Fifty people have been placed in quarantine in northern Sierra Leone after the death of a middle-aged woman from the Ebola virus, medical officials said Tuesday,  in a setback for the country's bid to gain Ebola-free status.

"We are conducting an epidemiological investigation to trace the extent of the transmission" as the woman ho died was sick for 5-10 days without the authorities being alerted, Ibrahim Sesay of the  National Ebola Response Centre (NERC) told a local radio station.

Three out of four Americans' hearts are older than their chronological age, raising the risk of heart disease, stroke and premature death, officials said Tuesday.

An online tool at www.cdc.gov/heartdisease/heartage.htm can help people determine how old their heart is, based on factors like weight, smoking, diabetes and high blood pressure, said the U.S. Centers for Disease Control and Prevention.

One more reason to watch the waistline: New research says people's weight in middle age may influence not just whether they go on to develop Alzheimer's disease, but when.

Obesity in midlife has long been suspected of increasing the risk of Alzheimer's. Researchers at the National Institutes of Health took a closer look and reported Tuesday that being overweight or obese at age 50 may affect the age, years later, when Alzheimer's strikes. Among those who eventually got sick, more midlife pounds meant an earlier onset of disease.

Casey Reyes struggled for a way to explain the "sci-fi" surgery doctors were proposing to save her 87-year-old grandfather's badly burned hand.

"They're gonna put your hand inside your stomach, kind of like a hoodie," she told him.

Britain on Tuesday became the first country to implement a vaccination program for all newborn babies against meningitis B, which is fatal in one in 10 cases.

Campaigners hope the vaccine, which will be given to babies at two, four and 12 months old, will prevent up to 4,000 cases by 2025.

Pope Francis on Tuesday called on priests to pardon women who have abortions, and the doctors who perform them, during the upcoming Jubilee year -- overruling hardline traditionalists within the Catholic Church.

"I have decided, notwithstanding anything to the contrary, to concede to all priests for the Jubilee Year the discretion to absolve of the sin of abortion those who have procured it and who, with contrite heart, seek forgiveness for it," he said.

President Muhammadu Buhari wants Nigeria to continue efforts to win certification as a polio-free country by 2017 after recording its last case in July last year, his office said Tuesday.

"I want to reaffirm the commitment of the federal government to sustain the gains and momentum to enable Nigeria to achieve certification by 2017," Buhari told a meeting of state governors in Abuja late Monday.

Being overweight at the age of 50 may speed the onset of Alzheimer's disease in old age, said a study Tuesday in the journal Molecular Psychiatry.

A statistical comparison showed that every extra unit in body mass index (BMI, a height-to-weight ratio) in middle age corresponded to earlier onset of Alzheimer's by about 6.5 months -- what the authors termed a "robust" correlation.

The number of cigarette smokers in the United States has dropped to about 15 percent of the population, its lowest point in decades, U.S. health authorities said Tuesday.

"The prevalence of current cigarette smoking among U.S. adults declined from 24.7 percent in 1997 to 15.2 percent in January–March 2015," said the report by the Centers for Disease Control and Prevention's National Center for Health Statistics.

A woman who died last week in northern Sierra Leone tested positive for Ebola, the National Ebola Response Center (NERC) said Monday, in a setback for the country's bid to gain Ebola-free status.

There had been celebratory scenes last week when the country's last known Ebola patient was released from hospital in the central city of Makeni after being cured of the virus, raising hopes the west African nation may finally have beaten the devastating epidemic.