Immunizing Mosquitoes To Fight Malaria
By Jesse Emspak, International Business Times
Millions of people in the tropics suffer from malaria, a mosquito-borne disease that has been difficult to treat and which costs many developing countries millions of dollars per year in lost productivity. Up to now, efforts at controlling it have focused on attacking the parasites that cause it, keeping mosquitoes from biting, or killing the insects.
But at Johns Hopkins University, Rhoel Dinglasan, an entomologist and biologist, decided to try another tack: immunizing mosquitoes.
Mosquitoes carry a species of parasite called plasmodium. The parasite lives in the mosquito’s gut. The parasites then spread to the mosquito’s salivary glands, and when the insect bites an uninfected person, they enter the bloodstream. At that point the plasmodium goes from the blood to a person’s liver, where it matures, escaping to the bloodstream to infect the red blood cells in a form called a merozoite.
Once in the blood cells, the parasite reproduces until the red cell bursts, releasing more merozoites. This cycle repeating itself causes the characteristic fever, chills and ache associated with the disease.
…
When a mosquito bites an infected human, it takes up some of the gametocytes.They aren’t dangerous to people at that stage. Since plasmodium is vulnerable there, and that is the point that Dinglasan chose to attack.
Full story here
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Here’s the very first Press Release from Johns Hopkins university citing this idea:
Vaccine Blocks Malaria Transmission in Lab Experiments
Researchers at the Johns Hopkins Malaria Research Institute have for the first time produced a malarial protein (Pfs48/45) in the proper conformation and quantity to generate a significant immune response in mice and non-human primates for use in a potential transmission-blocking vaccine. Antibodies induced by Pfs48/45 protein vaccine effectively blocked the sexual development of the malaria-causing parasite, Plasmodium, as it grows within the mosquito. Sexual development is a critical step in the parasite’s life cycle and necessary for continued transmission of malaria from mosquitoes to humans. The study is published in the July 22 edition of the journal PLoS ONE.
“Development of a successful transmission-blocking vaccine is an essential step in efforts to control the global spread of malaria. In our study, we demonstrate the relative ease of expression and induction of potent transmission-blocking antibodies in mice and non-human primates. This approach provides a compelling rationale and basis for testing a transmission-blocking vaccine in humans,” said Nirbhay Kumar, PhD, senior author of the study and professor in Johns Hopkins Bloomberg School of Public Health’s W. Harry Feinstone Department of Molecular Microbiology and Immunology.
For the study, the research team expressed full-length Pfs48/45 in E. coli bacteria to produce the vaccine. Previous attempts to fully express the protein had not been successful. The vaccine was first given to mice in the laboratory. The vaccine was also tested in non-human primates (Olive baboons) in Kenya with similar results. According to the study, a single-dose vaccine provided a 93 percent transmission-blocking immune response, reaching greater than 98 percent after a booster given several months later.
“This is an exciting beginning to what might become an important tool in the arsenal for malaria control and progressive elimination of malaria transmission,” said Kumar. There is no animal reservoir for human malaria and in that regard it is possible to gradually reduce malaria transmission to a point of almost eradication. However, Kumar cautioned that more research is needed to achieve that goal. For one, similar research efforts are needed to reduce transmission of Plasmodium vivax, another major human malaria parasite.
Malaria affects greater than 500 million people worldwide and is estimated to kill over one million people each year, most of whom are children living in Africa.
In addition to Kumar, “A Potent Malaria Transmission-Blocking Vaccine Based on Condon Harmonized Full Length Pfs48/45 Expressed in E. Coli” was published by Debabani Roy Chowdhury, a postdoctoral fellow of the Johns Hopkins Bloomberg School of Public Health; Evelina Angov of the U.S. Military Malaria Vaccine Program; and Thomas Kariuki of the Institute of Primate Research in Nairobi, Kenya.
The research was supported by grants from the National Institutes of Health and the Johns Hopkins Malaria Research Institute.
Save the mosquito ….
The (solar, wind, hybrid, electric) mosquito
Sexually inactive
Fluorescent gonads speed mosquito control
Nature Biotechnology pp 1414 – 1417
Researchers have found a reliable way of rapidly identifying sterile male mosquitoes for use in pest eradication programs for controlling malaria. In the November issue of Nature Biotechnology, Andrea Crisanti and colleagues establish a genetic approach for identifying male larvae of the malaria vector mosquito Anopheles stephensi through the specific expression of a green fluorescent protein in their gonads. By releasing an overabundance of these sterile males in the field, wild male mosquitoes would be unable to mate with females, leading to rapid decline in fertile eggs and the eventual eradication of the mosquito population in the area of release.
The sexing strategy described by Crisanti and colleagues solves the longstanding problem of how to differentiate female sterile mosquitoes,……..
http://www.nature.com/nbt/press_release/nbt1105.html
I’m surprised a DDT ban even worked, considering how trivial it is to make DDT with some bleach, grain alcholol, benzene, sulfuric acid drain cleaner, and some ph-Up from a pool and spa store.
My concern about the vaccination idea is how will they keep vaccinating the mosquitos? A protein won’t last very long in the environment and mosquitos constantly breed.
Prominent on the grounds of the NC Natural History Museum and next door to the NC General Assembly Building is a disgusting tribute to Rachael Carson in the form of a small garden display featuring a bronze of Carson leading a group of children on a pond excursion. It brings to mind the Pied Piper and the children of Hamlin. This semi official memorial to Carson is black mark on the cultural and intellectual state of North Carolina, USA.
DDT, before it was banned, was inexpensive to use and is effective. What is being proposed is no more than “pie in the sky bye and bye.”
Even with all of the DDT that was sprayed, the mosquito did not become extinct. Nor was there ever an effort to make mosquitoes extinct, simply eradicate them from human populated areas.
In any event, I have not seen that without mosquitoes any other species would suffer famine or go hungry, nor become extinct.
So I say, bring back DDT. It was entirely safe for other than its intended vectors, and was never demonstrated to harm any other than what was intended.
Wow, you should see the entry on DDT at Wikipedia. Amazing. When will we wake up.
Question 1. What is the world population of mosquitoes?
Question 2. How many generations each year?
Question 3. Does this immunisation pass from one generation to the next?
Question 4. Can other insects etc. act as vectors for malaria?
Question 5 More cost effective than DDT, or other controlling methods in current use?
Just askin’, cos I know NOTHING about this subject.
I have noticed in other fields that half-solved problems can lead to a situation where certain businesses develope the problem into an anually producing cash cow.
john r
I am always amazed at the amount of DDT misinformation out there. DDT has never been banned for use on Malaria in the USA or anywhere else where it is needed. Megatons of DDT were exported for many years by US chemical companies following its 1972 EPA restriction (the so called “ban” which removed its permit for CROP use but still allowed DDT use on insect vectors). MEGATONS of DDT annually are currently used to control Malaria in ANY country that wishes to – more than 30 countries currently hold DDT permits from “WHO” for DDT use. MEGATONS of DDT are produced every year in India and China and any competent biochemist can produce it. These companies happily export all one can pay for to anyone who pay. DDT use on insect vectors has NEVER stopped since its first use in the 1940s and continues to this date. The only serious global attempt to stop DDT use (Stockholm Convention ~ 2000) was totally rejected by the signitories who concluded DDT was needed for vector control.
The only thing that has stopped DDT use are intelligent managers who know when it DOES NOT control the insect vectors because of pesticide resistance. BTW, MOST BEDBUG populations are completely resistant to DDT – it will hurt you more than it hurts them.
Just being a ……………………….. sceptic?
It turns out, all we have to do is take one drop of chlorine dioxide otherwise known as the chemical salt ClO2 in some citric acid, and guess what?
World peace will break out, cancer will be cured, malaria will be eliminated…. I cannot tell you how great it will be.
Come on guys, pull the other one!
Yeah, but if there are any unintended side effects suffered by the mosquitoes, like frequent urination, dry eye or mood swings, a group of mosquitoes will surely sue the chemical companies.
It is totally unacceptable that the government funds the creation of wetlands in our country, always siting them near populated areas and city centers; and having created wetlands you will find local governments banning one by one effective insecticides.
Not only is the tax money used to create these wetlands stolen from our road maintenance funds in some cases, but there are also federal programs to subsidize turning private property into wetlands.
While greatly increasing the habitats for mosquitos near cities, the government is also responsible for the amount and types of vaccines available, and for tracking and communicating dangers of infectious outbreaks through the CDC. The potential for gov’t ineptitude here I hope needs no emphasis.
So in context of the fact that government policy is bringing back huge vector populations and banning insecticides, this token effort at some experimental vaccine which the malaria bug could easily and quickly become immune to – this is preposterous and dangerous nonsense.
George Turner says:
October 30, 2010 at 9:13 am
My concern about the vaccination idea is how will they keep vaccinating the mosquitos? A protein won’t last very long in the environment and mosquitos constantly breed.
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The protein (vaccine) is injected into the humans (all, if possible). The humans make antibodies that, in this case, are boosted by the natural expression of the protein on the surfaces of the parasite while still in the human, apparently. The mosquito takes up both antibodies and parasites and the parasites are then unable to develop in the mosquito to the next life cycle stage (the sporozoite) that is injected into the next human. In other words, the mosquito is passively immunized with human antibodies, and the infection cycle is blocked.
I’m not overly confident of this strategy working. Too many things can go wrong in complex ecological, biological and immunological systems.
Could probably also add political, economical and sociological to the above -icals too
john ratcliffe says:
October 30, 2010 at 10:20 am
Question 1. What is the world population of mosquitoes?
Question 2. How many generations each year?
Question 3. Does this immunisation pass from one generation to the next?
Question 4. Can other insects etc. act as vectors for malaria?
Question 5 More cost effective than DDT, or other controlling methods in current use?
Just askin’, cos I know NOTHING about this subject.
I have noticed in other fields that half-solved problems can lead to a situation where certain businesses develope the problem into an anually producing cash cow.
——————-
I know this field really well.
Questions 1, 2, and 3:
It doesn’t matter, because the only relevant mosquitos are the ones that have taken up blood with parasites in it during a human blood meal. What matters is the coverage of all the sources of the blood meal (i.e. all the humans) with the vaccine and, of course, the neutralizing strengths of the antibody response.
Question 4: No, although I’m not sure if mutations could evolve that would lead to passage through (unimmunized) primates and then back into the humans.
Question 5 and your final point: It would be difficult to calculate the cost-effectiveness of this approach without knowing how well it works – which they don’t.
I can see no way where anyone could make money off a program like this. It would have to be funded by agencies like USAID, the Gates Foundation, etc. Lots of money could go missing through the usual corruption mechanisms in Africa, but no company could make money off a vaccine such as this.
Does this parasite, plasmodium, infect all of the mosquito? Does it eventually reduce it’s reproductive processes? Does it kill it?
All we are told is that the parasite “…spreads to the mosquito’s salivary glands…”
The reason I ask is this, if the parasite is ultimately beneficial to the human race, by debilitating mosquitos in some way, wouldn’t it be dangerous for the human race if scientists made it possible for mosquitoes to live longer, and thereby infect more humans?
How do they propose to vacinate the mosquitoes?
Mosquito’s are Gods way of making us feel wanted. Even the most miserable excuse of a human can have a few 1000 friends. Up here the food chain is heavily dependant on insects so no bugs no fish. Interesting idea but how many generations of/years of immunity injections before effective?
I’m someone who has more than three decades of experience in pest control – chemical pest control. I have always thought controlling Malarial mosquitoes with DDT was a good idea. But I have to tell you guys, this is a way better approach to controlling the disease. If it works – it will be more effective. Its really exciting to read about.
You can’t eradicate a pest using pesticides. Your obtainable object is, “control.” Suppressing organisms until you achieve an economic objective. When the cost of control exceeds the benefit you know its time to stop controlling. It’s the iron law of diminishing returns. If you eradicated the malarial mosquito with DDT it would be a first. Nobody ever eradicated a pest with a pesticide. (although 24-d hammered the wild grapes & now they are a thin shadow of their former selves – but you can still find wild grapes)
Environmentalists would hate this new idea too. It is just as manipulative (more so) as spraying DDT. And at the root of it all that is what environmentalists hate most – man manipulating the environment. We are lucky – Malarial mosquitoes and the malarial parasite have really bad press. The already are “Franken-Mosquitoes” Burt if there is the least little bit of broad spectrum concern they can turn up they will be against this technology too.
Peter Melia says:
October 30, 2010 at 12:16 pm
Does this parasite, plasmodium, infect all of the mosquito? Does it eventually reduce it’s reproductive processes? Does it kill it?
—————-
Nope, it just sexually reproduces in the gut of the mosquito and forms the sporozoite stage which is injected into another human during a blood meal. The sporozoite then migrates to the human liver and starts up a new infection cycle.
M2Cents says:
October 30, 2010 at 12:31 pm
How do they propose to vacinate the mosquitoes?
————
As I mentioned above, it is the human that is vaccinated. The mosquito picks up the antibodies, along with the parasite, during a blood meal. The human antibodies then block parasite reproduction in the mosquito.
Greek Black Hole
I think the black hole (or perhaps another one) is situated somewhere in a deep channel in the Greek islands. It was like this, (I’ve dressed it out a bit, to compete with the History Channel. Please forgive me.)
I had a ship, a VLCC, laid up, it was hard times, like now, but some time ago.
I had to move the ship from it’s layup “trot” to a working berth were it was being prepared for returning to active service, and this move required having it towed down through the channel. I was out there overseeing the work.
Before the tow I inspected the tug, a big deep sea job, which was very well equipped for the task of towing my ship. The Salvage Association also agreed that the tug was suitable.
Whilst in the tugmasters cabin I noticed a photograph on the wall of the tug, in it’s earlier days, towing a cargo ship which had a severe list, I recognised the two ships. The cargo ship was the “Flying Enterprise” and the tug was at that time called “Turmoil”, although in it’s Greek incarnation it had another name. As I was leaving the tugmaster’s cabin I pointed at the photo and asked him if he knew what it portrayed. Yes, he said, “..of course, everyone knew that, it was his tug saving the Flying Enterprise..” I pointed out that it didn’t in fact save the Flying Enterprise, it lost the tow, soon after the photo was taken, and the cargo ship went down. I told him to make damn sure that the Turmoil didn’t lose this particular tow, my ship. I was assured that this time there would be no problem.
During the tow the tug did in fact lose it’s line to the VLCC (how history repeats itself!) just as the wind came up. The VLCC had to anchor in a hurry, but the first anchor was lost. The anchors and chains on these giant ships are so big and heavy that if they start to run out of control, it can prove impossible to regain control and the anchor and chain can be lost, the chain tearing itself out of the bitter end, which is the junction of the chain to the ship. Thus the saying …”to the bitter end”. Fortunately the second anchor held and the ship was OK.
But now there was a ship’s huge anchor, weighing several tons, and 900 feet of chain, each link about 3 feet long, also very heavy, sitting somewhere on the bottom of the channel.
I decided to have a go at locating and retrieving the anchor.
In Cambridge there was a company which made Magnetic Anomaly Detectors, and the nice people on the phone told me that it was, basically, a magnetic field detector, and yes, certainly, a mass of iron on the scale I described to them, would without a doubt have a detectable magnetic field.
So I hired one, had it flown out to Athens, then delivered to the ship. The company providing the MAD also kindly included a set of instructions for use. I explained my plan to an incredulous ships master. He had wanted to know, quite reasonably, what exactly he was looking for. I had no idea, but the people in Cambridge had mentioned that the bigger the iron mass the larger the magnetic field.
So I improvised. I told him that the anchor first snagged on a rock, this tightened the chain, which payed out quicker than expected, with the chain jumping out of the chain guiding wheel, (which was sort of like a negative bicycle chain wheel). So the anchor was stuck in the rocks and the chain stretched out in a line, until the end broke free and then it all fell down vertically. Magnetically, the screen should show a hump (anchor) followed by a much larger hump (the heap of chain). Like, I said, “..a Loch Ness monster..”.
I hired a boat, and the master set off with a couple of crew members, plus the MAD, for a few days boating amongst the Greek Islands. The MAD we had was like a little torpedo which could be towed from a small boat, at any depth required, and it would continually detect any magnetic fields within range, and display them as a graph on a CRT screen.
In the meantime I got on with recommissioning the ship, and every evening the master and me would have a chat on the phone.
The first day he had nothing to report, nothing bumpy on the screen at all. The second day, he was very positive, he had definitely spotted my two humps, but they were not clear, something to do with the equipment. The third day he was jubilant and downcast, at the same time. Jubilant because he had made several runs up and down, each time getting better readings, they could only be his anchor and chain. So he decided to send his little torpedo down closer, real close. Downcast because he sent it too close in fact, and the torpedo snagged on something and was irretrievably lost.
So the effort was abandoned, the Owner would not pay for another MAD, in fact they hinted that I was mad to think of it in the first place.
And there it is.
Somewhere down in the bottom of a Greek island channel lies about 150 tons of forged steel, it’s signature like a Loch Ness monster, clearly detectable with even an early MAD.
Although not Greek, as a gesture of European solidarity, I claim a black hole on behalf of the people of Greece.
Sorry folks, my comment above should have been attached to the next piece, the Black Hole in the Bermuda Triangle one.
Sorry again.
REPLY: We can’t move it, copy paste and post it there – Anthony
“john ratcliffe says:
October 30, 2010 at 10:20 am
Question 1. What is the world population of mosquitoes?
Question 2. How many generations each year?
Question 3. Does this immunisation pass from one generation to the next?
Question 4. Can other insects etc. act as vectors for malaria?
Question 5 More cost effective than DDT, or other controlling methods in current use?”
——————————————————————–
1 – lol – depends on the time of year, but it’s “billions and billions”; however, only some of the mosquitoes of the genus Anopheles transmit Malaria. So, you can ignore most other 3000+ species of mosquitoes and thousands of other biting insect species.
2- generation time of Anopheles can be as little as 2 or 3 weeks but it depends on species and temperature. In the tropics, one can get 10 + generations per year, which is why development of complete resistance to insecticides like DDT can take as little as several years.
3- no idea
4- No, as far as we know, only roughly 100 of 450 species of Anopheles are confirmed to transmit Malaria.
5- When DDT is effective (it frequently is NOT effective when vector populations have developed resistance) cost is very low when it is used inside habitations, typically less than $5 per household per year because DDT “activity” is persistent, but costs vary considerably. There is some utility for DDT even after it no longer kills Anopheles vectors due to it’s “irritability//repellent effect”. I doubt that costs for this new technique have been determined since it is not even known if it’s use is effective at this point.
It is important that a mosquito must bite TWO people to transmit malaria. Things like residual indoor spraying would reduce mosquito bites significantly and reduce the likelihood of a single mosquito biting two people much more. Malaria is, thus reduced much more than the mosquito population.
This explains the precipitous drop in malaria rates in African nations which have resumed RIS with DDT. Also, as malaria rates drop, the probability of a mosquito biting an infected person drops too. Thus, this precipitous drop accelerates as long as RIS continues. While some have, rightly, argued that it is unreasonable to hope for the elimination of the mosquito, the elimination of malaria is much more feasible.
Adding this new vaccination strategy to RIS could be the killer combo. If we dedicate the resources to really go after this, a permanent victory, in the style of smallpox, is not beyond possibility. It’d be a huge effort — but worth it.
Another recent post on WUWT reported on a study that purported to show that the decline of malaria in developed countries was more a result of changes in living conditions and household structure than any overt control of vectors. People living in individual homes and apartments and in nuclear, rather than extended families, reduce the size of the reservoir for the parasite, and infection declines rapidly.
If this is true, then the real long-term solution in malarial areas is development, not mosquito control.
In the short term, doubtless DDT can help, but as Biobob says:
I’m surprised that nearly all of the advocates of DDT seem to ignore the problem of resistance. What is the time frame for the rise of resistant mosquito populations? Once that happens, you’ve lost the edge that DDT gives you.
So vaccinating all the people (not the mosquitos!) in a malarial region might be a more effective medium-term solution than anything else. This research is not, as some above have portrayed it, a frivolous exercise at all.
/Mr Lynn
Interesting, though it shouldn’t be heralded without criticism, which I’m glad to see from more than a few posters. In particular is the point raised by Zeke the Sneak. I don’t know that it easily could or rapidly would, but it’s a worthwhile question.
Anyway, there is a question I have concerning resistence and exposure. I’m no professional in this field, but…
I don’t get it. If I take any land/air lifeform and keep drowning them in water for several generations, they wouldn’t just become increasing aquatic. Maybe Lysenko would say so, but reality has the final say. So why are insecitcides, possibly insect immunization, and antibiotics different? Does exposure to them increase resistance or is it…?
Maybe things go on evolving simply because it is not possible to kill ALL insects in an area nor wipe out ALL harmful bacteria in a body with antibiotics. If so, the survivors simply live on to go through changes as a matter of natural course, not from the exposure to the chemical or medicine itself. Naturally, they would pass these traits on to their offspring.
Maybe some chemicals do cause resistance from exposure, but… every single beneficial one? I’ve a hard time believing that.
Why do most people who have made comments on this issue seem to assume that using DDT and trying to immunise mosquitoes are two mutually exclusive choices? We know that DDT used properly is pretty effective but on its own is unlikely to to completely erradicate malaria. The disease used to be present in many parts of Europe from Sicily in the south to parts of England in the north. Draining swamps helped to erradicate it but
I don’t know enough about history to say what other measures were used.
If the immunisation idea can be made to work on a large scale then using it and DDT together might achieve better results than just using DDT alone.