More than 2,400 suspected cases of microcephaly have been reported this year in 20 Brazilian states, compared with 147 cases last year. Doctors are investigating 29 related infant deaths.

Microcephaly results in babies being born with abnormally small heads that cause, often serious, developmental issues and sometimes early death.

As a result, six states have declared a state of emergency. In Pernambuco state alone, more than 900 cases have been reported.

Brazil advises against pregnancy because of Zika Virus

Brazil is warning pregnant women to stay inside and avoid mosquito bites during the upcoming summer season, due to an apparent link between the spread of a mosquito-borne virus and babies born with birth defects.

That’s the message for would-be parents, especially in the country’s northeast, after officials linked a mosquito-borne virus called Zika to a surge in newborn microcephaly, a neurological disorder that can result in incomplete brain development.

Brazil is investigating more than more than 2,400 suspected cases of microcephaly and 29 deaths of infants that occurred this year. Last year the country saw only 147 cases of microcephaly.

Brazil’s Health Ministry reported this week that it has recorded up to 2,782 cases of microencephaly– or, abnormally small skulls — in newborns this year, compared to only 147 cases recorded last year. The condition can cause developmental issues and sometimes early death. Doctors are investigating some 29 infant deaths this year from microencephaly.

“It’s a very personal decision, but at this moment of uncertainty, if families can put off their pregnancy plans, that’s what we’re recommending,” Angela Rocha, the pediatric infectologist at Oswaldo Cruz Hospital in Brazil’s hardest-hit state, told CNN.

“These are newborns who will require special attention their entire lives. It’s an emotional stress that just can’t be imagined,” Angela Rocha, the pediatric infectologist at Oswaldo Cruz Hospital in Brazil, told CNN. “Here in Pernambuco, we’re talking about a generation of babies that’s going to be affected.”

What is the Zika Virus?

The so-called Zika virus has been found mostly in the northeast of Brazil and can have severe effects on the brain development of babies. A surge in newborn microcephaly, which is a neurological disorder that may result in incomplete brain development, has been linked to Zika. Health officials are telling Brazilians that, if they can, it’s best to put off pregnancy plans for the moment to avoid the risks posed by the outbreak.

The number of cases has exploded in the last year. In 2015, there have been 2,400 suspected cases of microcephaly reported across 20 of the country’s 27 states. There were just 147 cases in 2014, and doctors are currently investigating as many as 29 infant deaths that could be associated with the Zika virus.

The pathogen, known as Zika and first discovered in forest monkeys in Africa over 70 years ago, is the new West Nile — a virus that causes mild symptoms in most but can lead to serious neurological complications or even death in others. Brazil’s health ministry said on Nov. 28 that it had found the Zika virus in a baby with microcephaly — a rare condition in which infants are born with shrunken skulls — during an autopsy after the child died. The virus was also found in the amniotic fluid of two mothers whose babies had the condition.