On Tuesday, officials announced that 49 pregnant women tested positive for the Zika virus in New York City since April. A baby was born with microcephaly. Most of the people tested were infected when they travelled to Zika-affected areas and very few were infected due to sexual transmission.

The mosquito-borne disease was declared a global emergency by the WHO in February 2016. The virus, discovered in 1947, is now a pandemic. Zika is primarily spread by the bite of the Aedes mosquito.

However, most people infected with the virus do not fall sick. In fact, most don’t show any symptoms at all. In those who did fall sick, an itchy red rash is a common sight. Other symptoms include fever, headache, joint and muscle pains, and inflamed eyes. People are likely to recover in two to seven days.

The virus does not cause severe sickness, unless you’re pregnant, and it doesn’t stick around for too long.

Professor of epidemiology at Columbia University Stephen Morse reportedly said, “We’re still learning about this, but usually the virus remains in the body for maybe a couple of weeks.”

“There is insufficient data on the question of whether it is safe for a woman who has been infected with Zika to get pregnant later. But given what we know so far, she should probably be safe after recovery,” Morse added.

He also said that once a person is infected, the person becomes immune to the virus but “we don’t know if immunity is lifelong.”

CNN’s Dr. Sanjay Gupta said that four out of five people infected with the virus do not show any symptoms and are likely to never realize that they even had the virus. The virus, he said, can stay in the person’s body for about a week. “The Red Cross is saying that they don't want you to donate blood for 28 or 30 days after you get back from one of the affected places. Part of the reason they wait so long is that they want to be careful. There's an abundance of caution,” he said.

The biggest problem occurs when a pregnant woman is infected with the virus. The virus is linked to a condition called microcephaly, a birth defect that prevents the baby’s brain from growing to its normal size. The virus can also cause hearing and vision problems in the fetus.

Another condition linked to Zika is the Guillain-Barré Syndrome (GBS). Several affected countries reported an increase in the number of people suffering from GBS after the Zika outbreak. GBS affects the nervous system in such a way that the person’s immune system attacks nerve cells and causes muscle weakness and even paralysis.