Infectious disease

record-measles-outbreak-in-oregon-blamed-on-vaccine-exemptions

Record measles outbreak in Oregon blamed on vaccine exemptions

CDC, children, Infectious disease, measles, MMR, Oregon, Science, vaccination, vaccine exemptions, vaccines / /

consequences —

Vaccine exemptions at nearly 9% in the state, enabling sustained transmission.

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A US child infected with measles during a 2024 outbreak. The child’s cheek shows the characteristic rash associated with this viral infection.

Enlarge / A US child infected with measles during a 2024 outbreak. The child’s cheek shows the characteristic rash associated with this viral infection.

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.

Since the start of the year, Oregon has tallied 31 cases of measles, all in unvaccinated people. The cases have been accumulating in sustained waves of transmission since mid-June.

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.

Two doses of MMR vaccine (measles, mumps, and rubella) are 97 percent effective against measles, and that protection is considered life-long.

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.

While Oregon’s current outbreak has broken its state records, the largest outbreak this year was in Illinois, where a total of 67 cases were reported amid spread at a Chicago-area migrant shelter.

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.

Record measles outbreak in Oregon blamed on vaccine exemptions Read More »

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Massive nationwide meat-linked outbreak kills 5 more, now largest since 2011

boar's head, CDC, deli meat, health, Infectious disease, listeria, listeriosis, Meat, outbreak, recall, Science / /

Hardy germs —

CDC implores consumers to check their fridges for the recalled meats.

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Listeria monocytogenes.

Enlarge / Listeria monocytogenes.

Five more people have died in a nationwide outbreak of Listeria infections linked to contaminated Boar’s Head brand meats, the Centers for Disease Control and Prevention reported Wednesday.

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.

Massive nationwide meat-linked outbreak kills 5 more, now largest since 2011 Read More »

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COVID shot now or later? Just getting it at all is great, officials respond.

CDC, COVID-19, fda, flu, health, HHS, Infectious disease, respiratory virus, RSV, Science, vaccines / /

Viral defences —

As the summer wave peaks, officials are prepping for the coming winter wave.

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A 13-year-old celebrates getting the Pfizer-BioNTech COVID-19 vaccine in Hartford, Connecticut, on May 13, 2021.

Enlarge / A 13-year-old celebrates getting the Pfizer-BioNTech COVID-19 vaccine in Hartford, Connecticut, on May 13, 2021.

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.

Only 22.5 percent of adults and 14 percent of children in the country are estimated to have gotten the 2023–2024 vaccine. In contrast, 48.5 percent of adults and 54 percent of children were estimated to have gotten a flu shot. The stark difference is despite the fact that COVID-19 is deadlier than the flu, and the SARS-CoV-2 virus is evolving faster than seasonal influenza viruses.

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.

COVID shot now or later? Just getting it at all is great, officials respond. Read More »

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Town urges curfew over mosquito-spread disease that kills up to 50% of people

CDC, curfew, deaths, Eastern equine encephalitis, eee, health, Infectious disease, massachusetts, mosquito, Oxford, Science, virus / /

“Critical risk” —

Eastern Equine Encephalitis is very rare in the US, but when it strikes, it’s bad.

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A mosquito collected to test for mosquito-borne diseases.

Enlarge / A mosquito collected to test for mosquito-borne diseases.

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.

In 2019, there was a multi-state outbreak of EEE, leading to a high of 38 cases. Twelve of the cases occurred in Massachusetts, and six died.

Town urges curfew over mosquito-spread disease that kills up to 50% of people Read More »

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Mpox outbreak is an international health emergency, WHO declares

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PHEIC —

The declaration is “the highest level of alarm under international health law.”

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A negative stain electron micrograph of a mpox virus virion in human vesicular fluid.

Enlarge / A negative stain electron micrograph of a mpox virus virion in human vesicular fluid.

The World Health Organization on Wednesday declared an international health emergency over a large and rapidly expanding outbreak of mpox that is spilling out of the Democratic Republic of the Congo.

It is the second time in about two years that mpox’s spread has spurred the WHO to declare a public health emergency of international concern (PHEIC), the highest level of alarm for the United Nations health agency. In July 2022, the WHO declared a PHEIC after mpox cases had spread across the globe, with the epicenter of the outbreak in Europe, primarily in men who have sex with men. The outbreak was caused by clade II mpox viruses, which, between the two mpox clades that exist, is the relatively mild one, causing far fewer deaths. As awareness, precautions, and vaccination increased, the outbreak subsided and was declared over in May 2023.

Unlike the 2022–2023 outbreak, the current mpox outbreak is driven by the clade II virus, the more dangerous version that causes more severe disease and more deaths. Also, while the clade I virus in the previous outbreak unexpectedly spread via sexual contact in adults, this clade II outbreak is spreading in more classic contact patterns, mostly through skin contact of household members and health care workers. A large proportion of those infected have been children.

To date, Democratic Republic of the Congo (DRC), where the virus is endemic, has reported more than 22,000 suspect mpox cases and more than 1,200 deaths since the start of January 2023. In recent months, the outbreak has spilled out into multiple neighboring countries, including Burundi, Central African Republic, Republic of the Congo, Rwanda, Kenya, and Uganda.

Earlier on Wednesday, the WHO convened an emergency committee to review the situation, in which experts from affected countries presented data to independent international experts. The committee concluded that the outbreak constituted a PHEIC, and WHO Director-General Dr. Tedros Adhanom Ghebreyesus followed their recommendation.

“The emergence of a new clade of mpox, its rapid spread in eastern DRC, and the reporting of cases in several neighboring countries are very worrying,” Tedros said in a statement announcing the PHEIC. “On top of outbreaks of other mpox clades in DRC and other countries in Africa, it’s clear that a coordinated international response is needed to stop these outbreaks and save lives.”

On Tuesday, the Africa Centers for Disease Control and Prevention declared a similar emergency. Africa CDC Director General Dr. Jean Kaseya said the declaration will “mobilize our institutions, our collective will, and our resources to act—swiftly and decisively. This empowers us to forge new partnerships, strengthen our health systems, educate our communities, and deliver life-saving interventions where they are needed most.”

For now, the US Centers for Disease Control and Prevention assess the risk to the US public to be “very low,” given that there is limited and no direct travel between the US and the epicenter of the outbreak. So far, no clade I cases have been detected outside of central and eastern Africa.

Mpox outbreak is an international health emergency, WHO declares Read More »

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Troubling bird flu study suggests human cases are going undetected

bird flu, CDC, dairy, H5N1, health, human infections, Infectious disease, outbreak, poultry, Science, vaccine / /

Poor surveillance —

A small sample of farm workers is enough to confirm fears about H5N1 outbreak.

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Troubling bird flu study suggests human cases are going undetected

Tony C. French/Getty

A small study in Texas suggests that human bird flu cases are being missed on dairy farms where the H5N1 virus has taken off in cows, sparking an unprecedented nationwide outbreak.

The finding adds some data to what many experts have suspected amid the outbreak. But the authors of the study, led by researchers at the University of Texas Medical Branch in Galveston, went further, stating bluntly why the US is failing to fully surveil, let alone contain, a virus with pandemic potential.

“Due to fears that research might damage dairy businesses, studies like this one have been few,” the authors write in the topline summary of their study, which was posted online as a pre-print and had not been peer-reviewed.

The study authors, led by Gregory Gray, were invited to two undisclosed dairy farms in Texas that experienced H5N1 outbreaks in their herds starting in early and late March, respectively. The researchers had a previously approved research protocol to study novel respiratory viruses on dairy farms, easing the ability to quickly begin the work.

Rare study

“Farm A” had 7,200 cows and 180 workers. Illnesses began on March 6, and nearly 5 percent of the herd was estimated to be affected during the outbreak. “Farm B” had 8,200 cows and 45 workers. After illnesses began on March 20, an estimated 14 percent of the herd was affected.

The researchers first visited Farm A on April 3 and Farm B on April 4, collecting swabs and samples at each. Based on the previously approved protocol, they were limited to taking nasal swabs and blood samples from no more than 10 workers per farm. On Farm A, 10 workers provided nasal swabs and blood samples. On Farm B, only seven agreed to give nasal swabs, and four gave blood samples.

While swabs from cows, milk, a dead bird, and a sample of fecal slurry showed signs of H5N1, all of the nasal swabs from the 14 humans were negative. However, when researchers looked for H5N1-targeting antibodies in their blood—an indicator that they were previously infected—two of the 14, about 14 percent, were positive.

Both of the workers with previous infections, a man and a woman, were from Farm A. And both reported having flu-like symptoms. The man worked inside cattle corrals, close to the animals, and he reported having a cough at the time the samples were taken. The woman, meanwhile, worked in the cafeteria on the farm and reported recently recovering from an illness that included fever, cough, and sore throat. She noted that other people on the farm had similar respiratory illnesses around when she did.

The finding suggests human cases of H5N1 are going undetected. Moreover, managing to find evidence of two undetected infections in a sample of just 14 workers suggests it may not be hard to find more. The Centers for Disease Control and Prevention estimates that around 200,000 people work with livestock in the US.

A “compelling case”

To date, the virus has infected at least 175 dairy farms in 13 states. The official tally of human cases in the dairy outbreak is 14: four in dairy farm workers and 10 in workers on poultry farms with infections linked to the dairy outbreak.

“I am very confident there are more people being infected than we know about,” Gray told KFF, which first reported on the study. “Largely, that’s because our surveillance has been so poor.”

Known infections in humans have all been mild so far. But experts are anxious that with each new infection, the wily H5N1 virus is getting new opportunities to adapt further to humans. If the virus evolves to cause more severe disease and spread from human to human, it could spark another pandemic.

Federal officials are also worried about this potential threat. In a press briefing Tuesday, Nirav Shah, the CDC’s principal deputy director, announced a $5 million effort to vaccinate farm workers—but against seasonal flu.

Shah explained that the CDC is concerned that if farm workers are infected with H5N1 and the seasonal flu at the same time, the viruses could exchange genetic segments—a process called reassortment. This could give rise to the pandemic threat experts are worried about. By vaccinating the workers against the seasonal flu, it could potentially prevent the viruses from comingling in one person, Shah suggested.

The US does have a bird flu-specific vaccine available. But in the briefing, Shah said that the use of that vaccine in farm workers is not planned for now, though there’s still active discussion on the possibility. The lack of severe disease and no documented human-to-human transmission from H5N1 infections both argue against deploying a new vaccine, Shah said. “There has to be a strong and compelling case,” he added. Shah also suggested that the agency expects vaccine uptake to be low among farm workers.

Troubling bird flu study suggests human cases are going undetected Read More »

7-million-pounds-of-meat-recalled-amid-deadly-outbreak

7 million pounds of meat recalled amid deadly outbreak

CDC, deaths, health, Infectious disease, listeria, Listeria monocytogenes, Meat, outbreak, recall, Science, USDA / /

7 million pounds across 71 products —

Authorities worry that the contaminated meats are still sitting in people’s fridges.

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Shelves sit empty where Boar's Head meats are usually displayed at a Safeway store on July 31, 2024, in San Anselmo, California.

Enlarge / Shelves sit empty where Boar’s Head meats are usually displayed at a Safeway store on July 31, 2024, in San Anselmo, California.

Over 7 million pounds of Boar’s Head brand deli meats are being recalled amid a bacterial outbreak that has killed two people. The outbreak, which began in late May, has sickened a total of 34 people across 13 states, leading to 33 hospitalizations, according to the US Department of Agriculture.

On June 26, Boar’s Head recalled 207,528 pounds of products, including liverwurst, beef bologna, ham, salami, and “heat and eat” bacon. On Tuesday, the Jarratt, Virginia-based company expanded the recall to include about 7 million additional pounds of meat, including 71 different products sold on the Boar’s Head and Old Country brand labels. The products were sold nationwide.

The meats may be contaminated with Listeria monocytogenes, a foodborne pathogen that is particularly dangerous to pregnant people, people over the age of 65, and people with compromised immune systems. Infections during pregnancy can cause miscarriage, stillbirth, premature delivery, or a life-threatening infection in newborns. For others who develop invasive illness, the fatality rate is nearly 16 percent. Symptoms of listeriosis can include fever, muscle aches, headache, stiff neck, confusion, loss of balance, and convulsions that are sometimes preceded by diarrhea or other gastrointestinal symptoms.

The problem was discovered when the Maryland Department of Health—working with the Baltimore City Health Department—collected an unopened liverwurst product from a retail store and found that it was positive for L. monocytogenes. In later testing, the strain in the liverwurst was linked to those isolated from people sickened in the outbreak.

According to the Centers for Disease Control and Prevention, six of the 34 known cases were identified in Maryland, and 12 were identified in New York. The other 11 states have only reported one or two cases each. However, the CDC expects the true number of infections to be much higher, given that many people recover without medical care and, even if people did seek care, health care providers do not routinely test for L. monocytogenes in people with mild gastrointestinal illnesses.

In the outbreak so far, there has been one case in a pregnant person, who recovered and remained pregnant. The two deaths occurred in New Jersey and Illinois.

In a statement on the company’s website, Boar’s Head said that it learned from the USDA on Monday night that L. monocytogenes strain in the liverwurst linked to the multistate outbreak. “Out of an abundance of caution, we decided to immediately and voluntarily expand our recall to include all items produced at the Jarratt facility. We have also decided to pause ready-to-eat operations at this facility until further notice. As a company that prioritizes safety and quality, we believe it is the right thing to do.”

The USDA said it is “concerned that some product may be in consumers’ refrigerators and in retail deli cases.” The USDA, the company, and CDC warn people not to eat the recalled products. Instead, they should either be thrown away or returned to the store where they were purchased for a full refund. And if you’ve purchased one of the recalled products, the USDA also advises you to thoroughly clean your fridge to prevent cross-contamination.

7 million pounds of meat recalled amid deadly outbreak Read More »

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Bird flu virus from Texas human case kills 100% of ferrets in CDC study

animal experiments, bird flu, CDC, dairy cows, Ferrets, H5N1, Infectious disease, respiratory transmission, Science, texas, Transmission / /

Animal study —

H5N1 bird flu viruses have shown to be lethal in ferret model before.

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Bird flu virus from Texas human case kills 100% of ferrets in CDC study

The strain of H5N1 bird flu isolated from a dairy worker in Texas was 100 percent fatal in ferrets used to model influenza illnesses in humans. However, the virus appeared inefficient at spreading via respiratory droplets, according to newly released study results from the Centers for Disease Control and Prevention.

The data confirms that H5N1 infections are significantly different from seasonal influenza viruses that circulate in humans. Those annual viruses make ferrets sick but are not deadly. They have also shown to be highly efficient at spreading via respiratory droplets, with 100 percent transmission rates in laboratory settings. In contrast, the strain from the Texas man (A/Texas/37/2024) appeared to have only a 33 percent transmission rate via respiratory droplets among ferrets.

“This suggests that A/Texas/37/2024-like viruses would need to undergo changes to spread efficiently by droplets through the air, such as from coughs and sneezes,” the CDC said in its data summary. The agency went on to note that “efficient respiratory droplet spread, like what is seen with seasonal influenza viruses, is needed for sustained person-to-person spread to happen.”

In the CDC’s study, researchers infected six ferrets with A/Texas/37/2024. The CDC’s data summary did not specify how the ferrets were infected in this study, but in other recent ferret H5N1 studies, the animals were infected by putting the virus in their noses. Ars has reached out to the agency for clarity on the inoculation route in the latest study and will update the story with any additional information provided.

All six of the infected ferrets developed severe disease and died. To test how well the virus could spread among the ferrets, the CDC scientists set up experiments to test transmission through direct contact and respiratory droplets. For the direct transmission test, three healthy ferrets were placed in the same enclosures with three experimentally infected ferrets. All three healthy ferrets became infected.

For the respiratory transmission test, three healthy ferrets were placed in enclosures next to enclosures containing the experimentally infected animals. The infected and uninfected ferrets shared air, but did not have direct contact with each other. Of the three healthy ferrets, only one contracted the H5N1 virus (33 percent). Additionally, that one respiratory transmission event seemed to have a one- to two-day delay compared with what’s seen in the same test with seasonal influenza viruses. This suggests further that the virus is inefficient at respiratory transmission.

The CDC called the overall results “not surprising.” Previous ferret experiments with H5N1 isolates—collected prior to the current bird flu outbreak among US dairy cows—have also found that H5N1 is often lethal to ferrets. Likewise, H5N1 isolates collected from Spain and Chile during the current global outbreak also found that the virus was inefficient at spreading via respiratory droplets among ferrets—with rates ranging from 0 percent to 37.5 percent.

For now, the findings don’t affect the CDC’s overall risk assessment for the general public, which is low. However, it does reinforce the risk to those who have contact with infected animals, particularly dairy and poultry farm workers.

To date, there have been four human cases of H5N1 in the US since the current global bird flu outbreak began in 2022—one in a poultry farm worker in 2022 and three in dairy farm workers, all reported between the beginning of April and the end of May this year. So far, the cases have been mild, the CDC noted, but given the results in ferrets, “it is possible that there will be serious illnesses among people,” the agency concluded.

As of June 9, the US Department of Agriculture has confirmed H5N1 in 85 dairy herds and one alpaca farm across 10 states.

Bird flu virus from Texas human case kills 100% of ferrets in CDC study Read More »

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After mice drink raw H5N1 milk, bird flu virus riddles their organs

avian influenza, bird flu, CDC, cows, dairy cows, fda, flu, H5N1, Infectious disease, Mice, milk, outbreak, raw milk, Science, USDA, virus / /

Deadly dairy —

No, really, drinking raw milk during the H5N1 outbreak is a bad idea.

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Fresh raw milk being poured into a container on a dairy farm on July 29, 2023, in De Lutte, Netherlands.

Enlarge / Fresh raw milk being poured into a container on a dairy farm on July 29, 2023, in De Lutte, Netherlands.

Despite the delusions of the raw milk crowd, drinking unpasteurized milk brimming with infectious avian H5N1 influenza virus is a very bad idea, according to freshly squeezed data published Friday in the New England Journal of Medicine.

Researchers at the University of Wisconsin-Madison squirted raw H5N1-containing milk from infected cows into the throats of anesthetized laboratory mice, finding that the virus caused systemic infections after the mice were observed swallowing the dose. The illnesses began quickly, with symptoms of lethargy and ruffled fur starting on day 1. On day 4, the animals were euthanized to prevent extended suffering. Subsequent analysis found that the mice had high levels of H5N1 bird flu virus in their respiratory tracts, as well their hearts, kidneys, spleens, livers, mammary glands, and brains.

“Collectively, our data indicate that HPAI [Highly Pathogenic Avian Influenza] A(H5N1) virus in untreated milk can infect susceptible animals that consume it,” the researchers concluded. The researchers also found that raw milk containing H5N1 can remain infectious for weeks when stored at refrigerator temperatures.

Bird flu has not historically been considered a foodborne pathogen, but prior to the unexpected outbreak of H5N1 in US dairy cows discovered in March, it had never been found at high levels in a food product like milk before. While experts have stepped up warnings against drinking raw milk amid the outbreak, the mouse experiment offers some of the first data on the risks of H5N1 from drinking unpasteurized dairy.

Before the mouse data, numerous reports have noted carnivores falling ill with H5N1 after eating infected wild birds. And a study from March in the journal Emerging Infectious Diseases reported that over half of the 24 or so cats on an H5N1-infected dairy farm in Texas died after drinking raw milk from the sick cows. Before their deaths, the cats displayed distressing neurological symptoms, and studies found the virus had invaded their lungs, brains, hearts, and eyes.

While the data cannot definitely determine if humans who drink H5N1-contaminated raw milk will suffer the same fate as the mice and cats, it highlights the very real risk. Still, raw milk enthusiasts have disregarded the concerns. PBS NewsHour reported last week that since March 25, when the H5N1 outbreak in US dairy cows was announced, weekly sales of raw cow’s milk have ticked up 21 percent, to as much as 65 percent compared with the same periods a year ago, according to data shared by market research firm NielsenIQ. Moreover, the founder of California-based Raw Milk Institute, Mark McAfee, told the Los Angeles Times this month that his customers baselessly believe drinking H5N1 will give them immunity to the deadly pathogen.

In normal times, the Centers for Disease Control and Prevention and the Food and Drug Administration strongly discourage drinking raw milk. Without pasteurization, it can easily be contaminated with a wide variety of pathogens, including Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella, and Salmonella.

Fortunately, for the bulk of Americans who heed germ theory, pasteurization appears completely effective at deactivating the virus in milk, according to thorough testing by the FDA. Pasteurized milk is considered safe during the outbreak. The US Department of Agriculture, meanwhile, reports finding no H5N1 in retail beef so far and, in laboratory experiments, beef patties purposefully inoculated with H5N1 had no viable virus in them after the patties were cooked to 145°F (medium) or 160°F (well done).

To date, the USDA has reported that H5N1 has infected at least 58 dairy herds in nine states.

After mice drink raw H5N1 milk, bird flu virus riddles their organs Read More »

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It could soon be illegal to publicly wear a mask for health reasons in NC

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Senators skeptical of legal trouble for harmless masking after moving to make it illegal.

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It could soon be illegal to publicly wear a mask for health reasons in NC

The North Carolina State Senate on Wednesday voted 30–15, along party lines, in favor of a Republican bill that would make it illegal for people in the state to wear a mask in public for health reasons. The bill is now moving to the House, where it could potentially see changes.

The proposed ban on health-based masking is part of a larger bill otherwise aimed at increasing penalties for people wearing masks to conceal their identity while committing a crime or impeding traffic. The bill was largely spurred by recent protests on university and college campuses across the country, including North Carolina-based schools, against the war in Gaza. In recent months, there have been demonstrations in Raleigh and Durham that have blocked roadways, as well as clashes on the nearby campus of the University of North Carolina at Chapel Hill. Some demonstrators were seen wearing masks in those events.

But the bill, House Bill 237, goes a step further by making it illegal to wear a mask in public for health and safety reasons, either to protect the wearer, those around them, or both. Specifically, the bill repeals a 2020 legal exemption enacted amid the COVID-19 pandemic, which allowed for public health-based masking for the first time in decades.

Prior to 2020, laws dating back to 1953 largely prohibited public masking. The prohibition was part of a crackdown on “secret societies” at the time, or more specifically, an attempt to curtail the activities of the Ku Klux Clan in the state. Exemptions only existed for things like holiday costumes, theater productions, gas masks, and members of public parades or ceremonies that had obtained permits.

On Wednesday, North Carolina residents with compromised immune systems spoke—while masked—during a public comment section. Simone Hetherington told lawmakers that masking was the only way to protect herself in public from illness and feared passage of the bill would prevent her from doing so, according to reporting by the Associated Press.

But, according to The News & Observer, Republicans were dismissive of that possibility, arguing that in the decades prior to the pandemic, when public masking was largely illegal, they couldn’t recall anyone being prosecuted for wearing a mask for health reasons.

Raleigh-based news outlet WRAL quoted Sen. Sydney Batch, a Democrat from Wake, who criticized the bill along with fellow Democratic colleagues. Batch, a cancer survivor, spoke of how her husband and children wore masks to protect her while she underwent cancer treatments that weakened her immune system. “This bill criminalizes their behavior and mine,” she said. “We talk a lot about freedoms in this chamber. I hear it all the time. I should have the freedom—my children and my husband should have the freedom—to wear masks in order to protect and save my life, without fear of being arrested and charged.”

It could soon be illegal to publicly wear a mask for health reasons in NC Read More »

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We still don’t understand how one human apparently got bird flu from a cow

bird flu, cattle, CDC, cows, genetic surveillance, H5N1, human case, Infectious disease, mutations, outbreak, pandemic, Science, USDA, viral sequences, viruses / /
Holstein dairy cows in a freestall barn.

Enlarge / Holstein dairy cows in a freestall barn.

The US Department of Agriculture this week posted an unpublished version of its genetic analysis into the spillover and spread of bird flu into US dairy cattle, offering the most complete look yet at the data state and federal investigators have amassed in the unexpected and worrisome outbreak—and what it might mean.

The preprint analysis provides several significant insights into the outbreak—from when it may have actually started, just how much transmission we’re missing, stunning unknowns about the only human infection linked to the outbreak, and how much the virus continues to evolve in cows. The information is critical as flu experts fear the outbreak is heightening the ever-present risk that this wily flu virus will evolve to spread among humans and spark a pandemic.

But, the information hasn’t been easy to come by. Since March 25—when the USDA confirmed for the first time that a herd of US dairy cows had contracted the highly pathogenic avian influenza H5N1 virus—the agency has garnered international criticism for not sharing data quickly or completely. On April 21, the agency dumped over 200 genetic sequences into public databases amid pressure from outside experts. However, many of those sequences lack descriptive metadata, which normally contains basic and key bits of information, like when and where the viral sample was taken. Outside experts don’t have that crucial information, making independent analyses frustratingly limited. Thus, the new USDA analysis—which presumably includes that data—offers the best yet glimpse of the complete information on the outbreak.

Undetected spread

One of the big takeaways is that USDA researchers think the spillover of bird flu from wild birds to cattle began late last year, likely in December. Thus, the virus likely circulated undetected in dairy cows for around four months before the USDA’s March 25 confirmation of an infection in a Texas herd.

This timeline conclusion largely aligns with what outside experts previously gleaned from the limited publicly available data. So, it may not surprise those following the outbreak, but it is worrisome. Months of undetected spread raise significant concerns about the country’s ability to identify and swiftly respond to emerging infectious disease outbreaks—and whether public health responses have moved past the missteps seen in the early stages of the COVID-19 pandemic.

But another big finding from the preprint is how many gaps still exist in our current understanding of the outbreak. To date, the USDA has identified 36 herds in nine states that have been infected with H5N1. The good news from the genetic analysis is that the USDA can draw lines connecting most of them. USDA researchers reported that “direct movement of cattle based upon production practices” seems to explain how H5N1 hopped from the Texas panhandle region—where the initial spillover is thought to have occurred—to nine other states, some as far-flung as North Carolina, Michigan, and Idaho.

Bayes factors for inferred movement between different discrete traits of H5N1 clade 2.3.4.4b viruses demonstrating the frequency of movement.

Enlarge / Bayes factors for inferred movement between different discrete traits of H5N1 clade 2.3.4.4b viruses demonstrating the frequency of movement.

Putative transmission pathways of HPAI H5N1 clade 2.3.4.4b genotype B3.13 supported by epidemiological links, animal movements, and genomic analysis.

Enlarge / Putative transmission pathways of HPAI H5N1 clade 2.3.4.4b genotype B3.13 supported by epidemiological links, animal movements, and genomic analysis.

Putative transmission pathways of HPAI H5N1 clade 2.3.4.4b genotype B3.13 supported by epidemiological links, animal movements, and genomic analysis. [/ars_img]The bad news is that those lines connecting the herds aren’t solid. There are gaps in which the genetic data suggests unidentified transmission occurred, maybe in unsampled cows, maybe in other animals entirely. The genetic data is clear that once this strain of bird flu—H5N1 clade 2.3.4.4 genotype B3.13 —hopped into cattle, it could readily spread to other mammals. The genetic data links viruses from cattle moving many times into other animals: There were five cattle-to-poultry jumps, one cattle-to-raccoon transmission, two events where the virus moved from cattle to domestic cats, and three times when the virus from cattle spilled back into wild birds.

“We cannot exclude the possibility that this genotype is circulating in unsampled locations and hosts as the existing analysis suggests that data are missing and undersurveillance may obscure transmission inferred using phylogenetic methods,” the USDA researchers wrote in their preprint.

We still don’t understand how one human apparently got bird flu from a cow Read More »

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20% of grocery store milk has traces of bird flu, suggesting wider outbreak

bird flu, CDC, cows, fda, H5N1, health, Infectious disease, milk, Science, USDA, virus / /

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The milk is still considered safe, but disease experts are alarmed by the prevalence.

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20% of grocery store milk has traces of bird flu, suggesting wider outbreak

The Food and Drug Administration reported late Thursday that about 20 percent of retail milk samples from around the country tested positive for genetic fragments of the bird flu, aka highly pathogenic avian influenza (HPAI) virus H5N1. While retail milk is still considered to be safe, the finding suggests that the spread of the virus in cows is more extensive than is currently known.

The FDA used a test called quantitative polymerase chain reaction (qPCR), which can only detect the presence of genetic fragments. In pasteurized retail milk, it is highly likely that those genetic snippets are merely remnants of virus particles destroyed during pasteurization. The FDA is currently conducting additional testing using egg inoculation tests, a gold standard for detecting a live virus, to confirm the effectiveness of pasteurization. Meanwhile, the director of the National Institute of Allergy and Infectious Diseases, Jeanne Marrazzo, told reporters Wednesday that tests at the agency’s federal labs so far did not identify live virus from any of its sampling. Additionally, several previous studies have found that pasteurization of eggs—which is done at a lower temperature than it is for milk—was effective at destroying H5N1.

While experts are largely unconcerned with the safety of commercial milk, the potential for wide, unrecognized spread of bird flu in dairy herds is alarming. To date, the US Department of Agriculture has only confirmed infections in 33 herds in eight states. The FDA acknowledged that of its positive samples, “a greater proportion of positive results [are] coming from milk in areas with infected herds.” But with tens of thousands of dairy herds in the US, the finding suggests that infections are being missed. It does not necessarily suggest that 20 percent of all cows are affected, since milk is pooled for commercial distribution. But 33 herds alone are unlikely to explain the high prevalence.

Last week, The New York Times reported that the one dairy herd that tested positive for bird flu in North Carolina did not show any symptoms of the infection. The possibility of asymptomatic spread of the virus among cows will make containment and monitoring far more difficult—and could explain why infections may be easily missed. On Wednesday, the USDA issued a federal order requiring dairy cattle to have a negative H5N1 test before being moved across state lines.

For now, the risk to the public is still considered low by the Centers for Disease Control and Prevention. But the more the bird flu virus spreads among mammals—and mammals with close contact with humans—the more opportunities it has to evolve to jump to and among people, experts warn.

20% of grocery store milk has traces of bird flu, suggesting wider outbreak Read More »