Stories about: viruses

Culture shock: Why poliovirus had to live before it could die

Children with polio are treated in an iron lung
Pictured here in the 1950s, polio patients breathe with the help of an iron lung at Boston Children’s Hospital.

Today, stories of polio may seem like echoes from far-away history to those born after 1979, the year that polio was eradicated in the U.S. Since then, it has been customary for children to receive four doses of the polio vaccine to protect them from ever contracting the terrifying disease also known as “infantile paralysis.”

Polio, however, still afflicts people in some areas of the world today. It causes muscle wasting and — in the most severe cases — can completely rob a person of his or her ability to move or breathe, resulting in death.

In the U.S., research efforts to create a polio vaccine lasted much of the 20th century. Although the virus was thriving and spreading among people, researchers repeatedly failed at getting poliovirus to survive in culture.

Then, one of the most crucial breaks in the fight against polio occurred in a Boston Children’s Hospital laboratory in 1949, during the heyday of polio outbreaks.

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How social media and a mumps outbreak teach us that vaccines build herd immunity

Mumps virus, pictured here, is usually preventable by vaccination.
The mumps virus, pictured here, has been spreading through Arkansas communities. Surprisingly, many affected people say they have received vaccinations to prevent it. Analyzing social media data helped a Boston Children’s Hospital team understand why so many people got sick.

Residents of Arkansas have been under siege by a viral threat that is typically preventable through vaccination. Since August 2016, more than 2,000 people have been stricken with mumps, an infection of the major salivary glands that causes uncomfortable facial swelling.

The disease is highly contagious but can usually be prevented by making sure that children (or adults) have had two doses of the measles-mumps-rubella (MMR) vaccine. But strangely, about 70 percent of people in Arkansas who got sick with mumps reported that they had received their two doses of the MMR vaccine.

So, members of the HealthMap lab, led by Chief Innovation Officer and director of the Computational Epidemiology Group at Boston Children’s Hospital, John Brownstein, PhD, asked, “Why did this outbreak take off?”

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Q&A: Mosquitos, Zika virus and microcephaly in Brazil

mosquito-Thriving

As you may have heard, Brazil is facing a startling outbreak of microcephaly, a rare condition in which a child is born with a head and brain that are much smaller than normal. Microcephaly is almost always associated with neurologic impairment and can be life-threatening.

The epidemic has been linked to an influx of the mosquito-borne virus Zika, first detected in Brazil last April. This past Friday, January 16, the Centers for Disease Control and Prevention issued travel warnings advising pregnant women to avoid visiting El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela and Puerto Rico. And over the weekend, the first U.S. case of microcephaly linked to Zika reportedly surfaced in Hawaii.

Why this virus, why now? And how can a virus affect someone’s head size? In this Q&A on our sister blog, Thriving, Ganeshwaran Mochida, MD, of Boston Children’s Brain Development and Genetics (BrDG) Clinic, who specializes in microcephaly, and Asim Ahmed, MD, an infectious disease specialist at Boston Children’s, offer their insights.

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Drawing a ring around antiviral immunity

Ubiquitin RIG-I innate antiviral immunity Sun Hur
Ubiquitin (pink ovals) doesn’t just tag proteins for recycling. It also may help keep our antiviral immune response in balance. (Image courtesy: Sun Hur)

If you follow cancer biology, then you’ve probably heard of ubiquitin before. Ubiquitin tags a cell’s damaged or used proteins and guides them to a cellular machine called the proteasome, which breaks them down and recycles their amino acids. Proteasome-blocking drugs like Velcade® that go after that recycling pathway in cancer cells have been very successful at treating two blood cancers—multiple myeloma and mantle cell lymphoma—and may hold promise for other cancers as well.

Less well known, however, is the fact that ubiquitin helps normal, healthy cells raise an alarm when viruses attack. Ubiquitin works with a protein called RIG-I, part of a complex signaling pathway that detects viral RNA and triggers an innate antiviral immune response.

Sun Hur, PhD, a structural biologist in Boston Children’s Hospital’s Program in Cellular and Molecular Medicine, has been studying RIG-I and other members of the innate cellular antiviral response for some time. And in a recent paper in Nature, she provided a structural rationale for how ubiquitin helps RIG-I do its job, and how that might help keep our immune system from getting out of hand.

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A picture is worth a thousand words for understating innate immunity

What you’re looking at is one of the key ways in which our immune system recognizes viruses before they cause trouble: by sensing the physical presence of their genes. This image by Sun Hur, PhD, will help us better understand how.

Our immune system has immense powers of observation. It needs to in order to fend off the millions of bacteria, viruses, fungi, you name it, that we get exposed to every day.

I’m not talking about antibodies and T cells—parts of the immune system’s adaptive arm, which is fine-tuned to recognize a specific virus or bacterium. Rather, I’m talking about pattern recognition proteins—biological sensors capable of recognizing features and structures that only bacteria or viruses have. These make up the immune system’s innate arm, which essentially primes the body to attack anything that looks remotely like it doesn’t belong.

For instance, our cells carry sensors that can detect double-stranded RNA (dsRNA), which certain kinds of viruses use to encode their genome—like the rotavirus, which causes severe diarrhea in infants and small children. Our genome, by contrast, is encoded in DNA, and the RNA we make is single-stranded; if there’s dsRNA present, it means there’s a virus around.

In a recent paper in Cell, Sun Hur, PhD, of the Program in Cellular and Molecular Medicine at Boston Children’s Hospital, and one of her postdoctoral fellows, Bin Wu, PhD, spotlight one of our dsRNA pattern recognizers, a protein called MDA5.

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