New research has found inflammation in the choroid, retina and optic nerve among the fetuses of pregnant monkeys infected with Zika during their first trimester.
The study, published in PLOS Pathogens, found that every fetus was exposed to the virus after the mother monkey was infected. The research suggests that even babies who are apparently normal at birth may have been exposed to Zika and develop problems associated with the virus later in life.
Study author, Dr Thaddeus Golos, told OT that while the optical abnormalities were not severe, there was evidence of viral exposure.
“Given that there are also abnormalities of the eye noted in human infants from infected pregnancies as well as evidence that infection causes conjunctivitis in adults, we need to consider the eye as a target of the virus,” Dr Golos observed.
Dr Golos explained that the research was conducted in monkeys because the impact of maternal infection on human fetuses could only be studied in the event of stillbirth or maternal death.
Four pregnant rhesus macaque monkeys were infected with a Zika virus dose similar to that which would be transferred by a mosquito bite. A tissue analysis of the fetuses was carried out following caesarean section.
“We are now working with paediatricians, ophthalmologists and audiologists to move to the next study where we will conduct postnatal evaluations of eyesight, hearing and behaviour on infant monkeys to assess whether the Zika exposure we have demonstrated has a functional impact as well as a cellular impact,” Dr Golos concluded.