Scientists have succeeded in combating dengue fever thanks to Wolbachia, a bacterium that stops the replication of the virus in the mosquitoes that carry the disease. Mosquitoes are inoculated in the laboratory before being released into the wild… thus reducing the transmission of dengue fever! Explanations.
Dengue fever occurs worldwide, in tropical and subtropical regions and mainly in urban and semi-urban areas. This viral infection is transmitted to humans by the bite of infected female mosquitoes (mainly of the aedes aegypti species). These mosquitoes are also vectors of chikungunya, amaril and Zika. Dengue is the second most diagnosed febrile illness after malaria. In some countries in Asia and Latin America, severe dengue is one of the leading causes of serious illness and death. About half of the world’s population is at risk, but with 100-400 million infections annually, more than 80% are mild and asymptomatic. While before 1970, only nine countries had severe dengue epidemics, the disease has now become endemic in more than 100 countries in the WHO Regions of Africa, the Americas, the Eastern Mediterranean, South-East Asia and the Western Pacific.
Mosquitoes, when carrying Wolbachia bacteria, prevent the transmission of these arboviruses. The aim is to breed Wolbachia-infected mosquitoes with wild mosquitoes to create a new population of mosquitoes that are unable to transmit arboviruses.
Australia has pioneered this technique thanks to the work carried out for nearly 20 years by Scott O’Neill, Dean of the Faculty of Science at Monash University in Melbourne. He is the head of Eliminate Dengue, an international research collaboration that has developed the introduction of the bacteria into mosquitoes. Dengue fever is said to have been eliminated from Townsville in Australian Queensland by releasing these modified mosquitoes into the environment. After releasing between 10,000 and 20,000 mosquitoes over a ten-week period, more than 80% of the population became carriers of the Wolbachia bacteria (and were still carriers two months after the releases ended). The fight against dengue relies mainly on vector control measures. In parallel, the WHO also recommends better waste management and the destruction of breeding grounds. One of the major challenges of the project is to explain the principle to convince the population of the harmlessness of releasing these infected mosquitoes. This strategy is part of the implementation of public health policies. The poorer the population, the more virulent the dengue.
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