The World Health Organization has sought to boost research into a little-understood condition after declaring a surge of microcephaly cases in Latin America to be a "public health emergency of international concern".
There have been three previous such declarations in the UN agency's history: for polio, the H1N1 "swine" flu epidemic, and most recently, West Africa's Ebola outbreak.
‘Public health emergency of international concern is an event aimed to promote research into vaccines and diagnostic tools, and to standardize data collection to allow easy comparison between countries.’
Here are some of the key questions about the move.
- What is a "public health emergency of international concern"? -
An "extraordinary event" which could spread across borders and may require a coordinated international response, according to the WHO website. This means an outbreak that is "serious, sudden, unusual or unexpected", and could spread internationally.
- How is it decided? -
An emergency committee of disease experts advise the WHO director general, who makes the decision.
- What action does it unlock? -
This varies from case to case. This time, the aim was to aid research into the potential link between the rise in cases of microcephaly and other neurological disorders and an outbreak of the Zika virus, according to WHO official Monika Gehner.
It seeks to promote research into vaccines and diagnostic tools, and to standardize data collection to allow easy comparison between countries.
"This should also expedite political will and funding to rapidly scale up WHO?s and the international community?s initial, acute response to the current outbreaks," said Gehner.
- When has this happened before? -
June 11, 2009: The WHO raised the pandemic alert for H1N1, lifting it just over a year later. Uncovered in Mexico and the United States, the outbreak was not as deadly as first thought and vaccines were made within months. Swine flu killed about 18,500 people in 214 countries, but the world had been bracing for far worse, and governments were left with millions of unused vaccine doses. The strain is one of many types of flu which circulate every winter and kill thousands of people, mainly the weak and elderly.
May 5, 2014: The reemergence of polio, a crippling and potentially fatal disease that mainly affects children under the age of five. The disease had been all but eradicated due to a aggressive vaccine campaign, but remained endemic in Afghanistan, Nigeria and Pakistan, where vaccinators have been attacked by Islamists and tribal leaders. The emergency was declared after cases of cross-border transmission were detected -- from Pakistan to Afghanistan, Syria to Iraq and Cameroon to Equatorial Guinea. The virus spreads through contact with the stool of an infected person, or droplets from a sneeze or cough.
August 8, 2014: The WHO declared Ebola a "public health emergency of international concern" -- nearly a year after the first case was recorded in Guinea, becoming the worst outbreak since the virus was first identified in 1976. The outbreak infected almost 29,000 people and killed more than 11,300, mainly in Guinea, Liberia and Sierra Leone. The virus spreads through contact with the body fluids of infected people or animals.
Having admitted it was slow to respond to the Ebola outbreak, the WHO is under pressure to act quickly with Zika -- even though its suspected link to microcephaly, which can have many potential causes, has not yet been proven.