H5N1 Update
Published on October 25, 2024
Background
Avian influenza, also known as bird flu, has been recognized in poultry since the 1880s, occasionally transmitting to humans with high fatality rates (https://www.cdc.gov/bird-flu/avian-timeline/index.html). In March 2024, the variant of avian influenza known as H5N1 was found in dairy herds in Kansas and Texas. As of October 11th, 300 dairy herds have been affected in 14 states [1], and from 2022 to now, 20 cases have been reported in humans in the United States [2].
Current Situation
One person in Missouri without farm animal contact has tested positive for H5N1, and six healthcare workers who were in contact with this patient subsequently developed respiratory symptoms. The CDC is currently testing these healthcare workers for antibodies consistent with H5N1 infection [3].
The latest six identified H5N1-infected individuals in the US have been dairy workers in California [4]. The virus is spreading rapidly through the Californian dairy industry, the largest in the US. California had no infected herds as of August 2024, and by October 14 reported 100 infected herds, 90% of which in the previous 30 days. This comprises one third of all reported infected herds in the US [1].
Prevention / Needed Policy
The general public can lower the risk of infection by avoiding consumption of raw and undercooked milk, eggs, meat, and other animal products, and avoiding direct contact with wild birds and bird droppings [5].
The recent rapid increase in cases indicates an urgent need to implement measures to contain the spread of H5N1. The CDC and USDA have been criticized for taking inadequate action to address the ongoing infection of herds, the incidences of human infection, and the risk of human to human transmission [6].
Conversely, although Australia is the only continent not currently affected by an H5N1 outbreak, the Australian government is investing an additional $95 million in preventative measures to counteract the threat of Avian Flu, including preparing vaccines and increasing the biosecurity response and surveillance [7].
Good News
Harvard researchers are developing a nasal spray that may be effective at preventing a variety of airborne pathogens from entering the body [8]. Their preclinical studies show that the spray, known as Pathogen Capture and Neutralizing Spray (PCANS), protected mice from lethal doses of influenza and was retained in the nasal cavity for up to 8 hours. PCANS was formulated to act via capturing respiratory particles, blocking the transport of pathogens, and neutralizing pathogens directly. The authors indicate a need for future large animal studies to more accurately mimic aerosol disease challenge, and to confirm the effectiveness of PCANS against a variety of pathogens. Another limitation is that the nasal cavity has a small surface area compared to the rest of the respiratory tract and nasal sprays do not protect the lower respiratory tract. As such, nasal sprays may become a useful extra layer of protection, but not a replacement for wearing a high-quality mask.
Their recent study was published on September 24th in Advanced Material and is a peer-reviewed version of an article that was first published in pre-print on bioRxiv in 2023.
Who We Are
The WHN Science Content Team produces the WHN Newsletter and other science-based content. We are currently working on policy-relevant literature reviews on transmission in schools, and air purifiers. If you would like to join us, our Slack channel is #science-content-team, and if you’re not on Slack, you can email info@whn.global or fill out our interest form at https://whn.global/join-our-science-content-team/. No formal science writing experience is necessary.
Sources
[1] Animal and Plant Health Inspection Service. (2024, October 11). HPAI confirmed cases in livestock. US Department of Agriculture. https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/hpai-confirmed-cases-livestock
[2] Schnirring, L. (2024, October 7). California probes likely H5 infection in another dairy worker. CIDRAP. https://www.cidrap.umn.edu/avian-influenza-bird-flu/california-probes-likely-h5-infection-another-dairy-worker
[3] Shutt, J. (2024, October 7). CDC conducting extensive probe into bird flu contracted by Missouri resident. https://michiganadvance.com/2024/10/07/cdc-conducting-extensive-probe-into-bird-flu-contracted-by-missouri-resident/
[4] Reuters. (2024, October 11). Two additional human bird flu cases confirmed in California. Reuters. https://www.reuters.com/world/us/two-additional-human-bird-flu-cases-confirmed-california-2024-10-11/
[5] Bilodeau, S., Bar-Yam, Y., Gonzales, L., Heino, M. T., & Bertram, N. (2024). Avian Flu Outbreaks: Understanding the Impact and Taking Precautions. WHN Science Communications, 5(7), 1–1. https://doi.org/10.59454/whn-2407-224
[6] Barber, C. (2024, September 26). Bird flu casts a wider net as U.S. health officials keep drip-feeding information on Fridays. Fortune. https://fortune.com/2024/09/26/bird-flu-us-health-officials-h5n1-cdc-information/
[7] Department of Health and Aged Care. (2024, October 14). Australian government delivering more than $100 million to fight avian influenza. Department of Health and Aged Care. https://www.health.gov.au/ministers/the-hon-mark-butler-mp/media/australian-government-delivering-more-than-100-million-to-fight-avian-influenza?language=en
[8] Joseph, J., Baby, H. M., Quintero, J. R., Kenney, D., Mebratu, Y. A., Bhatia, E., Shah, P., Swain, K., Lee, D., Kaur, S., Li, X., Mwangi, J., Snapper, O., Nair, R., Agus, E., Ranganathan, S., Kage, J., Gao, J., Luo, J. N., … Joshi, N. (2024). Toward a Radically Simple Multi‐Modal Nasal Spray for Preventing Respiratory Infections. Advanced Materials, 2406348. https://doi.org/10.1002/adma.202406348