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Some develop resistance. Others alter their behaviour. Mosquitoes of the genus Anopheles , the vectors of malaria, always find a way to foil human attempts to protect themselves from this disease. Researchers from the IRD and their partners( 1) have revealed their great capacity for adaptation, which weakens the strategies to combatting their presence, recommended by the WHO. A clinical trial conducted in some thirty or so villages in Benin demonstrated that, the combined use over an 18 month period of mosquito nets impregnated with deltamethrin, and another powerful insecticide in spray form inside the homes, did not lead to a decline in the disease. Neither the number of cases nor the prevalence of the infection( 2) among young children were reduced in comparison with the use of mosquito nets alone. In some localities, the introduction of nets led to a change in the feeding habits of the insects of the Anopheles genus, which usually bite at night time. They are now rife outside dwellings at dawn.
The long-term effectiveness of the current measures to prevent and combat the disease is therefore called into question. Scientists will once again need to innovate if we are to one day eliminate this disease for good.
One and a half million people per year are poisoned by snake venom in Sub-Saharan Africa. An IRD researcher recently analysed around 100 surveys and medical reports published over the past 40 years. No large-scale study of the situation had hitherto been conducted and public health authorities had underestimated the size of the problem. This means that currently only 10% of victims are treated, owing to a shortage of antivenoms * and lack of awareness among health care practitioners. Yet the clinical complications can be very serious, even fatal. A bite from a cobra or mamba can bring on death by asphyxia –due to respiratory paralysis– within 6h after the incident. Venom injected by the ocellated carpet viper, common in the African savannah, can cause haemorrhages leading to the victim’s death in a few days.
This new study provides authorities with more detailed and reliable figures which should enable them to readjust their health-care services in better tune with needs.
Rice is the world’s most commonly used cereal food, feeding half of humanity. However, rice production will have to double within 20 years from now to meet the needs of a growing population.
Two species are used for cultivation, one Asian and the other African. The Asian species gives much stronger agronomic performances, but the African one is more rustic, more resistant to pathogens, more tolerant to drought and soil salinity.
With the aim of transferring these properties to Asian rice, IRD scientists and their research partners( 1) are seeking to overcome the sterility between the two species( 2). They used genome sequencing to compare the structure of a portion of chromosome, identified as the factor behind the reproductive barrier. These investigations, the first results of which were published recently in the journal PLoS One , have led to the definition of genetic markers allowing more rapid development of fertile lineages of improved Asian rice.
In the coming decades, the West African countries could benefit from a demographic window of opportunity to reduce their poverty. The arrival of 160 million young people on the labour market between 2010 and 2030 could accelerate economic growth. These countries could take advantage of this “demographic dividend”, which the emerging countries have been doing for 40 years. On condition that they lower their fertility rates, are still the highest in the world, with an average of five children per woman. That would enable them to reduce the number of economically non-active people being supported for each active individual..
An IRD researcher asserts this in a review published recently by the Agence française de développement (AFD), concerning a far-reaching survey( 1) conducted in 12 West African countries( 2): family planning and promotion of contraception are some of the main keys to sustainable economic growth. Yet to arrive at such a situation, these countries must assign 3 to 5 times the means currently given over to such a policy. Will they be able to manage this population turning point successfully?
Over 33 million people in the world are living with HIV, the Aids virus, and 75% of them live in Sub-Saharan Africa. Most of the people ill with the disease on that continent are women. In the Ivory Coast, the West African country most affected by the pandemic, two women are contaminated for every one man. Women are indeed physiologically more vulnerable to a sexually transmitted infection like HIV.
However, in spite of this gender inequality in relation to Aids, far more women than men are taking part in treatment programmes. Is it their concern to protect their children and see them grow up? Are programmes better geared to women? IRD researchers and their partners (1) recently found evidence for a “gender paradox” and are seeking to understand this by examining women’s experience with HIV care measures.