The top stories and research updates on avian influenza, swine flu, and pandemic influenza risks curated by Global Biodefense.
This Flu Focus includes the challenges of avian influenza infections in dairy herds, how our veterinarian shortage is bad for biosecurity, and the zoonotic potential of novel H1N2 and H3N2 swine influenza A viruses.
LATEST NEWS
21 Dairy Herds Across Seven States Confirmed for Avian Flu Infections
It’s been two weeks since the initial detection of a strain of bird flu in dairy cows. At least 21 herds had been infected across seven states (Texas, Kansas, Idaho, Michigan, Ohio and New Mexico, North Carolina). 17 states this week enacted restrictions on cattle importations from states where the virus is known to have infected dairy cows. AVMA, CIDRAP, NPR
Bird Flu Isn’t Killing Cows. The Experts Are Still Worried.
Since the U.S. Department of Agriculture announced first positive tests in cows on March 25, it’s become increasingly clear that authorities have little way of knowing how widespread the virus is among the nation’s nearly 90 million cattle. The positive tests came after nearly two months in which farmers in the Texas Panhandle struggled to explain a mysterious illness sweeping their dairy herds. Officials now believe the sickness was caused by avian flu. Barron’s
Texas Dairy Worker Tests Positive for Avian Flu
Texas health officials announced on 1 April the second human case of H5N1 ever recorded in the United States, and the first instance of human infection presumed to be from contact with infected dairy cows. The patient’s primary symptom was conjunctivitis; the individual is being treated with the antiviral drug oseltamivir. Global Biodefense, New York Times
Avian Influenza Vaccination: Why It Should Not Be a Barrier to Safe Trade
The devastating impacts of avian influenza extend beyond domestic and wild birds, threatening livelihoods, food security and public health. The use of sanitary control measures alone may no longer be a sustainable solution to effectively contain the disease. Poultry vaccination can no longer be excluded from the available alternatives and should be considered a complementary tool. World Organization for Animal Health (WOAH)
Virologist Ron Fouchier on the Risk H5N1 Poses to Humans
Fouchier, a leading expert on H5N1, takes little solace from the fact that current versions of H5N1 seem to infect people less frequently, and to cause mostly mild illness when they do. The global range of H5 viruses — the sheer volume of the virus in nature — and the numbers of mammals H5 has shown itself capable of sickening is unprecedented, he said, making anticipating its future path harder than ever to gauge. STAT
Scientists Investigate Thousands of Dead Antarctic Penguins for Bird Flu
A scientific expedition last month found at least 532 frozen, dead Adelie penguins, with thousands more thought to have died. In February, researchers confirmed that H5N1 had finally turned up—as long feared—in Antarctica. Winter starts in March in Antarctica, so birds were already starting to scatter to their wintering areas, but there is grave concern for the next spring breeding season for penguins and birds (October to early December). Reuters, Science
Largest U.S. Egg Producer Detects Bird Flu at Texas Plant
Cal-Maine Foods said it culled about 1.6 million hens and 337,000 pullets (young hens) after some of its chickens at a Parmer County, Texas, facility tested positive. The culled chickens at Cal-Maine Foods represent 3.6 percent of its flock. Washington Post
Minnesota Goat Confirmed to Have Highly Pathogenic Avian Influenza
MN ag health officials reported on 20 March a goat kid (juvenile goat) residing on a farm with a Highly Pathogenic Avian Influenza (HPAI) positive poultry flock tested positive for the same virus. This is the first U.S. detection of HPAI in a domestic ruminant (cattle, sheep, goats, and their relatives). All poultry on the property were already quarantined from the February HPAI detection. MN Board of Animal Health
PANDEMIC PREPAREDNESS
How Prepared the U.S. is for a Bird Flu Pandemic
Top officials at the Centers for Disease Control and Prevention said the agency is well poised to detect if a person has H5N1 through the agency’s regular surveillance for seasonal flu at more than 100 public health labs in all states as well as enhanced monitoring put in place in 2022 for anyone who has been exposed to birds infected with that strain. Two candidate vaccine viruses — essentially the building blocks manufacturers use to produce a vaccine — appear well matched to protect against the H5N1 strain circulating among dairy cattle and birds, according to federal health officials. It’d probably be weeks to months before those shots could first be made available if needed. Washington Post, New York Times
Swine Flu Outbreaks in 2023 Illustrate Reality of Zoonotic Influenza
The outbreaks highlighted here, which occurred in 2023, illustrate the reality of zoonotic influenza, the fact that all ages can be vulnerable, that those with and without comorbidities can be at risk, and that various exposures can lead to swine-origin influenza A(H1N1) influenza infection. Global Biodefense
Drivers for a Flu Pandemic and Options for One Health Mitigation Measures
Key options for actions include enhancing surveillance targeting humans and animals, ensuring access to rapid diagnostics, promoting collaboration between animal and human sectors, and considering the implementation of preventive measures such as vaccination of poultry. Effective communication to different involved target audiences should be emphasized, as well as strengthening veterinary infrastructure, enforcing biosecurity measures at farms, and reducing wildlife contact with domestic animals. European Centre for Disease Control and Prevention
What’s Behind the U.S.’s Critical Veterinarian Shortage?
The shortages are being felt most in rural areas. Part of the reason is that veterinary school graduates have to go where the money is – given the student debt they are often lumbered with – and jobs in cities pay more. Veterinarians are an important role in protecting the health of individual animals, but also protecting the health of populations of animals. “Veterinarians are on the frontlines of detection and surveillance… and when we don’t have veterinarians in a community, those diseases can go undetected until it’s too late.” The Guardian
JOURNAL WATCH
New Study Highlights Importance of Bird Flu Surveillance in Live Bird Markets
A new study describes findings from avian influenza A(H5) virus surveillance in live bird markets across Vietnam over a nearly six-year period (March 2017- September 2022). The study found almost 40% of samples taken from live markets in Vietnam were positive for influenza A viruses with the prevalence of H5 bird flu increasing in 2022. Active surveillance (regular testing) was better at detection than passive surveillance (receiving reports), especially when poultry did not show signs of illness. Live bird market surveillance remains a vitally important activity for situational awareness around bird flu, bird flu mitigation, and pandemic preparedness activities. Influenza and Other Respiratory Viruses
Experimental M2e Peptide Swine Flu Vaccine Doesn’t Protect Upon Challenge
A vaccine is needed that improves cross-protection of pigs against multiple strains of IAV. In this study, an experimental vaccine using a highly conserved M2e peptide was evaluated. Both vaccinated and non-vaccinated control pigs challenged 4 weeks later developed fever and had moderate gross and microscopic lesions with no differences among groups suggesting that under the conditions of this study, the M2e vaccine did not protect pigs against challenge with pandemic H1N1 strain. This suggests that a humoral immune response, based only on the M2e protein, was not sufficient for protection. Vaccine
Recent Changes in Patterns of Mammal Infection with Highly Pathogenic Avian Influenza A(H5N1) Virus Worldwide
In the current panzootic, 26 countries have reported >48 mammal species infected by H5N1 virus; in some cases, the virus has affected thousands of individual animals. The geographic area and the number of species affected by the current event are considerably larger than in previous waves of infection. The most plausible source of mammal infection in both periods appears to be close contact with infected birds, including their ingestion. Some studies, especially in the current panzootic, suggest that mammal-to-mammal transmission might be responsible for some infections; some mutations found could help this avian pathogen replicate in mammals. Emerging Infectious Diseases
Evolution and Spread of HPAI in Wild Birds, South Korea, 2022–2023
Understanding the movement and host characteristics of migratory waterfowl, which are natural hosts of avian influenza, is crucial for understanding the evolution and transmission pathways of Highly Pathogenic Avian Influenza A(H5N1) virus. Integrative analysis of real-time surveillance data in wild birds and spatial distribution data of poultry farms can serve as an early warning system for forecasting the risk for HPAI avian influenza spillover from wild birds to poultry. Emerging Infectious Diseases
Smallscale Poultry Keepers and Their Understanding of Guidance HPAI
Backyard keepers often lack an understanding of the legal requirements in relation to varying highly pathogenic avian influenza (HPAI) restrictions, alongside a general lack of disease knowledge and biosecurity. This may be due to a misunderstanding of the guidance from official sources, which is predominantly aimed at commercial flocks. Preventive Veterinary Medicine
Exploring Associations Between Viral Titer Measurements and Disease Outcomes in Ferrets Inoculated with 125 Contemporary Influenza A Viruses
Compilation of viral titer and clinical data from >1,000 ferrets inoculated with 125 contemporary IAV under a consistent experimental protocol (including high- and low-pathogenicity avian, swine-origin, and human viruses, spanning H1, H2, H3, H5, H7, and H9 subtypes) and examined which meaningful and statistically supported associations were present among numerous quantitative measurements. Viral titers correlated positively between ferret nasal turbinate tissue, lung tissue, and nasal wash specimens, though the strength of the associations varied, notably regarding the particular nasal wash summary measure employed and properties of the virus itself. IAV possessing mammalian host adaptation markers in the HA and PB2 exhibited more rapid growth in the ferret upper respiratory tract early after infection, supported by quantities derived from infectious titer data to capture infection progression, compared with viruses bearing hallmarks of avian IAV. Journal of Virology
Novel Influenza A Viruses in Pigs with Zoonotic Potential, Chile
This study evaluated the zoonotic potential of novel H1N2 and H3N2 swine influenza A viruses (IAVs) recently been identified in Chile. Serological data indicate that the general population is susceptible to the H3N2 virus and that elderly and young children also lack protective antibodies against the H1N2 strains, suggesting that these viruses could be potential zoonotic threats. Continuous IAV surveillance and monitoring of the swine and human populations is strongly recommended. Microbiology Spectrum
QUOTE OF THE DAY
“We are trying to be at the forefront of documenting, recording and providing early warning. We’ve been in this area for 30 years. We know these species. We work with scientists who have 30 years of data on these populations, so we can know what will be important for the future. We have to give voice to these poor creatures. Nobody’s taking note of how big this is.”
Marcela Uhart, a wildlife veterinarian with the UC Davis School of Veterinary Medicine’s One Health Institute, on the magnitude of avian influenza adapting to spread to marine mammals.
IN CASE YOU MISSED IT
- Case Study: Fatal Avian Influenza Infection in Cat in Poland
- Bird Flu Undergoing Changes That Could Increase Risk of Widespread Human Transmission
- Scientists Find New Strains of Influenza A in Pigs, Potentially Posing a Pandemic Risk
- CSL Seqirus Awarded Contract for Influenza A(H5N8) Candidate Vaccine
HISTORICAL REFLECTIONS
2011: Lessons from the H1N1 pandemic should be incorporated into future planning (GAO)
2011: Seeing terror risk, U.S. asks journals to cut flu study facts (New York Times)
2009: Obama declares national emergency as US swine flu deaths hit 1,000 (The Guardian)
2009: Surveillance for pediatric deaths from 2009 pandemic influenza A (H1N1) (MMWR)
1976: The fiasco of the 1976-1977 swine flu affair (BBC)
1968: Fifty years of influenza A(H3N2) following the pandemic of 1968 (AJPH)