Joint teams from the U.S. and Brazil are set to begin their search for mothers and infants for a study that determines if the Zika virus is linked to microcephaly, a condition that causes babies to be born with unusually small heads and brains. The Zika virus has spread in regions like South and Central America, Mexico and the Caribbean and when it affects pregnant women, the child is said to be born with severe cranial deformity that can be fatal in some cases.

Although Brazil's Health Minister Marcelo Castro claimed he is “absolutely sure” that the Zika virus is the reason behind an increase in cases of microcephaly, a specific scientific study has not yet been published to prove the link between the two, according to the Associated Press (AP). The latest study is being conducted jointly by Brazil’s health ministry and the U.S. Centers for Disease Control and Prevention and plans to find answers by comparing the babies affected by microcephaly and their mothers, to infants without the condition.

Erin Staples, a Colorado-based epidemiologist who heads the CDC contingent in the northeastern Brazilian state of Paraiba, said, according to AP, that the popular “understanding is that Zika virus (behind the microcephaly spike). How much of that is Zika virus is really one of the important goals of this study.”

She also said: “I do believe there is something occurring that is unique and knowable, but we really need to understand better, mostly so we can prevent this from happening to other generations,” adding: “If we can provide some basic information or show a potential association, that will allow us another avenue of how do we prevent this and what do we need to do next.”

Eight joint teams of American and Brazilian health workers will conduct the study in the Paraiba state, and plan to recruit at least 130 babies with microcephaly and their mothers for it. For comparison, they plan to recruit up to three times the mothers and their babies born in the area without the condition at about the same time. The recruitment process is expected to be completed in nearly five weeks but the AP report added that the time table will depend on how receptive the subjects are.

The researchers will collect blood samples from the babies and the mothers to be examined in labs in Brazil and the U.S. to test for Zika and dengue, both of which are transmitted by the same Aedes aegypti mosquito. The tests will determine if the mothers, whose babies are affected by microcephaly, are also affected by Zika. If yes, then at what stage of the pregnancy was the child affected.

A training session was conducted Monday in the state’s capital Joao Pessoa, where the teams discussed how they will approach families and the ethical concerns regarding it. The teams reportedly faced a language barrier in the Portuguese-speaking country.

“There is a lot of anxiety out there, and people really want to understand what's going on,” Priscila Leite, who leads the Health Ministry's contingent, said, according to AP, adding that she expects the recruitment to be higher due to the increased concerns about Zika in Brazil.

Since October, 56 cases of microcephaly have been confirmed in Paraiba alone, while 423 suspected cases are being investigated, AP reported. Before this, Brazil used to have a national average of about 150 cases. However, critics point out that an increase in microcephaly seems to be restricted to Brazil, while the Zika virus is being reported in neighboring countries like Colombia. They also say that the cases of microcephaly could have been under-reported for years because the local health officials were not needed to inform the Health ministry about such cases. However, Staples disagreed with critics.

“I come from a pediatric infectious disease background and am also a mom, so looking at these children clinically, they were distinct from other congenital infections I've seen,” Staples, who spent time in Brazil recently as part of a World Health Organization mission, said, according to AP, adding: “The scope and the size of the children who were presenting (microcephaly) at the same time, it really made it apparent to me that there was something unique happening in this situation.”

Zika virus is considered to be a mild illness and the Washington State Department of Health says that 80 percent of those affected by the Zika virus do not show any symptoms. However, the few, who show symptoms, suffer from fever, rash, joint pains and red eyes, which can last up to a week.