CHICAGO, March 6 (Xinhua) -- Climate in the tropics has a larger influence on transmission of the sometime deadly rotavirus than previous shown, University of Michigan (UM) researchers found.

Using sophisticated modeling and conducting the work in rural coastal Ecuador along three rivers that have different water flow rates, UM School of Public Health researchers found that draw water from large, slow-moving or stagnant sources in cooler seasons have more transmission of the virus than those that access free-flowing water.

"Our research shows water can both disseminate rotavirus between communities and amplify within-community transmission cycles," said Alicia Kraay, a research fellow in epidemiology at the UM School of Public Health and first author of the study.

"For example, rotavirus can also be transmitted through contact with contaminated surfaces and the amount of time that rotavirus can survive on these surfaces depends on both temperature and humidity," Kraay added.

Specifically, the meta-analysis showed a single-degree Celsius temperature increase in stagnant water systems led to up to a 2.4-percent decrease in incidence of the virus.

"Even though we knew incidence varied with temperature, we were not sure waterborne transmission was part of the reason why. Our results helped explain why we see these associations in the literature," Kraay said.

"These results emphasize the importance of wastewater treatment. Currently, billions of people globally (largely in the tropics) are exposed to polluted waters due to the lack of sufficiently treating wastewater," said Joseph Eisenberg, senior author of the study and chair of the School of Public Health's Department of Epidemiology

Rotavirus is a disease characterized by watery diarrhea, vomiting, fever and abdominal pain. It is most common in infants and small children, who can often lose their appetites and become dehydrated.

Diarrheal disease is the fifth-leading cause of death worldwide and third-leading cause among children under five. Studies have shown that rotavirus is one of four pathogens responsible for most of the severe diarrheal diseases.

The study has been published in Proceedings of the National Academy of Sciences.