How Zika virus induces congenital microcephaly

Epidemiological studies show that in utero fetal infection with the Zika virus (ZIKV) may lead to microcephaly, an irreversible congenital malformation of the brain characterized by an incomplete development of the cerebral cortex. However, the mechanism of Zika virus-associated microcephaly remains unclear.

Combined analysis of human fetuses infected with Zika virus, cultures of human neuronal stem cells and mice embryos showed that ZIKV infection of cortical progenitors -stem cells for cortical neurons) controlling neurogenesis triggers stress in the endoplasmic reticulum -where some of the cellular proteins and lipids are synthesized in the embryonic brain, inducing signals in response to incorrect protein conformation.

When it reaches the brain, Zika virus infects neuronal stem cells, which will generate fewer neurons, and by inducing chronic stress in the endoplasmic reticulum, it promotes apoptosis-the early death of these neuronal cells. These two combined mechanisms explain why the cerebral cortex of infected fetuses becomes deficient in neurons and is therefore smaller in size.

 Researchers administered an inhibitors of protein-folding re-sponse in cortical progenitors and found that this inhibited the development of microcephaly in mice embryos infected with Zika virus. The defects observed are specific to an infection by ZIKV, as other neurotropical viruses of the flavivirus family- West Nile virus and yellow fever did not cause microcephaly, in contrast to Zika virus.
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Improved, safer Zika vaccine

Scientists have come up with better plant-based Zika vaccine that is more potent, safer and cheaper. It's based on key Zika protein. The vaccine works against a part of a Zika viral protein, called DIII, the part of the virus that infect people.

All flaviviruses have the envelope protein on the outside part of the virus. It has three domains. The domain III has a unique stretch of DNA for the Zika virus, this is used to generate a protective immune response that is unique for Zika.

Scientists carried out immunization experiments in mice, which induced antibody and cellular immune responses that have been shown to confer 100 percent protection against multiple Zika virus strains in a mouse.

The envelope protein were grew in bacteria, then switched to prepare the DIII protein domain in tobacco plants.
Producing plant-based vaccines, especially in tobacco plants, is safer than using chemical-based.

The protein-based vaccine uses the smallest and most unique part of the Zika virus that can still draw out a potent and good immune response.

Scientists made a pseudovirus- fake virus. The pseudovirus displays only the DIII part of the envelope protein on the surface. Making the full native envelope protein as the basis for a vaccine, it induced antibodies against DI, DII and the DIII domains of the protein.

Women were advised not to become pregnant because Zika virus can cause abnormalities in babies. It can cause
severe brain defect known as microcephaly, in which the head and brain don't develop properly.

It can also cause vision, hearing defects and learning disabilities associated with less severe infections. Gullian-Barre syndrome in adults  has also been linked to Zika virus.
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Previous exposure to flaviviruses can enhance effects of Zika

Flavivirus is a group of related viruses, some of them are West Nile virus, dengue virus, yellow fever virus, Zika virus and others.

A new study that used human samples tested in mice discovered that prior infection with any flavivirus can increase the chance of Zika infection.

Exposure to one of these virus leads to more disease when exposed to related virus. Zika is spreading very fast in regions that is prone to other flaviviruses.

Human antibodies were transferred from infected human to mice to expose them to Zika virus.

The mice not giving antibodies survived Zika infection while those that received infected human antibodies did not.