By contrast, a 2001 study of adults born to mothers infected with rubella, or German measles, during the last American epidemic, which lasted from 1964 to 1965, found that 20 percent had schizophrenia symptoms. The expected rate among adults is below 1 percent.
It was certainly possible that Zika virus may pose a similar risk.
Although children may be troubled, the hallucinations, voices and paranoia of true schizophrenia do not normally emerge until late adolescence, when there is a lot of rearranging and pruning in the brain
The effects of Zika mimic those of rubella, some experts noted: Both cause only a mild rash in adults, but can cause stillbirths, microcephaly and eye malformations in newborns.
In the 1964-65 rubella epidemic, about 20,000 newborns suffered consequences: A total of 11,000 were born deaf, 3,500 were born blind, and at least 1,800 were later found to have mental problems.
That epidemic infected an estimated 12 million Americans. More than 500 million people live in the countries of Latin America and the Caribbean to which the World Health Organization has predicted that Zika will spread.
It is also possible that children who survived maternal Zika infections with no signs of microcephaly could still display mental deficits as they grow.
Any virus in the blood of a pregnant woman is a risk to the fetus, so ultimately there may be damage. Many children who survived the 1964-65 epidemic suffered from autism, learning disabilities and behavioral disabilities.
The Zika virus seems to zero in on nerve cells even more than does rubella, which also causes heart defects, for example.
Pathologists in Ljubljana, Slovenia, who dissected a microcephalic fetus aborted at 32 weeks by a European woman who had become pregnant in Brazil reported last week that they found “severe fetal brain injury associated with ZIKV infection with vertical transmission” — meaning the Zika virus had come from the mother’s infection.
But a pathogen may not even have to reach the fetus to cause damage.
Flu viruses do not cross the placenta, but the mother’s immune reaction creates a storm of cytokines, some of which do. Cytokines are small “signaling” proteins that can cause cells to stop growing. How much damage is done depends not just on the virus and the mother’s immune response, but at which stage of pregnancy the infection strikes.
First-trimester infections may cause brain tissue to calcify and die; later ones may have subtler, but still insidious, effects.
Reports suggest that Brazil, which was facing economic crises even before the Zika outbreak, has little capacity to cope with a surge of mentally disabled children.
European researchers initially paid little attention to the South American outbreak, but the information is just overwhelming as a whole generation of children might be affected.
