Zika Virus and Microcephaly

[Ygggdrasil]

The CDC has released a statement confirming that Zika virus, a mosquito-borne pathogen currently spreading throughout the Americas, causes microcephaly and other birth defects in children born to mothers who contract the virus during pregnancy:

"This study marks a turning point in the Zika outbreak. It is now clear that the virus causes microcephaly," CDC director, Dr. Tom Frieden said.

Previously, the agency said it's likely the virus in pregnant women was the cause of the rare birth defect that results in an underdeveloped brain and that the evidence was mounting. However, they maintained that more research was needed before they could conclusively say it is causal.

There was no smoking gun that lead to this proclamation, according to a special report detailing the evidence published online by the New England Journal of Medicine Wednesday.

Based on all of the available evidence, the CDC said two separate sets of criteria to determine a pathogen or environmental exposure causes a birth defect have been met.

http://www.cnn.com/2016/04/13/health/cdc-zika-virus-microcephaly/

Here's the summary of the NEJM article cited:

The Zika virus has spread rapidly in the Americas since its first identification in Brazil in early 2015. Prenatal Zika virus infection has been linked to adverse pregnancy and birth outcomes, most notably microcephaly and other serious brain anomalies. To determine whether Zika virus infection during pregnancy causes these adverse outcomes, we evaluated available data using criteria that have been proposed for the assessment of potential teratogens. On the basis of this review, we conclude that a causal relationship exists between prenatal Zika virus infection and microcephaly and other serious brain anomalies. Evidence that was used to support this causal relationship included Zika virus infection at times during prenatal development that were consistent with the defects observed; a specific, rare phenotype involving microcephaly and associated brain anomalies in fetuses or infants with presumed or confirmed congenital Zika virus infection; and data that strongly support biologic plausibility, including the identification of Zika virus in the brain tissue of affected fetuses and infants. Given the recognition of this causal relationship, we need to intensify our efforts toward the prevention of adverse outcomes caused by congenital Zika virus infection. However, many questions that are critical to our prevention efforts remain, including the spectrum of defects caused by prenatal Zika virus infection, the degree of relative and absolute risks of adverse outcomes among fetuses whose mothers were infected at different times during pregnancy, and factors that might affect a woman’s risk of adverse pregnancy or birth outcomes. Addressing these questions will improve our ability to reduce the burden of the effects of Zika virus infection during pregnancy.

http://www.nejm.org/doi/full/10.1056/NEJMsr1604338

 

[gjonesy]

Apparently mosquitos aren't the only method of transmission, its sexually transmitted also

http://www.cdc.gov/zika/transmission/sexual-transmission.html

 

[waternohitter]

It can be sexually transmitted between gay men as well.

http://www.pbs.org/newshour/rundown/sexual-transmission-of-zika-seen-between-gay-men-for-first-time/

 

[gjonesy]

It can be sexually transmitted between gay men as well.

Yeah good point all sexual contact can resultant in exposer. But heterosexual transmission could be a way of transmitting the virus through fertilization directly into the ovum. I can see how that could cause the chromosome damage at the onset of pregnancy.

The virus could adhere to the zygote directly during cell division and development causing the egg itself to become infected.

 

[jim mcnamara]

@gjonesy - do you have a link for that? Sounds interesting.

 

[gjonesy]

do you have a link for that? Sounds interesting

I'll try to find the article, I think its mostly speculative at this early stage. Zika being linked directly to microcephaly. It would stand to reason that the transmission of the virus sexually during conception would be the optimal way to transmit the disease to the unborn child.

https://www.statnews.com/2016/02/26/sexual-transmission-zika/


http://www.cdc.gov/zika/pregnancy/index.html

http://www.cdc.gov/zika/pregnancy/index.html


This is the best article: its still speculative its known that its transmitted across the placenta, what's not known is if fetal infection can occur first transmitting it straight to the egg. But the article leaves room for that inference.

http://www.cbsnews.com/news/zika-virus-and-pregnancy-what-women-need-to-know/