Friday, January 29, 2016

Debunking the myths surrounding the Zika virus outbreak in South America

So there have been several conspiracy theories presented to suggest that the Zika virus outbreak in Brazil was man made. I'll try and address two regarding the outbreak that I have come across.

The first and easiest CT to debunk is the the notion that the Zika virus outbreak occurred because of the field trial of the genetically engineered mosquitoes in Brazil. This is based on the outbreak occurring after the field trial (conducted in 2011) and starting in the general area the field trial happened. However, when the evidence is examined, this CT falls apart.

The location of the Zika virus outbreak in Brazil, 2015

The interesting thing about this image is that it is shows the occurrence of microcephaly cases and the start of the outbreak. A similar image with the heading intact can be found here. But this map does show an important clue to the start of the outbreak. A large number of microcephaly cases are concentrated around the city of Natal in the state of Rio Grande do Norte (on the eastern tip where the cases are clustered). This is in fact the city where symptoms similar to Zika (but not Dengue or Chikungunya) were first described in Brazil. This next connection is a stretch; the location of the field trials of GE mosquitoes conducted by Oxitec. 

The "location" of the Oxitec GE mosquito field trials
The problem here is that the Oxitec field trials happened in Juazeiro in the state of Bahia and this map is pointing at Juazeiro do Norte in the state of Ceará. Juazeiro do Norte is about 626.1 km from Natal and 371.8 km from Juazeiro. It is 880 km from Juazeiro to Natal (note these are driving distances). So, the actual city where the field trials began is a bit further away from the start of the outbreak. It's still plausible, but less likely. Part of this is because mosquitoes can only travel about 58.2 m so that is a great distance for them to be carried. It also helps to understand exactly what the trials tested.

The field trial tested the ability of GE male Aedes aegypti mosquitoes to impact the population size in the trial location.The results were astounding with a population reduction of >90%. The way that the mosquitoes were altered plays a huge role in the success of the experiment. The mosquito has been genetically sterilized in an improvement on the sterile insect technique. Normally, male insects are sterilized with radiation but that has the drawback of zapping insects with radiation which can reduce their fitness. The GE mosquito is still as fit as any other male mosquito, it just doesn't produce viable offspring. But there is a catch, a common antibiotic called tetracycline can interfere with the genetic mechanism that causes the mosquito to be sterile. This increases the fertility of the males a bit.

The way tetracycline inhibits the sterilization of Oxitec GE mosquitoes.

There is an issue here though, this assumes that the tetracycline would be present in high enough levels to increase fertility, the level needed for this has been empirically determined. Unfortunately for the CT, the levels of tetracycline compounds would need to be 746 to 2500 times greater than the highest reported environmental levels of tetracycline compounds.

Another issue that I haven't brought up is there are two Aedes mosquitoes in Brazil that are of concern, the aforementioned Aedes aegypti and a relative, Aedes albopictus. Although it hasn't been demonstrated to be a vector, A. albopictus populations (I'll have another blog post on this soon) would not be impacted by sterile A. aegypti males. So with two potential vector species (there may be more but that is another blog post), it's not likely that failing to fully knock out ones that escaped the field trial would increase the spread of a virus.

One last point here, I also came across another GE mosquito CT that Bill Gates was spreading Zika virus with the GE mosquitoes. This is crazy because the GE mosquitoes are male and male mosquitoes don't bite. To release something they don't have approval for would be the end of a small company like Oxitec.

The final CT I will discuss, is the claim that the Tdap vaccine is what is causing the microcephaly. This runs the gambit from tainted vaccine to just regular old vaccine and it is harder to address. The basis for this idea is that the Zika virus was discovered in 1947 and there have been no records of microcephaly until the outbreak in Brazil. There are several problems with this idea. The first is that Zika virus was a rare virus in humans until very recently. Also, further analysis of the outbreak in French Polynesia has shown an increase in neurological defects in babies during that time. Another problem is that the Tdap vaccine has never been associated with microcephaly and Brazil has had a 20-fold increase in cases since the outbreak began. They are also suggesting the wrong vaccine if they'd like a chance of being plausible with the CT. Rubella is another virus that causes microcephaly (27% chance if infection occurs in the first trimester), so the MMR vaccine would be the logical choice. 

So in summation, please don't trust everything you read on the internet. Some of it may be the insane ramblings of someone on Reddit, or it might be scare tactics to try and further an agenda.


  1. Also a lot of claims say that the TDAP was given to pregnant mothers nationwide, however the microcephalic outbreak was not nationwide but clustered

  2. also if gmo mosquitoes surviving and reproducing were to blame then there should be lots of gmo mosquitoes in the affected areas. Since the oxitec mosquitoes have a flourescence gene it should be easy enough to capture mosquitoes specially females and then see if they glow under blacklight

  3. Isn't most of the TCN concern with Wolbachia population control?

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  5. Hello, I found your article very convincing. I don't find Oxitec rosponsible either..
    However, there is still a major theory (with scientific backup, check the link please) for the microcephaly outbreak, which is the wide use of Atrazine as fertilizer in Brasil, and specially in the area of the outbreak

    I would like to hear your opinion about it :)

    1. Round Up (Gliphosphate) is linked with microcephaly:
      Congenital malformations and pesticide exposure].

      Risk for congenital malformations in pregnant women exposed to pesticides in the state od Nayarit, Mexico].

      [Article in Spanish]

      Medina-Carrilo L1, Rivas-Solis F, Fernández-Argüelles R.

      Maternal and paternal occupational exposure to agricultural work and the risk of anencephaly.

      Lacasaña M1, Vázquez-Grameix H, Borja-Aburto VH, Blanco-Muñoz J, Romieu I, Aguilar-Garduño C, García AM.

      Congenital Malformations Associated with Toxic Agricultural Chemicals"

      Malformaciones congénitas asociadas a agrotóxicos
      Congenital Malformations Associated with Toxic Agricultural Chemicals
      Benítez-Leite S1, Macchi ML1, Acosta M2.

      1. Cátedra de Pediatría. Centro Materno Infantil (CMI). Facultad de Ciencias Médicas. UNA-Paraguay.

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  9. «One last point here, I also came across another GE mosquito CT that Bill Gates was spreading Zika virus with the GE mosquitoes. This is crazy because the GE mosquitoes are male and male mosquitoes don't bite.»

    — But male mosquitoes can transmit arboviruses to female mosquitoes when they mate:

    (p. 7) «When vertical transmission occurs, the infectious agents are equally distributed between male and female progeny. In Drosophila melanogaster infected with sigma virus (which is not an arbovirus), vertical transmission to the following generation is possible through both male and male lines (Section 41.3.2.b). With mosquito-borne arboviruses, only vertical transmission through the female line is known. Infection of spermatozoa and direct transfer from adult male mosquitoes to their progeny have never been described, but it has been looked for in only one or two species, so a blanket dismissal of the possibility would be rash. Some arboviruses can be transmitted horizontally by venereal transmission, i.e., from male to female mosquitoes during copulation, and this can lead to indirect transference of arbovirus from adult male hosts to their progeny.»

    (pp. 119-124) «44.5 VENEREAL TRANSMISSION
    44.5.1 Introduction»

    «Venereal transmission has not ben observed between mosquitoes in the field, but it has been demonstrated in the laboratory with species of Ochlerotatus, Stegomya and Halaedes, and arboviruses of the families Bunyaviridae, Flaviviridae and Togaviridae.»

    — Alan N Clements. "The Biology of Mosquitoes, Volume 3: Transmission of Viruses and Interactions with Bacteria." CABI, 2012. ISBN-13: 978-1845932428


    • Mavale M et al. "Venereal transmission of chikungunya virus by Aedes aegypti mosquitoes (Diptera: Culicidae)." The American Journal of Tropical Medicine and Hygiene (2010) vol. 83 (6) pp. 1242-4

    • Thompson WH and Beaty BJ. "Venereal transmission of La Crosse (California encephalitis) arbovirus in Aedes triseriatus mosquitoes." Science (1977) vol. 196 (4289) pp. 530-1

    1. Apparently, Oxitec Ltd., the company that produces the GM mosquitoes, hasn't been fully honest as to the information provided in its website:

      «Do all mosquitoes spread Dengue Fever or Chikungunya?
      No. Aedes aegypti is the species of mosquito which is primarily responsible for spreading dengue. Also, only female mosquitoes can spread dengue or chikungunya. Males do not bite or spread disease (in fact males cannot bite).»

      — Oxitec Ltd. "Do all mosquitoes spread Dengue Fever or Chikungunya?"

      • Mavale M et al. "Venereal transmission of chikungunya virus by Aedes aegypti mosquitoes (Diptera: Culicidae)." The American Journal of Tropical Medicine and Hygiene (2010) vol. 83 (6) pp. 1242-4

    2. It´s well known that only females bite and spread disease, but, SO FAR, HOW CAN ONE BE SURE THAT ONLY MALES WERE RELEASED TO THE ENVIRONLMENT??? First of all, the selection process was done manually.
      Besides, Brazil is third in the world for its use of tetracycline in its food animals. As a study by the American Society of Agronomy, et. al., explained, “It is estimated that approximately 75% of antibiotics are not absorbed by animals and are excreted in waste.” One of the antibiotics (or antimicrobials) specifically named in that report for its environmental persistence is tetracycline.

      In fact, as a confidential internal Oxitec document divulged in 2012, that survival rate could be as high as 15% — even with low levels of tetracycline present. “Even small amounts of tetracycline can repress” the engineered lethality. Indeed, that 15% survival rate was described by Oxitec:

      “After a lot of testing and comparing experimental design, it was found that [researchers] had used a cat food to feed the [OX513A] larvae and this cat food contained chicken. It is known that tetracycline is routinely used to prevent infections in chickens, especially in the cheap, mass produced, chicken used for animal food. The chicken is heat-treated before being used, but this does not remove all the tetracycline. This meant that a small amount of tetracycline was being added from the food to the larvae and repressing the [designed] lethal system.”

  10. I’ve concluded that the way TDap causes microcephaly is that there is an undisclosed ingredient: tachyons! They travel back in time from when they’re administered in the third trimester to make microcephaly visible in the second.QED.

  11. I really like your writing style, great thankyou for posting.
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