Enlarge / Xorides praecatorius is a parasitoid wasp. (credit: TorriPhoto via Getty )

If you puncture the ovary of a wasp called Microplitis demolitor , viruses squirt out in vast quantities, shimmering like iridescent blue toothpaste. “It’s very beautiful, and just amazing that there’s so much virus made in there,” says Gaelen Burke, an entomologist at the University of Georgia.

M. demolitor is a parasite that lays its eggs in caterpillars, and the particles in its ovaries are “domesticated” viruses that have been tuned to persist harmlessly in wasps and serve their purposes. The virus particles are injected into the caterpillar through the wasp’s stinger, along with the wasp’s own eggs. The viruses then dump their contents into the caterpillar’s cells, delivering genes that are unlike those in a normal virus. Those genes suppress the caterpillar’s immune system and control its development, turning it into a harmless nursery for the wasp’s young.

The insect world is full of species of parasitic wasps that spend their infancy eating other insects alive. And for reasons that scientists don’t fully understand, they have repeatedly adopted and tamed wild, disease-causing viruses and turned them into biological weapons. Half a dozen examples already are described, and new research hints at many more.

Enlarge / Holstein dairy cows in a freestall barn. (credit: Getty | )

The US Department of Agriculture this week posted an unpublished version of its genetic analysis into the spillover and spread of bird flu into US dairy cattle , offering the most complete look yet at the data state and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.

Enlarge / A bathroom on an Airbus A321neo. (credit: Getty | Nicolas Economou/NurPhoto )

The US Centers for Disease Control and Prevention is considering blending sewage sampling from airplanes into the mix of its wastewater surveillance system, which has proven useful for monitoring the spread and prevalence of a variety of pathogens, particularly SARS-CoV-2.

Amid the pandemic, the CDC launched wastewater testing programs across the nation, trying to get ahead of SARS-CoV-2 surges. Viral particles are often shed in fecal matter and can be an early indication of an infection. The fecal focus has proven useful for sniffing out community-wide transmission trends and disease spread for not only COVID-19 but also other recent outbreaks as well, namely polio and mpox (formerly monkeypox). Adding surveillance from airplanes and airports could flush out yet more information about infectious disease spread, such as global travel patterns and the debut of novel viral variants.

A study published last week in PLOS Global Public Health found such sewage surveillance in UK airport terminals and airplanes was effective at tracking SARS-CoV-2 among international travelers. Overall, the surveillance data suggested that it is a "useful tool for monitoring the global transfer rate of human pathogens and other disease-causing agents across international borders and should form part of wider international efforts to monitor and contain the spread of future disease outbreaks," the authors, led by Kata Farkas of Bangor University, concluded.

Enlarge / Chicken eggs are disposed of at a quarantined farm in Israel's northern Moshav (village) of Margaliot on January 3, 2022. (credit: Getty | JALAA MAREY / AFP) )

The ongoing bird flu outbreak in the US is now the longest and deadliest on record. More than 57 million birds have been killed by the virus or culled since a year ago, and the deadly disruption has helped propel skyrocketing egg prices and a spike in egg smuggling.

Since highly pathogenic avian influenza (HPAI) A(H5N1) was first detected in US birds in January 2022, the price of a carton of a dozen eggs has shot up from an average of about $1.79 in December 2021 to $4.25 in December 2022, a 137 percent increase, according to data from the US Bureau of Labor Statistics . Although inflation and supply chain issues partly explain the rise, eggs saw the largest percentage increase of any specific food, according to the consumer price index .

And the steep pricing is leading some at the US-Mexico border to try to smuggle in illegal cartons, which is prohibited. A US Customs and Border Protection spokesperson told NPR this week that people in El Paso, Texas, are buying eggs in Juárez, Mexico, because they are " significantly less expensive ." Meanwhile, a customs official in San Diego tweeted a reminder amid a rise in egg interceptions that failure to declare such agriculture items at a port of entry can result in penalties up to $10,000 .

Enlarge / A microscope image of Streptococcus pyogenes , a common type of group A strep. (credit: Getty | BSIP )

Scarlet fever is spiking in the UK, with case numbers more than fourfold higher than normal for this time of year. And a rare but serious invasive disease caused by the same bacteria that causes scarlet fever and strep throat—Group A streptococci—is also surging, killing at least eight children in the UK, according to media reports .

The unusual rise is seen as yet another anomalous disease transmission cycle rippling in the wake of the COVID-19 pandemic. Like many other seasonal infections, scarlet fever cases in the UK virtually flattened at the end of the 2019–2020 season and bottomed the chart throughout the 2020–2021 season, according to data released by the UK Health Security Agency .

Now, with most pandemic-related health restrictions lifted or at least eased, a throng of seasonal infections—particularly those that hit children the hardest—have returned. Many have returned with some ferociousness, finding a yet larger pool of susceptible victims than usual after a hiatus. Many of these disease-cycle anomalies have been seen in seasonal viruses, namely enteroviruses, adenoviruses, influenza, and RSV (respiratory syncytial (sin-SISH-uhl) virus), which are currently swamping hospitals and pediatric wards in the US.

Enlarge (credit: Getty | Future Publishing )

The new bivalent COVID-19 booster spurred neutralizing antibody levels that were fourfold higher against the omicron subvariants BA.4/BA.5 in older adults than those seen after the original booster, Pfizer reported Friday .

The new data may help calm concerns about whether the updated booster is an improvement over the previous booster. But the fall booster campaign—aimed at preventing another devastating winter wave—still faces considerable challenges. For one thing, a shockingly low number of Americans are rolling up their sleeves to get the shot.

Better boost

Experts all agree that the new booster shot, like the old one, will revive waning immune responses to SARS-CoV-2 and provide strong protection from severe COVID-19. But some experts have expressed skepticism about whether the updated bivalent booster—which in part targets omicron subvariants BA.4/BA.5—will offer a clinically meaningful advantage over the previous booster in preventing mild infections against the subvariant.

Enlarge / A bottle of influenza vaccine at a CVS pharmacy and MinuteClinic on September 10, 2021, in Miami. (credit: Getty | Joe Raedle )

The pandemic coronavirus' debut wrought universal havoc—not even seasonal flu viruses were spared. Amid travel restrictions, quarantines, closures, physical distancing, masking, enhanced hand washing, and disinfection, the 2020-2021 flu season was all but canceled. That meant not just an unprecedented global decrease in the number of people sick with the flu but also a dramatic collapse in the genetic diversity of circulating flu strains. Many subtypes of the virus all but vanished. But most notably, one entire lineage—one of only four flu groups targeted by seasonal influenza vaccines—went completely dark, seemingly extinct.

Researchers noted the absence last year as the flu was still struggling to recover from its pandemic knockout. But now, the flu has come roaring back and threatens to cause a particularly nasty season in the Northern Hemisphere. Still, the influenza B/Yamagata lineage remains missing, according to a study published this week in the journal Eurosurveillance . It has not been definitively detected since April 2020. And the question of whether it's truly gone extinct lingers.

What B/Yamagata's absence might mean for future flu seasons and flu shots also remains an open question. For a quick refresher: Four main types of seasonal flu have been circulating globally among humans in recent years. Two are influenza type A viruses: subtypes of H1N1 viruses and H3N2 viruses. The other two are influenza type B viruses: offshoots of the Victoria and Yamagata lineages. (For a more detailed explanation of influenza, check out our explainer here .) Current quadrivalent vaccines target season-specific versions of each of these four types of flu viruses.

Enlarge (credit: KATERYNA KON )

Vertebrates such as ourselves rely on a complicated, multi-layer immune system to limit the impact of pathogens. Specialized B and T cells play a central role by recognizing specific pathogens and providing a memory of past infections.

Obviously, single-celled organisms like bacteria and archaea can't take the same approach. But that doesn't mean they're defenseless. They also have an adaptive defense system that maintains a memory of past infections (and happens to make a great gene editing tool ). Now, researchers have found that a family of related proteins is used to fight viruses in organisms ranging from bacteria to humans. While the effects it triggers vary among organisms, it appears to be capable of recognizing a wide range of viruses.

Finding family members

Mammals have a family of immune proteins called STAND (for reasons that are unimportant) that are part of what calls the innate immune system. This arm of our immune system doesn't recognize specific pathogens; instead, it recognizes general features of infection, such as molecules that are found on the surface of most bacteria.