Our sci-fi future just got a whole lot closer to becoming a reality, after the Food and Drug Administration gave the okay to a field trial that would release genetically modified Zika-killing mosquitoes in the Florida Keys.
On Friday, the FDA released a final environmental assessment of the trial, finding that it “will not have significant impacts on the environment.” The project, led by Oxitec, a biotech company that focuses on insect control, calls for the release of thousands of genetically engineered male Aedes aegypti mosquitoes. The lab insects are bred so that over time they could kill off much of the local mosquito population by passing on a gene fatal to any offspring they have with wild females.
Oxitec’s mosquitoes are engineered to include two copies of the baby-mosquito killing genes, overriding natural selection to make it almost certain that their offspring receive the killer gene from dad. Oxitec claims that trials in Brazil, Panama and the Cayman Islands have reduced mosquito populations by 90%, calling the success “an unprecedented level” of human control over nature. (The World Health Organization, which has also studied using such tactics against disease, has stated that while the technology “has demonstrated the ability to reduce the populations in small-scale field trials” there is still “an absence of data on epidemiological impact.”)
Been following this tech for awhile. I kind of have mixed feelings about it. Given the great success rate, I think it is much better then the rampant spraying of chemicals. But there is always the laws of unintended consequences. I will this affect the food chain of all the species that live off eating mosquitos? In the end, I think Mother Nature will overcome this, in any case. Just needs a little time.
Our sci-fi future just got a whole lot closer to becoming a reality, after the Food and Drug Administration gave the okay to a field trial that would release genetically modified Zika-killing mosquitoes in the Florida Keys.
On Friday, the FDA released a final environmental assessment of the trial, finding that it “will not have significant impacts on the environment.” The project, led by Oxitec, a biotech company that focuses on insect control, calls for the release of thousands of genetically engineered male Aedes aegypti mosquitoes. The lab insects are bred so that over time they could kill off much of the local mosquito population by passing on a gene fatal to any offspring they have with wild females.
Oxitec’s mosquitoes are engineered to include two copies of the baby-mosquito killing genes, overriding natural selection to make it almost certain that their offspring receive the killer gene from dad. Oxitec claims that trials in Brazil, Panama and the Cayman Islands have reduced mosquito populations by 90%, calling the success “an unprecedented level” of human control over nature. (The World Health Organization, which has also studied using such tactics against disease, has stated that while the technology “has demonstrated the ability to reduce the populations in small-scale field trials” there is still “an absence of data on epidemiological impact.”)
(...) The similarities between Boccaccio’s approach to the plague all those centuries ago and our approach to Zika now, in our supposedly enlightened and medically advanced societies, are striking. First, although we know that Zika is spread by Aedes aegypti, we learned only a few months ago that the virus is also sexually transmissible. And, since most people who have the disease never show clear symptoms, being certain you are avoiding sexual exposure is nearly impossible, except through abstinence. (Precisely how that sexual exposure works also remains a mystery; no one knows the contagious lifespan of the virus in the body of an infected person.) Second, while we’ve long thought of the aegypti mosquito as living only in far-south regions, the insect has been recently found in considerable numbers in places such as Washington, D.C. Clearly, we do not fully understand the primary vector of Zika. Third, the best course of action for containing the disease is uncertain: How do you combat a disease that’s spread by mosquitoes to people, by people to people, by people back to mosquitoes, and then back to people?
In the Middle Ages, all the uncertainty about the bubonic plague left only one real option: pray. Now, given the current state of medical science, we have a far more effective option: Find a vaccine. Because there are real reasons to think Zika will disproportionately affect nation states that lack the infrastructure or financial wherewithal to conduct extensive medical research, wealthier nation states absolutely must take on the task of finding a vaccine. It is patently the right thing to do, and it is without question in those wealthier countries’ best interests to do so. It is a ludicrous fantasy to think that any nation state or any population will get off lightly in its exposure to Zika.
Bubonic plague, of course, was a far more virulent and lethal disease than Zika. If a disease more like bubonic plague were churning its fatal way through Central and South America and the Caribbean, Congress might be more eager to do something about it - for instance, if Ebola got a real foothold there. Or, let’s be honest, if Zika disproportionately affected privileged, wealthy men, as opposed to underprivileged women, Congress would probably also be much more eager to spend money to find a vaccine.
But Zika is an extremely serious illness, one that threatens to bring a generation of children with severe disabilities into the world, and that, as a result, threatens to disrupt family life, economic life, and social life in affected areas - affected areas which, in fact, may well eventually include your own hometown. No one in Italy thought they’d have a problem with a Near Eastern plague in 1347. Certainly no one in England thought they’d wind up with the same plague. But by the middle of the 1350s, one in three English people had died - people of all socioeconomic classes, of all ages, of all genders. (...)
The Zika virus is the primary suspect in the large increase in microcephaly cases in 2015-6 in Brazil, however its role is unconfirmed despite individual cases of viral infections found in neural tissue. Here we consider the alternative that the insecticide pyriproxyfen, used in Brazilian drinking water for mosquito control, may actually be the cause. Pyriproxifen is an analog of juvenile hormone, which corresponds in mammals to regulatory molecules including retinoic acid, a vitamin A metabolite, with which it has cross-reactivity and whose application during development causes microcephaly. Methoprene, another juvenile hormone analog approved as an insecticide has metabolites that bind to the retinoid X receptor, and causes developmental disorders in mammals. Isotretinoin is another example of a retinoid causing microcephaly in human babies via activation of the retinoid X receptor. Moreover, tests of pyriproxyfen by the manufacturer, Sumitomo, widely quoted as giving no evidence for developmental toxicity, actually found some evidence for such an effect, including low brain mass and arhinencephaly—incomplete formation of the anterior cerebral hemispheres—in rat pups. Finally, the pyriproxyfen use in Brazil is unprecedented—it has never before been applied to a water supply on such a scale. Claims that it is not being used in Recife, the epicenter of microcephaly cases, do not distinguish the metropolitan area of Recife, where it is widely used, and the municipality, where it is not. Given this combination of information we strongly recommend that the use of pyriproxyfen in Brazil be suspended pending further investigation.
Comments:
6 pages
Subjects:
Quantitative Methods (q-bio.QM); Biomolecules (q-bio.BM); Neurons and Cognition (q-bio.NC); Tissues and Organs (q-bio.TO)
Report number:
New England Complex Systems Institute Report 2016-04-02
rulers should consider using use ddt cautiously to control the mosquitoes responsible
"It's a tricky mosquito to control. It doesn't bite at night like the mosquitoes that transmit malaria, so bed nets are not necessarily useful. They rest both inside and outside houses so there's not an easy way to target the adult mosquito {with pesticides}."
The first case of locally acquired Zika in the continental United States has occurred through sexual transmission in Texas, the Centers for Disease Control and Prevention said Tuesday.
The case, announced by Dallas County health officials, involved a patient who had sex with someone who had recently returned from Venezuela infected with the mosquito-borne virus.
In a statement to CNN, the CDC said it confirmed the test results showing Zika present in the blood of a "nontraveler in the continental United States." They stressed that there was no risk to a developing fetus in this instance.
Based on that, the CDC says it will soon provide guidance on sexual transmission, with a "focus on the male sexual partners of women who are or who may be pregnant."
Earlier Tuesday, CDC Director Tom Frieden told CNN's Chief Medical Correspondent Sanjay Gupta: "There have been isolated cases of spread through blood transfusion or sexual contact and that's not very surprising. The virus is in the blood for about a week. How long it would remain in the semen is something that needs to be studied and we're working on that now."
Frieden added that studies on sexual transmission are not easy studies to do, but the CDC is continuing to explore that avenue of transmission. "What we know is the vast majority of spread is going to be from mosquitoes," Frieden added. "The bottom line is mosquitoes are the real culprit here." (...)
German researchers have developed a diagnostic test that can accurately detect the Zika virus in humans. Until now, the only way to determine if someone had the illness was to wait to see if the disease’s distinctive symptoms appeared.
Genekam, a German biotechnology company, has created technology that can not only reveal the presence of Zika pathogens in a blood sample, but also shed light on the quantity in the patient’s blood, Deutsche Welle (DW) reports.
The new test can therefore definitely determine if a person is a carrier of the Zika virus, as only one in five people infected actually becomes ill, the media reports. Additionally, the test renders diagnostic results in real time, which is relatively quick for a virus of this kind.
“Our test examines DNA and works with chemicals that react to the Zika virus only,” Sudhir Bhartia, a virologist and one of the co-developers of the innovation, told DW. The researcher also added that the test provides sufficient accuracy, as “similar pathogens like Dengue fever won’t show up in the results.”
However, the technology has its limitations, as it can only be employed in specialized medical facilities and laboratories having the appropriate equipment and personnel with sufficient know-how.
“The test must only be used by qualified personnel so that mistakes can be avoided,” Bhartia stressed.
At the same time, it is rather cheap, costing about €5.
According to Deutsche Welle, the first kits containing the new tests have already been sent to Brazil, which is suffering from a Zika virus epidemic in which up to 1.5 million people may have been infected. Under normal circumstances, the test would go through a lengthy authorization phase. However, due to the emergency situation in South America, authorities have made an exception in this case. (...)
This virus has also caused the birth of new conspiracy theories...
When Brazilian doctor Ernesto Marques saw the first signs of what eventually would become the Zika virus, he didn't think much of it. Then he started to see a link to brain defects in newborns. He also saw it spreading.
Now the World Health Organization says the mosquito-borne Zika virus could infect four million people in the Americas this year. The Zika virus is believed to cause microcephaly, a rare brain defect in babies.
Marques, an associate professor in Vaccine Research at the University of Pittsburgh, believes the WHO's predictions are accurate.
"It's as good an estimate as anyone can get," he tells As It Happens host Carol Off.
The link between Zika and birth defects was first noticed last year by two neuro-paediatricians who work in Recife, Brazil — the epicentre of the outbreak.
They started comparing notes on the amounts of microcephaly they were seeing. The doctors contacted a virologist who did the math and realized the babies were in the first trimester of development at the same time the Zika virus was first peaking.
Most of the countries affected by the virus are in Central and South America, according to the Centers for Disease Control and Prevention. (CBC)
In the Brazilian state of Pernambuco, there were 150,000 births last year and approximately 1,100 cases of microcephaly.
"I don't know how confident you are in not getting a mosquito bite" says Marques, "I would say most women (in the area) are postponing their plans to start a family."
Marques says a vaccine isn't likely soon.
"It all depends on how much money is invested," he says. "We need more effort in funding and organization to get the response ready quickly."
WHO director general Dr. Margaret Chan says Zika is now a threat of "alarming proportions" and announced a special meeting of the WHO on Feb. 1 to decide if Zika should be declared a global emergency.
Canadian Blood Services is expected to announce they will stop accepting blood donations from people returning from countries hit by the Zika virus. Full details will be released in the coming days.
Since the mosquitoes that carry and transmit the virus do not live in Canada due to the climate, health authorities expect only travel-related cases in this country.
