infectious diseases

alarming-superbug-from-deadly-eyedrop-outbreak-has-spread-to-dogs

Alarming superbug from deadly eyedrop outbreak has spread to dogs

gone to the dogs —

It’s unclear how the dogs became infected with the same strain in the eyedrops.

A dog gets examined by veterinary technicians in Texas.

Enlarge / A dog gets examined by veterinary technicians in Texas.

Two separately owned dogs in New Jersey tested positive last year for a dreaded, extensively drug resistant bacterial strain spread in the US by contaminated artificial eye drops manufactured in India. Those drops caused a deadly multi-state outbreak in humans over many months last year, with at least 81 people ultimately infected across 18 states. Fourteen people lost their vision, an additional four had eyeballs surgically removed, and four people died.

The preliminary data on the dogs—presented recently at a conference of disease detectives hosted by the Centers for Disease Control and Prevention—highlights that now that the deadly outbreak strain has been introduced around the US, it has the potential to lurk in unexpected places, spread its drug resistance to fellow bacteria, and cause new infections in people and animals who may have never used the drops.

The two dogs in New Jersey were not known to have received the drops linked to the outbreak: EzriCare Artificial Tears and two additional products made by the same manufacturer, which were recalled in February 2023. Such over-the-counter products are sometimes used in animals as well as people. But the dogs’ separate owners said they didn’t recall using the drops either. They also didn’t report any exposures in health care settings or recent international travel that could explain the infections. One of the dogs did, at one point, receive eye drops, but they were not an outbreak-associated brand. The only connection between the two dogs was that they were both treated at the same veterinary hospital, which didn’t stock the outbreak-associated eyedrops.

The dogs’ infections were caught between March and June 2023 when clinicians at the veterinary hospital were working to address a chronic cough in one of the dogs and a stubborn ear infection in the other, according to CBS News, which was present for the CDC’s conference of its Epidemic Intelligence Service in Atlanta. The ear and lung swabs were sent to an academic veterinary laboratory in Pennsylvania, where a microbiologist noticed that bacteria from both swabs had uncommon drug-resistance features. The microbiologist then uploaded genetic sequences of the bacterial strains to a national database, where they caught the attention of the CDC and state health authorities.

The genetic sequences uploaded were of the carbapenemase-producing carbapenem-resistant Pseudomonas aeruginosa (CP-CRPA) strain—and they were highly similar to the bacterial strain identified in the deadly eyedrop outbreak. These bacteria are extensively resistant to antibiotics, resisting even last-line drugs, and can silently colonize animals and humans for months or years. An investigation ensued.

Infection gaps

Emma Price, the CDC epidemic intelligence service officer who presented the investigation’s findings at the conference, suggested it was fortunate they were able to make the connection. “Because [the academic veterinary laboratory] had a grant and a veterinary microbiologist works there, he did his great due diligence and uploaded the results. That’s how we got the notification, because the strain matched the outbreak strain,” Price told CBS News.

However, the disease detectives were ultimately unable to identify exactly how the two dogs became infected. “Shared exposures included treatment in the veterinary hospital’s surgical preparation and recovery areas for both canines and ophthalmology department visits by either the affected canine or another animal in the same household,” Price and colleagues wrote in their findings. But all of the sampling done of the veterinary hospital where the dogs were treated turned up negative for the eyedrop outbreak strain.

In the process of the investigation, the epidemiologists also conducted an infection control assessment of the veterinary hospital, finding a variety of “gaps.” These included problems with hand hygiene practices, personal protective equipment use—including use of gloves—and equipment and environmental cleaning and disinfection at the hospital. Price noted that these problems are not uncommon and that there is a general lack of emphasis on infection control in veterinary settings.

Though Price and her colleagues were unable to identify the direct route of infection, they suspect the dogs were likely infected either by exposure to a contaminated product or secondary transmission at the veterinary hospital.

Both dogs have since made full recoveries, but because CRPA strains can silently colonize many body sites on both humans and animals, it’s possible that the bacteria still linger on the dogs or on the other pets and people in their households. Price warned the owners of possible future transmission and recommended they flag this risk to their health care providers. She also noted the potential for the bacteria to spread from dog to dog. It would be ideal to “keep the dogs away from other dogs in the future, which we understand is a difficult thing to do,” she said.

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cats-suffer-h5n1-brain-infections,-blindness,-death-after-drinking-raw-milk

Cats suffer H5N1 brain infections, blindness, death after drinking raw milk

Spillover —

Mammal-to-mammal transmission raises new concerns about the virus’s ability to spread.

Farm cats drinking from a trough of milk from cows that were just milked.

Enlarge / Farm cats drinking from a trough of milk from cows that were just milked.

On March 16, cows on a Texas dairy farm began showing symptoms of a mysterious illness now known to be H5N1 bird flu. Their symptoms were nondescript, but their milk production dramatically dropped and turned thick and creamy yellow. The next day, cats on the farm that had consumed some of the raw milk from the sick cows also became ill. While the cows would go on to largely recover, the cats weren’t so lucky. They developed depressed mental states, stiff body movements, loss of coordination, circling, copious discharge from their eyes and noses, and blindness. By March 20, over half of the farm’s 24 or so cats died from the flu.

In a study published today in the journal Emerging Infectious Diseases, researchers in Iowa, Texas, and Kansas found that the cats had H5N1 not just in their lungs but also in their brains, hearts, and eyes. The findings are similar to those seen in cats that were experimentally infected with H5N1, aka highly pathogenic avian influenza virus (HPAI). But, on the Texas dairy farm, they present an ominous warning of the potential for transmission of this dangerous and evolving virus.

The contaminated milk was the most likely source of the cat’s fatal infections, the study authors concluded. Although it can’t be entirely ruled out that the cats got sick from eating infected wild birds, the milk they drank from the sick cows was brimming with virus particles, and genetic data shows almost exact matches between the cows, their milk, and the cats. “Therefore, our findings suggest cross-species mammal-to-mammal transmission of HPAI H5N1 virus and raise new concerns regarding the potential for virus spread within mammal populations,” wrote the authors, who are veterinary researchers from Iowa, Texas, and Kansas.

The early outbreak data from the Texas farm suggests the virus is getting better and better at jumping to mammals, and data from elsewhere shows the virus is spreading widely in its newest host. On March 25, the US Department of Agriculture confirmed the presence of H5N1 in a dairy herd in Texas, marking the first time H5N1 had ever been known to cross over to cows. Since then, the USDA has tallied infections in at least 34 herds in nine states: Texas, Kansas, Michigan, New Mexico, Idaho, Ohio, South Dakota, North Carolina, and Colorado.

The Food and Drug Administration, meanwhile, has detected genetic traces of H5N1 in roughly 20 percent of commercial milk samples. While commercial milk is still considered safe—pasteurization is expected to destroy the virus and early testing by the FDA and other federal scientists confirms that expectation—the finding suggests yet wider spread of the virus among the country’s milk-producing cows.

Cows are only the latest addition to H5N1’s surprisingly broad host range. Amid a global outbreak over the past several years that has devastated wild bird populations and poultry farms, researchers have documented unexpected and often deadly outbreaks in mammals. Since 2022, the USDA has found H5N1 in over 200 mammals, from big cats in zoos to harbor seals, mountain lions, raccoons, skunks, squirrels, polar bears, black bears, foxes, and bottlenose dolphins.

“The recurring nature of global HPAI H5N1 virus outbreaks and detection of spillover events in a broad host range is concerning and suggests increasing virus adaptation in mammals,” the authors wrote. “Surveillance of HPAI viruses in domestic production animals, including cattle, is needed to elucidate influenza virus evolution and ecology and prevent cross-species transmission.”

In the meantime, it’s definitely not the time to start drinking raw cow’s milk. While drinking raw milk is always dangerous because it carries the threat of various nasty bacterial infections, H5N1 also appears to be infectious in raw milk. And, unlike other influenza viruses, H5N1 has the potential to infect organs beyond the lungs and respiratory tract, as seen in the cats. The authors of the new study note that a 2019 consumer survey found that 4.4 percent of adults in the US consumed raw milk more than once in the previous year, suggesting more public awareness of the dangers of raw milk is necessary.

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health-experts-plead-for-unvaxxed-americans-to-get-measles-shot-as-cases-rise

Health experts plead for unvaxxed Americans to get measles shot as cases rise

MMR is safe and effective —

The US hit last year’s total in under 12 weeks, suggesting we’re in for a bad time.

A view from a hospital as children receiving medical treatment, in capital Kabul, Afghanistan on April 18, 2022. More than 130 children have died from the measles in Afghanistan since the beginning of this year.

Enlarge / A view from a hospital as children receiving medical treatment, in capital Kabul, Afghanistan on April 18, 2022. More than 130 children have died from the measles in Afghanistan since the beginning of this year.

The Centers for Disease Control and Prevention and the American Medical Association sent out separate but similar pleas on Monday for unvaccinated Americans to get vaccinated against the extremely contagious measles virus as vaccination rates have slipped, cases are rising globally and nationally, and the spring-break travel period is beginning.

In the first 12 weeks of 2024, US measles cases have already matched and likely exceeded the case total for all of 2023. According to the CDC, there were 58 measles cases reported from 17 states as of March 14. But media tallies indicate there have been more cases since then, with at least 60 cases now in total, according to CBS News. In 2023, there were 58 cases in 20 states.

“As evident from the confirmed measles cases reported in 17 states so far this year, when individuals are not immunized as a matter of personal preference or misinformation, they put themselves and others at risk of disease—including children too young to be vaccinated, cancer patients, and other immunocompromised people,” AMA President Jesse Ehrenfeld said in a statement urging vaccination Monday.

The latest data indicates that vaccination rates among US kindergarteners have slipped to 93 percent nationally, below the 95 percent target to prevent the spread of the disease. And vaccine exemptions for non-medical reasons have reached an all-time high.

The CDC released a health advisory on Monday also urging measles vaccination. The CDC drove home the point that unvaccinated Americans are largely responsible for importing the virus, and pockets of unvaccinated children in local communities spread it once it’s here. The 58 measles infections that have been reported to the agency so far include cases from seven outbreaks in seven states. Most of the cases are in vaccine-eligible children aged 12 months and older who are unvaccinated. Of the 58 cases, 54 (93 percent) are linked to international travel, and most measles importations are by unvaccinated US residents who travel abroad and bring measles home with them, the CDC flagged.

The situation is likely to worsen as Americans begin spring travel, the CDC suggested. “Many countries, including travel destinations such as Austria, the Philippines, Romania, and the United Kingdom, are experiencing measles outbreaks,” the CDC said. “To prevent measles infection and reduce the risk of community transmission from importation, all US residents traveling internationally, regardless of destination, should be current on their [measles-mumps-rubella (MMR)] vaccinations.” The agency added in a recommendation to parents that “even if not traveling, ensure that children receive all recommended doses of MMR vaccine. Two doses of MMR vaccine provide better protection (97 percent) against measles than one dose (93 percent). Getting MMR vaccine is much safer than getting measles, mumps, or rubella.”

For Americans who are already vaccinated and communities with high vaccination coverage, the risk is low, the CDC noted. “However, pockets of low coverage leave some communities at higher risk for outbreaks.” This, in turn, threatens wider, continuous spread that could overturn the country’s status of having eliminated measles, which was declared in 2000. The US was close to losing its elimination status in 2019 when outbreaks among unvaccinated children drove 1,247 cases across 31 states. Vaccination rates have only fallen since then.

“The reduction in measles vaccination threatens to erase many years of progress as this previously eliminated vaccine-preventable disease returns,” the AMA’s Ehrenfeld warned.

As Ars has reported previously, measles is among the most contagious viruses known and can linger in airspace for up to two hours. Up to 90 percent of unvaccinated people exposed will contract it. Symptoms can include high fever, runny nose, red and watery eyes, and a cough, as well as the hallmark rash. About 1 in 5 unvaccinated people with measles are hospitalized, while 1 in 20 infected children develop pneumonia, and up to 3 in 1,000 children die of the infection. Brain swelling (encephalitis) can occur in 1 in 1,000 children, which can lead to hearing loss and intellectual disabilities. The virus can also destroy immune responses to previous infections—a phenomenon known as “immune amnesia”—which can leave children vulnerable to various other infections for years afterward.

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“Very sick” pet cat gave Oregon resident case of bubonic plague

Surprise plague —

The person’s cat was reportedly extremely ill and had a draining abscess.

A cat, but not the one with plague.

Enlarge / A cat, but not the one with plague.

An Oregon resident contracted bubonic plague from their “very sick” pet cat, marking the first time since 2015 that someone in the state has been stricken with the Black Death bacterium, according to local health officials.

Plague bacteria, Yersinia pestis, circulates cryptically in the US in various types of rodents and their fleas. It causes an average of seven human cases a year, with a range of 1 to 17, according to the Centers for Disease Control and Prevention. The cases tend to cluster in two regions, the CDC notes: a hotspot that spans northern New Mexico, northern Arizona, and southern Colorado, and another region spanning California, far western Nevada, and southern Oregon.

The new case in Oregon occurred in the central county of Deschutes. It was fortunately caught early before the infection developed into a more severe, systemic bloodstream infection (septicemic plague). However, according to a local official who spoke with NBC News, some doctors felt the person had developed a cough while being treated at the hospital. This could indicate progression toward pneumonic plague, a more life-threatening and more readily contagious variety of the plague that spreads via respiratory droplets. Nevertheless, the person’s case reportedly responded well to antibiotic treatment, and the person is recovering.

Health officials worked to prevent the spread of the disease. “All close contacts of the resident and their pet have been contacted and provided medication to prevent illness,” Richard Fawcett, Deschutes County Health Officer, said in a news release.

Fawcett told NBC News that the cat was “very sick” and had a draining abscess, indicating “a fairly substantial” infection. The person could have become infected by plague-infected fleas from the cat or by handling the sick cat or its bodily fluids directly. Symptoms usually develop two to eight days after exposure, when the infection occurs in the lymph nodes. Early symptoms include sudden onset of fever, nausea, weakness, chills, muscle aches, and/or visibly swollen lymph nodes called buboes. If left untreated, the infection progresses to the septicemic or pneumonic forms.

It’s unclear how or why the cat became infected. But cats are particularly susceptible to plague and are considered a common source of infection in the US. The animals, when left to roam outdoors, can pick up infections from fleas as well as killing and eating infected rodents. Though dogs can also pick up the infection from fleas or other animals, they are less likely to develop clinical illness, according to the CDC.

While plague cases are generally rare in the US, Deschutes County Health Services offered general tips to keep from contracting the deadly bacteria, namely: Avoid contact with fleas and rodents, particularly sick, injured, or dead ones; Keep pets on a leash and protected with flea control products; Work to keep rodents out and away from homes and other buildings; and avoid areas with lots of rodents while camping and hiking and wear insect repellant when outdoors to ward off fleas.

According to the CDC, there were 496 plague cases in the US between 1970 and 2020. And between 2000 and 2020, the CDC counted 14 deaths.

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Contact-tracing software could accurately gauge COVID-19 risk

As it turns out, epidemiology works —

Time spent with infected individuals is a key determinant of risk.

A woman wearing a face mask and checking her phone.

It’s summer 2021. You rent a house in the countryside with a bunch of friends for someone’s birthday. The weather’s gorgeous that weekend, so mostly you’re all outside—pool, firepit, hammock, etc.—but you do all sleep in the same house. And then on Tuesday, you get an alert on your phone that you’ve been exposed to SARS-CoV-2, the virus that causes COVID-19. How likely are you to now have it?

To answer that question, a group of statisticians, data scientists, computer scientists, and epidemiologists in the UK analyzed 7 million people who were notified that they were exposed to COVID-19 by the NHS COVID-19 app in England and Wales between April 2021 and February 2022. They wanted to know if—and how—these app notifications correlated to actual disease transmission. Analyses like this can help ensure that an app designed for the next pathogen could retain efficacy while minimizing social and economic burdens. And it can tell us more about the dynamics of SARS-CoV-2 transmission.

Over 20 million quarantine requests

The NHS COVID-19 app was active on 13 to 18 million smartphones per day in 2021. It used Bluetooth signals to estimate the proximity between those smartphones while maintaining privacy and then alerted people who spent 15 minutes or more at a distance of 2 meters or less from a confirmed case. This led to over 20 million such alerts, each of which came with a request to quarantine—quite a burden.

The researchers found that the app did, in fact, accurately translate the duration and proximity of a COVID-19 exposure to a relevant epidemiological risk score. The app assessed a contact’s risk by multiplying the length of contact, the proximity of contact, and the infectiousness of the index case as determined by how long it had been since the index case started showing symptoms or tested positive.

There was an increasing probability of reported infection as the app’s risk score increased: more contacts whom the app deemed were at a high transmission risk did go on to test positive for COVID-19 within the following two weeks than those who were notified but had lower risk levels. (That’s positive tests that were reported by using the app. Some of the high-risk people probably did not test at all, did not report their test results, or did not report them within the allotted time. So this is an underestimation of the correlation between notification of risk and infection.)

More exposure = higher risk

When the researchers separated the factors contributing to the risk of an exposure, they found that duration was the most important indicator. Household exposures accounted for 6 percent of all contacts but 41 percent of transmissions.

One caveat: The app didn’t record any contextual variables that are known to impact transmission risk, like if people live in an urban or rural area, was the meeting indoors or outdoors, was it during the week or over the weekend, was anyone vaccinated, etc. Including such data could make risk assessment more accurate.

Based on their work, the researchers suggest that an “Amber Alert” stage could have been introduced to the app, in which people deemed to have an interim degree of risk would be guided to get a PCR test rather than immediately jumping to quarantine. Including this intermediate Amber Alert population could have significantly reduced the socioeconomic costs of contact tracing while retaining its epidemiological impact or could have increased its effectiveness for a similar cost. Performing analyses like this early on in the next pandemic to determine how it is transmitted might minimize illness and strain on society.

Nature, 2023.  DOI:  10.1038/s41586-023-06952-2

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