Coronavirus News: Canadian Researchers Say SARS-CoV-2 Poses Major Threat To Marine Mammal Species. Seafood Supplies Possibly Next?

Coronavirus News: A study conducted by scientists from Dalhousie University in Halifax, Canada, has alarmingly discovered that many species of marine mammal are highly vulnerable to infection with the SARS-CoV-2 coronavirus.


Marine mammal species predicted to be susceptible belong to the IUCN Red list. Many of the species predicted to be susceptible are members of the IUCN Red list of Threatened Species . 
 
The researchers say poor wastewater management can lead to these species being exposed to the coronavirus, which could have devastating effects on marine mammal populations that are already on the decline.
 
The study findings were published on a preprint server and are being peer-reviewed. https://www.biorxiv.org/content/10.1101/2020.08.13.249904v1
 
While SARS-CoV-2 was initially thought to be primarily a respiratory illness, studies have recently pointed to multi-organ infection, including the gastrointestinal tract. Researchers have also shown that patients with COVID-19 shed viable SARS-CoV-2 in their urine and stool and that the virus can be been detected in untreated wastewater in many countries, including Italy, Spain, France, and Australia.
 
Corresponding author Dr Graham Dellaire from the department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax told Thailand Medical News, “The absence or failure of a wastewater treatment plant can lead to sewage being another form of transmission that affects both humans and susceptible species.”
 
The study team says many types of marine mammals that are found close to contaminated natural water systems will be exposed to SARS-CoV-2 and that it is vital to identify which animals are most at risk.
 
The study team examined all publicly available data on the sequenced genomes of marine mammals and used a modeling approach to predict their susceptibility to SARS-CoV-2 infection.
 
The researchers found that most species of cetacean (18 of 21) are more susceptible than humans. Since many of the species are social such as the beluga whale and bottlenose dolphin, they are especially vulnerable to intraspecies transmission.

The study team pointed out that cetaceans, especially whales, are known to express ACE2 receptors with high similarity levels to humans, which means they can be vulnerable to the infection. The researchers estimate that a medium-sized whale could receive 5.65 million copies of the virus every second based on some of the current studies showing the levels of virus contamination in waste waters in certain regions.
 
Also it was found that the majority of seal species (8 of 9) were also highly susceptible to infection. The one exception was the California sea lion, owing to a mutation in the animal’s angiotensin-converting enzyme 2 orACE2 receptor, which the SARS-CoV-2 coronavirus uses to infect host cells.
 
Interestingly of all the mammalian species analyzed, the Atlantic Walrus had the ACE2 with the most significant binding affinity for the virus. Otters were also highly susceptible to infection.
 
Significantly it was found that more than 50 percent of the species that were identified as being highly susceptible to infection are already categorized as “near threatened,” “vulnerable,” “endangered,” or “critically endangered.”
 
Dr Dellaire added, “If these organisms are infected by SARS-CoV-2, their already dwindling population numbers will be even more at risk.”
 
Furthermore, geo-mapping studies showed how poor wastewater management in Alaska might further increase the risk to marine mammals.

As Alaska is home to many well-documented marine populations, the researchers analyzed this information together with data available on wastewater treatment plants across the state.
 
Fortunately municipalities in the southern and northern shores primarily used secondary treatment, which has previously been shown to remove most traces of SARS-CoV-2.
 
But the western shores primarily rely on lagoon treatment, a primary type of treatment that is less effective at removing infectious viral particles. Three species of seal are found along these shores, and the researchers say it will be important to gather data on their ACE2 receptor sequence to predict the potential risk to these populations accurately.
 
The researchers also identified some high-risk locations that use lagoon treatments on southern shores. These included Cold Bay in Naknek, which is home to highly susceptible sea otter species and Bristol Bay, where endangered Beluga whales are found.
 
The study team added, “Efforts to mitigate and carefully assess the impact of the wastewater effluent discharged only after primary treatment into these marine mammal habitats will be important for protecting these species. We must act with foresight to protect marine mammal species.”
 
The study team says it will be key to assess and appropriate wastewater treatment to reduce the impact of sewage-based transmission in natural water systems and those high risk areas should be particularly careful regarding how wastewater is managed and treated.
 
Dr Graham further added, “At this point in the pandemic, the available evidence indicates that wastewater is an important vector for SARS-CoV-2 transmission for humans and susceptible wildlife. Given the proximity of marine animals to high-risk environments where viral spill over is likely, we must act with foresight to protect marine mammal species predicted to be at-risk and mitigate the environmental impact of the COVID-19 pandemic.”
 
Thailand Medical News had published an article based on another study that showed the presence of stable SARS-CoV-2 in water for up to 25 days. https://www.thailandmedical.news/news/breaking-news-covid-19-research-shows-that-sars-cov-2-coronavirus-can-survive-in-water-for-up-to-25-days-and-could-also-be-water-borne


 
The study team concluded, “The research findings suggest that public interactions with rivers and coastal waters following wastewater spills should be minimized to reduce the risk of infection. The main risk is human-to-human spread, but it could also allow the virus to infect new animal species and, in turn, result in a future re-entry of the virus into the human population.”
 
Although there is no proof that the novel coronavirus can survive in salt water environments or even infect the normal fish species, the possibility of the virus evolving to withstand high salinity environments and being able to harbor in fish species cannot be ruled out and warrants further research as it could have serious impacts on the seafood industry as well. Already China has reported of finding the SAR-CoV-2 on imported frozen salmon.

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