Controversy on Pyriproxyfen larvicide established in Latin America

A real controversy was established in Latin America from a possibility raised by the NGO PCST (Physicians in the Crop-Sprayed Towns), in which doctors and Argentinean researchers affirm that the brain malformation – caused by the zika virus – could be worsened by the Pyriproxyfen larvicide. The product, manufactured by Sumitomo Chemical, is widely used by the Brazilian government combating the Aedes aegypti, which transmits the disease.

With the release of the PCST report, the Health Department of the state of Rio Grande do Sul in Brazil, a neighboring state with Argentina, suspended this weekend the applications of Pyriproxyfen. “We've decided to suspend the use of the product in water for human consumption until there is a position of the Health Ministry and, therefore, we will strengthen the appeal for the population to eliminate any possible focus of the mosquito,” explained the state's Health secretariat, João Gabbardo dos Reis.

However, the hypothesis of the NGO was not validated by any scientific institution, being published just at the website of the University Network of Environment and Health (REDUAS). The Brazilian Health Ministry announced officially stating that there is no epidemiological study connecting Pyriproxifen to microcephaly.

The Brazilian government sustains yet that the product is recommended by the World Health Organization. In a statement, the Health Ministry guarantees that uses only products that pass through “the rigorous procedure of evaluation of the World Health Organization Pesticide Evaluation Scheme (WHOPES)”, and that Pyriproxifen “has a certification of the National Health Surveillance Agency (Anvisa)”.

“Contrary to the relation between zika and microcephaly, which has already had its confirmation attested on tests that indicated the presence of the virus in blood samples, tissue and amniotic fluid, the association between the use of pyriproxifen and microcephaly does not have a scientific basis,” said the official statement.

The manufacturer of the product, Sumitomo Chemical, clarifies that “there is no scientific basis” in the statement of the NGO PCST. “Pyriproxyfen is a product approved by Anvisa for the use in public health campaigns, like the larvicide-insecticide, controlling the disease vectors, among them the mosquitos Aedes aegypt, Culex quinquefasciatus and the housefly”.

The product is registered in the country since 2004 and it is used to combat the Aedes aegypti in countries such as Turkey, Saudi Arabia, Denmark, France, Greece, Netherlands, Spain, Dominican Republic and Colombia. “According to WHO, in its document on Pyriproxyfen in Drinking-water, published in 2004 – also published by the U.S. Environmental Protection Agency in 2001 -, Pyriproxyfen is not mutagenic, genotoxic, carcinogenic nor teratogenic. The product was submitted to strict toxicological tests that did not demonstrate reproduction effects over the central nervous system,” said the Sumitomo statement.