On Tuesday, doctors confirmed that a baby has been born with Zika-linked microcephaly at the Hackensack University Medical Centre in New Jersey.

This is the second time an infant has been born in the United States with microcephaly linked to Zika virus. The first case was reported in Hawaii back in February.

The WHO has declared Zika a global health emergency, with experts confirming after months of research that the virus does indeed cause microcephaly - a condition in which the head and brain are born abnormally small. Scientists have been able to improve diagnostic tests for the virus, but we still don't have a vaccine.

The mother of the second confirmed case contracted Zika in her home country, Honduras, and then visited her relatives in New Jersey. Manny Alvarez, one of the doctors caring for the patient, told Christopher Mele from The New York Times that:

"[T]he woman knew before coming to visit relatives in New Jersey that, based on blood test results, she had the virus. He said scans on Friday showed the girl was underweight for her gestational age and doctors did not want to risk further exposure to the virus, so they delivered the baby, the woman's second child, by caesarean section on Tuesday."

The virus is most frequently transmitted via mosquitos, but recent reports have shown that it can also be transmitted via sex. The real concern is if mosquitoes begin spreading the virus within the US, and unfortunately it's a possibility, now that a number of cases have been confirmed on the mainland.

As Peter Dockrill reported for us back in March:

"With warmer temperatures on their way, conditions favourable to populations of the Aedes aegypti mosquito that spreads the infection mean that areas in the southern and eastern United States are most vulnerable to transmission of the virus. In addition to their temperate climates, much of this region is also located nearest to the current outbreak further south in Latin America and the Caribbean."

Even though this latest birth is the first confirmed case of a baby being born in the continental US carrying the disease, there are reports that there might be earlier cases on the mainland. 

Abdulla Al-Khan, another doctor caring for the New Jersey mother, told Fox News that another child has been born with the disease somewhere in the South. But at this stage it's not been confirmed if this baby also has microcephaly, and the location has not yet been disclosed. 

The Centre for Disease Control and Prevention (CDC) says there are now over 300 pregnant woman in the US with "laboratory evidence of possible Zika virus infection". Not every baby that's born with Zika will have microcephaly or brain defects, but the CDC estimates the number between 1-13 percent.

The CDC has also advised pregnant woman to avoid travelling to the areas where mosquitos have been shown to carry Zika. This has also put a strain on the Olympic Games in Rio de Janeiro, with some athletes speaking out about those competing this summer.

Although this is a tragic situation, there is still hope. Genetically modified mosquitos are an option the WHO is looking into, and many labs around the world are working on a vaccine.

Let's just hope they find something soon.