Infection

Common virus may be celiac disease culprit

reovirus
A VIRAL TRIGGER A reovirus (illustrated here) may jump-start celiac disease by turning the immune system against gluten, a new study in mice suggests.

A common and usually harmless virus may trigger celiac disease. Infection with the suspected culprit, a reovirus, could cause the immune system to react to gluten as if it was a dangerous pathogen instead of a harmless food protein, an international team of researchers reports April 7 in Science.

In a study in mice, the researchers found that the reovirus, T1L, tricks the immune system into mounting an attack against innocent food molecules. The virus first blocks the immune system’s regulatory response that usually gives non-native substances, like food proteins, the OK, Terence Dermody, a virologist at the University of Pittsburgh, and colleagues found. Then the virus prompts a harmful inflammatory response.

“Viruses have been suspected as potential triggers of autoimmune or food allergy–related diseases for decades,” says Herbert Virgin, a viral immunologist at Washington University School of Medicine in St. Louis. This study provides new data on how a viral infection can change the immune system’s response to food, says Virgin, who wasn’t involved in the study.

Reoviruses aren’t deadly. Almost everyone has been infected with a reovirus, and almost no one gets sick, Dermody says. But if the first exposure to a food with gluten occurs during infection, the virus may…

Getting dengue first may make Zika infection much worse

dengue antibody and dengue virus
FRIEND OR FOE A dengue antibody (blue, shown bound to a dengue virus protein, red, in this molecular model) can ease Zika’s entry into cells, a new study finds.

Being immune to a virus is a good thing, until it’s not. That’s the lesson from a study that sought to understand the severity of the Zika outbreak in Brazil. Experiments in cells and mice suggest that a previous exposure to dengue or West Nile can make a Zika virus infection worse.

“Antibodies you generate from the first infection … can facilitate entry of the Zika virus into susceptible cells, exacerbating the disease outcome,” says virologist Jean K. Lim. Lim and colleagues report the results online March 30 in Science.

The study is the first to demonstrate this effect in mice, as well as the first to implicate West Nile virus, notes Sharon Isern, a molecular virologist at Florida Gulf Coast University in Fort Myers.

Zika is similar to other members of its viral family, the flaviviruses. It shares about 60 percent of its genetic information with dengue virus and West Nile virus. Dengue outbreaks are common in South and Central America, and dengue as well as West Nile are endemic to the United States.

Exposure to a virus spurs the body to create antibodies, which prevent illness when a subsequent infection with the virus occurs. But a peculiar phenomenon called antibody-dependent enhancement has been described in dengue patients (SN: 6/25/16, p. 22). The dengue virus has four different versions. When a person with immunity to one dengue type becomes sick with another type, the illness is worse the second time. The antibodies from the previous dengue exposure actually help the subsequent dengue virus infect cells, rather than blocking them.

Outcomes of Zika infections for mice depended on whether certain viral antibodies were present in their systems….

How to grow toxin-free corn

transgenic corn infected with fungus
GRAIN TRAINING Genetically altered corn infected with Aspergillus fungus (shown) may be able to prevent the fungus from releasing carcinogenic toxins.

Corn genetically engineered to make ninjalike molecules can launch an attack on invading fungi, stopping the production of carcinogenic toxins.

These specialized RNA molecules lie in wait until they detect Aspergillus, a mold that can turn grains and beans into health hazards. Then the molecules pounce, stopping the mold from producing a key protein responsible for making aflatoxins, researchers report March 10 in Science Advances. With aflatoxins and other fungal toxins affecting up to 25 percent of crops worldwide, the finding could help boost global food safety, the researchers conclude.

“If there’s no protein, no toxin,” says study coauthor Monica Schmidt, a plant geneticist at the University of Arizona in Tucson.

Schmidt and colleagues used a technique called RNA interference, which takes advantage of a natural defense mechanism organisms use to protect against viruses. The researchers modified corn to make it produce short pieces of RNA that match up to sections of an RNA in the fungus made from the aflC gene. That gene encodes the first step of a biochemical pathway that the fungus uses to make the toxins. When the corn’s modified RNAs match up with those of the fungus, that triggers Aspergillus to chop up its own RNA, preventing a key protein, and thus the toxin, from being made.

Then, the team infected both…

For Ebola patients, a few signs mean treatment’s needed — stat

Ebola scorecard
EBOLA BY THE NUMBERS Looking at some key risk factors may help healthcare workers triage Ebola patients.

A new scorecard may help doctors quickly decide who needs additional care to survive Ebola.

In the latest outbreak, which raged in Guinea, Liberia and Sierra Leone from 2014 to 2016, 28,616 people were infected with virus and 11,310 people died. Doctors might be able to improve the odds of surviving by looking for a few warning signs in people who need to be treated more intensively, Mary-Anne Hartley, of the international charity GOAL Global and the University of Lausanne in Switzerland, and colleagues report February 2 in PLOS Neglected Tropical Diseases.

“It can be very difficult to avoid bias when choosing which Ebola patient should be given extra care when you have limited time and resources,” Hartley says. “Should it…

Rapid Ebola test to detect early infection in the works

Ebola virus
TEAM PLAYERS Researchers are designing antibody pairs that can help detect the Ebola virus (shown) sooner.

WASHINGTON — Diagnosing Ebola earlier is becoming almost as easy as taking a home pregnancy test.

Scientists are developing antibodies for a test that can sniff out the deadly virus more quickly and efficiently than current tests, researchers reported February 6 at the American Society for Microbiology Biothreats meeting.

Detecting Ebola’s genetic material in patients’ blood samples now takes a full day and requires access to a specialized laboratory. Simpler and speedier tests are available. They use antibodies — specialized proteins that latch onto and flag virus particles — and work somewhat like a pregnancy test. Within…