Microcephaly cases linked to Zika virus rise in Brazil

Fewer than 150 such cases were seen in all of 2014.

The Health Ministry has said the surge is linked to Zika virus, amosquito-borne disease similar to dengue.

• New mosquito-borne virus in Brazil linked to thousands of birth defects, CBC Radio's The Current

Oliviera spoke at a press conference Wednesday.

Claudio Maierovitch, who heads the ministry'stransmissible disease department, said officials are learning
quickly about microcephaly and Zika, but much still remains unknown.

Canadian and U.S. health officials haveissued alerts advising pregnant women and those considering becoming pregnant to discuss their travel plans with their health care provider to assess their risk and to consider postponing travel to areas where the Zika virus is circulating.

Zika virus, first detected in Africa in the 1940's, wasunknown in the Americas until last year when it appeared innortheastern Brazil. The virus has quickly spread through LatinAmerica.

With Brazil's rainy season underway, authorities arescrambling to fight the seasonal surge in mosquito populations.

Two weeks ahead of Carnival celebrations, a highlight ofBrazil's tourism calendar, officials want to stem internationalconcern about the virus.

One potential strategy to curb cases involves agenetically modified mosquito tohelpreduce the proliferation of mosquitoes spreading Zikaand other dangerous viruses in Brazil, its developers say.

The self-limiting strain of the Aedes aegypti mosquito wasdeveloped by Oxitec, the U.K.-subsidiary of U.S. synthetic
biology company Intrexon.

"If we can control this mosquito properly, then we can control and reduce the viruses that it spreads," said OxitecCEO Hadyn Parry.

Modified male mosquitoes arereleased so their offspring will die before being able to reproduce. The male mosquitoes don't bite or spread disease.

PopulationsofAedesaegypti were reduced by about 90 per cent.

"You can't get near that level of control with chemicals. The reason it's effective is reallywe're using biology, we're using a male to go and find a mate and male mosquitoes are very good at finding female mosquitoes," Parry said.

In Brazil'sPiracicaba neighbourhood, authorities reported a drop in dengue cases spread by the same mosquito species after25 million transgenicinsects were released between April and November.

Maierovitch cautioned the sterile mosquitosolution is not yet ready to beused on a large scale.

For the moment, the best way to prevent transmission is by doingaway with stagnant water where the insects breed, using repellentand wearing covering clothing, he said.