New coronavirus found in Malaysia; could be transmitted from dogs
Scientists have found a new type of coronavirus that can infect humans while looking into pneumonia cases in Malaysia. What's interesting is that this an alphacoronavirus, which mostly infects cats and dogs. Scientists say the more we look into unknown coronaviruses, the more likely we are to prevent them from evolving into viruses that cause pandemics, such as the ongoing COVID-19 pandemic.
A team of researchers published a study in the medical journal Clinical Infectious Diseases on Thursday. The study said an alphacoronavirus was isolated from a human pneumonia patient. This could be the eighth coronavirus known to infect humans. The samples came from 301 hospitalized pneumonia patients in Sarawak, Malaysia, between 2017 and 2018. Eight samples (2.7%) were found to be carrying the novel coronavirus.
The researchers said in the study, "Two of eight specimens contained sufficient amounts of CCoVs (canine coronaviruses) as confirmed by less-sensitive single-step RT-PCR assays, and one specimen demonstrated cytopathic effects (CPE) in A72 cells." "Complete genome sequencing of the virus causing CPE identified it as a novel canine-feline recombinant alphacoronavirus (genotype II) that we named CCoV-HuPn-2018," they added.
The researchers initially had doubts if their findings were correct. However, virologist Anastasia Vlasova at the Ohio State University confirmed that the virus was in fact a canine coronavirus, which were not thought to be transmitted to humans earlier. Vlasova told NPR that she tried to grow the coronavirus using a solution that worked well with canine coronaviruses and it grew "very well."
Looking at the genome of the virus, Vlasova said the virus had likely infected cats and pigs at one point. However, considering that the majority of the genome was canine coronavirus, she said it was likely the virus jumped directly from dogs to humans. The study noted that most sampled pneumonia patients were children in rural areas with frequent exposure to domesticated animals.
Vlasova also said, "We did discover a very, very unique mutation—or deletion—in the genome." She said this deletion is not present in other canine coronaviruses but is present in human coronaviruses. "It's a mutation that's very similar to one previously found in the SARS coronavirus and in [versions of] SARS-CoV-2 ... [that appeared] very soon after its introduction into the human population," she said.
Virologist Xuming Zhang at the University of Arkansas for Medical Sciences told NPR there is no evidence of human to human transmission. Zhang said it is too early to irrefutably state that the canine coronavirus causes pneumonia in humans. The virus has only been associated with the disease. Genetic data does suggest that this virus was caught early in its journey in infecting humans.
The findings highlight the importance of better surveillance of coronaviruses and catching them early before they turn highly infectious or even fatal for humans. Dr. Gregory Gray—one of the study's authors—told SCMP, "What this suggests is that because we don't have diagnostics that would pick up new coronaviruses in the common hospital laboratory setting, we are missing opportunities to detect pre-pandemic viruses."