A potent new painkiller hit the U.S. market this week, despite warnings from top experts that the drug may deliver a deadly setback in America's battle with opioid addiction.

Zohydro ER can contain 10 times the amount of hydrocodone as the most popular prescription painkiller, Vicodin, and is easily crushable so it could be snorted, bearing none of the recent safeguards added to pills like OxyContin (oxycodone).

Authorities in southern Pakistan on Friday ordered a probe into the death of 41 children who reportedly died of pneumonia and malnutrition in a stretch of the Thar desert.

Officials were alarmed by media reports from Mithi, one of the least developed and most remote districts in southern Sindh province, suggesting that more than 100 people had died because of famine and malnutrition.

E-cigarette use among U.S. youths doubled in just one year, and those who tried the unregulated devices were more likely to smoke conventional cigarettes as well, a study said Thursday.

Commonly sold at convenience stores and gas stations, e-cigarettes are battery powered gadgets that deliver nicotine through a vapor that may be fruit or candy-flavored.

Malaria is on the march to higher elevations as temperatures warm due to climate change, a trend that could increase the number of people sickened by the disease, researchers said Thursday.

The study in the U.S. journal Science was based on records from highland regions of Ethiopia and Colombia, raising concern about a potential spike in cases of the the mosquito-borne disease, which killed some 627,000 people in 2012.

A British woman won a High Court battle on Thursday to preserve her late husband's sperm for at least another decade so that she can bear his children.

Beth Warren, 28, had challenged a ruling by fertility regulators that the sperm stored by her husband Warren Brewer before his death in 2012 should be destroyed next year.

Saudi health authorities said Thursday a man has died from the MERS coronavirus, bringing the death toll from the respiratory disease in the worst-hit country to 62.

The 55-year-old national, who died in Riyadh from the Middle East Respiratory Syndrome, was suffering from "chronic illness," the health ministry website said.

Deaths from Alzheimer's disease are under-reported in the United States and the most common form of dementia may be taking as many lives as heart disease or cancer, said a study Wednesday.

Alzheimer's disease currently ranks sixth among causes of death in the United States, according to the Centers for Disease Control and Prevention. Heart disease is first, and cancer second.

A new gene therapy approach that engineers a person's T cells so that they become resistant to the human immunodeficiency virus has shown early signs of success, researchers said Wednesday.

Also called gene editing, the process acts like molecular scissors to snip off an entry portal for HIV so the virus cannot enter these key immune cells.

A baby treated for HIV within hours of birth is free of the virus nearly a year later, in the second case that has raised hopes about early treatment, doctors said Wednesday.

The approach mirrored that taken for a Mississippi baby, who has been off treatment for 21 months and still has no detectable virus in her system.

U.S. lawmakers who support steady relaxation of state laws on marijuana sparred with Obama administration officials who continue to label the drug in the same high-danger category as heroin.

The Drug Enforcement Administration's chief deputy said marijuana deserved to remain listed as a "Schedule 1" narcotic -- a list which includes severely addictive drugs including LSD and ecstasy -- even though he could not identify a single fatal overdose attributable to cannabis last year.