Denmark and Switzerland on Wednesday joined a growing number of European countries to report Zika infections in tourists returning from Latin America, where the mosquito-borne virus has been blamed for a surge in birth defects.

"A Danish tourist who travelled to Central and South America was diagnosed on his return with the Zika virus," a hospital in eastern Denmark said in a statement late Tuesday.

Colombia issued an alert Tuesday over the Zika virus, which has already infected 13,800 people in the country, as it warned that the number is likely to uptick as the disease spreads.

The Ministry of Health advised mayors of towns below a certain elevation to "declare a green alert for public and private hospitals facing a possible increase in Zika cases."

Thai health authorities Tuesday said they had placed 33 people in quarantine after an Omani national seeking medical help in the kingdom tested positive for Middle East Respiratory Syndrome (MERS).

The unnamed man, 71, arrived in Thailand Friday with a fever that doctors in Oman could not treat, Thai officials said.

At least 50 people have died of swine flu in Russia since last month, according to Agence France Presse calculations based on data from regional health authorities, as the virus seems to gain ground in the country.

Health authorities in the southern region of Rostov told RIA Novosti state news agency on Monday that an additional two people had succumbed to the virus, bringing the region's swine flu death toll to eight.

Childhood obesity has reached alarming rates globally and has become an "exploding nightmare" in the developing world, including in Africa, where the number of obese children has nearly doubled since 1990, a WHO commission said Monday.

The authors of the report from the Commission on Ending Childhood Obesity stressed that the epidemic has historically not been treated as a grave public health issue and was regarded by some as a product of lifestyle choices by individuals and families. 

The Zika virus, a mosquito-borne disease suspected of causing serious birth defects, is expected to spread to all countries in the Americas except Canada and Chile, the World Health Organization said.

Zika has suspected but unproven links to microcephaly -- in which babies born to women infected during pregnancy have abnormally small heads.

Britain's finance minister and tech billionaire Bill Gates unveiled Monday a plan to spend billions to eradicate "the world's deadliest killer" malaria.

Chancellor George Osborne and Gates announced £3 billion ($4.28 billion, 4 billion euros) in funding over the next five years for research and to support efforts to eliminate the mosquito-borne disease, in a joint article in The Times.

Rio de Janeiro carnival goers celebrated the coming Olympics on Saturday and even turned fear of infection from Zika-carrying mosquitoes into an excuse to party.

Participants at one of the many street parties popping up ahead of the official carnival, which starts February 5, honored the city's hosting of the Summer Games in six months by dressing in ancient Greek garb.

Three people in New York have tested positive for the Zika virus, which has been blamed for a surge in babies born with abnormally small heads in Latin America, city officials said Friday.

All three had travelled to areas outside the United States where the mosquito-borne ailment is spreading rapidly, the New York State Department of Health said, without specifying where.

With the sting of a mosquito bite and a fever, many pregnant women may not know that they caught the Zika virus -- until it strikes their unborn child.

Now authorities in some Latin American countries are warning women to avoid getting pregnant, after thousands of cases of birth defects linked to the disease over recent months.