El Nino linked to Zika outbreak

The Zika outbreak sweeping through the Americas was triggered by the El Nino phenomenon and global warming, a new study has concluded.

Meanwhile Colombia on Friday said three people have died after contracting the Zika virus and developing a rare nerve disorder.

Health Minister Alejandro Gaviria said there was a "causal connection" between Zika, the Guillain-Barre disorder and the three deaths.

Earlier, Brazilian scientists said they had detected for the first time active samples of Zika in urine and saliva. However, it is not clear whether the virus can be transmitted through bodily fluids.

Zika, a mosquito-borne disease, has been linked to cases of babies born in Brazil with microcephaly - underdeveloped brains. Brazil has seen 4,783 suspected cases of babies born with small brains.

However, it has not yet been proved that Zika causes either microcephaly or Guillain-Barre.

"We have confirmed and attributed three deaths to Zika," said the head of Colombia's National Health Institute, Martha Lucia Ospina.

"In this case, the three deaths were preceded by Guillain-Barre syndrome."

Guillain-Barre is a rare disorder in which the body's immune system attacks part of the nervous system. It isn't normally fatal.

Ospina said another six deaths were being investigated for possible links to Zika.

Meanwhile, scientists said the exceptionally hot and dry winter and spring recently experienced in northeast of the country created the perfect conditions for the Zika-carrying Aedes mosquito to thrive.

While the high temperatures recorded in the region encouraged the growth of the mosquito population, the drought that ensued also played a role, they added.

In times of drought people are compelled to store reservoirs of water in containers near their homes, thus creating a convenient habitat for the mosquito, experts at the University of Haifa and the European Center for Disease Prevention and Control (ECDC), said.

The World Health Organization declared the current outbreak, which erupted last summer, a public health emergency on Monday, over fears the virus is linked to a serious birth defect.

In Brazil more than 4,000 cases of microcephaly - where a baby is born with an unusually small head, and often brain damage - are feared to be linked to the virus.

Some experts have attributed the outbreak to heavy rains in parts of Latin and Central America - another result of El Nino.

But Dr Paz and his colleagues say their findings suggest the opposite El Nino effect is to blame.

He said the relevant factor was not the heavy rain, which actually fell in areas removed from the outbreak, but rather the intense spell of hot weather in northeast Brazil.

According to the findings, based on data from the US agency the National Oceanic and Atmospheric Administration (NOAA), the latter half of 2015 - the winter and spring season in the southern hemisphere - saw the highest temperatures since records began, combined with severe drought.

Dr Paz noted the Zika outbreak erupted in these areas in the weeks that followed.

He said it is known that high temperatures - up to a limit - encourage an upsurge in the growth rates of the Aedes mosquito, which carries the Zika virus.

Meanwhile, the US has advised men to abstain from sex or use condoms after visiting affected countries, if their partner is pregnant.

The US Centers for Disease Control believes a recent case of Zika was spread through sex. Meanwhile, the governor of Puerto Rico has declared a public health emergency over Zika. The US territory has 22 confirmed cases.