Friday, December 3

M-CoV: The coronavirus that traveled by boat to the Canary Islands | Science

Merchants at anchor in front of the port of Santa Cruz de Tenerife.
Merchants at anchor in front of the port of Santa Cruz de Tenerife.Ports of Tenerife

Coronaviruses, not just the one that causes covid-19, spread through Europe more easily than we assume. This is the main conclusion drawn by the authors of a study that has detected the presence of the murine coronavirus (M-CoV) for the first time in Spain. M-CoV is a pathogen that would only affect rodents. The RNA of this coronavirus – the virus genome – has been identified in common mouse feces from the Canary Islands.

The job, published last August in the magazine Frontiers in veterinary science, has been led by scientists from the University of Barcelona (UB) and the University of La Laguna (Tenerife). The team led by the UB ecoepidemiologist Jordi Serra-Cobo collected between 2015 and 2019 more than 250 samples of common mouse feces (mouse muscle), black rat (rattus rattus) and gray rat (rattus norvegicus). The prevalence of coronavirus RNA was identified in a range of 10.5% to 5.2% of the common mouse samples from El Hierro, Tenerife and Lanzarote.

The evidence was drawn from urban areas and rural populations. Pilar Foronda, a professor at the University of La Laguna, specifies that the samples from Tenerife were taken in the areas with the highest urban density on the island, in Santa Cruz and in San Cristóbal de La Laguna; those of El Hierro were collected on the shoulder of a road that crosses a municipality, and those of Lanzarote, in cultivated areas.

Mice and rats are not endemic to the Canaries, they were introduced by new human settlements and by maritime trade – the gray rat was the last to arrive, probably in the 18th century, the study points out. It is precisely in vessels of the current merchant routes that Serra-Cobo speculates that specimens of mice infected with M-CoV landed in the archipelago. It happened in the last two decades, according to the estimate of this expert in virus ecosystems, because the RNA analyzed is similar to that of a strain identified in 2010 in Germany, in the main study carried out to date on M-CoV in rodents in the wild.

The Canary Islands study warns “of the potential role of rodents and other invasive species in spreading diseases in remote places through exchanges with the continent. It is important to take these aspects into account for the sanitary control of the islands ”. Its authors emphasize that rodents are the most common order of mammals on the planet and are “a great zoonotic source of infectious diseases for humans.”

Zoonotic diseases are those that jump from animals to humans. The five different coronaviruses that have affected humans in the 21st century have had a zoonotic origin, the most aggressive being SARS, MERS and SARS-Cov-2, the cause of covid-19. The main reservoir of these coronaviruses are bats, but the World Health Organization (WHO) emphasizes that rodents are also transmitters of viruses that are lethal to humans, such as rabies. The WHO has registered more than 200 diseases of zoonotic origin.

Lower risk, but on alert

The work headed by Serra-Cobo recalls that some of the 2,000 known rodent species are synanthropic, “they live in close proximity to humans, which could represent a zoonotic risk.” “Betacoronaviruses, such as M-CoV, are more aggressive, they are the ones that can pose a zoonotic risk, as happened with SARS and MERS,” says Serra-Cobo. Foronda believes that the main value of the study is that these conditions “can mutate”: “It is a risk that must be taken into account because they are wild animals, but they live close to us.” Foronda says that it is not an alarm, and believes that “the risk is lower”, because they are rodents that have lived with people for centuries or millennia and the M-CoV has not affected us. “But the risk is if the pathogen passes to other animals,” says this Canarian biologist expert in parasitology and zoonoses. Serra-Cobo cites MERS as an example of this potential danger: the most probable original reservoir of this virus is the bat; from bats it passed to dromedaries and from these to humans.

The murine coronavirus is also known as the mouse hepatitis virus. It was first isolated in 1947. It has been extensively studied in captive specimens for the investigation of hepatitis and sclerosis. But beyond Asia, its existence in nature has been scarcely studied, explains Meradieg Ar Gouilh, a researcher at the University of Normandy and a collaborator of Serra-Cobo.

More information

Ar Gouilh, who has also participated in the study of the Canaries, stresses that it is important to know “what viruses these rodents carry because they are species very close to people.” “We do not believe that the murine has jumped to other species, it has not been detected beyond rodents. But coronaviruses evolve quickly and we have already found that they adapt more easily to different species ”, explains Ar Gouilh.

That the M-CoV RNA detected in the Canary Islands is close to that identified in Germany a decade ago does not mean that it comes from this country, Ar Gouil points out: what he means is that there are no other studies in Europe that have thoroughly searched for its presence In nature. “It could have come to the Canary Islands from another point on the continent. If it has reached these islands, it is most likely that it is spread across Europe ”. Foronda provides a counterpoint: many factors determine the geographic expansion of a living being and there are cases that show that the distribution may be more extensive in the invaded territory than in the area of ​​origin.

You can follow MATTER on Facebook, Twitter e Instagram, or sign up here to receive our weekly newsletter.

Leave a Reply

Your email address will not be published. Required fields are marked *