A study published in Frontiers of veterinary science reveals the presence of murine coronavirus ─ the murine hepatitis virus or M-CoV─ in mice from the Canary Islands archipelago (Spain) which could have reached the islands by sea transport from the European continent. This is the first eco-epidemiological study to examine the presence of coronaviruses which circulate in mice and rats of the natural and urban environment of the islands of La Palma, El Hierro, Tenerife and Lanzarote.
The study is led by Jordi Serra-Cobo, lecturer at the Faculty of Biology and member of the Biodiversity Research Institute (IRBio) of the University of Barcelona, and counts on the participation of teams from the Faculty of Pharmacy and Food Sciences and University Institute of Tropical Diseases and Health of the University of La Laguna, among other institutions.
M-CoV: a virus studied in laboratory mice
The SARS-CoV-2 pandemic has placed coronaviruses at the center of intense research activity around the world. In recent years, five new coronaviruses have been identified: SARS-CoV, HCoV-NL63, HCoV-HKU1, MERS-CoV and SARS-CoV-2. These viruses have been identified as viruses capable of causing respiratory pathologies in humans.
Murine hepatitis virus (M-CoV) is a coronavirus that was first isolated in 1947 from rodents. Although contagion to the human population has not been recorded, the virus is highly infectious and is transmitted mainly through aerosols and direct contact. This pathogen has mainly been studied in laboratory mice, and few studies have been carried out in wildlife. “The murine hepatitis virus is highly infectious and is one of the most common pathogens in laboratory mice. Symptoms of this infection vary depending on the genotype and age of the mouse. This virus can be very aggressive in mice, and has a tendency to cause hepatitis, enteritis and encephalitis ”, notes Jordi Serra-Cobo, UB and IRBio expert in eco-epidemiological studies.
As part of the research, conducted from 2015 to 2019, the team applied the nRT-PCR technique on fecal samples from three rodent species (Mus musculus, Rattus rattus and Rattus norvegicus) to detect the potential presence of coronavirus. These mice and rats, which are not native to the Canary Islands, arrived in the archipelago centuries ago and have spread throughout the geography of the islands.
The results revealed the presence of M-CoV RNA in the Mus musculus house mouse population in urban environments of three islands – El Hierro, Tenerife and Lanzarote─ in a similar proportion on both a geographic and temporal scale. Concerning the black rat (R. rattus) and the brown rat (R. norvegicus), all the results for the detection of M-CoV were negative.
A journey from the European continent to the Canary Islands archipelago
Everything indicates that the murine genera coronavirus Beta-coronavirus and sub-genres EmbecovirusThe found in mice of the Canary Islands is phylogenetically linked to murine coronaviruses of the European continent. In particular, to the coronavirus which was first identified in 2010 in wild populations of mice Mus musculus and the field vole (Glareolae myodes) by the team led by Professor Jan Felix Drexler (University of Bonn, Germany).
“The data obtained showed us that the most likely origin is European, which makes sense considering the high trade relations between the Canary Islands and Europe,” notes speaker Jordi Serra-Cobo.
The differentiation between coronavirus strains between the Canary Islands and mainland viruses is said to be a fairly recent process in time. Another important aspect is the diversity of M-CoV variants circulating in the population of house mice on the three islands.
Coronavirus, invasive species and global health
The article published in Frontiers of veterinary science shows the potential role of rodents and other invasive species that inhabit outside their natural range – in the process of spreading infectious diseases.
In this context, it is a priority to control the arrival of non-native species which are potential reservoirs of pathogens, particularly in island environments. Additionally, in the case of mice, alpha and beta coronaviruses are relatively common and as research studies advance, new pathogenic strains are identified in these rodents.
“Regarding global health,” says Serra-Cobo, “the study warns us against the arrival of microorganisms that can be pathogenic for local fauna or humans, as well as the arrival of non-native species. The murine coronavirus affects rodent species, but given the rapid evolution of these viruses, we cannot exclude the possibility of its adaptation to infect other groups of mammals ”.
“It is therefore important to analyze incoming goods and holds, especially in boats, to verify that there are no rodents. It is not easy, but it is necessary to prevent the spread not only of M-CoV but also of other viruses, which in some cases can be zoonotic and therefore cause infections in the human population ”, concludes the speaker. Jordi Serra-Cobo.