Local climate affects dengue transmission in a region

Washington, Feb 17 (ANI): It's the local climate and short-term changes in temperature and precipitation that affects dengue transmission in a region, according to a new study.

Researchers from the US Centers for Disease Control and Prevention (CDC) and the Johns Hopkins Bloomberg School of Public Health confirmed the finding in Puerto Rico.

"Previous studies have shown that there are biological relationships between temperature, precipitation and dengue ransmission, but empirical evidence of these relationships is inconsistent," said Michael Johansson, a postdoctoral fellow with the CDC's National Center for Zoonotic, Vector-Borne and Enteric Diseases Dengue Branch in San Juan, Puerto Rico.

He added: "This finding on how local climate moderates the relationship between temperature, precipitation and dengue incidence helps explain previous discrepancies. It also suggests that the effects of global climate change on dengue transmission will be local rather than global."

For the study, the researchers analysed 20 years of data from 77 municipalities in Puerto Rico, and showed how local climate alters the patterns of disease transmission.

It was found that even in a relatively small geographical area, there were differences in the relationship between weather and dengue transmission.

For example, in the southwestern coast, where it is hot and dry, precipitation played a very strong role and temperature a lesser role in dengue transmission because in these dry areas, the lack of water limits mosquito reproduction.

On the other hand, in the cooler central mountains, temperature is more important and precipitation less important because the lower temperatures there slow mosquito and virus development.

Dengue is caused by any one of four closely related viruses (DENV-1, DENV-2, DENV-3, or DENV-4), which are transmitted to humans by the bite of an infected mosquito Aedes aegypti. Both the viruses and vector are endemic to most of the tropical and subtropical regions of the world, where they cause seasonal epidemics varying in size.

The findings of the study have been published in the open-access journal PLoS Neglected Tropical Diseases. (ANI)