Names | |
---|---|
IUPAC names 4-Phenoxyphenyl (R/S)-2-(2-pyridyloxy)propyl ether 2-[1-(4-Phenoxyphenoxy)propan-2-yloxy]pyridine | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChemSpider | |
ECHA InfoCard | 100.102.814 |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
| |
| |
Properties | |
C20H19NO3 | |
Molar mass | 321.376 g·mol−1 |
Appearance | Colorless crystals [1] |
Density | 1.2 g/cm3 [1] |
Melting point | 48–50 °C (118–122 °F; 321–323 K) [2] |
Boiling point | 318 °C (604 °F; 591 K) [2] |
0.367 mg/L [2] | |
Pharmacology | |
QP53AX23 ( WHO ) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Pyriproxyfen is a pesticide which is found to be effective against a variety of insects. [3] It was introduced to the US in 1996, to protect cotton crops against whitefly. It has also been found useful for protecting other crops. [4] It is also used as a prevention for flea control on household pets, for killing indoor and outdoor ants and roaches. [5] Methods of application include aerosols, bait, carpet powders, foggers, shampoos and pet collars. [6]
Pyriproxyfen is a juvenile hormone analog (IRAC group 7C) and an insect growth regulator. [7] It prevents larvae from developing into adulthood and thus rendering them unable to reproduce. [8]
In the US, pyriproxyfen is often marketed under the trade name Nylar, [9] and is one of two active ingredients in Advantage II. In Europe, pyriproxyfen is known under the brand names Cyclio (Virbac) [10] and Exil Flea Free TwinSpot (Emax).
Pyriproxyfen has low acute toxicity. [11] According to WHO and FAO, at elevated doses exceeding 5000 mg/kg of body weight, pyriproxyfen affects the liver in mice, rats and dogs. [12] It also changes cholesterol levels, and may cause modest anemia at high doses. [13]
Starting in 2014, pyriproxifen was put into Brazilian water supplies to fight the proliferation of mosquito larvae. [14] This is in line with the World Health Organization (WHO)'s Pesticide Evaluation Scheme (WHOPES) for larvicides. [15] In January 2016, the Brazilian Association for Collective Health (Abrasco; Portuguese : Associação Brasileira de Saúde Coletiva) criticized the introduction of pyriproxyfen in Brazil. Abrasco demanded the "immediate suspension of [use of] 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. [16]
On February 3, the rumor that pyriproxyfen, not the Zika virus, is the cause of the 2015-2016 microcephaly outbreak in Brazil was raised in a report of the Argentinean organization Physicians in the Crop-Sprayed Villages (PCST). [17] It attracted wide media coverage. [18] [19] The statement from Abrasco was cited in the PCST report; subsequently, Abrasco clarified that position as a 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". [20] 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." [21]
On February 13, the Brazilian state of Rio Grande do Sul suspended pyriproxyfen's use, citing both Abrasco and PCST positions. [22] [23] 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, stated "there is no scientific basis for such a claim" and also referred to the approval of pyriproxyfen by the World Health Organization since 2004 and the United States Environmental Protection Agency since 2001. [24] [25]
George Dimech, the director of Disease Control and Diseases of the Health Department of Pernambuco in Brazil, gave an interview to the BBC where he pointed out that the city of Recife 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." [20]
Noted skeptic David Gorski called the claim a conspiracy theory and pointed out that antivaccine proponents had also claimed that the Tdap 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 physiochemical understanding of pyriproxyfen coded in the WHO Guidelines for Drinking-water Quality, which concluded in a past evaluation that the insecticide is not genotoxic, and that the doctor organization making the claim has been advocating against all pesticides since 2010, complicating their reliability. [26] [27] [28]
A professor from the University of Adelaide 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." [29] 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." [29] 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." [29]
Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains—particularly in the back—and headaches. Symptoms typically improve within five days. In about 15% of people, within a day of improving the fever comes back, abdominal pain occurs, and liver damage begins causing yellow skin. If this occurs, the risk of bleeding and kidney problems is increased.
Dengue fever is a mosquito-borne disease caused by dengue virus, prevalent in tropical and subtropical areas. It is frequently asymptomatic; if symptoms appear they typically begin 3 to 14 days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic skin itching and skin rash. Recovery generally takes two to seven days. In a small proportion of cases, the disease develops into severe dengue with bleeding, low levels of blood platelets, blood plasma leakage, and dangerously low blood pressure.
Aedes is a genus of mosquitoes originally found in tropical and subtropical zones, but now found on all continents except Antarctica. Some species have been spread by human activity: Aedes albopictus, a particularly invasive species, was spread to the Americas, including the United States, in the 1980s, by the used-tire trade.
An insect repellent is a substance applied to the skin, clothing, or other surfaces to discourage insects from landing or climbing on that surface. Insect repellents help prevent and control the outbreak of insect-borne diseases such as malaria, Lyme disease, dengue fever, bubonic plague, river blindness, and West Nile fever. Pest animals commonly serving as vectors for disease include insects such as flea, fly, and mosquito; and ticks (arachnids).
Aedes aegypti, the yellow fever mosquito, is a mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito can be recognized by black and white markings on its legs and a marking in the form of a lyre on the upper surface of its thorax. This mosquito originated in Africa, but is now found in tropical, subtropical and temperate regions throughout the world.
Temefos or temephos is an organophosphate larvicide used to treat water infested with disease-carrying insects including mosquitoes, midges, and black fly larvae.
Mosquito control manages the population of mosquitoes to reduce their damage to human health, economies, and enjoyment. Mosquito control is a vital public-health practice throughout the world and especially in the tropics because mosquitoes spread many diseases, such as malaria and the Zika virus.
Methoprene is a juvenile hormone (JH) analog which acts as a growth regulator when used as an insecticide. It is an amber-colored liquid with a faint fruity odor.
A larvicide 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, or (increasingly) biological control agents.
Zika fever, also known as Zika virus disease or simply Zika, is an infectious disease caused by the Zika virus. Most cases have no symptoms, but when present they are usually mild and can resemble dengue fever. Symptoms may include fever, red eyes, joint pain, headache, and a maculopapular rash. Symptoms generally last less than seven days. It has not caused any reported deaths during the initial infection. Mother-to-child transmission during pregnancy can cause microcephaly and other brain malformations in some babies. Infections in adults have been linked to Guillain–Barré syndrome (GBS).
Mosquito-borne diseases or mosquito-borne illnesses are diseases caused by bacteria, viruses or parasites transmitted by mosquitoes. Nearly 700 million people contract mosquito-borne illnesses each year, resulting in more than a million deaths.
Zika virus 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, where the virus was first isolated in 1947. Zika virus shares a genus with the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Since the 1950s, it has been known to occur within a narrow equatorial belt from Africa to Asia. From 2007 to 2016, the virus spread eastward, across the Pacific Ocean to the Americas, leading to the 2015–2016 Zika virus epidemic.
Naled (Dibrom) is an organophosphate insecticide. Its chemical name is dimethyl 1,2-dibromo-2,2-dichloroethylphosphate.
A lethal ovitrap is a device which attracts gravid female container-breeding mosquitoes and kills them. The traps halt the insect's life cycle by killing adult insects and stopping reproduction. The original use of ovitraps was to monitor the spread and density of Aedes and other container-breeding mosquito populations by collecting eggs which could be counted, or hatched to identify the types of insects. Since its conception, researchers found that adding lethal substances to the ovitraps could control the populations of these targeted species. These traps are called lethal ovitraps. They primarily target Aedes aegypti and Aedes albopictus mosquitoes, which are the main vectors of dengue fever, Zika virus, west Nile virus, yellow fever, and chikungunya.
Oxitec is a British biotechnology company that develops genetically modified insects in order to improve public health and food security through insect control. The insects act as biological insecticides. Insects are controlled without the use of chemical insecticides. Instead, the insects are genetically engineered to be unable to produce offspring. The company claims that this technology is more effective than insecticides and more environmentally friendly.
An epidemic of Zika fever, caused by Zika virus, began in Brazil and affected other countries in the Americas from April 2015 to November 2016. The World Health Organization (WHO) declared the end of the epidemic in November 2016, but noted that the virus still represents "a highly significant and long term problem". It is estimated that 1.5 million people were infected by Zika virus in Brazil, with over 3,500 cases of infant microcephaly reported between October 2015 and January 2016. The epidemic also affected other parts of South and North America, as well as several islands in the Pacific.
In October 2013, there was an outbreak of Zika fever in French Polynesia, the first outbreak of several Zika outbreaks across Oceania. With 8,723 cases reported, it was the largest outbreak of Zika fever before the outbreak in the Americas that began in April 2015. An earlier outbreak occurred on Yap Island in the Federated States of Micronesia in 2007, but it is thought that the 2013–2014 outbreak involved an independent introduction of the Zika virus from Southeast Asia. Investigators suggested that the outbreaks of mosquito-borne diseases in the Pacific from 2012 to 2014 were "the early stages of a wave that will continue for several years", particularly because of their vulnerability to infectious diseases stemming from isolation and immunologically naive populations.
This article primarily covers the chronology of the 2015–16 Zika virus epidemic. Flag icons denote the first announcements of confirmed cases by the respective nation-states, their first deaths, and relevant sessions and announcements of the World Health Organization (WHO), and the U.S. Centers for Disease Control (CDC), as well as relevant virological, epidemiological, and entomological studies.
Celina Maria Turchi Martelli is a Brazilian epidemiologist, graduated by Federal University of Goiás and researcher at Fundação Oswaldo Cruz in Recife. She first associated the link between zika virus and microcephaly in newborn babies during the 2015 disease outbreak in Brazil; she was listed by Nature magazine as one of the 10 most notable people in science in 2016, and by Time magazine as one of the 100 most influential people of 2017.
Howard Carter is a British inventor and businessman. He foundered Incognito in 2007. He is an expert in the field of insects and specifically as a mosquito bite prevention expert. After contracting two life-threatening diseases from mosquito bites, despite using a high-percentage DEET-based repellent, he was motivated to invent a totally natural, equally effective mosquito repellent, incognito anti-mosquito. This was, in part, because statistics were suggesting more mosquitoes were becoming resistant to synthetic repellents that contained controversial pesticides such as DDT and DEET.
...it was not necessary to establish an acute reference dose because of the low acute toxicity of pyriproxyfen.
reivindicamos das autoridades competentes a adoção das medidas a seguir: ... (3) Nas medidas adotadas pelo MS [Ministério da Saúde] para controle de Aedes aegypti em suas formas larva e adulto, imediata suspensão do Pyriproxyfen (0,5 G) e de todos os inibidores de crescimento como o Diflubenzuron e o Novaluron, ou qualquer outro produto químico ou biológico em água potável.