Zika virus particles (red) shown in African green monkey kidney cells. Credit: NIAID

The birth rate in Brazil has fallen by its fastest rate in nearly three decades after the Zika and microcephaly crisis of 2016.

Brazil's statistics agency says on Tuesday there were 2.79 million births in 2016, a 5 percent decrease from the year prior.

The fell by 10 percent in the northeastern state of Pernambuco, where the Zika crisis hit particularly hard.

The Zika virus is spread primarily through mosquito bites and causes babies to be born with abnormally small heads and other severe brain defects.

Analysts from the Institute of Geography and Statistics believe the country's long also contributed to the decrease.