Access: Zika and microcephaly: things to know
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Rosemary McDonald, in reply to
After an exhaustive websearch, well into the wee hours, I can find no mention of a link between the Zika virus and microcephaly prior to the recent reports.
What was extremely prominent was the 'conspiracy theory' that there is some link between the release of the Bill Gates GE super mosquito in that particular region of Brazil (the north east) and the current Zika outbreak and microcephaly.
I know. I know. These are maybe not 'credible' sources...but...from the horses mouth.. http://www.oxitec.com/health/florida-keys-project/
We have introduced a gene into the mosquitos so that their cells do not function as they should, and this effect is specific to the mosquito (also known as a ‘self-limiting’ gene because it makes mosquito reproduction a dead end – the offspring do not survive to adulthood). As a result over 95% of the Oxitec mosquitos die before they become adults and do not live to breed further, and the population is reduced. Aedes aegypti do not produce offspring with other species so the control is species-specific and the genes don’t spread. The released mosquitos and their offspring die and so the genes also do not persist in the environment.
all good so far, but
We need to be able to rear millions of males per week, so we have engineered the mosquito to make production cost effective. If the mosquito larvae in the production unit are given tetracyclines, these act as an antidote inactivating the self-limiting gene. The antidote is not present in sufficient quantities in the environment to allow inactivation of the self-limiting gene, so offspring of the Oxitec mosquito will not reach adulthood.
Unfortunately, that particular part of Brazil has one of the highest rates of agricultual use of tetracyclines in the world.
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Hilary wrote:
the main effect of Zika Virus infection seems to be the risk of microcephaly to babies born to infected mothers.
Once a women is infected does that mean she is forever at risk of giving birth to a child with microcephaly?
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Breathe easy...MoPI is on the case.
In 2015, four live female Aedes-aegypti were caught by MPI officers in Auckland.
Three were found at Auckland International Airport and one was found in a container of pineapples from the Philippines at Turners and Growers in Auckland.
I wonder if anyone from MoPI is checking out for possible incursions in the winterless north?
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Hilary Stace, in reply to
I've no idea. But it seems to be a growing fear. Of course, Rosemary might be right and it is not quite as straightforward.
As a historian of polio and autism I find the parallels with the current 'Zika-caused microcephaly crisis' fascinating.
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Rosemary McDonald, in reply to
Rosemary might be right and it is not quite as straightforward.
or she may be wrong...
This article says that Zika could be similar to the cytomegalovirus..."CMV"
About one in 750 children in the United States is born with or develops permanent problems due to CMV infection during pregnancy, according to the Centers of Disease Control and Prevention. A national survey in 1995 found close to 40 percent of congenital CMV cases — those detected at birth — may experience microcephaly. In general, more than 5,000 U.S. children per year suffer permanent problems caused by CMV infection during pregnancy. CMV spreads by direct contact with bodily fluids — urine, saliva, or breast milk — and not mosquitoes.
But how? Spindler says the connection between CMV and brain abnormalities isn’t completely understood, but one study suggests that the virus attacks stem cells during early brain development while also causing the general destruction of other brain tissue. The early loss of stem cells may keep a fetal brain from forming the correct architecture.
Who knows?
But...Zika has been found to infect humans since 1952...why the sudden spike now?
And why is it now linked to microcephaly, in Brazil anyway.
This gets weirder by the minute.
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Bart Janssen, in reply to
After an exhaustive websearch, well into the wee hours, I can find no mention of a link between the Zika virus and microcephaly prior to the recent reports.
What was extremely prominent was the ‘conspiracy theory’ that there is some link between the release of the Bill Gates GE super mosquito in that particular region of Brazil (the north east) and the current Zika outbreak and microcephaly.
There is a much simpler and more scientifically plausible explanation.
Zika has been widespread in Africa for 40+ years. Most Africans will have been exposed to it as a child and will have developed an immunity.
So when it come time to have children none of the mother will catch Zika, they are already immune.
Now Zika has spread to South America, which has no history of Zika. None of the women have any immunity, so as Zika spreads it infects pregnant women and appears to lead to microcephaly.
In a generation, once Zika is established in South America the rates will drop again. However nobody wants to wait because that would be inhumane.
No weird super mosquito conspiracy theory needed.
BTW that "super mosquito" was far from super. They were males modified to mate with females but fail to produce viable offspring, since mosquito females only mate once in their lives that means a generation of mosquitos fails. The results of the trials were better than anyone could have hoped.
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Rosemary McDonald, in reply to
and appears to lead to microcephaly.
I could find no reference, anywhere, that prior to this current outbreak of Zika in Brazil that the Zika virus causes microcephly in the unborn babies of infected pregnant women.
If Zika has been widespread in Africa for forty plus years, and Zika is the cause of the rather large spike of babies born with micocephaly in Brazil over the past few months then there must surely be a corresponding rate of microcephaly in the babies of African women infected with Zika over the past forty years. The only 'data' I could find on rates of microcephaly worldwide came with a red print warning that the data was unreliable.
http://www.rightdiagnosis.com/m/microcephaly/stats-country.htm
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linger, in reply to
there must surely be a corresponding rate of microcephaly in the babies of African women infected with Zika
No, for the same reason that we don’t have a high incidence of shingles in the adult population (i.e., most people get chicken pox in childhood and thereby become immune).
Where Zika and its carrier are endemic, then people get, and recover from, and become immune to, Zika in childhood, therefore don’t get it during pregnancy. It’s only where the carrier invades new territory (as in Brazil) that large numbers of previously unexposed adults can get Zika. -
Hilary Stace, in reply to
My understanding is that you can readily get shingles even after having chickenpox. That is a different type of virus, and includes other manifestations such as cold sores. It lurks and pops up in times of immune stress. But you can't get chicken pox twice (unless you are immune compromised from something like cancer treatment).
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You’re right that chickenpox isn’t a perfect protection against shingles (if you get it before 18 months of age, or if your immune system is weakened, it can reactivate as shingles in later life), but they are caused by the same virus:
Shingles is due to a reactivation of varicella zoster virus (VZV) within a person’s body. Chickenpox is due to an initial infection with VZV
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As one would expect; an intelligent, measured, sensitive piece about the disadvantage those with disabilities in general, and microcephaly in particular, face in Brazil.
From Al Jazeera
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Bart Janssen, in reply to
That is a different type of virus
No it is the same virus – it’s just that after 50 or so years the immunity you developed as a child degrades enough to allow the virus to reemerge.
Oh and there is a free vaccine for us old folks - just ask your doctor - trust me you don't want shingles.
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Bart Janssen, in reply to
If Zika has been widespread in Africa for forty plus years, and Zika is the cause of the rather large spike of babies born with micocephaly in Brazil
As Linger said, that is because African women are already immune by the time they ever get pregnant.
There almost certainly was a low level of Zika-induced microcephaly in Africa but it probably was never enough to stand out as unusual. As we've seen microcephaly is not incredibly rare.
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Hilary Stace, in reply to
I meant different virus from Zika - ie the shingles/chickenpox Varicella zoster virus stays in the body and can emerge at times of immune stress.
On the first exposure you will get chickenpox and have some immunity but decades later an exposure of someone who has already had chickenpox can get shingles.
I have a friend who was very sick in her 50s from chickenpox which she caught from her .grandchildren. My daughter, having had cancer treatment as a child, had chickenpox first and then has had several doses of shingles (as a child and adult). I am considering getting a shingles immunisation - as I have seen how debilitating it can be in older people - but it costs about $200.
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Bart Janssen, in reply to
– but it costs about $200.
I thought it was free if you were er of a certain age?
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Hilary Stace, in reply to
Haven't heard that. Maybe in some practices but shingles immunisation is not subsidised as far as I know.
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Latest theory seems to be that the Zika virus is mutating so that it is taken up more easily by the mosquito and is more infectious to humans.
Meanwhile new polio cases have appeared in Pakistan/Afghanistan when it finally appeared a few months ago to be eradicated. I find the links between these viruses causing panic and epidemic re disabled children 100 years apart so interesting.
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Rosemary McDonald, in reply to
Latest theory seems to be that
....the rate of microcephaly now being seen in Brazil is about the same rate as in the USA....
Very interesting blog from an actual virologist.
Possible Association Between Zika Virus Infection and Microcephaly — Brazil, 2015
Reads as though some great data may finally show us a hint of an association between Zika virus (ZIKV) infection and microcephaly disease. Right?
Nope. There are none. At least none that could approach satisfying that title which highlights that it is not just the popular media who can generate misleading titles (headlines in their case).
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The Scientist reports...
A review of four years’ worth of medical records finds far greater numbers of microcephaly cases from before the ongoing Zika virus epidemic than had been officially reported.
and references this Lancet article which suggests that..
Although there is evidence of an increased number of cases of microcephaly in Brazil, we show that the number of suspected cases relied on a screening test that
had very low specificity and therefore overestimated the actual number of cases by including mostly normal children with small heads. We recommend that national
and international agencies should refrain from reporting suspected cases and speed up investigation to report on confirmed cases with laboratory or radiological evidence. It is also important that health workers measure head circumference in all newborn babies using standardised anthropometric techniques, and report results in mm. -
it appears there are many ‘angles’ dancing on these 'pinheads'….
luckily the quantity of possible ‘angels’ has been fully examined:
http://www.improbable.com/airchives/paperair/volume7/v7i3/angels-7-3.htm
…eventually they will get to the point! -
linger, in reply to
Latest theory seems to be that the Zika virus is mutating so that it is taken up more easily by the mosquito and is more infectious to humans
Yes, comparing the Brazilian outbreak to its earlier spread through Asia (mild effects only; this is attributed, speculatively, to previous vaccination programmes against encephalitis in the region) and French Polynesia (associated with significantly higher than usual incidence of Guillain-Barre syndrome, and – on subsequent checking – slightly but nonsignificantly higher microcephaly). So there are other local factors in play, making direct comparison difficult to interpret.
The possibility of a Brazil-specific Zika mutation can’t yet be ruled out*, and seems plausible at first sight given the widespread use there of mutagenic pesticides banned elsewhere … but also, the evidence that microcephaly is linked to Zika in Brazil is still only circumstantial: the causal chain, if it exists, has not yet been established (as per Rosemary’s links above).(* It's something that should be relatively easy to check, though: presumably someone is now doing a gene sequence comparison that could establish whether this has actually occurred.)
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Rosemary McDonald, in reply to
mutagenic pesticides banned elsewhere
I was going to bring that up....one report I read from a pesticide awareness group from 1999 had the rate of reported miscarriage among agricultural and horticultural workers in the Pernambuco region as 73%...The stats for reported birth defects (sorry Hilary, its not a nice term) were strange. Some of the 'defects' reported by mothers were not actually defects. And some of the so called 'normal' babies actually had significant defects.
linger...here in NZ there is still widespread use of a significantly mutagenic fungicide...a benomyl derivative. Benomyl has been linked to babies born without eyes...http://www.ecochem.com/ENN_costillo.html
The mutagenic fungicide used widely in New Zealand is 2-methyl-benzimidasole carbamate. Research into effects of Benomyl almost always include carbedazim. Throw benomyl into the air and it will probably have converted to carbendazim by the time it hits the ground. http://www.ncbi.nlm.nih.gov/pubmed/10633176
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here in NZ there is still widespread use of a significantly mutagenic fungicide…a benomyl derivative.
Rosemary, I don't believe Benlate (or Benomyl) is available in New Zealand now. It has certainly not been for sale for domestic use through garden centres for a very long time. I can't see it available for commercial use. I think it was banned after the evidence for birth injuries became clear. I could see one listing for it on Trade Me but the price on the packet was clearly a very old one, so probably out of someone's garage cleanup. If anyone has any good information on current use of this fungicide in NZ I would be interested.
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Rosemary McDonald, in reply to
It has certainly not been for sale for domestic use through garden centres for a very long time. I can’t see it available for commercial use. I think it was banned after the evidence for birth injuries became clear
1. Carbendazim for sale at RD1.
2. Safety Data Sheet for Mycotak
3. List of HSNO classifications
4. Determination of benomyl (as carbendazim) and carbendazim in water...
5. Carbendazim is the metabolite of benomyl
6. Benomyl, according to Wikipedia
Over the next few weeks this chemical will be loaded into helicopters and dispersed widely and with little or no controls, regulation or enforcement. The advertisement for Mycotak states that there is no withholding period for carbendazim...
yet for another carbendazim based product, made by a different company...
It is an offence for users of this product to cause residues exceeding the relevant MRL in the New Zealand (Maximum Residues Limits of Agricultural Compounds) Food
Standards.
WITHHOLDING PERIODS: Stonefruit - DO NOT use after start of petal fall, Apples - 7 days, Cucurbits - 7 days, Grapes - 7 days, Raspberries, brambles, strawberries - 1
day, Lettuce - 21 days, Beans - 14 days, Field & Glasshouse Tomatoes - 3 days, Wheat & Barley - 60 days, Onions - 14 days. Ryegrass Seed Crop - Allow 14 days between last
application and harvest (cutting). Allow 35 days between last application and introduction of stock for grazing.If anyone has any good information on current use of this fungicide in NZ I would be interested.
Depends on what you mean by "good".
The official line is that there is no issue with the use of this product in NZ.
I beg to differ,
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So… the blurb is saying apply this to your pasture, it’s perfectly safe and saves a lot of hassle, but the stuff is an environmental hazard and toxic to humans.
We are in New Zealand aren’t we?She'll be right. Yeah. Right.
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