At least 15 species of endangered marine mammals may be susceptible to COVID-19, and the discharge of untreated wastewater could be carrying the virus into natural water systems, particularly in developing nations, a new study suggests.
For the study, published in the journal Science of the Total Environment, Director of Research in the Department of Pathology at Dalhousie University, Graham Dellaire, led research that used a modeling approach to predict a marine mammal’s susceptibility to the coronavirus strain SARS-CoV-2.
“In the past, these animals have been infected by related coronaviruses that have caused both mild disease as well as life-threatening liver and lung damage,” said Dellaire in a statement from the university.
Saby Mathavarajah, a pre-doctoral fellow in Dr. Dellaire’s lab, who co-authored the report, said that a significant concern may be areas of the globe “where there already exists a disparity in public health and the wastewater treatment infrastructure required to handle the COVID-19 crisis.”
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While many jurisdictions have at least primary waste treatment, the researchers note that sewage systems can be overwhelmed under certain conditions, leading to the overflow of raw sewage directly into waterways that are home to vulnerable mammals.
The study refers to a June 16, 2020 report from Ecuador, a country with primitive sanitation, where SARS-CoV-2 was detected in river water. Also of note, the researchers say, is to recall the 2002-2003 Ebola pandemic, when more than 5,000 gorillas died from a strain of the virus.
There have been no documented cases of SARS-CoV-2 in marine mammals to date, but both dolphins and beluga whales have been previously infected with related coronaviruses, the study states.
Primary treated wastewater can be released from settling ponds or lagoons, a risk the researchers say they identified as a potential issue in Alaska, where beluga whales could be infected from sewage leaking into local waterways from the state’s system of lagoons. Additionally, the study warns that Alaskan areas such as Cold Bay, Naknek, Dillingham and Palmer may require additional treatment of their wastewater to prevent virus spillover through sewage.
Despite the perceived risk, researchers identified that most of the Alaskan wastewater treatment plants in the vicinity of marine mammals were utilizing secondary treatment, likely ruling out the possibility of virus exposure in these areas.
The researchers acknowledge that how the SARS-CoV-2 virus fares in the environment and the conditions influencing its stability in wastewater are still poorly understood.