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Public release date: 3-Sep-2013 [ | E-mail | Share ]

Contact: Gina Bericchia Gina.Bericchia@NationwideChildrens.org 614-355-0495 Nationwide Children's Hospital

The hepatitis C virus hijacks the body's immune system, leaving T cells unable to function. A new study in animal models suggests that blocking a protein that helps the virus thrive could restore immune function, allowing the body to fight infection. The work, led by teams at The Research Institute at Nationwide Children's Hospital and Emory University, was published online Aug. 26 in the Proceedings of the National Academy of Sciences.

Previous studies show that antibody treatments that inhibit the protein, called programmed cell death 1 (PD-1), can shrink tumors in humans. This new work suggests that anti-PD-1 antibodies might be equally effective in treating hepatitis C and other persistent human viral infections, says Christopher Walker, PhD, a senior author on the study and director of the Center for Vaccines and Immunity at Nationwide Children's.

PD-1 is a regulatory protein that helps keep the immune system in check. Normally, PD-1 acts as a switch to turn off immune responses when an infection is under control. Some viruses such as HCV manipulate the PD-1 off switch so that T cells lose their ability to fight the infection, a condition scientists call "T-cell exhaustion." The result is life-long persistence of HCV in the liver, which increases the risk of cirrhosis, liver cancer and other serious diseases.

The researchers treated animal models with persistent HCV infection with repeated doses of an anti-PD-1 antibody. Although the responses were mixed, one animal did show a dramatic increase in HCV-specific T cell activity in the liver and a sharp decrease in viral load. A closer examination of the data found that the animal had more HCV-specific T cells in the liver before therapy, which could mean that therapeutic success hinges on the amount of HCV-specific T cells in the liver before treatment.

"Our supposition is that these T cells remained in the liver for years at levels too low to detect before treatment, and had the capacity to expand after treatment," Dr. Walker says. "The animal that responded to therapy had a broad, strong response during the early acute phase of infection. This suggests that one predictor of response to an anti-PD-1 antibody is the quality of the T-cell response when the initial infection occurs."

Another interesting finding was the impact of the antibody on CD4+ T cells, helper cells that promote the development of killer T cells called CD8+, which target and destroy virus-infected liver cells. One hallmark of chronic HCV is the collapse of CD4+ cells.

"We have no information on whether PD-1 signaling is a primary mechanism for silencing helper cells, so recovery of the CD4+ helper cell response in this instance provides some indirect evidence that PD-1 signaling also impairs the helper cells," Dr. Walker says.

Because much of the research focus on HCV is now directed at developing antiviral therapies, it's likely that these new findings may have a greater impact on treatments for chronic hepatitis B (HBV), rather than the virus studied in this experiment, Dr. Walker says.

Excerpt from:
Study examines ways to restore immunity to chronic hepatitis C infection

NEW JERSEY (CNN) --

A measles-like virus is being linked to the deaths of dozens of dolphins along the East Coast and scientists appear unable to stop it.

Scientists prepared to examine a bottlenose dolphin among the latest likely victims of morbillivirus.

Bottlenose dolphins, known for their graceful moves and high intelligence, are under attack by an invisible enemy that doesn't discriminate.

"There's no pattern really to either geographic or age or sex. It really seems to be an equal opportunity killer," said Lawrence Hajna, with the New Jersey Department of Environmental Protection.

New Jersey Governor Chris Christie is paying a state lab to speed up necropsies and stepping up air and sea patrols.

Off the Jersey Shore, it would be very hard to see a dolphin that is dead or dying because they lie so low in the water.

If the state fish and wildlife patrol does spot one, they will tow it to shore for testing.

Through August, nearly 300 dolphins have died from New York to North Carolina. The highest numbers are in Virginia and New Jersey.

In 1987 and 1988, NOAA scientists suspected the same virus wiped out 740 bottlenose dolphins along the East Coast, about half the population.

Link:
New Jersey working to solve mystery of dolphin deaths

A virus similar to measles in humans has tentatively been identified as the cause of a massive dolphin die-off along mid-Atlantic states.

The possible killer is morbillivirus, which is common in some marine mammals, said officials from the National Oceanic and Atmospheric Administration.

If the virus is indeed causing the deaths, its unclear why it has become so lethal this summer. Factors such as some other germ or a natural toxin could be contributing to the deaths, officials said.

Since July 1, 357 dolphins have turned up dead or dying from New York to North Carolina. Thats more than nine times the normal number for that period in that region.

More than two dozen of the dead animals have tested positive for the morbillivirus or are suspected of having had the virus.

An investigation is continuing, and it could take months.

Original post:
Measles-like virus seen as cause of dolphin deaths

By BROCK VERGAKIS Associated Press

NORFOLK, Va. (AP) - Federal officials identified a virus Tuesday as the likely reason hundreds of bottlenose dolphins died along the East Coast, but they say there's little they can do to stop the deaths.

More than 330 dolphins have been stranded between New York and North Carolina since July 1, with nearly all of them dead by the time they wash up on shore, the National Oceanic and Atmospheric Administration said.

That's more than nine times the historical average for dolphin strandings in the region during July and August.

"Along the Atlantic seaboard, this is extraordinary," Teri Rowles, NOAA Fisheries Marine Mammal Health and Stranding Response Program coordinator, said in a conference call with reporters.

Earlier this month, NOAA declared an unusual mortality event so it could provide additional resources to study what was behind the rapid increase in deaths - more than half of which have occurred in Virginia. At the time, they suspected the cetacean morbillivirus was causing the deaths, just as it did during the last major dolphin die-off. In 1987 and 1988, the virus was blamed for causing 740 dolphin deaths between New Jersey and Florida.

Although research will continue, NOAA said it has collected enough evidence to declare the virus as the "tentative cause" in the most recent string of deaths as well. Morbillivirus is found in a broad range of mammals, and dolphins with it typically experience symptoms such as skin lesions, brain infections and pneumonia. The virus is usually spread through inhalation of respiratory particles or direct contact between animals, although officials said there's no risk of humans catching it. Bottlenose dolphins are typically found in groups of two to 15.

"At this point there isn't anything we can do to stop the virus," Rowles said. "We don't have a vaccine that is developed that could be easily deployed in a wild population of bottlenose dolphins or subpopulations."

Officials at the Virginia Aquarium & Marine Science Center said many of the dolphins washing up on the state's beaches are badly decomposed. State and federal officials say there are untold numbers of other dolphins that have also died and haven't washed ashore, likely making the total death count much higher.

"We've definitely gotten reports of floating carcasses that we were not able to recover - and there are plenty of those," said Margaret Lynott, the aquarium's stranding coordinator.

Continued here:
NOAA: Virus likely causing dolphin deaths

Getty Images/Tom Ervin

Mosquitoes are responsible for millions of deaths each year through the spread of diseases like malaria,dengue fever, and West Nile virus.

Malaria, a flu-like illness caused by parasites that only mosquitoes carry, infected 219 million people in 2010 and killed 660,000, according to theWorld Health Organization.

By comparison, sharks, snakes, and bears combined only kill about 100,100 people every year mostly because of the snakes.

According to American Mosquito Control Association technical advisor Joe Conlon, malaria kills the equivalent of nine Boeing 747s full of children every year.

"Now think about what the headlines would read if we had nine airlines crashing in the jungle every day and killing all the children," Conlontold Business Insider.

Fortunately, malaria is treatable. But many other mosquito-borne illnesses some that haven't yet reached the United States don't have proven antidotes.

"The nastiest diseases on the planet are only a 7-hour plane ride away," Conlon said.

Below are some of the worst mosquito-borne illnesses. Currently, none of them have any treatments or vaccines.

Continue reading here:
The Most Dangerous Animal On Earth Can Fit On Your Fingertip