Scientific newssheets
Page 1 : Results 1 to 5 on 11
417 - AIDS: in Africa, men are less responsive to treatment
November 2012
In Africa, more than 25 million people, most of them women, are currently infected by the AIDS virus. However, a study conducted by Epicentre( 1) and IRD researchers shows that men are less responsive to treatment. The provision of healthcare is intended to restore the level of lymphocyte cells, called T-CD4, reduced by HIV. Based on 13,000 patients monitored through four programmes carried out by Médecins sans frontières France in Malawi, Uganda and Kenya, the study shows that the reconstitution of these white blood cells is slower in men than in women.
Due to stigmatisation and work- and transport-related constraints, among others, men often receive healthcare at a later stage and are less responsive to treatment. However, this gender-based difference could also stem from biological causes, such as physiologically lower rates of T-CD4 lymphocytes.
This study underlines the fact that men should therefore receive special attention from programmes aimed at fighting the disease.
415 - Obesity weighs down on tunisian women
October 2012
Men and women in Tunisia are not equal before the scales. Tunisian women are three times as likely to suffer from obesity as their male compatriots. This great inequality was revealed in a study by IRD and its partners ( 1), and differs from what nutritionists have observed in the North, where more men tend to be overweight. The disparity is even greater in cities: a sedentary lifestyle, temptations offered by mass-market retail… Their role in society makes women particularly vulnerable to risk factors in an urban environment. Body mass index (BMI) is also increasing among those with a lower education level and without employment, further broadening the difference from their masculine counterparts.
A BMI above 25 increases health risks: cardiovascular diseases, diabetes, cancer, high blood pressure… The latter already affects nearly a third of all Tunisians above the age of 35, of which almost a million are obese today. Prevention is better than cure: healthcare authorities must aim their actions at the population segment that is most at risk, namely women.
414 - Studying rodents’ habitats to prevent leptospirosis
October 2012
Leptospirosis is a water-related bacterial disease with a high incidence in Southeast Asia. People usually become infected through exposure to water contaminated by the urine of infected animals, mainly rats and mice. In the framework of the CERoPath ( 1) program, IRD researchers and their partners ( 2) have revealed the relationship between rodents’ environment and infection by leptospirosis bacteria. They showed that, whereas people mainly get infected in rice fields, the bacteria are present in a variety of environments, and particularly at the frontiers of fields and forests. The use of remote sensing and Geographic Information Systems (GIS) has helped to expand knowledge on rodents’ habitats. These studies allow a better understanding of their behaviour, depending on land use changes, and infection risks caused by human activities, including leisure.
413 - Malaria: vector mosquitoes are constantly adapting
September 2012
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.
412 - The tiger mosquito is more flighty than first thought
September 2012
Female tiger mosquitoes, vectors of the chikungunya virus and of dengue fever, had been thought to mate only once during their short few weeks of life. They are apparently much less faithful than imagined, however. A team representing the IRD and its partners( 1) has discovered that they may in fact mate with several males during their short lives. What is more, the same clutch of eggs can be engendered by different fathers! For their part, the males can mate with over 10 different females.
These recent studies, conducted on the island of Reunion and published notably in the journal PLOS ONE , will make it possible to perfect the "sterile insect technique". This innovative approach to fighting against vectors of disease consists of fooling females into mating with infertile males so as to reduce the population of mosquitoes in the wild. Researchers will, in particular, be able to establish what quantity of sterilised males to release in order to compensate for the infidelities of the females.
Dengue fever and the chikungunya virus continue to take their toll all over the world. In the absence of either a vaccine or effective treatment, attacking the vector remains the sole course of action. If this new method proves promising, it will offer an ecologically acceptable alternative to the use of insecticides.
