For the first time in the history of heart disease research, a certain type of treatment has proven more effective in women than in men, according to a U.S. study published Monday.

The research found that women saw a 70 percent reduction in heart failure compared to men who saw a 35 percent drop when using cardiac resynchronization therapy with defibrillator (CRT-D), indicating it works twice as well in women.

Scientists in Britain have successfully tested a vaccine which could work against all known flu strains, the Guardian newspaper reported Monday.

The new vaccine, developed by scientists at Oxford University, differs from traditional treatments by targeting proteins inside the flu virus rather than proteins on the flu's external coat.

Female genital mutilation has established itself in Western countries in recent years because of growing migration flows, the head of an international migration agency said on Friday.

"With the growth in migration in recent years, the phenomenon has unfortunately reached Europe (and) the United States," said William Lacy Swing, head of the International Organization for Migration (IOM).

A "tsunami of obesity" is unfurling across the world, resulting in a near-doubling of the numbers of dangerously overweight adults since 1980, doctors warned on Friday.

More than half a billion men and women -- nearly one in nine of all adults -- are clinically obese, according to research by a team from Imperial College London, Harvard and the World Health Organization (WHO).

Researchers have found a new mosquito in the west African nation of Burkina Faso that appears to be highly susceptible to malaria parasites and could help the disease spread, said a study Thursday.

The new subtype of Anopheles gambiae mosquitoes is believed to live mainly in the wild, whereas other species collected by scientists have been plucked from indoors where they are easier to find.

Nearly 3 million lives have been saved by HIV/AIDS treatment but scare resources are being misspent and stigma is still keeping the most vulnerable from seeking help, according to a new book by researchers commissioned by the U.N.

The failings are particularly worrying at a time when worldwide recession and donor fatigue are hurting spending on AIDS, the researchers say.

The cancer drug Avastin, also known as bevacizumab, is linked to a higher risk of death when combined with chemotherapy, said a study Tuesday in the Journal of the American Medical Association.

The drug has previously been found to raise the risk of blood clots in the legs and lungs by 33 percent, and in December the U.S. Food and Drug Administration said it was neither safe nor effective against breast cancer.

The U.S. government on Monday released new dietary guidelines urging all Americans to cut their daily salt intake by one-third and those over 50 to make more drastic reductions.

'"The 2010 Dietary Guidelines are being released at a time when the majority of adults and one in three children is overweight or obese," Agriculture Secretary Tom Vilsack said in a statement.

Children injected with the Pandemrix swine flu vaccine were nine times more likely to contract narcolepsy than those who were not vaccinated, a preliminary study by Finland's National Institute for Health and Welfare, THL, showed Tuesday.

"Currently, the most likely explanation is that the increase in narcolepsy is by joint effect of the vaccine and some other factor(s)," THL said.

A section of the brain involved in memory grew in size in older people who regularly took brisk walks for a year, researchers reported Monday.

The new study reinforces previous findings that aerobic exercise seems to reduce brain atrophy in early-stage Alzheimer's patients, and that walking leads to slight improvement on mental tests among older people with memory problems.