Pyriproxyfen is a pesticide which is found to be effective against a variety of
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s. It was introduced to the US in 1996, to protect cotton crops against
whitefly
Whiteflies are Hemipterans that typically feed on the undersides of plant leaves. They comprise the family Aleyrodidae, the only family in the superfamily Aleyrodoidea. More than 1550 species have been described.
Description and taxonomy
The A ...
. It has also been found useful for protecting other crops. It is also used as a prevention for flea control on household pets, for killing indoor and outdoor ants and roaches. Methods of application include aerosols, bait, carpet powders, foggers, shampoos and pet collars.
Pyriproxyfen is a
juvenile hormone analog and an
insect growth regulator. It prevents larvae from developing into adulthood and thus rendering them unable to reproduce.
In the US, pyriproxyfen is often marketed under the trade name ''Nylar''. In Europe, pyriproxyfen is known under the brand names Cyclio (
Virbac
Virbac is a French company dedicated to animal health located in Carros, near Nice. It was founded in 1968 by veterinarian Pierre-Richard Dick.
The company is the 6th the largest veterinarian pharmaceutical group with a turnover of 948 million ...
) and Exil Flea Free TwinSpot (Emax).
Toxicity in mammals
Pyriproxyfen has low acute toxicity.
According to
WHO
Who or WHO may refer to:
* Who (pronoun), an interrogative or relative pronoun
* Who?, one of the Five Ws in journalism
* World Health Organization
Arts and entertainment Fictional characters
* Who, a creature in the Dr. Seuss book '' Horton He ...
and
FAO
The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
, at elevated doses exceeding 5000 mg/kg of
body weight
Human body weight is a person's mass or weight.
Strictly speaking, body weight is the measurement of weight without items located on the person. Practically though, body weight may be measured with clothes on, but without shoes or heavy accessor ...
, pyriproxyfen affects the liver in mice, rats and dogs.
It also changes cholesterol levels, and may cause modest
anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
at high doses.
Rumor of link to microcephaly outbreak in Brazil
Starting in 2014, pyriproxifen was put into Brazilian water supplies to fight the proliferation of mosquito larvae. This is in line with the
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
(WHO)'s
Pesticide
Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
Evaluation Scheme (
WHOPES) for
larvicide
A larvicide (alternatively larvacide) is an insecticide that is specifically targeted against the larval life stage of an insect. Their most common use is against mosquitoes. Larvicides may be contact poisons, stomach poisons, growth regulators, o ...
s. In January 2016, the Brazilian Association for Collective Health (''Abrasco''; pt, Associação Brasileira de Saúde Coletiva) criticized the introduction of pyriproxyfen in Brazil. Abrasco demanded the "immediate suspension of
se of
SE, Se, or Sé may refer to:
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* ''Sé'' (album), by Lúnasa, 2006
* Se (instrument), a traditional Chinese musical instrument
Businesses and organizations
* Sea Ltd (NYSE: SE), tech conglomerate headquartered in Singapore ...
pyriproxyfen and all growth inhibitors ... in drinking water." The organization is opposed to the use of growth inhibitors in the context of an ongoing outbreak of fetal malformation.
On February 3, the rumor that pyriproxyfen, not the
Zika virus
''Zika virus'' (ZIKV; pronounced or ) is a member of the virus family ''Flaviviridae''. It is spread by daytime-active ''Aedes'' mosquitoes, such as '' A. aegypti'' and '' A. albopictus''. Its name comes from the Ziika Forest of Uganda, whe ...
, is the cause of the 2015-2016
microcephaly
Microcephaly (from New Latin ''microcephalia'', from Ancient Greek μικρός ''mikrós'' "small" and κεφαλή ''kephalé'' "head") is a medical condition involving a smaller-than-normal head. Microcephaly may be present at birth or it ...
outbreak in
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
was raised in a report of the Argentinean organization Physicians in the Crop-Sprayed Villages (PCST).
["Report from Physicians in the Crop-Sprayed Villages regarding Dengue-Zika, microcephaly, and mass-spraying with chemical poisons", Coordinator: Dr. Medardo Avila Vazquez](_blank)
''“Malformations detected in thousands of children from pregnant women living in areas where the Brazilian state added pyriproxyfen to drinking water is not a coincidence, even though the Ministry of Health places a direct blame on Zika virus for this damage, while trying to ignore its responsibility and ruling out the hypothesis of direct and cumulative chemical damage caused by years of endocrine and immunological disruption of the affected population.,”'' PCST said. It attracted wide media coverage.
The statement from Abrasco was cited in the PCST report; subsequently, Abrasco clarified that position as an misinterpretation of their statement, saying "at no time did we state that pesticides, insecticides, or other chemicals are responsible for the increasing number of microcephaly cases in Brazil". They also condemned the behavior of the websites that spread the misinformation, adding that such "untruths...violates the anguish and suffering of the people in vulnerable positions".
[Entidade diz ter sido mal-interpretada e não ver ligação entre microcefalia e larvicida](_blank)
/ref> In addition, the coordinator for the PCST statement, Medardo Ávila Vazquez, acknowledged in an interview that "the group hasn’t done any lab studies or epidemiological research to support its assertions, but it argues that using larvicides may cause human deformities."
On February 13, the Brazilian state of Rio Grande do Sul
Rio Grande do Sul (, , ; "Great River of the South") is a Federative units of Brazil, state in the South Region, Brazil, southern region of Brazil. It is the Federative_units_of_Brazil#List, fifth-most-populous state and the List of Brazilian st ...
suspended pyriproxyfen's use, citing both Abrasco and PCST positions. The Health Minister of Brazil, Marcelo Castro, criticized this step, noting that the claim is "a rumor lacking logic and sense. It has no basis." They also noted that the insecticide is approved by the National Sanitary Monitoring Agency and "all regulatory agencies in the whole world". The manufacturer of the insecticide, Sumitomo Chemical
is a major Japanese chemical company. The company is listed on the first section of the Tokyo Stock Exchange and is a constituent of the on the Nikkei 225 stock index. It's a member of the Sumitomo group and was founded in 1913 as a fertilize ...
, stated "there is no scientific basis for such a claim" and also referred to the approval of pyriproxyfen by the World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
since 2004 and the United States Environmental Protection Agency
A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
since 2001.
George Dimech, the director of Disease Control and Diseases of the Health Department of Pernambuco in Brazil, gave an interview to the BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
has the current highest reported number of cases of microcephaly, yet pyriproxyfen is not used in the region, but another insecticide altogether. He added that "this lack of spatial correlation weakens the idea that the larvicide is the cause of the problem." In addition, the BBC interviewed researchers in Pernambuco, where no evidence has been found of the cases being linked to any environmental cause like an insecticide. Neurologist Vanessa van der Linden stated in an interview, "Clinically, the changes we see in the scans of babies suggest that the injuries were caused by congenital infection and not by larvicide, drug or vaccine."
vaccine was the cause of the microcephaly outbreak, due to its introduction in 2014, along with adding, "One can’t help but wonder what else the Brazilian Ministry of Health did in 2014 that cranks can blame microcephaly on." Gorski also pointed out the extensive
, and that the doctor organization making the claim has been advocating against all pesticides since 2010, complicating their reliability.
in Australia, stated that "The effect of pyriproxyfen on reproduction and fetal abnormalities is well studied in animals. In a variety of animal species even enormous quantities of pyriproxyfen do not cause the defects seen during the recent Zika outbreak."
A colleague also from the University of Adelaide stated that "While the evidence that Zika virus is responsible for the rise in microcephaly in Brazil is not conclusive, the role of pyriproxyfen is simply not plausible."
Another professor in Australia concluded that "insect development is quite different to human development and involves different hormones, developmental pathways and sets of genes, so it cannot be assumed that chemicals affecting insect development also influence mammalian development."