GM Mosquito Could Fight Malaria 281
qw0ntum writes "The BBC is reporting that a genetically modified (GM) variety of mosquitoes could be effective in combating the spread of malaria to humans. These GM insects carry a gene that prevents them from being infected by the malaria parasite and has the added benefit of providing a fitness advantage to the mosquitoes. From the article: 'In the laboratory, equal numbers of genetically modified and ordinary wild-type mosquitoes were allowed to feed on malaria-infected mice. As they reproduced, more of the GM, or transgenic, mosquitoes survived. According to the researchers, whose results appear in Proceedings of the National Academy of Sciences journal, after nine generations, 70% of the insects belonged to the malaria-resistant strain. [...] The modified mosquitoes had a higher survival rate and laid more eggs.' This has major implications for the billions of people living in areas with endemic malaria. The question in my mind, though, is what effects on the ecosystems of these areas will replacing an organism low on the food chain with a GM version? Between the news we saw last week and biomagnification, could this wind up substituting one problem for another?"
Re:Building a better mosquito (Score:3, Informative)
Unless, of course, the parasite adapts to the new super-mosquitos and create a new, super malaria that is more infectious with a higher mortality rate.
Re:Setting up for disaster (Score:5, Informative)
Re:So, um... (Score:3, Informative)
Thing is, anything that lowers the infection rate -- with the stipulation that there are no other unintended bio-consequences -- at the mosquito level -- is superior because every dose of the vaccine has an associated production cost, where mosquitoes breed for free. So if the disease vector is disrupted for free 70% of the time now (and perhaps a higher percentage down the road), this gives the researchers an edge the race to develop a human malaria vaccine before the damned parasite can re-adapt.
Re:Setting up for disaster (Score:4, Informative)
Re:Just use DDT (Score:5, Informative)
See here for details. [timlambert.org]
Re:Setting up for disaster (Score:5, Informative)
This is a really risky move.
To be sure, but from TFA:
"I think it will be 10 to 20 years before transgenic mosquitoes are released into nature. It's very difficult to predict what will happen when we release these things," he added.
"There is quite a lot of research that needs to be done, both in terms of genetics and the ecology of the mosquitoes; and also research to address all the social, ethical and legal issues associated with releasing transgenic organisms into the environment."
It is good to see that the scientists involved are, well, being good scientists.
Re:Setting up for disaster (Score:5, Informative)
The food chain implys there are no cycles and cross-linkages so to speak.
Mosquitos eat plant matter [wikipedia.org] normally, only the females drink blood, and then only when they are pregnant. So most of the time they are quite low, and plenty of stuff eats them. Actually, the only mosquitos that are truely carnivorus for at least part of their life cycles (and in both genders), only eat other mosquito species at that stage...
Just beacause it's a predator in some cases, doen't mean it can't be prey in others: Consider that a wild dog/wolf will eat a a samller cat (or would be eaten by a lion or other big cat). In all of these cases of eating, it is a predator that eats another predator.
The Coming Plague (Score:2, Informative)
"Following World War II the worlds public health community mounted two ambitious campaigns to eradicate microbes from the planet. One effort would succeed, becoming the greatest triumph of modern public health. The other would fail so miserably that the targeted microbes would increase both in number and in virulence, and the Homo sapiens death toll would soar. Humanity's great success story would be smallpox... On May 8, 1980, the World Health Assembly formally declared that "the World and all its peoples have won freedom from smallpox, which was a most devastating disease sweeping in epidemic form through many countries since earliest times, leaving death, blindness, and disfigurement in its wake and which only a decade ago was rampant in Africa, Asia, and South America.".
A very different outcome awaited those who fought to eradicate malaria worldwide. Between 1958 and 1963 alone, $430 million was spent on a series of failed attempts to eliminate malaria. In 1991 dollars that consituted an expenditure of over $1.914 billion. Between 1964 and 1981, the United States spent an additional $793 million."
"The Coming Plague" Laurie Garrett (page 30-47)
DDT was, at first, a very effective fight against the malaria carrying mosquitoes.
"In 1956, malarioligist Paul Russell, then at Harvard's University's School of Public Health, authored a report for the International Development Advisory Board recommending the immediate global eradication of malaria.
Generally, it takes four years of spraying and four years of surveillance to make sure of three consecutive years of no mosquito transmission in an area. After that, normal health department activities can be depended upon to deal with occasional introduced cases.... Eradication can be pushed through in a community in a period of eight to ten years, with not more than four to six years of actual spraying without much danger of resistance. But if countries, due to lack of funds, have to proceed slowly, resistance is almost certain to appear and eradication will become economically impossible. Time is of the essence[his emphasis] because DDT resistance has appeared in six or seven years."
"The Coming Plague" Laurie Garrett (page 48)
Unfortunately, around 1963, when malaria control efforts were just beginning to break down due to the sudden drop of funding from Congress, agricultural use of DDT and its sister compounds were soaring. Resistant mosquito populations appeared all over the world. At the same time Russel was worrying over his new resistant pest problem, two people who were taking chloroquine(the current very effective treatment to malaria) developed malaria in South America. Almost instantly chloroquine-resistant strains appeared all over the world. Soon resistances to all forms of quinine were appearing as well as other drugs introduced in the 1960's.
"In 1975 the worldwide incidence of malaria was about 2.5 times what it had been in 1961, midway through Paul Russell's campaign. In some countries the disease was claiming horrendous numbers of people. China, for example, had an estimated 9 million cases in 1975, compared to about 1 million in 1961. India jumped in that time period from 1 million to over 6 million cases...
A new global iatrogenic form of malaria was emerging-"iatrogenic" meaning created as a result of medical treatment. In its well-meaning zeal to treat the world's malaria scourge, humanity had created a new epidemic."
"The Coming Plague" Laurie Garrett (page 52)
So at the same time while this is a huge opportunity to complete what we started in our original goal of eradicating malaria, it is also a huge risk, the problem we caused by trying to eradicate it in the first place will plague us for some time.
Where did it say they were harder to kill? (Score:5, Informative)
"However, when both sets of insects were fed non-infected blood they competed equally well."
They aren't harder to kill.
Re:Huh? (Score:4, Informative)
It's also relatively useless against malaria, and has been for years. Pity, really, I rather enjoy a nice gin'n'tonic in malaria-infested areas. (Tonic water is flavored with quinine.)
About twenty years ago (last time I was in malaria country) the drug of choice was chloroquine -- a quinine derivative, yes, but not quinine. Even then, there were warnings about some areas where chloroquine-resistant malaria was prevalent. That resistance is pretty much everywhere, these days. The effective antimalarials are also pretty rough on the system if you're taking them for more than a couple of months.
Re:Setting up for disaster (Score:5, Informative)
The only advantage the parasite free mosquitoes have is that they don't carry the parasite. Its not like they increased their breeding rate or anything. When there is a source of uninfected blood the GM mosquitoes lose their advantage.
Re:Setting up for disaster (Score:3, Informative)
None of it. No vaccine exists for malaria, though we've been trying to develop one for decades.
We could spend it on prophylactic drugs, but all the known prophylactics have serious side effects that make them unsuited for long-term use -- and long-term use would be required for people living their whole lives in a malarial area.
Spending the money on indoor residual DDT spraying would work fairly well, but there's an aversion by environmentalists to spraying DDT.
Spending it on bed nets would work well, if it weren't for the fact that proper bed nets make excellent fishing nets, and thus wind up diverted from their intended use. (And then have severe environmental impact as people do things like net an entire river, indiscriminately catching all the fish.)