Enlarge / The Centers for Disease Control and Prevention (CDC) headquarters stands in Atlanta, Georgia, on Saturday, March 14, 2020. (credit: Getty | Bloomberg )

The Centers for Disease Control and Prevention on Tuesday recommended that everyone ages six months and older get an updated COVID-19 vaccine booster shot this fall or winter.

The recommendation came quickly on the heels of a meeting of CDC advisors who voted 13-to-1 strongly in favor of making the updated versions of mRNA COVID-19 vaccines available to everyone ages 6 months and older.

"The virus that causes COVID-19 is always changing, and protection from COVID-19 vaccines declines over time," the CDC said in an announcement. "Receiving an updated COVID-19 vaccine can restore protection and provide enhanced protection against the variants currently responsible for most infections and hospitalizations in the United States."

Enlarge / Competitors take part in "Tough Mudder" at the Glen Helen Raceway in San Bernardino, California, United States on April 2, 2023. (credit: Getty | Tayfun CoÅkun )

Hundreds of people who participated in a recent Tough Mudder event—a very muddy obstacle course race—held in Sonoma, California, have fallen ill with pustular rashes, lesions, fever, flu-like symptoms, nerve pain, and other symptoms, local health officials and media outlets report.

The cases could be caused by various infectious agents, including Staphylococcus bacteria, but the leading culprit is the relatively obscure Aeromonas bacteria— specifically A. hydrophila , according to the Sonoma County health department. In a statewide alert this week, the California Department of Public Health said it is considering it an Aeromonas outbreak, noting that multiple wound cultures have yielded the hardy bacterium.

A spokesperson for the Sonoma County health department told the Los Angeles Times on Thursday that, based on calls and emails the department had received, health officials estimate that the outbreak involves around 300 cases . Tough Mudder participants, meanwhile, have tallied as many as 489 cases in online forums.

Enlarge / In this 1960 photograph are two, Ascaris lumbricoides nematodes, i.e., roundworms. The larger of the two is the female of the species, while the normally smaller male is on the right. Adult female worms can grow to over 12 inches in length. (credit: CDC )

Parasitic worms are having a slimy moment. In the wake of news that a 3-inch snake parasite burrowed into a woman's brain comes the horrifying report of giant intestinal worms that went wandering in a man's innards, only to cause a rare, dangerous traffic jam in his bile duct.

According to a report in the New England Journal of Medicine , doctors in Colombia extracted not one, not two, but three large intestinal worms that had crammed themselves into the normally narrow duct, causing an uncommon, dangerous condition called biliary ascariasis.

The worms in this case, Ascaris lumbricoides , are typically found in humans. In fact, A. lumbricoides is among the most common parasitic worms found in humans, estimated to infect some 807 million to 1.2 billion people worldwide, according to the Centers for Disease Control and Prevention.

Enlarge / Detection of Ophidascaris robertsi nematode infection in a 64-year-old woman from southeastern New South Wales, Australia. A) Magnetic resonance image of patient’s brain by fluid-attenuated inversion recovery demonstrating an enhancing right frontal lobe lesion, 13 × 10 mm. B) Live third-stage larval form of Ophidascaris robertsi (80 mm long, 1 mm diameter) removed from the patient’s right frontal lobe. C) Live third-stage larval form of O. robertsi (80 mm long, 1 mm diameter) under stereomicroscope (original magnification ×10). (credit: Emerging Infectious Diseases )

A neurosurgeon in Australia pulled a wriggling 3-inch roundworm from the brain of a 64-year-old woman last year—which was quite the surprise to the woman's team of doctors and infectious disease experts, who had spent over a year trying to identify the cause of her recurring and varied symptoms.

A close study of the extracted worm made clear why the diagnosis was so hard to pin down: the roundworm was one known to infect snakes—specifically carpet pythons endemic to the area where the woman lived—as well as the pythons' mammalian prey. The woman is thought to be the first reported human to ever have an infection with this snake-adapted worm, and it is the first time the worm has been found burrowing through a mammalian brain.

When the woman's illness began, "trying to identify the microscopic larvae, which had never previously been identified as causing human infection, was a bit like trying to find a needle in a haystack," Karina Kennedy, a professor at the Australian National University (ANU) Medical School and Director of Clinical Microbiology at Canberra Hospital, said in a press release.

Enlarge / WHO's COVID-19 technical lead, Maria Van Kerkhove, looks on during a press conference at the World Health Organization's headquarters in Geneva, on December 14, 2022. (credit: Getty | FABRICE COFFRINI )

With global attention and anxiety locked onto the latest coronavirus omicron subvariant BA.2.86, health officials and experts are still mostly in the dark about how the highly mutated virus will play out.

At the start of the week, amid a flurry of headlines, researchers had only six genetic sequences of the virus in the public repository GISAID, even though the virus had already spread to at least four countries (Denmark, Israel, UK, and the US). As of the time of publication of this article on Friday, there are still only 10 sequences from five countries (Denmark, Israel, UK, US, and South Africa). According to the World Health Organization, the variant has also appeared in wastewater sampling from Thailand and Switzerland.

As Ars reported Monday , BA.2.86 gained attention for having a large number of mutations compared with BA.2, the omicron subvariant from which it descended. The number of mutations in BA.2.86's critical spike protein is over 30, rivaling the number seen in the original omicron subvariant, BA.1, which went on to cause a tidal wave of cases and hospitalizations. BA.2.86's spike mutations appear geared toward evading neutralizing antibody protections built up from past infections and vaccinations. But with such scant and spotty detection, it's impossible to say whether this variant can outspread its many omicron-subvariant cousins to cause a wave of infection. It's also still not possible to determine if it can cause more severe disease than other variants. So far, severe disease symptoms have not been reported from the 10 cases—but that is not enough data to draw any conclusions. As the Centers for Disease Control and Prevention reported in a risk assessment Wednesday, it's " too soon to know " the impact of BA.2.86 on transmission and disease severity.

Enlarge / An armadillo prepares to cross a gravel road as the space shuttle Endeavour rests on the launch pad at Kennedy Space Center before the scheduled launch of STS-130 in Cape Canaveral, Florida, February 4, 2010. (credit: Getty | JIM WATSON )

A Florida man's unexplained case of leprosy last year adds to mounting evidence that the rare and often misunderstood bacterial infection has become endemic to the central part of the Sunshine State—and that it may, in fact, lurk in the environment there, possibly in the soil.

In a research letter appearing in the August issue of Emerging Infectious Diseases, three dermatologists detailed the man's case and their concerns for local transmission. They note that the 54-year-old man, like several others in the state who contracted the disease, reported no established risk factors that might explain their infection. He hadn't traveled abroad, where he could have picked up the infection, or had any exposure to armadillos, which live in Florida and naturally carry the bacteria that cause leprosy. He also didn't have any prolonged contact with people from leprosy-endemic countries or connections to anyone known to have leprosy.

But he did spend a lot of time outdoors; he worked as a landscaper. In fact, many of the recent Florida cases lacked traditional risk factors but reported spending a lot of time outdoors. The similarity "supports the investigation into environmental reservoirs as a potential source of transmission," the doctors wrote.

Enlarge / A vector ecologist displays a vial of live lone star ticks. (credit: Getty | Ben McCanna )

A little over a decade ago, researchers discovered that bites from lone star ticks could cause some people to develop a food allergy to meat and meat products —an allergic condition called alpha-gal syndrome (AGS) , which can vary from mild to life-threatening.

The condition is named after a carbohydrate called galactose-α-1,3-galactose (aka alpha-gal), which is commonly found on proteins in most mammals—with the important exception of primates, like humans. Alpha-gal shows up on all sorts of non-primate mammalian tissue, which means it's also in meat—such as pork, beef, rabbit, and lamb—and animal products, like milk and gelatin. Its presence on animal tissue is one of the big, long-recognized barriers to xenotransplantation—that is, transplanting pig hearts into people, for example. Human immune systems will, in part, reject the organ because of the presence of the foreign alpha-gal.

But, in recent years, researchers have also discovered that alpha-gal is in tick saliva . And, for reasons researchers still haven't worked out, some people bitten by ticks develop a type of antibody called anti-alpha-gal IgE . This antibody may help protect people from tick bites but also renders them allergic to anything with alpha-gal—i.e., mammalian meat and animal products. It's a double-edged sword that's been hypothesized to be an " allergic klendusity ."

Enlarge / The Plaza Mayor or Plaza de Armas of Lima in Peru, part of a Unesco world heritage site in Lima. (credit: Getty | Frédéric Soltan/Corbis )

Over 230 people in Peru have developed a rare, paralyzing neurological disorder called Guillain-Barré Syndrome, leading government officials to declare a national emergency and the World Health Organization to send out a disease outbreak alert.

So far, four people have died from the disorder, which involves the immune system attacking peripheral nerves. It often starts with progressive muscle weakness and numbness that can lead to paralysis and, in about a quarter of the cases, the need for mechanical ventilation.

Peru—a country of over 34 million people—typically sees fewer than 20 suspected cases per month of Guillain-Barré Syndrome (pronounced ghee-yan bar-ray or abbreviated GBS). But, between June 10 and July 15, the country tallied 130 cases, including the four deaths, bringing the year's total to 231, the WHO reported Tuesday.

An Anopheles stephensi mosquito, which can carry the malaria parasite. (credit: CDC)

A seventh person has been diagnosed with a locally acquired case of malaria in Florida's Sarasota County, state health officials reported this week .

The rare outbreak is now in its third month after authorities in the Sunshine State reported the first case in May. When Florida had identified four cases by late June, the Centers for Disease Control and Prevention released a health alert to clinicians calling locally acquired malaria cases in the US a "public health emergency."

Florida's outbreak and a single, unrelated case in Texas from June collectively mark the first time in two decades that the US has seen locally acquired malaria cases, which, if left untreated, can be deadly. In the last instance, in 2003, Florida officials reported a small outbreak of at least seven people in Palm Beach.