The World Health Organization on Wednesday released its initial response plan to the Zika virus outbreak, launching a funding appeal for the $56 million (50 million euros) operation. 

The unprecedented outbreak of the virus, first discovered in Uganda in 1947, has become a global concern, with Zika now strongly suspected of causing two serious neurological disorders, microcephaly and Guillain-Barre syndrome. 

Women who ate more than the recommended three servings of fish per week while pregnant gave birth to children at a higher risk of obesity than expectant moms who ate less, a study said Monday.

The study in the Journal of the American Medical Association (JAMA) Pediatrics found an association between higher fish intake and the likelihood of rapid growth and obesity in offspring, but researchers cautioned that they had not proven any cause and effect.

Organic milk and meat contain about 50 percent more beneficial omega-3 fatty acids than conventionally produced equivalents, according to a pair of large-scale studies published Tuesday.

Previous research has linked omega-3 with reduced rates of cardiovascular disease, improved neurological development, and better immune function.

Russia's health minister said Monday that an Ebola vaccine developed by the country over the last 15 months had shown encouraging results and would undergo further testing in West Africa. 

"Phases one and two of testing were managed in Russia with volunteers and showed that the vaccine was very effective," health minister Veronika Skovortsova told reporters in Geneva.

A yellow fever outbreak in Angola has killed 51 people out of 241 suspected cases, in the first epidemic of the disease to hit the country in 30 years, official statistics showed Monday.

The center of the outbreak is the capital Luanda's eastern suburb of Viana where 29 deaths and 92 cases have been reported over the last six weeks, national director of public health Adelaide de Carvalho said.

Men are twice as likely as women to get cancer of the mouth and throat linked to the human papillomavirus, or HPV, one of the most common sexually transmitted infections, researchers say.

For men, the risk of HPV-driven cancers of the head and neck rise along with the number of oral sex partners, researchers said Friday at the American Association for the Advancement of Science (AAAS) annual meeting in the U.S. capital. 

The Zika virus, linked to a surge in infants born with abnormally small heads, is likely to spread this year to Brazil's densely populated cities where it has barely surfaced, a top health official told Agence France Presse.

Zika has struck hard in hot and humid southeastern and central Brazil, but largely spared bigger cities like Sao Paulo or Rio de Janeiro, said Claudio Maierovitch, head of the communicable diseases surveillance department at the Ministry of Health.

American scientists traveled to Colombia to investigate the mosquito-borne Zika virus and help find a vaccine for the disease that is plaguing Latin America, the U.S. ambassador to Bogota said Friday.

The U.S. experts are studying "the possibility of a vaccine" alongside specialists from the Colombian Health Ministry, Ambassador Kevin Whitaker said from Bogota, capital of the second worst-hit nation.

Brazilian laboratories say delays in providing kits to test for mosquito-borne dengue have forced them to store patient blood samples until the kits are delivered.

In Sao Paulo, the state government's Adolfo Lutz Institute says in a statement it has not received any of the 2,500 kits it requested from the Health Ministry five months ago.

Dementia rates in the United States may be falling, an influential study released Wednesday said, offering hope that some cases of the disease might be delayed or even preventable.

The findings, published in the New England Journal of Medicine, appeared to defy fears over an explosion in the disease among the country's aging population.