Avian Flu Grand Rounds: A Summary

With approximately 2,000 registered attendees, members of the veterinary and human health communities, scientists, media, policymakers, general public and others showed their concerns about avian flu by tuning into the February 19 UC Health Grand Rounds. The one-hour, online session featured three experts from the UC Davis School of Veterinary Medicine and one from UC Davis Health. This panel—which included animal disease experts, epidemiologists and public health professionals—discussed the current outbreak, its impact on various species, and public health implications.

After an introduction by Dr. Deena Shin McRae, the associate vice president for academic health sciences at UC Health, Dr. Mark Stetter, dean of the School of Veterinary Medicine and Diplomate of the American College of Zoological Medicine, opened the session by saying, "Avian influenza is not new...But what is new is this virus is changing." He highlighted the virus's jump to unexpected species like cows, cats, and seals, and the increasing number of human infections with unknown sources. "It's also begun to jump to humans... there's more and more concern about how it might be exposing humans in ways that we hadn't predicted before," Stetter warned.

Stetter then focused on California, which has high infection incident rates in its poultry and dairies. "We literally feed the nation," he pointed out, emphasizing the importance of a One Health approach, bringing together experts from diverse disciplines to address this complex issue.

Dr. Ashley Hill, Director of the California Animal Health and Food Safety Laboratory system (CAHFS) at UC Davis, described the diagnostic function of the lab system, and noted that avian flu "…is making the news now in large part because we're seeing sustained mammal to mammal transmission in cows, and that's something new."

She highlighted the differences in disease progression and mortality between poultry and cattle, explaining how these differences influence detection and control strategies. Regarding the spread in cattle, she explained, "Remember in cows it's mostly spread dairy to dairy. And we have a lot of dairies in California with a lot of contact between them," underscoring why California is particularly affected.

Hill reassured the audience about food safety, stating, "cooking inactivates the virus and sick birds do not enter the food chain." However, she acknowledged the impact on egg supply: "Lots of poultry farms have been affected... that's more than 150 million eggs a week that disappeared from supermarket shelves in the last month." Hill detailed the testing procedures, including PCR and sequencing, used to identify and track the virus.

Like other health units within the University of California, CAHFS partners with the State and nationally, including the U.S. Department of Agriculture and American Association of Veterinary Laboratory Diagnosticians (AAVLD) National Animal Health Laboratory Network (NAHLN) and the California Department of Food and Agriculture/USDA H5N1 Task Force, which serves on the front lines of disease response.

Hill concluded by offering safety advice, including basic food hygiene, avoiding raw milk, and wearing appropriate PPE when handling potentially infected animals. She also provided contact information for reporting sick or dead animals:

• The California Department of Food and Agriculture (CDFA) Sick Bird Hotline is (866) 922-2473
• The hotline for sick and deceased wildlife is the California Department of Fish and Wildlife at (916) 358-2790 (do not touch wildlife).
• If you think your cat may be sick, call your veterinarian.

Dr. Christine Johnson, Professor of Epidemiology and Ecosystem Health at UC Davis, provided a broader context for the current H5N1 situation. She explained the typical transmission cycle of avian flu and emphasized that the current situation deviates significantly from this norm. "The marine mammal outbreaks were really the first harbinger that the epidemiology of H5N1 in mammals was dramatically changing." Johnson explained how the virus has evolved to sustain transmission in multiple species, including seals, sea lions, and cows.

Johnson placed the H5N1 outbreak within the broader context of emerging infectious diseases, highlighting the complexity and interconnectedness of animal and human health. She concluded by clearing common misunderstandings that can cause inaction and emphasized the need for a comprehensive, multidisciplinary approach to address the evolving threat.

Dr. Angel Desai, Assistant Clinical Professor Division of Infectious Diseases at the School of Medicine, finished the panel with observations on the impact of avian flu on humans. "There are actually nine known subtypes of (avian flu) H5 that have infected humans in the past." Desai said. "We've seen sporadic H5 infections for several decades, presenting with a spectrum of disease in terms of H5N1…since 2003, there have been more than 900 human cases reported worldwide…and about 67 cases in the Unites States."

Desai noted that most of the U.S. cases have occurred in the California, among individuals with exposure to dairy cow herds. Infected individuals generally experience mild illness, exhibiting symptoms like conjunctivitis, mild cough, fever, shortness of breath, headache, nasal congestion and respiratory symptoms.

A new mutation may have made it easier for the virus to replicate more effectively in mammalian tissues. The incubation period has historically been from 2-7 days, but can be variable to up to 17 days. Desai detailed the technical characteristics of the virus and its mutations, and correlated them to symptoms.

Almost all known human infections are correlated to direct contact with infected animals or other vectors of known transmission, but Desai expressed concern that a couple of recent human infections had no obvious route of transmission.

Desai also covered the basic treatment of infections including supportive care and antiviral treatment. She emphasized prevention through PPE and by not consuming raw milk.

Desai wrapped up by providing a state of potential avian flu vaccines, which have been developed and stockpiled previously. Although they are not currently available, Moderna is in a phase three trial that potentially could make a vaccine widely available.

The panel discussion highlighted the complexity of the H5N1 situation, the importance of interdisciplinary collaboration, and the need for ongoing surveillance and research to understand and mitigate the virus's impact on animal and human health. The speakers emphasized the importance of food and workplace safety practices and the need for vigilance in monitoring animal populations for signs of infection.

RELATED: Find out more about how the University of California is a critical partner in pandemic preparedness and health security.

Watch the Grand Rounds session on YouTube

This article was drafted with the assistance of Google Gemini AI and has been fully reviewed by UC Davis staff.