Zika Virus Outbreak Prompts CDC To Expand Travel Advisory (washingtonpost.com)

turkeydance writes: The U.S. Centers for Disease Control and Prevention is asking pregnant women to avoid 22 countries that have seen outbreaks of the Zika virus. That's up eight from just yesterday. Disturbingly, the mosquito-borne virus, which may be causing abnormally small heads in newborns, has also been linked to yet another debilitating disease. The Zika virus has been spreading rapidly over the past several months, most prominently in Brazil. Its spread has been associated with a dramatic increase in microcephaly, a rare condition in which babies are born with abnormally small heads.

Comments

"Yet another debilitating disease"

[Nemyst]

... which isn't mentioned in the summary. It's apparently the Guillain-Barre syndrome.

Re:"Yet another debilitating disease"

[hjf]

I'm from the affected area. North-east Argentina, near Paraguay. There have been hundreds of cases of Dengue Fever in the past week. All of this is happening because of the floodings, caused by excessive rainfall by El Niño. Temperatures have been extremely high too (37C at my city today).

The thing I don't understand is why now?

[Johnny Loves Linux]

1. The Zika virus has been Africa and Southeast Asia since forever.

2. They don't seem to have microcephalic cases like Brazil has.

3. The virus was introduced into Brazil sometime around 2015.

4. 2015 Brazil sees a 10x increase in microcephalic cases.

So far that seems compelling that Zika is causing the cases. But why aren't we seeing the same thing in Africa or Asia? It's not like the Zika virus in Brazil has had thousands of years to mutate into a version that causes microcephaly, but not the original strain in Africa and Southeast Asia. It's the same virus.

It's not like the people in Brazil don't have the same "immunity" that people in Africa and Southeast Asian people have -- a large percentage of the Brazilian people *have* West African ancestors where the Zika virus has been found.

Here's an alternate hypothesis: some kind of chemical has been introduced into Brazil in 2015 that's causing the birth defects. Maybe a pesticide that hasn't been properly tested, or a morning sickness drug that wasn't tested.

Citations:

For pesticides and birth defects: http://www.counterpunch.org/20... http://americanpregnancy.org/p... and http://www.beyondpesticides.or...

Pesticides and microcephaly: http://www.ncbi.nlm.nih.gov/pm... and http://www.gmls.eu/beitraege/1...

For morning sickness drugs: http://www.aboutkidshealth.ca/...

Re:The thing I don't understand is why now?

[Yaztromo]

But why aren't we seeing the same thing in Africa or Asia? It's not like the Zika virus in Brazil has had thousands of years to mutate into a version that causes microcephaly, but not the original strain in Africa and Southeast Asia. It's the same virus.

First off, it doesn't take a thousand years for a virus to mutate. Influenza mutates on a yearly basis, for example. And as a general rule, any organism that finds itself in a different environment faces different selective pressures, which may influence the mutation rate, or at the very least, the likelihood of a mutation being more fit for the environment than the pre-mutated strain.

If the cause were due to chemicals, you should see an equal number of non-Zika infected mothers giving birth to children with microcephaly. That doesn't seem to be happening from what I've read. There is no data pointing towards chemicals being involved in any manner. Obviously more diagnosis and testing is needed -- as yet we don't know whether or not Zika has mutated in South America, how the virus is passing the placental barrier, or the exact action which is causing the microcephaly once infected. Wild guesses won't get us closer to a solution to these outstanding questions.

Yaz

Re:Aren't all babies...

[germansausage]

No. The little bastards have abnormally large heads.
 
Signed
 
Mothers Everywhere

Re:What would be helpful

[Yaztromo]

I've seen in the news items of women who were tested for Zika after microcephaly, but that's just confirmation basis (sic).

It's incomplete data, but it isn't confirmation bias.

If the researchers were taking tests of women who gave birth to microcephalic babies, and Zika was not the cause, you'd expect that the women being tested would have some closer-to-even distribution between Zika infected and non-Zika infected, given a suitable sample size.

Now if the testing were done the other way around (checked for microcephaly only in women known to have had the Zika virus), then you'd potentially have confirmation bias if the results appeared to show a correlation. The problem you'd run into here is that without checking against the birth results of mothers who didn't have Zika, you wouldn't know if there were some other cause for the microcephaly.

This of it this way. If you went to a village and rounded up every mother who had a microcephalic baby, and you found that 99+% of them had Zika, there is no confirmation bias. You'd still want to determine how many other mothers infected with Zika had non-microcephalic babies, and you'd further need to determine when during pregnancy the Zika infection began (as it's possible that microcephaly only occurs if caught at or before a certain point of gestation), but the result would point to possible avenues for research.

If, however, you rounded up all of the women who had Zika during their pregnancy, and found that 80% of them had microcephalic babies and stopped there, then you'd have a case of confirmation bias. It could turn out that 80% of non-Zika infected mothers also had microcephalic babies. That is confirmation bias. What you called "confirmation bias" is good research methods. It's certainly not the end of the research, but correlations are not confirmation biases in and of themselves.

Yaz