Abraar Karan, MD, MS, MPH, DTM&H

@abraarkaran.bsky.social

Infectious disease doctor, epidemiologist, researcher at Stanford

Good review article on #H5N1 bird flu & gaps that need to be addressed. -lack cow-specific data in terms of infections on farms -unclear how cows are continuing to be infected although multiple hypotheses journals.asm.org/doi/10.1128/...

mGem: Transmission and exposure risks of dairy cow H5N1 influenza virus | mBio

Highly pathogenic avian influenza (HPAI) H5N1 virus of the 2.3.4.4b clade has been circulating in North America since 2022 (1–3). On 25 March 2024, a strain in this clade, genotype B3.13, was confirmed to be infecting dairy cows in Texas and Kansas (Fig. 1A). Since then, dairy herds in several other states tested positive for this strain and spillover into dairy workers has followed (4–7). Infections of other domestic and peridomestic animals, such as cats and raccoons, have also occurred on the same premises containing infected cows (7, 8). Notably, the spread of cow H5N1 to poultry flocks has resulted in the culling of millions of birds and the infection of workers involved in culling operations on multiple occasions (9). As of 12 December 2024, over 800 dairy herds in 16 states have had confirmed infections, including three of the five biggest dairy-producing states (Fig. 1B) (10, 11). At least 58 known human cases of H5N1 including those exposed to dairy cows, poultry, or unknown exposure source have been reported by the CDC as of 12 December 2024 (12). Disturbingly, in September, cow H5N1 infections were confirmed in two housemates in Missouri without livestock contact (13, 14). Understanding how cow H5N1 transmits within and between farms is critical for curtailing the outbreak. Below, we discuss knowledge regarding the spread of cow H5N1 between farms, between cows, and the risk to humans.

journals.asm.org

If testing via PCR for Ebola/Marburg & other endemic zoonotic pathogens is negative, the next clear step for someone with high risk zoonotic exposures (bat consumption) here would be to do pathogen agnostic sequencing.

The Washington Post@washingtonpost.com · last yr.

An unknown illness has killed 53 people in a northwest region of the Democratic Republic of Congo, with a significant portion of deaths taking place within 48 hours of the onset of symptoms.

Both severe cases of #H5N1 - including the death in Louisiana, and the teenager in critical condition in Canada- were D1.1 genotype viruses. This has now been detected in dairy cattle, where most of the infections in humans have been occurring (previous dairy spillovers were w/ B3.13)

Helen Branswell 🇨🇦@helenbranswell.bsky.social · last yr.

4 dairy herds in Nevada recently diagnosed with #H5N1 #birdflu were infected with a different version of the virus than has been spreading in cows elsewhere. Evidence of a second (at a minimum) spillover points to the challenge of stopping spread, experts say. www.statnews.com/2025/02/05/u...

Global health has become the latest target of the current administration’s cuts. But as both covid19 & H5N1 have shown, our epidemic response systems have significant holes. Communicable disease threats know no boundaries; & US isolationism makes us more blind to what is coming our way.

Atul Gawande@agawande.bsky.social · 2y ago

The shut down of USAID and its activities that reach hundreds of millions is already harming humanity and America. www.foxnews.com/video/636820...

1) This #H5N1 case is showing us what can happen when the virus continues to evolve in an infected host. Remember this was a person now in medical care and isolation. If this occurs in a person who doesn’t access the medical system for whatever reason, the consequences could be very different.

Abraar Karan, MD, MS, MPH, DTM&H@abraarkaran.bsky.social · 2y ago

Important CDC update on the severe #H5N1 case in Louisiana patient 1) Some of the virus population detected in this patient had amino acid changes that facilitate binding upper respiratory tract cells. No human-human transmission detected though.

1/ The child in Alameda County with #H5N1 without known exposures was infected with the strain found in dairy cattle and dairy farm workers. This case was picked up through our testing protocol at Stanford specifically through the assay developed by the Pinsky Lab www.cdc.gov/bird-flu/spo...

Technical Update: Summary Analysis of the Genetic Sequence of a Highly Pathogenic Avian Influenza A(H5N1) Virus Identified in a Child in California

CDC provides an update on genetic sequencing of the first pediatric case of avian influenza A(H5N1)

cdc.gov