Sunday, July 10, 2016

Conspiracy Theory of the week: It's not Zika, it's the pesticide

I missed the articles last February questioning if the microcephaly epidemic blamed on the Zika virus was due to a pesticide used in Brazil,  maybe because experts quickly denied this was true... even NPR denied the link, so I figured it was another conspiracy theory by those who hate chemicals, big Agribusiness, and Monsanto.

but now a study in the NEJM suggests, uh, if Zika causes microcephaly, then why are there so few cases in Colombia?

ScienceDaily report here.

NEJM has several articles on it but the review article is HERE discussing the epidemiological studies that made them suspect the Zika virus, but notes why doctors were not as quick to blame the virus as the MSM, including the observation that the increase in microcephaly in a Pacific Island outbreak was minimal.

Link for the NEJM preliminary report from doctors in Colombia.

Summary: A lot of the moms who got Zika in early pregnancy haven't delivered yet, so data is lacking, but if you got Zika later in pregnancy you and your baby probably will do okay.

I should note that I've read anecdotal cases of Zika encephalitis in newborns causing the brain to shrink.

the NECSI report is here.

Summary: They found Zika in the brain on autopsy, so that is good evidence that Zika encephalitis can cause the brain to shrink.

The Colombia data suggests otherwise, but may change as more information comes in.

The strongest evidence is in favor of Zika, through the observation of Zika virus in neural tissue, though a key piece of evidence is missing in the expected rise of cases in other locations, specifically Colombia. Evaluation of the potential role of pyriproxifen is difficult due to the limited number and nature of available studies, which should be revisited as they include some evidence for neurodevelopmental toxicity. The possibility of DPT immunizations of pregnant women as a factor is largely ruled out by an increase in immunization in countries in which microcephaly cases are not being reported. There is no direct evidence for GM mosquitoes as a cause.

If there is a dramatic increase in cases of microcephaly in Columbia in the next three months, the case for Zika will be dramatically strengthened, and the case for pyriproxyfen and GM mosquitoes will be essentially ruled out.

On the other hand if the cases do not materialize, Zika will essentially be ruled out and pyriproxyfen would become the strongest case with GM mosquitoes a speculative alternative along with other environmental toxins.

their report on pyriproxyfen toxicity is here. 

summary: It's action and metabolite is similar to another chemical that can cause microcephaly, the toxicity studies claimed it was safe but did show problems, and the chemical was overused in Brazil, i.e. giving moms a higher dosage than elsewhere.

A longer version of this with comments is at my medical blog.

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