Massive New Study Suggests Pesticide the Cause of Microcephaly — NOT Zika Virus

RECIFE, BRAZIL - JANUARY 25: Estafany Perreira holds her nephew David Henrique Ferreira, 5 months, who has microcephaly, on January 25, 2016 in Recife, Brazil. In the last four months, authorities have recorded close to 4,000 cases in Brazil in which the mosquito-borne Zika virus may have led to microcephaly in infants. Microcephaly results in newborns with abnormally small heads and is associated with various disorders including decreased brain development. According to the World Health Organization (WHO), the Zika virus outbreak is likely to further spread in South, Central and North America. At least twelve cases of Zika in the United States have now been confirmed by the CDC. (Photo by Mario Tama/Getty Images)

A new scientific study carried out by the New England Complex Systems Institute (NECSI) is casting doubt on the assumed connection between the Zika virus and microcephaly. The study was prompted by the fact that no similar epidemics of microcephaly are being found in other countries hit hard by the Zika virus.

“Recently, the New England Journal of Medicine published the preliminary results of a large study of pregnant Colombian women infected with Zika. Of the nearly 12,000 pregnant women with clinical symptoms of Zika infections until March 28, no cases of microcephaly were reported as of May 2. At the same time, four cases of Zika and microcephaly were reported for women who were symptomless for Zika infections and therefore not included in the study itself.”


The four cases are consistent with the expected normal background rate of microcephaly–2 in 10,000. Also, there have been almost 50 microcephaly cases in Colombia up to April 28 with no connection to the Zika virus.

The mathematical analysis demonstrates that there are at least 60,000 Zika-infected pregnancies in Colombia, yet the near absence of microcephaly calls for a renewed investigation into the cause of this birth defect.

Four days after the NECSI study was reported by media, five new cases of microcephaly with Zika infections were found prior to June 18. However, this is still consistent with the random co-occurrence of each of the separate conditions.

Reports out of Colombia over the next few weeks will provide much more evidence on whether there is a causal connection between Zika virus and microcephaly. If there is a link, the number of microcephaly cases should rise dramatically.

The U.S. Centers for Disease Control and the New England Journal of Medicine (NEJM) have already concluded that Zika is a cause of microcephaly. However, the NEJM acknowledges that no experimental evidence exists yet to support that conclusion. Also, “no flavivirus has ever been shown definitively to cause birth defects in humans, and no reports of adverse pregnancy or birth outcomes were noted during previous outbreaks of Zika virus disease in the Pacific Islands.”

In keeping with the spirit of scientific inquiry, all avenues should remain open in determining the cause of the microcephaly outbreak in Brazil. Evidence could build for the Zika virus link, but scientists are insisting that the insecticide pyriproxyfen should also be explored as a possible cause.


In February we reported that doctors in Brazil and Argentina sounded the alarm over pyriproxyfen, which is used for mosquito control by targeting the larval stage. This chemical was sprayed in the areas most affected by microcephaly, but more significantly, was added to drinking water in the Brazilian state of Pernambuco.

The doctors’ report was widely lambasted in the corporate media, but that has not diminished the possibility of a link between pyriproxyfen and microcephaly. The NECSI, which published the new study on Colombia, has provided a comprehensive review of the facts leading to this hypothesis.

“Pyriproxyfen acts as a larvicide by interfering with the development of mosquito larvae. It may unintentionally do the same in humans. Its structure mimics the role of juvenile hormone, which has been shown to correspond in mammals to a number of molecules including retinoic acid, a metabolite of vitamin A, with which it has cross-reactivity. The application of retinoic acid during development has been shown to cause microcephaly. Methoprene, another juvenile hormone analog that was approved as an insecticide based upon tests performed in the 1970s, has also been shown to bind to the mammalian retinoid X receptor, and to cause developmental disorders in mammals. Isotretinoin is another example of a retinoid causing microcephaly in human babies via maternal exposure and activation of the retinoid X receptor in developing fetuses.”

Pyriproxyfen had never been applied to drinking water on such a scale as it was in Brazil, which began the application in 2014–just before the outbreak of microcephaly. Combined with the fact that other countries with Zika outbreaks are not seeing cases of microcephaly beyond the normal rates of co-occurrence, there is certainly cause for suspicion.

The increase in developmental brain abnormalities following a Zika outbreak in French Polynesia—widely cited by corporate media as proof against the pesticide-microcephaly link—was not a valid comparison due to the much smaller population and relatively few cases. Even the New England Journal of Medicine acknowledged that the French Polynesia case does not provide compelling evidence of Zika being the cause.

Adding another layer of suspicion is the fact that Sumitomo, the Monsanto-linked manufacturer of pyriproxyfen, claimed there is no evidence for developmental toxicity in their product, when in fact a review of their own data found this claim to be false.

Philippe Grandjean, a neurodevelopmental toxicologist affiliated with the Harvard School of Public Health, discovered “an animal test shows possible link to teratogenic effects and smaller skull.” Sumitomo failed to mention their own tests showing “low brain mass and arhinencephaly—incomplete formation of the anterior cerebral hemispheres—in rat pups.”

“Few pesticides have been properly tested for developmental neurotoxicity,” said Grandjean. “This is unfortunate as pesticides are suspected of causing a silent pandemic of neurotoxicity. In this case the absence of proper toxicological data confuses the search for causes of the reported surge in microcephaly.”
While politicians and corporate media continue to ignore the possibility that an insecticide may be causing the microcephaly outbreak in Brazil, continued application of the chemical may be aggravating the problem.

The chemical approach to addressing problems such as mosquitoes is standard procedure for centralized, corporate-backed governments, as it rakes in profits for chemical manufacturers such as Suminoto, which in turn line the pockets of politicians who pushed for the measure.

Viable alternatives are lost in the push for more chemicals. The World Health Organization describes how fish that eat mosquito larvae are an effective part of an integrated biological control program. When El Salvador began putting larvivorous fish in water storage containers, dengue vanished along with the mosquitoes that transmit the disease.

In Guatemala, researchers developed a highly effective mosquito trap called an ovillanta. The device is nothing more than 20-inch cut tire pieces hung in a certain fashion with a pheromone-laden non-toxic solution poured into the bottom, and a piece of floating wood or paper where female mosquitoes are drawn to lay their eggs. Use of the traps prevented new cases of dengue during the entire length of the study.

It is also worth noting that environmental degradation and poverty play a part in mosquito-borne outbreaks such as Zika.

Dino Martins, a Kenyan entomologist, said that “the explosion of mosquitoes in urban areas, which is driving the Zika crisis” is caused by “a lack of natural diversity that would otherwise keep mosquito populations under control, and the proliferation of waste and lack of disposal in some areas which provide artificial habitat for breeding mosquitoes.”



The Free Thought