Genes, bugs and radiation: WHO backs new weapons in Zika fight

[HuckleB]

Source: Reuters

Countries battling the Zika virus should consider new ways to curb disease-carrying mosquitoes, including testing the release of genetically modified insects and bacteria that stop their eggs hatching, the World Health Organization said on Tuesday.

"Given the magnitude of the Zika crisis, WHO encourages affected countries and their partners to boost the use of both old and new approaches to mosquito control as the most immediate line of defence," it said.

The WHO also highlighted the potential of releasing sterile irradiated male mosquitoes, a technique that has been developed at the United Nations’ International Atomic Energy Agency (IAEA).

Zika, which is now sweeping the Americas, is transmitted primarily by the Aedes aegypti mosquito, which the U.N. health body described as an "opportunistic and tenacious menace".

Read more: http://www.reuters.com/article/us-health-zika-idUSKCN0VP15D

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[Duval]

1. I heard Hartmann mention something about a chemical that was sprayed in the country where

the virus has caused birth defects. He mentioned that another country didn't use this pesticide and although the virus is there, too, there are no cases yet of birth defects. Interesting, I think. We need more investigation.

[HuckleB]

2. That was probably a version of a bad conspiracy theory going around.

http://scienceblogs.com/insolence/2016/02/15/say-it-aint-so-george-george-takei-falls-for-a-zika-virus-conspiracy-theory/

https://www.scimex.org/newsfeed/expert-reaction-is-a-pesticide-not-zika-virus-causing-microcephaly

Alas, too many people are too willing to spread things that are nearly implausible, these days.

[Yo_Mama]

3. No, it's not the larvacide pyriproxyfen

https://en.wikipedia.org/wiki/Pyriproxyfen

That's been in use for a very long time in a very wide range of countries. It is very non-active in mammals, because it targets a hormone found in insects, not in mammals. It's in anti-flea agents used in households in the US.

Honest to God, it really isn't the larvacide.

The suggestion that Columbia's pregant females who have tested positive for zika but-no-microcephaly disproves the zika thing is nonsense, and is proof that those alleging this are ignorant, lying, or have deluded themselves. Because first, there is not a good test for zika. You need PCR to confirm, which believe me they are not doing. Some of the pregnant women who tested positive probably don't have it at all and instead are carrying cross-reactive antibodies from similar viruses.

Second, testing positive for antibodies only says that you have encountered the virus. It doesn't say when. It seems likely that the initial illness has to occur during pregnancy, and probably during a particular time in pregnancy, in order to cause the associated brain infection. Many of the pregnant women with zika may test positive but have encountered the virus before pregancy, or may not have the virus at all.

Third, you have to wait and see. They will follow the women to see if their fetus develop problems, or they have miscarriages, or so forth.

Further, the timing of the Guillain-Barre and the microcephaly doesn't match with the larvacide initiation in the particular locale, nor are all the microcephaly cases from that region by a long shot.

http://www.foxnews.com/health/2016/02/15/guillain-barre-on-rise-in-five-latam-countries-no-proven-link-to-zika-who.html

Dengue and zika were linked to Guillain-Barre in French Polynesia, and the full sequence of the zika virus found in the brain of the Slovenian/Brazilian case matched to the French Polynesia variant quite closely.

http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20720
This article about the zika/Guillain Barre case is from 2014 and is reported from French Polynesia.

It appears that zika is involved. One of two things may be true. The first is that the virus mutated during its travels and became neurotropic to a degree that it was not before. The second is that the human population in the area where the virus was known had immunities, and so systemic zika infection was very much less likely and therefore this problem wasn't noted before.

Or both may be true.

Pregnant women's immune systems are naturally somewhat suppressed, so a pregnant woman exposed to a virus that was novel to the area might get a more severe case than normal.

It is very, very, very, very, very, very, very unlikely, as in just not the case, that a larvacide has anything to do with this. You practically have to drink a cupful of pyriproxyfen to get ill.

There is necessarily a delay between infection in earlier pregnancy and the discovery of the problem at birth, and the virus is new to that area. After introduction it takes a while to spread. Sadly, if zika is the cause of the microcephaly cases, those will show up eventually in Columbia as well.

Brazil had about three million births in 2014. They have cast a wide surveillance net, and come up with a total of about 4,000 microcephaly cases based purely on head circumference. Some of those are just normal variation. Some of the microcephaly cases will have other causes. It's impossible to estimate an incidence rate at this juncture, but whatever it is, it is not that high.