The disease transmitted by mosquitoes named Zika have swept its way across Latin America and the Caribbean infecting 650,000 people and ten thousands of expectant mothers who are the most at risk. The disease, which was first observed in Brazil, has caused fetal deformities and shrunken brains in born infants.

Zika was declared a global health problem since almost a year ago, but scientists are confused why the fetal deformities were not manifested in most of the newer infections observed.

UN records have shown that the more than 75 percent of 2,175 babies born with undersized brains can be traced to northeastern Brazil. Scientists conclude that there must be an underlying cause of this phenomenon and they are giving much attention to northeastern Brazil to find the reason why shrunken head cases are mostly confined in that particular area.

One theory is that there are underlying causes such as the incidence of Dengue or Chikungunya which are also viruses borne by the same mosquitoes. Another possibility is that there may be hereditary, environmental, or immunity factors are combining with Zika virus to make it more infectious to pregnant women.

Fatima Marinho, Director of Brazil's Ministry of Health, Non-communicable Disease Department does not believe that Zika virus alone can cause the deformity. She has observed that in the other contaminated parts of the country where the virus was spreading, the increase in deformity was not significant.

Health officials and researchers cautioned that the lowered number of cases of deformities might be because the damage to the brain of infected infants does not manifest at birth but some point later in the child's development.

Meanwhile, scientists in Brazil have developed a solution to contain the spread of the Zika virus. They are releasing millions of laboratory-grown mosquitoes to breed with the Zika-carrying mosquitoes and wipe out the next generation in the process.