The Rising Threat of Zoonotic Viruses

The emergence of IDV and canine coronavirus underscores the constant threat of zoonotic diseases – illnesses that jump from animals to humans. These viruses, long circulating within animal populations, are now exhibiting characteristics that raise concerns among infectious disease specialists. A recent report in Emerging Infectious Diseases, published by the US Centers for Disease Control and Prevention (CDC), highlighted the critical need for enhanced monitoring and testing to mitigate potential risks.

John Lednicky, a research professor at the University of Florida (UF) College of Public Health and Health Professions, explains that both viruses demonstrate the potential to cause respiratory illness in people. “If either virus were to develop efficient human-to-human transmission, the consequences could be significant, potentially leading to epidemics or even pandemics, given the widespread lack of pre-existing immunity,” he stated.

Influenza D Virus: A Growing Concern for Livestock and Humans

First identified in 2011, Influenza D virus (IDV) initially gained attention for its impact on pigs and cattle. However, its host range has since expanded to include a diverse array of animals, including poultry, deer, giraffes, and even kangaroos. The virus is a significant contributor to bovine respiratory disease, costing the American cattle industry an estimated $1 billion annually.

Studies examining cattle workers in Colorado and Florida revealed a surprisingly high prevalence of IDV antibodies – up to 97% – indicating substantial prior exposure. While these infections didn’t typically result in noticeable illness, researchers are observing rapid genetic changes within the virus. Notably, a strain isolated in China has already demonstrated the ability to spread between humans, a worrying development.

According to the CDC, IDV primarily affects cattle but possesses the capacity to spill over into other animal species. Further research, detailed in studies, confirms infections worldwide through various testing methods. The virus’s unique hemagglutinin-esterase fusion protein allows it to infect a broad range of hosts. Cattle are considered the primary reservoir, but camels, pigs, and other livestock are also susceptible. Wild animals, including deer and kangaroos, have also tested positive, suggesting a complex transmission network.

Canine Coronavirus: Beyond Canine Illness

While typically associated with gastrointestinal illness in dogs, canine coronavirus is now being linked to human respiratory infections, particularly in Southeast Asia. Researchers, including a team led by Lednicky at UF, isolated a strain – HuCCoV_Z19Haiti – from a medical worker who traveled from Florida to Haiti in 2017, who subsequently experienced mild fever and malaise.

In 2021, another strain, CCoV-HuPn-2018, was identified by a research group at the University of Texas Medical Branch in a hospitalized child in Malaysia. Genetic analysis revealed a close relationship to the Florida strain. Since then, CCoV-HuPn-2018 has been detected in patients with respiratory illness in Thailand, Vietnam, and Arkansas, confirming its global circulation.

What lessons can we draw from past outbreaks like SARS and COVID-19 to better prepare for potential pandemics caused by viruses like IDV and canine coronavirus? And how can international collaboration improve global surveillance efforts?

Frequently Asked Questions About Emerging Viruses