A new study says that Zika virus is associated with increased risk of brain damage, which might not be detected at earlier stages of pregnancy.
The brain tissue of the fetus infected with the Zika virus was found to have traces of the virus which might have caused severe defects in the brain, a study published in The New England Journal of Medicine said.
At the earlier stages of gestational age, the fetus showed no signs of any defects such as microcephaly. It has not yet been proven that microcephaly is caused by the Zika virus, but a link is suspected.
The study also linked intracranial calcifications and severe damage to the fetal nervous system to the Zika virus.
"There is an enormous amount we don't know about this current strain and outbreak of Zika virus. It seems to be behaving differently than in the past. What we do know for sure is if the fetal brain is affected this appears to be a very bad situation," Adre du Plessis of Children's National Health System and a co-author of the study, told Reuters.
The research also found that the virus affects muscle, liver, lung, and spleen of the fetus, apart from the brain, raising concerns that the virus could cause damage to fetus, which might be revealed very late.
"The latency period between [Zika] infection of the fetal brain and the detection of microcephaly and intracranial calcifications on ultrasonography is likely to be prolonged. Negative ultrasonographic studies during this period would be falsely reassuring and might delay critical time-sensitive decision making," the study said.
Dr. Rita Driggers, lead author of the study and director of Maternal-fetal Medicine at Sibley Memorial Hospital, Washington DC, suggested that Zika-infected pregnant mothers should get the anatomy of the fetal brain checked, as the head size is not the only indicator of Zika virus infection in the fetus.
Infected people may not always have any major symptoms, but only develop rashes. However, Zika has recently also been linked to Guillain-Barré syndrome, which is an immune disorder that can lead to temporary paralysis.
The virus genome was mapped by scientists in a separate study, who found eight mutations, which were different from the earlier strains reported.
Zika is transmitted through the Aedes aegypti mosquito, but the Center for Disease Control (CDC) recently reported that it can also be a sexually transmitted virus.
Brazil has been hardest hit by the virus, and has confirmed 900 cases of microcephaly, most of which are thought to be linked to Zika virus.
The study also said that two species of the mosquito may have spread further than previously known. The researchers estimate that the range of the mosquito Aedes aegypti may have spread as far as the northern US.
But the CDC did not reveal the density of mosquitoes in new regions, which are now said to be hosting the virus.
As yet, no cases of Zika virus infections from mosquito bites have been reported from US. Most of the 273 infected patients in the country had traveled to the places where it is endemic including Puerto Rico, Hawaii, and Brazil.
