Dilma Rousseff tries to ease wary nation amid Zika spread

Said that no resources would be spared in the fight against Zika

Brazil's president has promised a wary nation that no resources would be spared in the fight against Zika, addressing Congress a day after the World Health Organization declared the mosquito-borne virus an international emergency.

A spike in the number of Brazilian babies born with brain defects and abnormally small heads has been linked to their mother's contracting the virus during pregnancy.

Several thousand cases of microcephaly have been reported in Brazil since October, although researchers have so far not proven a definitive link to the virus. No vaccine or cure exists for Zika.

"We should all be worried about microcephaly," Brazilian President Dilma Rouseff said, calling on Congress to partner with her in the fight against the virus.

Before the Zika virus started grabbing international attention, Brazil was already struggling to prepare for this summer's Olympic Games, set to begin in August in Rio de Janeiro. Constructions projects have started and stopped, and questions have been raised about the safety of athletes after an Associated Press investigation found alarmingly high levels of bacteria and viruses in water bodies where competitions will take place.

Worry over the Zika virus was the main topic yesterday during an Olympic committee news conference. Instead of updates on venue construction or ticket sales, health officials attempted to ease fears that the virus would wreak havoc.

"Athletes are not at risk," declared Dr Joao Grangeiro, the organisers' medical director, promising the mosquito count will fall in August during Brazil's winter. "We will have Summer Games, but for us it's winter time."

Daniel Soranz, Rio's health secretary, told reporters the mosquitoes around the Olympic Park were not primarily the type that transmits Zika.

Still, Rio organising committee spokesman Mario Andrada was vague when asked how organisers were going to fund mosquito eradication efforts as they slash in other areas.

"In this case the most important thing to do is obviously to care for those who have been infected and to prevent new infections, and not to worry if we have budget or not," Andrada said.