Malaria immunity trigger found for multiple mosquito species

WASHINGTON, March 13 (Xinhua) -- Researchers at the Johns Hopkins Bloomberg School of Public Health have for the first time identified a molecular pathway that triggers an immune response inmultiple mosquito species capable of stopping the development of Plasmodium falciparum -- the parasite that causes malaria in humans.

By silencing the gene, caspar, the researchers were able to block the development of the malaria-causing parasite in Anophelesgambiae, A. stephensi and A. albimanus mosquitoes -- three mosquito species that spread malaria in Africa, Asia and the Americas. Their findings were published Friday in PLoS Pathogens.

According to the study, the transcription factor Rel 2 is a keymolecule involved in regulating several potent anti-Plasmodium defense genes that attack the parasite in the mosquito gut. Rel 2 is activated by the immune deficiency pathway which, in turn, is negatively regulated by the caspar gene; when caspar is silenced the Rel 2 is activated. The researchers found that silencing of the caspar gene through the manipulation of gene expression resulted in mosquitoes that successfully blocked the development of Plasmodium falciparum in the gut tissue. Silencing the gene known as cactus, which is part of another pathway called Toll, was shown to have similar effect in controlling the development of Plasmodium berghei, which causes malaria in rodents.

"When a mosquito is feeding on malaria-infected blood, the parasite will be recognized by the mosquito's immune system through receptors that then start the immune response. In the wild,this response is believed to occur too late to mount an efficient immune defense that would kill all parasites. At least a few Plasmodia will successfully develop inside the mosquito and enable transmission of malaria," explained George Dimopoulos, senior author of the study and associate professor at the Johns Hopkins Malaria Research Institute. "In the lab we activated this immune response in advance of infection, giving the mosquito a head start in defeating the invading parasite."

Dimopoulos and his colleagues also found that Rel 2 activation did not affect the survival and egg laying fitness of the modified mosquitoes.

"This came as a pleasant surprise since it essentially means that we one day could spread this trait in natural mosquito populations using genetic modification. Furthermore, by activating Rel 2, the genetically modified mosquitoes will attack the malariaparasite with several independent immune factors, and this will make it very difficult for Plasmodium to develop resistance," said Dimopoulos.

Malaria kills over 880,000 people worldwide each year, according to the World Health Organization. Malaria is especially a serious problem in Africa, where one in every five childhood deaths is due to the effects of the disease.

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U.S. health system to be burdened by aging baby boomers

LOS ANGELES, March 13 (Xinhua) -- More aging boomers are suffering from health problems, putting a heavy burden on the U.S. health system, a new study available here on Friday showed. Aging baby boomers, who are being hospitalized for heart attacks now than people their age were a generation ago, may swamp cardiac care wards across the nation, according to the study by researchers at the U.S. Centers for Disease Control and Prevention(CDC).

Baby boomers are not in good shape, even when compared with their counterparts 10 or 20 years ago, warned the study that was presented Thursday to the ongoing American Heart Association conference in Palm Harbor, Florida.

"The first baby boomers will begin turning 65 in a year-and-a-half, making the aging of this group an important public health issue," said Hylan Shoob, lead author of the study.

The 80 million baby boomers born between 1946 and 1964 now constitute a third of the U.S. population, raising the specter of more disease and more costs for the health-care system.

Born into relative affluence and peace after World War II, "this baby boomer population represents a huge volume of the population," said Dr. Carl J. Lavie, medical director of cardiac rehabilitation at the Ochsner Heart and Vascular Institute in New Orleans.

"In addition, unlike their parents, this population has largely enjoyed the 'good life,' with a lot of surpluses that have allowed them to avoid high amounts of physical work in their workplaces and large quantities of good-tasting, high-caloric, high-fat, high-processed, sugary foods."

The combination, Lavie said, has led to more "diabesity" -- or obesity plus diabetes, both strong risk factors for heart disease.

"There is no question that the medical costs that will be required to treat these man-made diseases will place a major burden on our already troubled health-care systems."

"I can confidently predict that the risk (for heart disease and related conditions) is increasing," Lavie said. "There was a study in the past year that showed that younger people are now having heart attacks and this is directly related with premature obesity."

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Low-salt intake reduces heart-related deaths

BEIJING, March 13 (Xinhuanet) -- A very modest reduction in salt intake by one gram a day could bring down the number of heart-related deaths by 200,000 over a decade,according to a new study.
The study by the American Heart Association also said there would be 250,000 fewer new cases of heart disease if Americans used reduced daily salt intake in the next ten years.Study researcher Kirsten Bibbins-Domingo, MD, PhD, an assistant professor of medicine and epidemiology at the University of California, San Francisco said, "A very modest decrease in the amount of salt -- hardly detectable in the taste of food -- can have dramatic health benefits for the U.S.”

“We found that everyone in the U.S. would benefit, but the benefits would be particularly great for African-Americans, who are more likely to have high blood pressure and whose blood pressure is more likely to be sensitive to salt," she said.

"In the last three decades salt consumption has jumped by 50 percent in the last three decades. Currently Americans consume 9 grams to 12 grams of salt a day, or 3,600 to 4,800 milligrams of sodium, with a majority coming from processed foods. Many health organizations recommend only 5 grams to 6 grams a day, which is 2,000 to 2,400 milligrams of sodium, which puts current consumption way over that limit," according to Bibbins-Domingo.

The researchers used a computer simulation called the Coronary Heart Disease Policy Model to estimate the impact of reducing salt by 0 grams to 6 grams on heart disease and deaths from heart disease for the study.

(Agencies)

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Depression increases risk for heart diseases

BEIJING, March. 11 (Xinhuanet) -- A relatively healthy woman with severe depression is at increased risk of heart disease than already sick woman, say U.S. researchers. Columbia University researchers Monday reported that depression may lead to heart disease in the first place.The scientists tracked 63,000 women from the long-running Nurses' Health Study between 1992 and 2004. None had signs of heart disease when the study began, but nearly 8 percent had evidence of serious depression.

The depressed women were more than twice as likely to experience sudden cardiac death - death typically caused by an irregular heartbeat, concluded the 12-year study, published Monday in the Journal of the American College of Cardiology. They also had a smaller increased risk of death from other forms of heart disease.

Sudden cardiac death seemed more closely linked with antidepressant use than with the depression symptoms the women reported.

That might simply mean that women who used antidepressants were, appropriately, the most seriously depressed, cautioned lead researcher Dr. William Whang. But he said the finding merited more research.

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Third EV71 infection case confirmed in Hong Kong

HONG KONG, March 11 (Xinhua) -- The Center for Health Protection (CHP) of the Hong Kong Department of Health announced Wednesday they are investigating the third confirmed EV71 infection case this year and urged the public to be vigilant against the disease. Further to the two confirmed Enterovirus-71 (EV71) cases reported earlier, A CHP spokesman said that the latest case involved a three-year-old girl who developed symptoms of Hand Foot Mouth Disease (HFMD) such as oral ulcers and rash over hands and feet on March 3.

Her stool specimen was tested positive for EV71. The girl sought medical treatment and did not require hospitalization. She is now in stable condition.

All the three confirmed cases of EV71 attended HKSPC Sze Wu Shu Min Nursery School. Thirteen other children in the same school had also developed HFMD symptoms since March 2. All of them sought medical treatment and are in stable condition.

The school has suspended classes starting March 11 until March 24 for thorough disinfection.

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