Rhesus macaque model | A scope to study Zika brain pathology

"Blood samples could be negative for virus, but there may still be virus in the brain," Van Rompay.

Rhesus macaque monkeys develop similar brain pathology to human infants when infected in utero with Zika virus, it has been demonstrated at the California National Primate Research Centre. Rhesus macaques is proved to be an appropriate model system to study the infection of Zika virus during pregnancy and its effects on the foetus as well as to find ways to prevent, diagnose, mitigate or treat it.

The foetuses caused brain disease when the Zika virus was directly administered into the amniotic fluid, unlike other related studies. Since all foetuses are affected, therapies can be tested using fewer animals.

The women who were exposed to Zika virus during pregnancy can lead their babies to display “Cogenital Zika Syndrome”. Microcephaly (unusually small head size), calcification of brain tissues and other signs of abnormal brain and eye development are the basic symptoms shown by the babies who develop Cogenital Zika Syndrome. The number of children born with abnormally small heads is less than that of affected by Zika virus-related brain damage.

The similar effects are also shown by the infected mice but the pregnancy as well as brain development is completely different in rodents and humans. The physiology and the development of brain and Central nervous system is similar in humans and Rhesus macaques.

The four macaque foetuses were infected by introducing Zika virus directly into the amniotic sac. One foetus infected died in early pregnancy; three others later survived to the term. Though the animals born at term did not show symptoms of Cogenital Zika Syndrome like microcephaly, but they had calcification of brain tissues and other brain damage. These findings were compared 3 foetuses those were not infected by Zika and their brains showed no signs of damage.

It has been extracted that the Zika virus infection cannot be diagnosed in humans just by testing the cord blood because when the brain tissues of infected animals were examined, the large amount of Zika virus were found, but not in the cord blood.