With prolonged infection may come more tissue damage
An infant born with microcephaly, but with an otherwise normal physical examination at birth, had evidence of the Zika virus in serum, saliva, and urine nearly 2 months after birth, a case report from Brazil found.
The mother of the male infant was potentially infected during her third trimester of pregnancy, and the baby was born at term (40 weeks) with microcephaly. Laboratory testing found evidence of Zika virus in the infant up through 2 months of age, and he began displaying neurological symptoms at 6 months of age, Danielle B.L. Oliveira, PhD, of Universidade de São Paulo in Brazil, and colleagues, reported in a research letter in the New England Journal of Medicine.
The authors said that despite being born with microcephaly, the infant had a normal vision and hearing test, and analysis of cerebrospinal fluid was normal at birth, with no abnormalities detected during an initial physical examination. In fact, the infant showed “no obvious illness or evidence of any immunocompromising condition” on day 54 of life.
“If Zika is shown to persist as a threat to infected newborns long after in utero exposure, there are serious implications for monitoring and managing exposed babies, even if there are no clinical manifestations noted at birth,” Irwin Redlener, MD, of Columbia University Mailman School of Public Health in New York City, who was not involved with the research, told MedPage Today via email.
But similar to the findings in a recent study, brain imaging revealed that the infant had reduced brain volume in the frontal and parietal lobes, with calcifications in subcortical areas. A polymerase chain reaction test was positive for Zika in serum, urine, and saliva at day 54 of life and positive for serum on day 67. The test was negative on day 216, although the authors noted that Zika-specific IgG titers were higher than in the first and second samples — potentially indicating that the infant had mounted an immune response to the virus.
“Prolonged viral shedding in the infant … may have had a role in the damage the virus was able to incite,” said Amesh Adalja, MD, a spokesperson for the Infectious Diseases Society of America. “It will be important to conduct more research in this vein in order to determine how common prolonged shedding is and if it is associated with a worsened clinical course,” he told MedPage Today via email.
At 6 months of age, the infant showed evidence of neuropsychomotor developmental delay, with global hypertonia, or spasticity, and spastic hemiplegia — a constant state of contraction of muscles on one side of the body, often associated with cerebral palsy. This is also consistent with recent research showing a delayed onset of symptoms in some infants with congenital Zika virus infection.
The other interesting detail about this case was that not only did the mother appear to contract Zika virus later in her pregnancy, but she may have done so through “suspected” sexual transmission from the father. The authors reported that the mother stayed in São Paulo for the duration of her pregnancy, but the father traveled to northeastern Brazil. The father then had symptoms of Zika virus infection when the mother was 23 weeks pregnant, but she did not show symptoms until 26 weeks.
“This report provides evidence that a third trimester infection with Zika, which has been generally considered to be lower risk than earlier periods in a pregnancy, is not always benign and can lead to microcephaly,” added Adalja.
Source: MedPage Today