A 4-month-old baby born with microcephaly is held by his mother in front of their house in Olinda
(Copyright Reuters 2016)
AMERICAN researchers have found evidence of the Zika virus replication in the fetal brain for up to seven months after the mother became infected with the virus, and they showed the virus can continue to exist even after the birth, according to a study published on Tuesday.
The findings confirm previous observations from the case studies suggest that the mosquito-borne Zika virus can grow in the fetal brain and women placentas.
“Our findings show that Zika virus can continue to replicate in the baby brain also after the birth, and that the virus remains present in the placentas months – much longer than we had expected,” Julu Bhatnagar, the lead of the molecular pathology team of CDC Infectious Diseases Pathology Branch and the study’s lead author, said in a statement.
The findings help explain how the virus causes devastating birth defects and pregnancy losses, even if a woman only had a small disease. In the last month, the World Health Organization (who) has declared that Zika no longer constitutes an international emergency, but stressed the need for a long-term effort to address the virus, which is linked to thousands of birth defects and complications.
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For the study, CDC researchers tested tissues of 52 patients with a suspicion of Zika virus infections, including the brain tissue of eight children who had microcephaly and later died. They also tested placenta tissue of 44 women, 22 of whom delivered apparently healthy babies and 22 whose pregnancies ended in a miscarriage, abortion, stillbirth or who have delivered babies with microcephaly. Zika is shown that microcephaly, a rare congenital defect where children are born with an undersized head and brain, which can lead to lifelong disability.
The researchers found Zika genetic material in fetal brain tissue and placentas more than seven months after the mothers contracted the virus. In one case, they also found evidence of the virus grows in an infant with microcephaly who died two months after the birth.
Of the eight children had microcephaly and later died, all tested positive for Zika. The mothers of all eight of these children contracted Zika during the first trimester of pregnancy, adding to prior evidence that Zika is the most dangerous early in the pregnancy.
“We do not know how long the virus can exist, but its persistence may have implications for babies born with microcephaly, and apparently healthy infants whose mothers had Zika during their pregnancy,” said Bhatnagar, whose findings were published in the CDC’s Emerging Infectious diseases journal.
There are no treatments or vaccines for Zika, who had earlier seen, causing only a mild illness.