U.S. doctors say they have saved a seven-year-old girl who was close to dying from leukemia by pioneering the use of an unlikely ally: a modified form of the HIV virus.

After fighting her disease with chemotherapy for almost two years and suffering two relapses, the young girl "faced grim prospects," doctors at Children's Hospital of Philadelphia said.

Brazil, the world's top beef meat exporter, sought Tuesday to calm fears over the discovery of an atypical case of mad cow disease that led Japan to suspend its imports.

The case of bovine spongiform encephalopathy was detected in an animal that died in 2010 in the southern state of Parana.

The United Nations on Tuesday launched a $2.2 billion appeal for a campaign to halt a cholera epidemic in Haiti, widely blamed on U.N. peacekeepers, which has killed more than 7,750 people.

With the number of reported cases exceeding 620,000 since the epidemic started in October 2010, U.N. leader Ban Ki-moon acknowledged the "heavy toll" as he launched the 10-year initiative.

New Yorkers are living longers than Americans overall, and the margin is increasing, Mayor Michael Bloomberg said Tuesday as he praised his administration's health policies.

A New Yorker born in 2010 has a life expectancy of 80.9 years, 2.2 years longer than the national life expectancy of 78.7 years at the time.

U.S. doctors say they have saved a seven-year-old girl who was close to dying from leukemia with a pioneering use of an unlikely ally: a modified form of the HIV virus.

After fighting her disease with chemotherapy for almost two years and suffering two relapses, the young girl "faced grim prospects," doctors at Children's Hospital of Philadelphia said.

Most remaining laboratory stocks of a devastating cattle disease should be destroyed to ensure the eradicated virus is not back into nature, the World Organisation for Animal Health (OIE) said Monday.

"If someone laid their hands on an eradicated virus it could cause a global disaster," OIE chief Bernard Vallat said.

Indonesia has identified the bird flu virus that killed hundreds of thousands of ducks in recent weeks as a more virulent type which is new to the country, according to a letter seen Tuesday.

"We found a highly pathogenic avian influenza sub-type H5N1 (virus) with clade 2.3..." the agriculture ministry's veterinary chief Syukur Iwantoro said in the letter obtained by Agence France Presse.

On the streets of Ulan Bator a people renowned for their horse riding skills have to contend every day with ever more Hummers, Land Cruisers and Range Rovers.

Mongolia's vast open steppes and deserts stretch for hundreds upon hundreds of kilometers (miles), and it has the lowest population density of any country in the world.

Japanese food company Ito En on Tuesday issued a huge recall of Chinese-grown tea after some of it was found to contain illegal levels of pesticide residue.

The firm said it was recalling about 400,000 packages of Oolong tea after spot testing revealed pesticide residue levels above Japanese food safety limits.

A new study on Monday showed increased HIV infection rates among pregnant women living in areas with high migrant labor in South Africa, the country with one of the world's highest caseloads.

Infections in the eastern province of Mpumalanga jumped from 34.7 percent in 2009 to 36.7 percent.