Semen appears to interfere with microbicide gels to prevent HIV, possibly explaining why they work in the lab but not in real-life situations, scientists said Wednesday.

Protein fragments found in semen hamper the work of microbicides applied to the vagina, said the report in the journal Science Translational Medicine.

Think the reason some people live beyond the age of 100 is because of their genes? Think again.

U.S. scientists said Wednesday they've found no genetic secrets shared between a group of 17 supercentenarians, or those who have lived beyond 110.

Scientists have discovered gene mutations that give people naturally lower cholesterol levels and cut their risk of heart disease in half.

That discovery may have a big implication: A blockbuster drug that mimics these mutations has long been sold without evidence that it cuts the chance of heart disease. Results of a large study that looked for that evidence will be revealed on Monday.

Health workers on the frontline of west Africa's Ebola crisis pleaded with G20 leaders on Thursday for more resources, describing horrific working conditions as they attempt to contain the deadly outbreak.

Liberian nurse Laurene Wisseh said health workers had been reduced to using plastic bags in an attempt to cover themselves due to a lack of rubber gloves and protective suits.

Indian police announced Thursday they had detained the doctor behind botched mass sterilization surgeries that left 13 women dead, as campaigners called for urgent reform of the government's family planning program.

R.K Gupta was seized for questioning amid mounting anger over the tragedy in central Chhattisgarh state where women were paid to undergo a procedure that also left dozens in hospital, senior police officers said.

Furious protesters took to the streets in central India on Wednesday, smashing up cars and demanding the chief minister resign, as the death toll from a mass government-run sterilization program rose to 13.

Another 14 women are seriously ill in Chhattisgarh state after the surgery, which women are paid 1,400 rupees ($23) to have under a government scheme to reduce population growth.

People with an algae virus in their throats had more difficulty completing a mental exercise than healthy people, and more research is needed to understand why, US scientists say.

A study in the Proceedings of the National Academy of Sciences showed that the virus was present in about half of 92 human subjects studied, and those who had it performed worse on certain basic tasks.

A second person from Mali has died from Ebola, just as hardest-hit Liberia hailed a dramatic drop in infections and the last-known sufferer in the United States was declared cured on Tuesday.

The death of a nurse who had treated an Ebola patient from neighboring Guinea came as a blow to authorities in Mali, just as they were beginning to lift quarantine restrictions on more than 100 people exposed to the country's first victim of the virus.

A group of more than 300 prominent doctors, religious leaders and ethicists on Wednesday urged President Barack Obama to change the current system for organ donation, saying too few people get life-saving transplants.

In an open letter to the Obama administration, the group called for the government to start researching ways to make organ donation more appealing to the general public, in order to end a chronic shortage of organs that is getting worse each year.

Health Minister Wael Abu Faour raised the alarm on Tuesday over food safety in the country, warning that “the food that the Lebanese are eating is full of diseases.”

“A large number of foodstuffs firms are operating without licenses and without meeting the proper health conditions,” the minister announced at a press conference.