Can changes in Indian Ocean temperatures help predict dengue outbreaks? New paper finds link

Researchers have found a potential link between sea surface temperature anomalies in the Indian Ocean and the intensity of global dengue fever outbreaks, raising hopes for improved predictions of dengue outbreaks. . The forecast could give countries enough time to prepare and respond.

A new paper has been published in a journal science identified a specific indicator of mean sea surface temperature change across the tropical Indian Ocean, the Indian Ocean Basin-wide (IOBW) index. Studies have shown that this index is closely associated with dengue outbreaks in both the Northern and Southern Hemispheres.

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The association between Indian Ocean temperatures and dengue fever incidence may be due to the influence on regional temperatures through teleconnections, large-scale atmospheric patterns that transmit heat and moisture over long distances.

“Our study shows that the IOBW index significantly influences regional temperatures around the world, which in turn influences dengue transmission,” the researchers wrote in their paper.

Dengue fever is a viral infection that is transmitted by being bitten by an infected person. Aedes Mosquito species. Before 1970, severe outbreaks of dengue fever were reported in only nine countries; now it affects almost half of the world's population, with 100 million to 400 million people infected each year. It is estimated that

Early warning systems can help public health officials predict and prepare for dengue outbreaks. Temperature and rainfall have previously been linked to infectious diseases, but their lead times are only about two weeks to three months, the researchers noted.

The researchers collected the total number of annual dengue cases reported from 46 Southeast Asian countries and the United States over a 30-year period from 1990 to 2019.

They also looked at dengue cases reported monthly from 24 countries over a six-year period from 2014 to 2019. We then analyzed how global climate patterns influenced the seasonal and annual scale of dengue outbreaks.

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IOBW has emerged as an important indicator for predicting the scale and timing of dengue epidemics in countries.

In the Northern Hemisphere, dengue fever peaks from July to October, and in the Southern Hemisphere from February to April, both of which are summer months.

Additionally, the amplitude of dengue incidence was higher when the index was positive and lower when the index was negative.

Additionally, the annual incidence of dengue fever is correlated with the IOBW index in both the Northern and Southern Hemispheres.

These initial findings suggested that this index may be a potential indicator for predicting the interannual and seasonal scale of global dengue epidemics.

However, the researchers added that the IOBW index's association with the Southern Hemisphere is stronger than its association with the Northern Hemisphere. This index has a more pronounced effect on temperatures in tropical regions. Brazil, for example, has one of the highest burdens of dengue fever in the Southern Hemisphere.

read more: Will climate change influence the trajectory of dengue fever in India?

Although promising, the researchers stressed that more data are needed to establish a causal relationship. This means that IOBW influences regional temperature changes and the consequent increase in dengue fever incidence in other countries.

They also acknowledge that the study has some limitations. For example, the team could not fully assess his IOBW index because annual and monthly case reports are not published in some countries.

This study did not take into account other factors that may influence dengue transmission, such as vector control, social and economic factors, and local herd immunity.

“Future research should focus on incorporating other potential factors and establishing a comprehensive set of indicators for a dengue early warning system,” the researchers said in the study. ing.