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ANIMALS: Researchers work on malaria-resistant mosquitoes

                                  PART 1

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SOURCE: Voice of America, USA

AUTHOR: Nancy Steinbach


DATE:   01.07.2007

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A team reports progress on a way to control the disease through genetic engineering of the insects that spread it.

Scientists say they have made more progress in developing malaria-resistant mosquitoes. The idea is to release genetically engineered insects like these into mosquito populations as a way to control the disease.

Each year more than three million people become infected with malaria. At least one million die, mostly young children and pregnant women in Africa. Malaria is also a problem in Asia and South America.

The parasites that cause malaria enter people’s blood when they are bitten by the mosquitoes that carry the organisms. The parasites travel to the liver where they divide and grow. After a week or two, they invade red blood cells and reproduce thousands of times. They can destroy major organs.

People die from malaria because they are not treated or treatment is delayed. Drugs can prevent the parasites from developing in the body. But experts still say the best way to prevent malaria is not to be bitten by a mosquito.

Their advice could change in the future with the help of mosquitoes genetically engineered to block development of the parasite. In other words, they would not be able to spread the disease. Computer studies show that if malaria control is to succeed, insects like these are needed to replace mosquitoes in the wild.

Researchers at Johns Hopkins University in the United States reported on their work in the Proceedings of the National Academy of Sciences. They put equal numbers of malaria-resistant mosquitoes in a box with other mosquitoes. The insects mated, and all of them fed on mice infected with the malaria parasite.

The researchers took eggs produced by the mosquitoes and kept them until they became adult mosquitoes. These insects were then permitted to feed on infected mice. The researchers did this again and again. After nine generations, seventy percent of the mosquitoes were malaria-resistant.

Earlier studies showed that disease-resistant mosquitoes would die early and not be able to replace wild ones. But in the new research, the scientists say they developed stronger mosquitoes. In any case, malaria-resistant mosquitoes might still need to be used in combination with drugs and insect poisons to control the disease.

                                  PART 2

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AUTHOR: L’Observatoire de la Genetique, Canada, by Christophe Boete, translated by Claire Robinson, GMWatch UK


DATE:   01.04.2007

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This important article by the evolutionary biologist Christophe Boete - a researcher at the Institute of Research for Development (IRD, Montpellier, France) - was translated into English for GM Watch by Claire Robinson. The French original and references at

L’Observatoire de la Genetique is a periodical of IRCM’s Centre de Bioethique (Centre for Bioethics). IRCM = Institut de Recherches Cliniques de Montreal [Clinical Research Institute of Montreal], affiliated with the Universite de Montreal.



Christophe Boete is a researcher at the Institute of Research for Development (IRD, Montpellier, France). He holds a doctorate in ecology from the Pierre and Marie Curie University of Paris and a post-doctoral qualification at the University of Wageningen (Netherlands) and in the Joint Malaria Programmes in Moshi, Tanzania...

The scientific media and reviews increasingly repeat the promise of the use of GM mosquitoes to fight malaria. However, as the author of this article explains, the success of such a use is only hypothetical and many questions remain unanswered. If research on GM mosquitoes can lead to useful and beneficial discoveries, it is however vital that it is not carried out at the expense of financing and access of the affected populations to prevention and treatments that exist right now. A plea in favour of the precautionary principle and the democratic orientation of science.

In January 2006, a citizens’ jury of cotton producers of the area of Sikasso (Mali) decided unanimously against the introduction of GMOs in their country. This exercise in participatory democracy, named ”Citizens’ Space of Democratic Interpellation [a procedure in some legislative bodies of asking a government official to explain an act or policy]” (ECID) was held at the request of the general assembly of Sikasso in order to obtain the opinion of cotton producers on the introduction of the GMOs into agriculture in Mali (1). What would be the result of such a step if the question did not relate to agricultural seeds, but to releasing GM mosquitoes, a hypothetical future means of fighting malaria?

There is a lot at stake, since the situation as regards malaria is far from improving: mortality has more than doubled during the last twenty years, because of biological factors (resistance to drugs, for example), but also because of political and socio-economic factors due in particular to measures of strict budgetary policy and reforms of public services dictated by structural adjustment plans of the IMF (2). Moreover, without effective intervention, it is estimated that the number of victims will double again in the next twenty years. It thus appears urgent to take all measurements likely to stop the propagation of this disease, which is mainly prevalent in developing countries.

Besides the tools of prevention and treatment we have right now (improvement of habitat, adequate treatment, impregnated mosquito nets, etc.), a number of researchers are exploring new paths. Among those, there is one that is being once again talked about in the press: GM mosquitoes.

Fighting malaria using GM mosquitoes

Researchers hope to create GM mosquitoes that are able to kill the malarial parasites and, in particular, Plasmodium falciparum, the species considered most dangerous of those able to infect man, in order to stop the transmission and the propagation of the disease. The objective is not to remove the mosquito vectors of malaria, but to replace all or part of the malaria-vector population with mosquitoes which, because of the genetic modification, should no longer transmit the parasite.

As for the method which would make it possible to achieve this goal, it was planned by a small group of molecular biologists at a meeting which took place at the beginning of the 1990s at Tucson, Arizona, USA(3). It is based on an ambitious programme which puts great emphasis on technology and does not seem to take account of any ecological, evolutionary and epidemiological aspects. The plan has three phases:

*to genetically modify in a stable way vector mosquitoes of the Anopheles type; *to genetically modify a mosquito so that it is resistant to the Plasmodium parasite and thus can no longer be the vector for it; *and finally, to understand how to provoke and control the propagation of this resistance to Plasmodium in natural populations.

To date, the first two stages have been achieved, but only to a certain extent. In effect, if a stable transformation were carried out and a mosquito resistant to Plasmodium were created, its resistance would be limited to the parasite Plasmodium berghei, a parasite of rodents which does not affect man.

As for the stage of propagation, a necessary condition, but insufficient to ensure the success of this method, it remains problematic today. Indeed, a recent study published by an American team showed that even under extremely favorable artificial conditions, it is difficult to introduce the genetic modification which is responsible for resistance to the parasite, into the whole target population of mosquitoes (4).

Lastly, as we shall further see, epidemiological and evolutionary aspects are often perplexing, when one takes into account the many pitfalls that must be avoided (5,6).

As yet unanswered questions ... and a dubious success

Thus, if the potential use of GM mosquitoes to combat malaria is considered by certain scientists, the effectiveness of this means of combat remains very dubious. It is therefore essential that the researchers involved in this type of research do not exploit hopes based on hypothetical solution that they present with an excessive, even delirious, optimism (7).

If they should avoid such optimistic flights in favour of technological progress, the researchers should also avoid exploiting certain fears in order to obtain more funds and in order to justify their research on GM mosquitoes. It is however the impression that they give when they put forward the possible risk of the appearance of parasitic stocks more virulent than those existing currently, or worse, of a hypothetical transmission of a virus hitherto not transmitted by mosquitoes. In effect, what is known about these significant points? Absolutely nothing. At the present time, it is not known, for example, if the introduction of genetic resistance to Plasmodium falciparum could provoke the selection of parasites more virulent for man (8). On the contrary, it is perfectly possible that the selection will work in favour of a more virulent stock against the mosquito itself, which actually would reinforce the effectiveness of a anti-malaria campaign based on GM mosquitoes.

In short, few things are known about the potential consequences of the use of GM mosquitoes and it is first a matter of putting relatively simple questions in order to know if this method can be valid: will resistance to the parasite be able to propagate in natural mosquito populations? Under what conditions? What will be the effect of this resistance on the epidemiology of the Plasmodium species mainly targeted (Plasmodium falciparum), but also on that of the minor species (9)? Will mechanisms of evolution select strains of parasites able to escape this resistance of the mosquito? If such a selection were to intervene, the situation could be similar to that caused during the 1950s and 1960s at the time of the malaria eradication programme involving the massive use of DDT. Indeed, that programme led to the selection of a resistance to DTT in the vector mosquitoes and has proved a failure. In spite of that, very few studies to date focus on the impact of ecology and evolution on such a campaign and the few results published in this respect prompt scepticism (5,6,10).

Need for adopting a responsible and democratic approach

Another point which raises a problem is that the development of this new technology seems unfortunately to follow the same road as that borrowed from a model dating from the 19th century and described in these terms by Tom Wakeford in a document for the Intermediate Technology Development Group (ITDG) (11): ”Development, for the majority of new technologies, employs a model unchanged since the 19th century - initially, to optimize the technology, then to check acceptance by the users, and finally to examine all regulations governing its use. Given the investments made in the first stages, it becomes difficult to re-develop a technology when potentially harmful social effects are identified later. Consequently, once confronted with the opposition to a new technology, the decision makers are obliged to defend it, a technocratic management response in which potential effects on society or the environment identified outside the narrow process of design are regarded as problems of acceptance by the users.”

Legal and ethical issues relating to the use of GM mosquitoes to fight malaria have received little attention. Moreover, civil society, communities concerned in the countries affected by endemic disease, associations working in the fields of development and public health, and NGOs were not consulted, while at the same time it seems vital to involve them in the process. It is now clear that the development of infrastructures and technologies relative to GM mosquitoes must involve those active in Africa (12). But, it is necessary also that this development is carried out so as to ensure the presence of democratic structures allowing informed and critical choices as to the orientation of sciences and technologies (13).

As for the decision makers, they should allow themselves to be guided by the precautionary principle which, in essence, recommends avoiding using a technology when the risks concerned are not rigorously evaluated and when they could exceed the anticipated benefits. It is this principle that should prevail when one plans to introduce GM mosquitoes into a natural environment for medical purposes.

Acting also and above all on the socio-economic level and with current means of combating malaria

Lastly, it is wise to recall that effective means to fight malaria exist already (drugs, impregnated mosquito nets, ...), but that very often, for the populations concerned, access is lacking. This is the sad corollary of an economic ruin largely caused by the ultra-liberal policies of the IMF (2,14). Indeed, how can one not connect this point to the study led by Paul Reiter on the cases of dengue fever (a viral infection, potentially fatal, transmitted by mosquitoes) on both sides of the border which separates Mexico from Texas (15). Between 1980 and 1999, in Texas, the number of cases of contracted dengue was 64, whereas it was 62,514 in the three adjacent Mexican states (Coahuila, Nuevo Leon and Tamaulipas). Such a contrast cannot be ascribed to global warming, but can well be ascribed to differences in the socio-economic conditions between the states of these two countries. It is necessary to work on economic levers, investing in social programmes rather than in emerging research, if one wants truly to place oneself in sight of an improvement in public health.

In addition, many false hopes have been raised in the fight against malaria during the last decades. The urgent need is to improve or facilitate access to, and use of, the current means of combating malaria: improvement of habitat, free distribution and use of impregnated mosquito nets, the access to quality care, the early diagnosis and adequate treatment by the derivatives of artemisinin (a natural substance [derived from wormwood, artemisia] contained in a new generation of drugs against malaria).

Without doubt, any research concerning the various aspects of malaria will bring unforeseen beneficial discoveries, but it is necessary to bear in mind that the financial dictates favoring research on GM mosquitoes could work to the detriment of financing and effective use of the current means of fighting malaria. Simultaneously with this risk, one might fear that science may lose its freedom if it is forced to be the bearer of concrete applications, as occurs when it is subject to geopolitical considerations or financial interests. Reduced to a medium of the technique, it would be no more than a technoscience, as Jacques Ellul said in his criticism of the technical society (16).

Whether one wonders what will become of science or one invests in the improvement of public health in developing countries, it is always necessary to entertain the results of scientific research and their possible effects on humanity with modesty and the greatest precaution.

Meanwhile, the situation of malaria does not improve and, without wanting to be cynical, the funds poured into research on GM mosquitoes, as into GM agriculture (17), remain a godsend for many research laboratories.

                                  PART 3

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SOURCE: IPP Media, Tanzania

AUTHOR: The Guardian, Tanzania, by Christine Afandi


DATE:   19.06.2007

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A new study shows that genetically modified insects have a higher survival rate and lay more eggs and as such scientists have created a mosquito that is resistant to malaria parasites, renewing hopes of conquering the world’s leading killer disease.

The study on the genes appears in Proceedings of the National Academy of Sciences journal.

According to the journal equal numbers of genetically modified and ordinary ’wild-type’ mosquitoes were allowed to feed on malaria infected mice in the laboratory.

The genetically modified (GM) mosquito has a gene that prevents infection by the malaria parasite, which leads to 16 to 18 million malaria cases and results into over 100,000 deaths every year in Tanzania.

Among pregnant women, malaria is responsible for 25 per cent of all maternal deaths. According to statistics obtained from the Ministry of Health and Social Welfare, Tanzania loses 3.4 per cent of its GDP estimated at USD 350 million (over 400bn/-) as direct and indirect costs of malaria.

Thus the American scientists will be able to save many people in Africa who are ever suffering due to malaria if their experiment proves beyond doubt that it is safe and efficient in the long run.

It will activate efforts by scientists and governments to control the tropical ailment, which accounts for 60 per cent of deaths among children below the age of five years.

In Africa malaria kills one child every 30 seconds.

Scientists will introduce the GM insects into wild populations and hope they will take over due to their ability to survive better than the disease-carrying strains in malaria endemic areas.

During the reproductive stage more of the GM or transgenic mosquitoes (created as a result of gene manipulations) survived, as compared to the disease-carrying strains.

”After nine generations, 70 per cent of the insects belonged to the malaria-resistant strains,”the journal said.

The gene for green fluorescent protein (GFP) was inserted by scientists into the transgenic mosquitoes, which made their eyes glow green. This helped the researchers to easily count the transgenic and non-transgenic insects.

”To our knowledge, no one has previously reported a demonstration that transgenic mosquitoes can exhibit a fitness advantage over non-transgenic,” Dr. Mauro Marrelli and his colleagues from John Hopkins University in Baltimore, Maryland say in the journal.

The study showed that modified mosquitoes had a higher survival rate and laid more eggs.

When both sets of insects were fed non-infected blood they competed equally well said Dr. Marrelli.

The scientists noted that for the study to have major impact on the world, resistant mosquitoes had to survive better than non-resistant ones, even when not exposed to the malaria bug.

The researchers however said, ”The results have important implications for implementation of malaria control by means of genetic modification of mosquitoes.”

The scientists add that GM mosquitoes would interfere with the development of the malaria parasite, making it difficult for the organism to become re-established after it had been eradicated from a target area.

Plasmodium falciparum and plasmodium vivax which are single celled parasites are known to spread malaria which is endemic in Africa, South and Central America and parts of Asia.

The organism is passed to humans through the bite of the female anopheles mosquito. Every year, more than 300 million people fall ill with some succumbing to the disease due to lack of effective treatment.

More than 90 per cent of the cases are in sub-Saharan Africa. In recent times, the world has been in a catch-22 situation as the disease continues to become resistant to available drugs, while research on a vaccine moves at a snail\’s pace.

Tanzania has not been spared either. Resistance to readily available sulphur based drugs forced the government to abandon common malaria medicines for Artemisinin Combination Therapy (ACT), which is currently recommended by the World Health Organization (WHO).

So far, 20 countries, seven of them in Africa, - have updated their malaria treatment, following increased drug resistance. Coartem, which has been adopted by many countries in Africa, was developed by Ciba and Sandoz laboratories in 1996.

The change in the first-line drugs will help countries like Tanzania, recently identified as a hot-spot for malaria, fight the disease.

It has also been established that when people with HIV/Aids contract malaria there is a surge in HIV in the blood making them more likely to infect their partners.

When HIV positive people are attacked by malaria, their immune system weakens significantly, creating the right environment for HIV to replicate.

Climate change and poor land use has also contributed significantly to the rise in malaria cases, these include swamp reclamation and deforestation.

Global warming has led to a rise in mosquito populations especially in the tropics and the rate at which the insects bite humans.

The severity of the disease has forced some scientists in Tanzania to push for re-introduction of DDT, which was banned in 1988 fro its adverse effects on the environment and animal health.

Recently, the US announced a five year USD 1.2 billion programme to halve malaria-related deaths in 15 hard-hit countries. Already Uganda, Tanzania, Angola, Malawi, Senegal and Rwanda have started to benefit from the initiative.

Those expected to be included in the programme next year are Liberia, Ethiopia, Mozambique, Kenya, Ghana and Benin.

President George W Bush said the US took the initiative since malaria inflicted a financial cost of USD 1.2 billion a year on sub-Saharan Africa.

The director of the UN Millennium Project, Prof Jeffrey Sachs says that giving peasant farmers in malaria prone areas high yield seeds, fertilizer and mosquito nets to prevent malaria infection and poverty would help spur economic growth.



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