A new report issued by a group of doctors with the University Network for Environment and Health, who practice in Brazilian villages that have water treated with the insecticide pyriproxyfen, suggests that the spike in microcephaly cases in the region may be caused by the chemical, rather than the mosquito-borne Zika virus.

This view has been disputed by Tirumalai Kamala, an immunologist with a Ph.D. in mycobacteriology. In a Quora post, the scientist noted two recent reports made by independent groups that demonstrate “clear and compelling evidence of Zika in placenta and brains of fetuses from miscarriages and from children born with microcephaly to mothers diagnosed with Zika in their 1st trimester of pregnancy. As such, other possible causes now become a bit moot.”

The Brazilian doctors noted that the areas of northeast Brazil that had witnessed the greatest number of microcephaly cases match with areas where pyriproxyfen is added to drinking water in an effort to combat Zika-carrying mosquitoes. Pyriproxyfen is reported to cause malformations in mosquito larvae, and has been added to drinking water in the region for the past 18 months.

The team with the University Network for Environment and Health also noted that Zika virus outbreaks have previously occurred in other areas with no reports of microcephaly. The doctors also suspect that the authorities responsible for the application of pyriproxyfen, which is recommended by the World Health Organization and produced by a Monsanto subsidiary, Sumimoto Chemical, are more concerned with orchestrating a “commercial maneuver” than effectively combating the spread of the Zika-carrying mosquitoes.

Many people who have contracted Zika virus may not exhibit symptoms, and even if they do, they may be mild. Though the actual number of Zika virus cases is unknown, the Brazilian Ministry of Health estimated that between 440,000 and 1.3 million people may have contracted Zika in 2015.

Dr. Kamala reports that pyriproxyfen has been used extensively for many years and is recommended by the World Health Organization.

“Pyriproxyfen ‘is unlikely to present an acute toxicological hazard and residues are therefore unlikely to present an acute risk to consumers.’ “

Pyriproxyfen is used for insect control on crops of citrus fruit in South Africa, Israel, Italy, and Spain, as well as for control of fire ants in California.

That the chemical has seen such widespread use raises the question of why cases of microcephaly have not appeared in areas where pyriproxyfen has been used for extended periods, according to Dr. Kamala. The scientist concedes that “dose may be a factor,” if citizens in Brazil received a larger amount pyriproxyfen in their bodies than elsewhere. However, she still questions why cases of microcephaly did not begin to appear in Brazil until December, 2015, when pyriproxyfen has been used in the affected areas for years.

Dr. Kamala also notes that patients with “observed Guillain–Barré syndrome” in a 2013 outbreak in French Polynesia “fits with a newly-developed neurotropic propensity for Zika.”

The question with regard to a possible link between pyriproxyfen and microcephaly was posed on Quora by a reported resident of Recife, Brazil, described as the “epicenter” of the Zika-virus outbreak. The resident stated that many in the area do not believe that Zika is responsible for the spike in microcephaly cases, and that a belief that “rubella vaccines, gmo mosquitoes, and lately, the drug pyriproxyfen” are the true culprit is held by many.

Genetically modified mosquitoes have been released in affected areas in Brazil. The plan was for the GM mosquitoes to mate with wild mosquitoes, which would produce nonviable larvae. The South American doctors responsible for the study have stated that the GM mosquitoes plan “failure is complete,” with less that 15 percent of larvae observed resulting from mating between wild female mosquitoes and GM males.

“Wild females are not accepting” of GM male mosquitoes, the authors of the report concluded.

[Photo by Mario Tama/Getty Images]