion using polymerase chain reaction (PCR) for all advanced animals. Histopathological assessments were also followed.
Shedders and non-susceptible species
Of the nine species assessed, three (i.e., deer mice, striped scorpions and shrubby tail bushes) shed infectious viral grains after challenge. On the other hand, the study showed that house mice, raccoons, fox squirrels, Wyoming ground squirrels, cotton rabbits and prairie dogs with black tails are not susceptible to SARS-CoV-2 disease.
In addition, all species with infectious viral infections developed neutral antibodies, while the other species did not. None of the animals tested showed any clinical signs of the disease at any time, nor were they seen to behave abnormally after infection compared to the acclimation period.
In addition, none of the animals had clear lesions at the time of necropsy. On histopathologic examination, small areas of white blood cells and macrophage infiltration were observed in the lungs of two deer and two woodpeckers. Finally, two sgunks were provided with enhanced bronchiole-associated lymphoid material, although the swelling was not evident in the lungs or other tumors.
Dangerous interactions of human wildlife
Our work expands the existing knowledge base of endangered species and provides evidence that human wildlife interactions may lead to continued release of SARS-CoV-2, ”study authors say .
Importantly, their work shows that, to date, most exposed wildlife species develop moderate or no clinical disease and either fail the virus at all, or peeling it at low levels. An equally important finding is that these experimental diseases mean that a number of common rodents, wild lagomorphs and raccoons can be selected as potential SARS-CoV-2 reservoirs.
However, the results of this and other work, together with the impressive response to diseases seen in some species such as mink, indicate that SARS-CoV-2 has the potential to affect deer. -life, establishing a cycle of dispersal, and becoming endemic. in non-human species ”, warn the authors of this study.
An incident like this would pose a direct threat to wildlife health, with the ability to establish a museum, which could stop our orchestrated control measures to stop spillage events not only SARS-CoV-2 , but other possible zoonotic diseases as well. Therefore, experimental research, modeling tools and sensitivity are the essential measures to address this issue.
* Important message
bioRxiv publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical practice / behavior, or be treated as information established.