A team of Spanish scientists has identified the first case of covid-19 in a Eurasian river otter (lutra lutra), located near a reservoir in the Valencian Community. The researchers, who attribute the contagion to the probable contact with contaminated sewageThey insist on the need to establish a surveillance system for this coronavirus in wild mustelidssince they could become reservoirs of the virus.
The finding represents first case of detection of the virus in this wild species worldwideand has just been published in the international scientific journal ‘Frontiers in Veterinary Science’.
Virus detection was performed using two different types of PCR tests on RNA extracted from the animal’s nasopharynx by swab and from lung tissue and mediastinal lymph nodes. Samples from two additional otters from distant sites were negative in identical tests.
The research, carried out by scientists from the CEU Cardenal Herrera University (CEU UCH) in Valencia, the Valencia Institute of Biomedicine (CSIC) and the Autonomous University of Barcelona (UAB), has confirmed the human origin of this contagionalthough the initial source of this emerging infectious disease is probably animal.
Animals have been involved in the three known outbreaks of severe respiratory syndrome coronavirus, recorded in the years 2005, 2012 and 2019. The pandemic nature of the SARS-CoV-2 outbreak increases the likelihood of human-caused infections in animal species susceptible that, therefore, could become secondary viral hosts and even disease reservoirs.
Contact with contaminated water
Consuelo Rubio, principal investigator of the Molecular Virology Group at CEU UCH and co-author of the work, pointed out that in the sequencing of the virus, changes were discovered that had already been identified in samples from human patients, “which points to the human origin of the virus detected in this wild otteralthough his specific combination was different & rdquor ;.
“The contagion could have been caused by contact with contaminated sewage with the virus present in the river area inhabited by the otter & rdquor ;, added Rubio.
This same team of researchers also detected in May of last year two positive cases of SARS-CoV-2 coronavirus in wild American mink, in two rivers in the province of Castellón. These were the first cases in Europe of the virus in wild animals, which had not been in direct contact with infected people.
Already then, in the article published in the journal ‘Animals’, the researchers raised the possible origin of contagion by contact of these aquatic life animals with contaminated wastewater in river areas.
“Different animal species have been involved in the three outbreaks of acute respiratory syndrome caused by other coronaviruses in previous epidemics. But in relation to the SARS-CoV-2 pandemic, our findings in both mink and otter specimens highlight the need to establish a surveillance system for this coronavirus in wild mustelids&rdquor ;, Rubio comments.
“This would make it possible to assess the risk that these animals could become SARS-CoV-2 reservoirs, giving rise to new mutations of the virus that can infect humans again or to other wild species in case of contact with infected mustelids & rdquor ;, he concludes.
Mink infections to human
In their previous investigation, this team of Spanish scientists had highlighted that in addition to the confirmed cases of human-to-mink infection, there are also suggestions that a mink-to-human infection occurs.
“To date, mink infections have been reported only in fur farmsexcept for a wild mink (Neovision mink) infected that lived in freedom near a fur farm in Utah, in the United States, which suggests a route of transmission from farms to wild minks & rdquor ;, they detailed in their report.
The researchers then reported the detection of coronavirus in two of the thirteen wild American mink they had tested, after being caught during an invasive species trapping campaign.
“They became trapped in riverbeds in sparsely inhabited rural areas known to support self-sustaining populations of wild mink. The closest fur farm is about 20 kilometers away & rdquor ;, the specialists pointed out.
In those cases, the SARS-CoV-2 RNA was detected by two-step PCR tests in the mesenteric lymph nodes of the animals, and it was found to correspond to wuhan sequencethe first known covid-19.
Experimental infections have revealed different levels of susceptibility among various animal species and families. A) Yes, poultry are not susceptible and pigs or cattle have shown low susceptibility, while felines and mustelids are vulnerable to contagion.
spread in animals
The spread of SARS-CoV-2 in vast human populations around the world has led to reports of transmission to animals that live in close association with infected people. In fact, in addition to American visions, covid has been detected in domestic and stray cats (Felis silvestris catus), in tigers ( panthera tigris) Y lions (Panthera leo) from zoos, and in domestic ferrets (Mustela putorius furo).
Outbreaks in farmed American mink have been particularly common. They were initially reported in the Netherlands and then in several other European countries (Denmark, France, Greece, Italy, Lithuania, Poland, Spain, and Sweden) and in North America (Canada and the United States), apparently as a consequence of the contact with infected workers.
To prevent the possible spread of the virus to humans, mass killings of infected farmed mink were carried out in some of these countries.
The American mink is a exotic species on the European continent capable of colonizing new environments and displacing critically endangered speciessuch as the European mink (Mustela lutreola), or to prey on the vulnerable Pyrenean desman (Galemys pyrenaicus) and the southern water vole (Arvicola sapidus). A) Yes, is included in the Spanish Catalog of Invasive Alien Speciesand is subject to eradication by trapping and culling.
Reference report: https://www.frontiersin.org/articles/10.3389/fvets.2022.826991/full