Washington: Zika may linger in the blood of an infected baby for more than two months, suggests a new study from Brazil that raises concerns about the potential of the virus to damage an infant's brain even after birth.
Physicians at the Santa Casa de Misericordia and researchers from the University of Sao Paulo in Brazil described the case of a baby born with Zika infection in January, who remained infected by the virus even two months and one week after birth.
This is the first reported case of prolonged Zika infection in newborns, researchers wrote in The New England Journal of Medicine.
The baby was 3 kg, 48 cm in length at birth, with the head perimeter of 32.5 cm, slightly smaller than the 33cm recommended by World Health Organisation (WHO).
At first, doctors did not detect signs of any neurological abnormality: the analysis of the cerebrospinal fluid and the exams of the eyes and the ears showed normal results.
Images taken by MRI, though, showed a reduced brain parenchyma, foci of calcification in the subcortical area and compensatory dilation of the supraventricular system.
These results and the fact that the mother's symptoms of Zika infection appeared in the seventh month of pregnancy - when it is thought that the damage to the foetus is less severe than when the infection occurs earlier in pregnancy - led to a first diagnosis of mild microcephaly.
After 54 days of life, the baby showed no illness or neurological impairment. However, at six months, doctors noticed delayed psychomotor development, with an abnormal increase in the muscle tone and reduced muscle stretchability.
Also, spastic hemiplegia (cerebral palsy) was detected. These characteristics imply a more serious condition than diagnosed before, researchers said.
The baby's father travelled to the Northeast of Brazil and showed symptoms of Zika before his wife.
It may indicate that the virus could have been sexually transmitted. Serological tests confirmed the infection in both parents, researchers said.