Brazil registers 1,638 microcephaly cases since October

RIO DE JANEIRO, June 30 (Xinhua) -- The Brazilian Health Ministry on Thursday said the number of microcephaly cases in newborns registered in the country since October 2015 has reached 1,638 due to an outbreak of Zika virus last year.

Zika virus, transmitted by the Aedes aegypti mosquito, has milder symptoms than dengue or chikungunya fever, also transmitted by the same bug. But when pregnant women are infected by Zika virus, they can give birth to babies with microcephaly or other health conditions.

According to the ministry, most microcephaly cases were registered in Brazil's northeastern regions, with states of Pernambuco, Bahia and Paraiba having the highest figures of 366, 263 and 147, respectively.

However, the World Health Organization says there is a low risk of the transmission of the virus during the Olympic Games.

The Olympics will be held in August, the coldest month of the year in Rio de Janeiro, when the mosquito numbers are at their lowest.