Although it is not possible to prevent dengue outbreaks, it is now possible to predict them in advance. Scientists have recently discovered a global climate indicator that could help improve predictions of the severity of dengue outbreaks several months ahead of time. This indicator, which can be applied to any region in the world, is based on fluctuations in surface temperatures in the Indian Ocean. Accurate long-term predictions could make it easier to address this increasingly prevalent infection, which poses a threat to half of the world’s population.
Although dengue outbreaks cannot be prevented, it is pIt is possible to predict dengue outbreaks several months in advance. A global climate indicator based on temperature fluctuations at the surface of the Indian Ocean has been identified by an international research team. This indicator, which can be used for any world region, may improve predictions about the magnitude of dengue outbreaks. The Institut Pasteur and Beijing Normal University in China are among the institutions involved in this research. Reliable long-term predictions could help in efforts to combat the increasing threat of dengue, which affects half of the world’s population. The research results were published in an international journal.The prestigious journal Science published an article on May 10, 2024, highlighting the significance of being able to predict dengue outbreaks. This is crucial for planning control measures against the disease-carrying mosquitoes and preparing hospital resources. Despite the availability of vaccines, there is no specific treatment for the symptoms of dengue, also known as “tropical influenza.” Furthermore, the severity of outbreaks can vary significantly from year to year due to the complex dynamics of the virus, which exists in four different forms, or serotypes, that can change annually.”From one season to the next, the magnitude of dengue outbreaks can vary considerably as the reproduction and infectivity of Aedes genus mosquitoes, which transmit dengue viruses, are closely correlated with local temperature and rainfall,” explains Simon Cauchemez, joint last author of the study and Head of the Mathematical Modeling of Infectious Diseases Unit at the Institut Pasteur. However, these parameters can only be predicted between two weeks and three months in advance, and the quality of forecasts decreases rapidly.for longer-term predictions. Global climate indicators like El Niño-Southern Oscillation (ENSO) can usually be predicted over a longer period, beyond six months. An international team, therefore, set out to investigate 30 global climate indicators to determine if monitoring such indicators could assist in predicting dengue outbreaks further in advance.
The team gathered two extensive datasets: the total number of annual dengue cases reported in 46 countries in South-East Asia and America over 30 years (1990-2019), and the monthly number of dengue cases in 24 countries over six years (2014-2019). They discovered that of all the indicators under consideration, the 15 that were linked to temperature were the most effective at predicting dengue outbreaks.Consideration of the Indian Ocean basin-wide (IOBW) index, which measures temperature fluctuations at the surface of the Indian Ocean, showed the closest correlation to annual dengue incidence in both the northern and southern hemispheres. The study’s co-last author, Huaiyu Tian, Director of the Center for Global Change and Public Health at Beijing Normal University, stated, “Our findings demonstrate that incorporating the IOBW index into our mathematical model resulted in predictions that closely matched real-world data, compared to the model excluding the IOBW index.” This integration also led to extended lead time and improved predictive capabilities.
ability underscore the importance of the IOBW index in dengue forecasting and early warning systems.”
These interesting theoretical findings will need to be verified in real-world conditions. “Our goal is to create predictive models for dengue outbreaks in Guadeloupe, French Guiana, and Martinique, and we will now investigate whether the IOBW index can effectively enhance these predictions,” explains Simon Cauchemez. “Climate is not the sole factor that impacts dengue outbreaks. For these predictive models, we will also need to consider other factors such as immunity levels in the population, previously circulating strains, etc.”
Researchers believe that a new indicator could potentially improve the prediction of dengue outbreaks, which would help in efforts to combat this infectious disease. The number of dengue cases has increased significantly in recent years, particularly in mainland France. For example, there were 1,679 imported dengue cases reported between January 1 and April 19, 2024, compared to 131 cases during the same period in 2023. This highlights the urgency of finding more effective ways to predict and manage dengue outbreaks.
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