Emerging Viruses: Canine Coronavirus and Influenza D Pose Potential Threat

Researchers have identified canine coronavirus and influenza D as zoonotic viruses – meaning they can spread from animals to humans – with a “considerable potential” to cause future epidemics. A recent analysis published in Emerging Infectious Diseases details the history of these viruses and documented instances of transmission to people.

The study highlights a critical gap in our understanding and preparedness: diagnostics and surveillance for these viruses are currently lacking. Data suggests these viruses represent “major newly recognized threats,” demanding increased attention from the medical community.

Evidence of Human Exposure

Investigations have revealed evidence of human exposure to both viruses. A study of cattle workers in Florida found that over 97% had neutralizing antibodies to influenza D, compared to only 18% of those without cattle exposure. Further research in Colorado, conducted in 2023, showed that 67% of dairy workers had evidence of the influenza D virus in their nasal washes.

Canine coronavirus, specifically a strain identified as CCoV-HuPn-2018, has resulted in documented – though rare – human cases involving serious respiratory symptoms. The virus has been detected in Malaysia, Haiti, Bangkok, Thailand, and even in the U.S. State of Arkansas. Eighteen patients with pneumonia in Vietnam were also found to have the virus, indicating a potentially widespread and increasing prevalence.

“Our review of the literature indicates these two viruses pose respiratory disease threats to humans, yet little has been done to respond to or prevent infection from these viruses,” stated John A. Lednicky, PhD, a research professor at the University of Florida. He cautioned that if these viruses develop the ability to easily transmit between people, they could potentially cause epidemics or even pandemics, given the general lack of existing immunity.

The initial identification of the virus originating in Haiti occurred in April 2017, when samples collected in March of that year yielded negative results for Zika and other arboviruses. Researchers initially suspected an enterovirus infection, but ultimately isolated a coronavirus with 97% nucleotide identity to a porcine coronavirus.

The canine coronavirus was first identified in May 2021 by a group led by Gregory Gray, MD, after analyzing a sample collected in 2017. Lednicky’s lab subsequently confirmed a 97% identity between the two strains.

What Could Happen Next?

Currently, no one knows the full global range or burden of these viruses. More research is needed to determine their prevalence and potential for spread. Existing tests are limited to those developed by the researchers involved in their discovery. The development of optimal tests, treatments, and potentially vaccines requires further funding.

For a large outbreak to occur, these viruses would need to develop the ability to transmit easily from person to person. It is also unknown whether exposure to other common human coronaviruses would provide any immunity. Global disease surveillance systems, as they currently exist, are unlikely to identify these viruses due to their unfamiliarity. However, once a significant outbreak occurs, testing capabilities could be rapidly implemented, similar to what happened during the COVID-19 pandemic.

Frequently Asked Questions

When were these viruses discovered?

Samples were initially collected in 2017, but final identification of the viruses occurred in early 2021 by research groups led by Gregory Gray, MD, and John A. Lednicky, PhD.

What is their current global range?

The viruses have been detected in the U.S., Haiti, Malaysia, Thailand, and Vietnam, but their full global range and burden are currently unknown.

Are there existing tests, treatments, or vaccines?

Existing tests are limited to those developed by the researchers. There are currently no specific treatments or vaccines available.

What role do you think increased global collaboration will play in addressing emerging viral threats like these?