@outbreakupdates Dec 18, 2024:
The Louisiana case isn’t important because it’s severe.
It’s important because it confirms H5N1’s trajectory.
An entrenched, mutating virus with growing access to human hosts.
The window for proactive intervention is closing
The first severe human case of H5N1 in the US is a signal event.
It’s not unexpected, but it is pivotal.
This case brings the virus into direct contact with a population and infrastructure unprepared for its trajectory.
This isn’t a case of random exposure.
It’s the inevitable result of a virus that has become entrenched in wild bird populations, spread to mammals, and now breached the human-animal barrier.
In a context where spillovers are increasingly normalized.
The data suggests inevitability.
A virus with high lethality, entrenched in multiple reservoirs, and adapting to mammalian hosts will eventually develop new transmission dynamics.
We don’t know the timeline.
But the trajectory is clear.
The severe Louisiana case emphasizes a failure of containment.
Backyard poultry systems directly interface with wild bird reservoirs, creating spillover opportunities.
These systems bypass industrial biosecurity but aren’t monitored at scale.
Severe disease in humans signals viral fitness within human hosts.
H5N1’s lethality (>50%) is tied to its efficient replication in lower respiratory cells.
The key risk is mutation toward upper respiratory replication, enhancing transmissibility while retaining lethality.
This case occurred in a nation with robust health infrastructure and surveillance capacity.
The implications for under-resourced regions are concerning.
The systemic risks are accumulating.
Industrial farming, migratory bird pathways, and backyard poultry farming create overlapping layers of vulnerability.
Add globalized trade and climate-driven habitat disruption, and containment becomes an abstract ideal.
The convergence of risks creates a pandemic-ready virus
H5N1 doesn’t need efficient human-to-human transmission to destabilize global systems.
Localized outbreaks with high mortality would disrupt supply chains, healthcare, and food security.
Vaccine development is progressing, but scalability and deployment remain logistical bottlenecks.
Even with mRNA tech, the timeline between outbreak and widespread immunization is months.
Time a virus like H5N1 would exploit ruthlessly.
This isn’t alarmism.
It’s basic risk calculus.
H5N1’s evolutionary potential is amplified by systems we’ve built.
Dense farming, fragmented surveillance, and ecological disruption.
Each case brings us closer to a threshold we may not detect until it’s crossed.
Mammals infected with H5N1 are no longer isolated anomalies.
They are evolutionary experiments.
H5N1 is entering a new phase of risk.
Louisiana resident in critical condition with H5N1 bird flu, The person is experiencing severe respiratory illness from the H5N1 infection by Beth Mole, Dec 18, 2024, ARS Technica
The Louisiana resident infected with H5N1 bird flu is hospitalized in critical condition and suffering from severe respiratory symptoms, the Louisiana health department revealed Wednesday.
The health department had reported the presumptive positive case on Friday and noted the person was hospitalized, as Ars reported. But a spokesperson had, at the time, declined to provide Ars with the patient’s condition or further details, citing patient confidentiality and an ongoing public health investigation.
This morning, the Centers for Disease Control and Prevention announced that it had confirmed the state’s H5N1 testing and determined that the case “marks the first instance of severe illness linked to the virus in the United States.”
In a follow-up, the health department spokesperson Emma Herrock was able to release more information about the case. In addition to being in critical condition with severe respiratory symptoms, the person is reported to be over the age of 65 and has underlying health conditions.
Further, the CDC collected partial genetic data of the H5N1 strain infecting the patient, finding it to be of D1.1. genotype, which has been detected in wild birds and some poultry in the US. Notably, it is the same genotype seen in a Canadian teenager who was also hospitalized in critical condition from the virus last month. The D1.1. genotype is not the same as the one circulating in US dairy cows, which is the B3.13 genotype.
Deadly version
While it remains unknown how the Canadian teenager became infected, Herrock told Ars last week that Louisiana health investigators found that the infected patient had contact with sick and dead wild and backyard birds thought to be infected with the virus.
In today’s announcement, the CDC said that:
A sporadic case of severe H5N1 bird flu illness in a person is not unexpected; avian influenza A(H5N1) virus infection has previously been associated with severe human illness in other countries during 2024 and prior years, including illness resulting in death. No person-to-person spread of H5 bird flu has been detected. This case does not change CDC’s overall assessment of the immediate risk to the public’s health from H5N1 bird flu, which remains low.
According to the latest data collected by the World Health Organization, there have been 939 H5N1 cases in humans between January 2003 to November 2024. Of those, 464 were fatal, for a case fatality rate of 49 percent.
This year, the US has tallied 61 human cases of H5N1, almost all of which have been in poultry or dairy workers. Until now, all of them have been mild infections. One unexplained case in Missouri was in a hospitalized patient, but the patient had underlying conditions and the detection of H5N1 was suspected of being an incidental finding.
The case in Louisiana is considered the country’s first severe H5N1 case and the first case linked to an animal exposure that was not in a commercial operation—in other words, not a dairy or poultry farm.
California declares state of emergency over H5N1 bird flu, Since April, total of 61 reported human cases of H5 bird flu reported in U.S. by Thomson Reuters with files from CBC News and The Associated Press, Dec 18, 2024, CBC News
The U.S. reported its first severe human case of bird flu on Wednesday in a Louisiana resident who is hospitalized in critical condition, the U.S. Centers for Disease Control and Prevention (CDC) said.
Agency officials didn’t immediately detail the person’s symptoms, but the Louisiana Department of Health said the patient is suffering severe respiratory illness.
The person is reported to have underlying medical conditions and is over the age of 65, putting the patient at higher risk, the department said.
California, the country’s most populous state, declared an emergency later Wednesday as the H5N1 virus spreads more widely in dairy herds. Data has shown 649 herds have tested positive since late August — roughly 60 per cent of the state total.
This year, more than 60 bird flu infections have been reported, and more than half of them in California. In two cases — an adult in Missouri and a child in California — health officials have not determined how they caught it.
Previous illnesses in the U.S. had been mild and the vast majority had been among farm workers exposed to sick poultry or dairy cows.
Dr. Maria Van Kerkhove, the World Health Organization’s director of epidemic and pandemic preparedness, is calling for increased surveillance globally of animal populations that are known to be susceptible to H5N1, including wild birds, poultry, swine and cattle.
The CDC confirmed the Louisiana infection on Friday, but did not announce it until Wednesday. It’s also the first U.S. human case linked to exposure to a backyard flock.
Partial viral genome data of the H5N1 avian influenza virus that infected the patient in Louisiana indicates the virus belongs to a genotype related to viruses recently detected in wild birds and poultry in the U.S. and in recent human cases in British Columbia and Washington state.
The D1.1 genotype of the virus differs from the one detected in dairy cows in the U.S. as well as human cases in multiple states and some poultry outbreaks in the country, the CDC said.
Bird flu has infected more than 860 dairy herds in 16 states since March and killed 123 million poultry since the outbreak began in 2022.
B.C.’s Office of the Provincial Health Officer said it won’t be providing any updates on the status of the teenaged patient in the province who contracted bird flu unless there is a need from a public health perspective to do so.
U.S. health officials say bird flu is still mainly an animal health issue, and the risk to the general public remains low. There’s been no documented spread of the virus from person to person.
“The best way to prevent H5 bird flu is to avoid exposure whenever possible,” the CDC said. “Infected birds shed avian influenza A viruses in their saliva, mucous and feces.”
Other infected animals may shed avian influenza A viruses in respiratory secretions and other bodily fluids such as in unpasteurized cow milk or raw milk.
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