UPDATE 5-Zika link to birth defects could be proven within weeks -WHO
* Growing evidence of Zika role in neurological disorders
* U.S. NIH, India's Bharat Biotech ahead in vaccine work
* WHO urges pregnant women to consider deferring travel
* Brazil reports new microcephaly numbers
* Virus may linger in semen, British doctors say (Updates with new Brazilian figures for microcephaly cases in paragraphs 4-5)
By Stephanie Nebehay and Ben Hirschler
GENEVA/LONDON, Feb 12 (Reuters) - The suspected link between the Zika virus and two neurological disorders, the birth defect microcephaly and Guillain-Barre syndrome, could be confirmed within weeks, the World Health Organisation (WHO) said on Friday.
A sharp increase in microcephaly cases in Brazil has triggered a global health emergency over the mosquito-borne virus, which had previously been viewed as causing only a relatively mild illness, and spurred a race to develop a vaccine, medicines and better diagnostic tests.
The WHO said U.S. government scientists and an Indian biotechnology firm were the front-runners in the vaccine effort but said it would take at least 18 months to start large-scale clinical trials of potential preventative shots. The U.N. health agency also for the first time advised pregnant women to consider delaying travel to Zika-affected areas. Continuación...