The H5N1 bird flu situation in the US seems more fraught than ever this week as the virus continues to spread swiftly in dairy cattle and birds while sporadically jumping to humans.
On Monday, officials in Louisiana announced that the person who had developed the country’s first severe H5N1 infection had died of the infection, marking the country’s first H5N1 death. Meanwhile, with no signs of H5N1 slowing, seasonal flu is skyrocketing, raising anxiety that the different flu viruses could mingle, swap genetic elements, and generate a yet more dangerous virus strain.
But, despite the seemingly fever-pitch of viral activity and fears, a representative for the World Health Organization today noted that risk to the general population remains low—as long as one critical factor remains absent: person-to-person spread.
“We are concerned, of course, but we look at the risk to the general population and, as I said, it still remains low,” WHO spokesperson Margaret Harris told reporters at a Geneva press briefing Tuesday in response to questions related to the US death. In terms of updating risk assessments, you have to look at how the virus behaved in that patient and if it jumped from one person to another person, which it didn’t, Harris explained. “At the moment, we’re not seeing behavior that’s changing our risk assessment,” she added.
In a statement on the death late Monday, the US Centers for Disease Control and Prevention emphasized that no human-to-human transmission has been identified in the US. To date, there have been 66 documented human cases of H5N1 infections since the start of 2024. Of those, 40 were linked to exposure to infected dairy cows, 23 were linked to infected poultry, two had no clear source, and one case—the fatal case in Louisiana—was linked to exposure to infected backyard and wild birds.
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.
So, the ultimate goal of the USDA is to eliminate cattle as a reservoir. When the Agency announced it was planning for this program, it noted that there were two candidate vaccines in trials. Until those are validated, it plans to use the standard playbook for handling emerging infections: contact tracing and isolation. And it has the ability to compel cattle and their owners to be more cooperative than the human population turned out to be.
The five-step plan
The USDA refers to isolation and contact tracing as Stage 3 of a five-stage plan for controlling H5N1 in cattle, with the two earlier stages being the mandatory sampling and testing, meant to be handled on a state-by-state basis. Following the successful containment of the virus in a state, the USDA will move on to batch sampling to ensure each state remains virus-free. This is essential, given that we don’t have a clear picture of how many times the virus has jumped from its normal reservoir in birds into the cattle population.
That makes it possible that reaching Stage 5, which the USDA terms “Demonstrating Freedom from H5 in US Dairy Cattle,” will turn out to be impossible. Dairy cattle are likely to have daily contact with birds, and it may be that the virus will be regularly re-introduced into the population, leaving containment as the only option until the vaccines are ready.
Testing will initially focus primarily on states where cattle-to-human transmission is known to have occurred or the virus is known to be present: California, Colorado, Michigan, Mississippi, Oregon, and Pennsylvania. If you wish to track the progress of the USDA’s efforts, it will be posting weekly updates.
Once infectious material gets into the water, disinfection systems that aren’t working properly or are inadequate can allow pathogens to gush from every nozzle. Splash pads aren’t unique in having to handle sick children in poopy swim diapers—but they are unique in how they are regulated. That is, in some places, they’re not regulated at all. Splash pads are designed to not have standing water, therefore reducing the risk of young children drowning. But, because they lack standing water, they are sometimes deemed exempt from local health regulations. Before 2000, only 13 states regulated splash pads. Though many states have since added regulations, some did so only after splash pad-linked outbreaks were reported.
Downpour of disease
The primary method for keeping recreational water free of infectious viruses and bacteria is chlorinating it. However, maintaining germ-killing chlorine concentration is especially difficult for splash pads because the jets and sprays aerosolize chlorine, lowering the concentration.
Still, in most splash-pad linked outbreaks, standard chlorine concentrations aren’t enough anyway. The most common pathogen to cause an outbreak at splash pads is the parasite Cryptosporidium, aka Crypto. The parasite’s hardy spores, called oocysts, are extremely tolerant of chlorine, surviving in water with the standard chlorine concentration (1 ppm free chlorine) for over seven days. (Other germs die in minutes.) In splash pads that might not even have that standard chlorine concentration, Crypto flourishes and can cause massive outbreaks.
In 2023, the CDC recommended new health codes that call for “secondary disinfection” methods to keep Crypto at bay, including disinfection systems using ozone or ultraviolet light. Another possible solution is to have “single-pass” splash pads that don’t recirculate water.
In all, to keep splash pads from being geysers of gastrointestinal parasites and pathogens, various changes have to happen, the CDC experts say.
“Prevention of waterborne disease outbreaks at splash pads requires changes in user behavior; recreational venue code updates; and improved venue design, construction, operation, and management of facilities,” they conclude. But it should all start with keeping kids from sitting on jets and drinking the water.
The milk-related risk of H5N1 is only from raw milk; pasteurized milk does not contain live virus and is safe to drink. Pasteurization, which heats milk to a specific temperature for a specified amount of time, kills a variety of bacteria and viruses, including bird flu. Influenza viruses, generally, are considered susceptible to heat treatments because they have an outer layer called an envelope, which can be destabilized by heat. Studies that have specifically looked at the effectiveness of heat-killing treatments against H5N1 have repeatedly found that pasteurization effectively inactivates the virus.
The advent of pasteurization is considered a public health triumph. Its adoption of a safe milk supply contributed to a dramatic reduction in infant deaths in the early 20th century. Before that, milkborne infections—including human and bovine tuberculosis, brucellosis, salmonellosis, streptococcal infections, diphtheria, and “summer diarrhea”—were common killers of infants.
As such, public health officials have long advised people against consuming raw milk, which has no evidence-based health benefits. Raw milk consumption, meanwhile, is linked to higher rates of outbreaks from pathogens including Salmonella, Listeria monocytogenes, toxin-producing E. coli, Brucella, Campylobacter, and many other bacteria.
Risky drinking
Since H5N1 was found spreading among dairy cows in March, health experts have warned about the additional risk of consuming raw milk. Still, consumption of raw milk has continued, and surprisingly increased, as supporters of the dangerous practice have accused health officials of “fearmongering.”
When the retail sampling of Raw Farm’s milk came back positive, the California Department of Food and Agriculture (CDFA) conducted testing at the company’s locations, which were negative for the virus. The CDFA will now begin testing Raw Farm’s milk for bird flu twice a week.
The recalled milk has lot code 20241109 and a “best by” date of November 27, 2024, printed on the packaging.
“Drinking or accidentally inhaling raw milk containing bird flu virus may lead to illness,” California’s public health department said. “In addition, touching your eyes, nose, or mouth with unwashed hands after touching raw milk with bird flu virus may also lead to infection.”
Some US dairy workers who contracted the virus from infected cows reported having had milk splash in their eyes and face. A common symptom of H5N1 infections in humans during the dairy outbreak has been conjunctivitis, aka eye inflammation.
A British Columbia teen who contracted Canada’s first known human case of H5 bird flu has deteriorated swiftly in recent days and is now in critical condition, health officials reported Tuesday.
The teen’s case was announced Saturday by provincial health officials, who noted that the teen had no obvious exposure to animals that could explain an infection with the highly pathogenic avian influenza. The teen tested positive for H5 bird flu at BC’s public health laboratory, and the result is currently being confirmed by the National Microbiology Laboratory in Winnipeg.
The teen’s case reportedly began with conjunctivitis, echoing the H5N1 human case reports in the US. The case then progressed to fever and cough, and the teen was admitted to BC’s Children’s hospital late Friday. The teen’s condition varied throughout the weekend but had taken a turn for the worse by Tuesday, according to BC provincial health officer Bonnie Henry.
“This was a healthy teenager prior to this—so, no underlying conditions—and it just reminds us that in young people, this is a virus that can progress and cause quite severe illness,” Bonnie Henry said in a media briefing streamed by Global News on Tuesday.
Health officials in the province have opened an investigation to understand the source of the outbreak. Around three dozen contacts of the teen have been tested, and all have been negative. “The source of exposure is very likely to be an animal or bird and is being investigated by BC’s chief veterinarian and public health teams,” health officials noted in the announcement over the weekend. The teen was reportedly exposed to pets, including dogs, cats, and reptiles, but testing so far has been negative on them.
California’s infections bring the country’s total number of affected herds to 255 in 14 states, according to the USDA.
In a new release Thursday, California health officials worked to ease alarm about the human case, emphasizing that the risk to the general public remains low.
“Ongoing health checks of individuals who interact with potentially infected animals helped us quickly detect and respond to this possible human case. Fortunately, as we’ve seen in other states with human infections, the individual has experienced mild symptoms,” Tomás Aragón, director of California’s Department of Public Health, said. “We want to emphasize that the risk to the general public is low, and people who interact with potentially infected animals should take prevention measures.”
The release noted that in the past four months, the health department has distributed more than 340,000 respirators, 1.3 million gloves, 160,000 goggles and face shields, and 168,000 bouffant caps to farm workers. The state has also received 5,000 doses of seasonal flu vaccine earmarked for farm workers and is working to distribute those vaccines to local health departments.
Still, herd infections and human cases continue to tick up. Influenza researchers and other health experts are anxiously following the unusual dairy outbreak—the first time an avian influenza is known to have spilled over to and caused an outbreak in cattle. The more opportunities the virus has to spread and adapt to mammals, the more chances it could begin spreading among humans, potentially sparking an outbreak or even a pandemic.
New York is facing an unusual boom in mosquitoes toting the deadly eastern equine encephalitis (EEE) virus, which has already led to one rare death in the state and a declaration of an “imminent threat” by officials.
While the state’s surveillance system typically picks up EEE-positive mosquitoes in two or three counties each year, this year there have been 15 affected counties, which are scattered all across New York, State Health Commissioner James McDonald said this week.
“Eastern equine encephalitis is different this year,” McDonald said, noting the deadly nature of the infection, which has a mortality rate of between 30 and 50 percent. “Mosquitoes, once a nuisance, are now a threat,” McDonald added. “I urge all New Yorkers to prevent mosquito bites by using insect repellents, wearing long-sleeved clothing, and removing free-standing water near their homes. Fall is officially here, but mosquitoes will be around until we see multiple nights of below-freezing temperatures.”
On Monday, McDonald issued a Declaration of an Imminent Threat to Public Health for EEE, and Governor Kathy Hochul announced statewide actions to prevent infections. At the same time as the declaration, the officials reported the death of a New Yorker who developed EEE. The case, which was confirmed in Ulster County on September 20, is the state’s first EEE case since 2015.
The disease is very rare in New York. Between 1971 and 2024, there were only 12 cases of EEE reported in the state; seven cases were fatal.
Rare but deadly
EEE is generally rare in the US, with an average of only 11 cases reported per year, according to the Centers for Disease Control and Prevention. The virus lurks in wild birds and spreads to people and other animals via mosquitoes. The virus is particularly deadly in horses—as its name suggests—with mortality rates up to 90 percent. In people, most bites from a mosquito carrying the EEE virus do not lead to EEE. In fact, the CDC estimates that only about 4–5 percent of infected people develop the disease; most remain asymptomatic.
Fo those who develop EEE, the virus travels from the mosquito bite into the lymph system and spreads from there to cause a systemic infection. Initial symptoms are unspecific, including fever, headache, malaise, chills, joint pain, nausea, and vomiting. This can progress to inflammation of the brain and neurological symptoms, including altered mental state and seizures. Children under the age of 15 and adults over the age of 50 are most at risk.
The CDC estimates that about 30 percent of people who develop severe EEE die of the disease. But, with small numbers of cases over time, the reported mortality rates can vary. In Massachusetts, for instance, about 50 percent of the cases have been fatal. Among those who survive neuro-invasive disease, many are left severely disabled, and some die within a few years due to complications. There is no vaccine for EEE and no specific treatments.
Overall numbers
While New York seems to be experiencing an unusual surge of EEE-positive mosquitoes, the country as a whole is not necessarily seeing an uptick in cases. Only 10 cases from six states have been reported to the CDC this year. That count does not include the New York case, which would bring the total to 11, around the country’s average number of cases per year.
In addition to New York, the states that have reported cases are Massachusetts, Vermont, New Jersey, Rhode Island, Wisconsin, and New Hampshire. Most cases have been in the Northeast, where cases are typically reported between mid-June and early October before freezing temperatures kill off mosquito populations.
EEE gained attention last month when a small town in Massachusetts urged residents to follow an evening curfew to avoid mosquito bites. The move came after the state announced its first EEE case this year (the state’s case count is now at four) and declared a “critical risk level” in four communities.
Between 2003 and 2023, the highest tally of cases in a year was in 2019, when states reported 38 EEE cases.
With one of the highest vaccine exemption rates in the country, Oregon is experiencing its largest measles outbreak in decades. This year’s count is now higher than anything seen since 2000, when the Centers for Disease Control and Prevention declared the highly contagious virus eliminated from the US.
Last month, when the outbreak tally was still in the 20s, health officials noted that it was nearing a state record set in 2019. There were 28 cases that year, which were linked to a large outbreak across the border in Washington state. But, with that record now surpassed, the state is in pre-elimination territory.
“Before 2019, you have to go all the way back to the early 1990s to see case counts this high,” Paul Cieslak, medical director for communicable diseases and immunization at Oregon Health Authority, said in a statement. “The reason is, we maintained very high vaccination rates and very high population levels of immunity. Unfortunately, we’ve seen an erosion in the percentage of people who are getting vaccinated against measles.”
Vaccination decline
In 2000, when measles was declared officially eliminated, only about 1 percent of kindergarteners in the state had exemptions from childhood vaccines, such as measles. But in the years since, Oregon has become one of the states with the highest exemption rates in the country. In the 2022–2023 school year, 8.2 percent of Oregon kindergarteners had exemptions from vaccinations, according to a CDC analysis published in November. Only Idaho had a higher rate, with 12.1 percent of kindergarteners exempt. Utah was a close third, with 8.1 percent, followed by Arizona (7.4 percent) and Wisconsin (7.2 percent).
Oregon’s exemption rate has risen since then, with the exemption rate now at 8.8 percent, according to the Oregon Health Authority. Any exemption rate above 5 percent is concerning. At that threshold, even if every non-exempt child is vaccinated, a state will not be able to achieve the target of 95 percent vaccine coverage expected to prevent sustained transmission of infectious diseases.
Health officials are directly linking the rise of non-medical exemptions to the current measles outbreak, which is centered in Clackamas, Marion, and Multnomah counties. All three are in the northwestern corner of the state, with Clackamas and Multnomah in the Portland area.
“In Clackamas County, as in other Oregon counties, pockets of unvaccinated people raise risk of infection in communities where they live,” Clackamas County Health Officer Sarah Present said. “That’s why the counties reach out to every case that’s been identified and try to determine exactly where they’ve been while infectious.”
Notorious virus
Measles is among the most infectious viruses known. It is notorious for its ability to stay aloft in indoor air for up to two hours after an infected person has been present. For unvaccinated people who are exposed, up to 9 out of 10 will end up falling ill. Those who become infected are contagious from about four days before developing the tell-tale rash and four days after it erupts. Other common symptoms of the infection include high fever, runny nose, cough, and conjunctivitis (pink eye). Many children become severely ill, requiring hospitalization.
In a small percentage of cases, measles can lead to severe complications, including pneumonia, encephalitis, and a progressive neurological disorder (subacute sclerosing panencephalitis), which develops five to 10 years after an initial infection. Additionally, measles is known to cause “immune amnesia.” That is, being infected with measles virus wipes out existing antibodies and immune responses to other germs, leaving people more vulnerable to other diseases.
So far this year, the US has logged 236 measles cases. Of those, 40 percent were in children under the age of 5, while 30 percent were in children and teens between the ages 5 and 19. Eighty-seven percent were either unvaccinated or had an unknown vaccination status. Forty-four percent (103 of 236) were hospitalized.
This year’s tally is already well ahead of the total for 2023, which reached just 59 cases. It is still significantly lower than the 1,274 cases seen in 2019, when the US nearly lost its elimination status.
To date, 57 people across 18 states have been sickened, all of whom required hospitalization. A total of eight have died. The latest tally makes this the largest listeriosis outbreak in the US since 2011, when cantaloupe processed in an unsanitary facility led to 147 Listeria infections in 28 states, causing 33 deaths, the CDC notes.
The new cases and deaths come after a massive recall of more than 7 million pounds of Boar’s Head meat products, which encompassed 71 of the company’s products. That recall was announced on July 30, which itself was an expansion of a July 26 recall of an additional 207,528 pounds of Boar’s Head products. By August 8, when the CDC last provided an update on the outbreak, the number of cases had hit 43, with 43 hospitalizations and three deaths.
In a media statement Wednesday, the CDC says the updated toll of cases and deaths is a “reminder to avoid recalled products.” The agency noted that the outbreak bacteria, Listeria monocytogenes, is a “hardy germ that can remain on surfaces, like meat slicers, and foods, even at refrigerated temperatures. It can also take up to 10 weeks for some people to have symptoms of listeriosis.” The agency recommends that people look through their fridges for any recalled Boar’s Head products, which have sell-by dates into October.
If you find any recalled meats, do not eat them, the agency warns. Throw them away or return them to the store where they were purchased for a refund. The CDC and the US Department of Agriculture also recommend that you disinfect your fridge, given the germs’ ability to linger.
L. monocytogenes is most dangerous to people who are pregnant, people age 65 years or older, and people who have weakened immune systems. In these groups, the bacteria are more likely to move beyond the gastrointestinal system to cause an invasive listeriosis infection. In older and immunocompromised people, listeriosis usually causes fever, muscle aches, and tiredness but may also cause headache, stiff neck, confusion, loss of balance, or seizures. These cases almost always require hospitalization, and 1 in 6 die. In pregnant people, listeriosis also causes fever, muscle aches, and tiredness but can also lead to miscarriage, stillbirth, premature delivery, or a life-threatening infection in their newborns.
With the impending arrival of the 2024–2025 COVID-19 vaccines approved yesterday, some Americans are now gaming out when to get their dose—right away while the summer wave is peaking, a bit later in the fall to maximize protection for the coming winter wave, or maybe a few weeks before a big family event at the end of the year? Of course, the group pondering such a question is just a small portion of the US.
In a press briefing Friday, federal health officials were quick to redirect focus when reporters raised questions about the timing of COVID-19 vaccination in the coming months and the possibility of updating the vaccines twice a year, instead of just once, to keep up with an evolving virus that has been producing both summer and winter waves.
“The current problem is not that the virus is evolving so much, at least in terms of my estimation,” Peter Marks, the top vaccine regulator at the Food and Drug Administration, told journalists. “It’s that we don’t have the benefits of the vaccine, which is [to say] that it’s not vaccines that prevent disease, it’s vaccination. It’s getting vaccines in arms.” When exactly to get the vaccine is a matter of personal choice, Marks went on, but the most important choice is to get vaccinated.
Estimates for this winter
The press briefing, which featured several federal health officials, was intended to highlight the government’s preparations and hopes for the upcoming respiratory virus season. The FDA, the Centers for Disease Control and Prevention, and the Department of Health and Human Services (HHS) are urging all Americans to get their respiratory virus vaccines—flu, COVID-19, and RSV.
CDC Director Mandy Cohen introduced an updated data site that provides snapshots of local respiratory virus activity, national trends, data visualizations, and the latest guidance in one place. HHS, meanwhile, highlighted a new outreach campaign titled “Risk Less. Do More.” to raise awareness of COVID-19 and encourage vaccination, particularly among high-risk populations. For those not at high risk, health officials still emphasize the importance of vaccination to lower transmission and prevent serious outcomes, including long COVID. “There is no group without risk,” Cohen said, noting that the group with the highest rates of emergency department visits for COVID-19 were children under the age of 5, who are not typically considered high risk.
So far, CDC models are estimating that this year’s winter wave of COVID-19 will be similar, if not slightly weaker on some metrics, than last year’s winter wave, Cohen said. But she emphasized that many assumptions go into the modeling, including how the virus will evolve in the near future and the amount of vaccine uptake. The modeling assumes the current omicron variants stay on their evolutionary path and that US vaccination coverage is about the same as last year. Of course, beating last year’s vaccine coverage could blunt transmission.
A small town in Massachusetts is urging residents to stay indoors in the evenings after the spread of a dangerous mosquito-spread virus reached “critical risk level.”
The virus causes Eastern equine encephalitis (EEE), which kills between 30 and 50 percent of people who are stricken—who are often children under the age of 15 and the elderly. Around half who survive are left permanently disabled, and some die within a few years due to complications. There is no treatment for EEE. So far, one person in the town—an elderly resident of Oxford—has already become seriously ill with neuroinvasive EEE.
EEE virus is spread by mosquitoes in certain swampy areas of the country, particularly in Atlantic and Gulf Coast states and the Great Lakes region. Mosquitoes shuttle the virus between wild birds and animals, including horses and humans. In humans, the virus causes very few cases in the US each year—an average of 11, according to the Centers for Disease Control and Prevention. But given the extreme risk of EEE, health officials take any spread seriously.
On August 16, the Massachusetts Department of Public Health announced the state’s first case and declared a “critical risk level” in the four communities of Douglas, Oxford, Sutton, and Webster. These all cluster in Worcester county near the state’s borders with Rhode Island and Connecticut.
Curfew
While the state health department did not identify the man as a resident of Oxford, the town’s manager confirmed his residence in a memorandum Wednesday. The manager, Jennifer Callahan, reported that the man remains hospitalized. She also reported that a horse across the border in Connecticut had recently died of EEE.
Also on Wednesday, the four towns—Douglas, Oxford, Sutton, and Webster—issued a joint health advisory, which included a recommended curfew.
Last night, The Oxford Board of Health voted to adopt the advisory, according to the Boston Globe. The recommendation is for residents to avoid mosquito’s peak activity time. They should “finish outdoor activities before 6: 00 PM through September 30th, 2024 and before 5: 00 PM October 1st, 2024 until the first hard frost.” The advisory also recommends residents wear insect repellent, wear protective clothing, and mosquito-proof their homes.
Officials emphasized that the curfew is a recommendation, not mandatory. However, to use town properties—such as recreation fields—people will first need to file an indemnification form and provide proof of adequate insurance coverage to the town.
To date, there have been only three cases of EEE in the US this year. One in Massachusetts, one in Vermont, and the last in New Jersey. All three are neuroinvasive. The CDC says that about 30 percent of cases are fatal, while Massachusetts health officials report that about half of people who develop EEE in the state have died.