US disease detectives have turned on a full outbreak mode over the Zika virus. They have gathered a team of hundreds of experts in an attempt to better understand its impact as its spreading in the Americas.

While speaking to Reuters, agency officials said that the US Centers for Disease Control and Prevention has devoted an emergency operations center on duty around the clock to deal with Zika, a mosquito-borne virus associated with severe birth defects in thousands of babies in Brazil, on Sunday.

Such command centers were set up by the CDC to deal with the Ebola outbreak in 2014 and the Haiti cholera epidemic that started in 2010. However, this time, the team consists of
many more experts on pregnancy given the strange impact of the mosquito-spread-virus.

In an interview, Tracee Treadwell, who is helping to lead the CDC's Zika response, said, “We always involve OB-GYNS and pediatricians. In this response, this team is actually much larger and is in many ways the focal point of the activities”.

On Thursday, the World Health Organization said that it would be considering the coming seven days to decide whether to declare Zika an international health emergency or not. It said that the as many as 4 million people are expected to get affected by the virus as the virus is spreading in Latin America and the Caribbean to North America in the approaching months.

Since the beginning of November last year, the US public health agency has been functioning with the Brazilian Ministry of Health and the WHO to understand the sudden rise in cases of microcephaly, which is a birth defect identified by tiny head size that is apparently associated with Zika. Brazil said that nearly 3,700 cases of microcephaly have been studies this week for signs of Zika.