Science & Research

Infectious disease outbreaks rising, study shows

U. researchers compile online database of outbreaks since 1980 to help predict future epidemics

By
Senior Staff Writer
Monday, November 3, 2014

Though Ebola has dominated mainstream media attention recently,  the total number of infectious disease outbreaks worldwide has been climbing since 1980, according to a new study published by Brown researchers in the current issue of the Journal of the Royal Society Interface. 

Though the rate of infectious disease outbreaks is increasing,  infectious diseases are affecting fewer people during each outbreak than in the past, the researchers wrote in the study.

As part of the study, the team of University researchers created a database of over 12,000 outbreaks of infectious diseases that have occurred since 1980, cataloguing occurrences of 288 out of the approximately 1,400 infectious diseases known to man, said author Katherine Smith, interim associate dean of biology and assistant professor of ecology and evolutionary biology. The database provided the information and analytics necessary to examine the trends in outbreaks the researchers presented in the recently published study.

The online database is accessible to the public through the Ramachandran Lab website, Smith said. Sohini Ramachandran, a biostatistician and assistant professor of biology, helped design the program for the database, she added.

Before the creation of this database, the Global Infectious Diseases and Epidemiology Network provided the most comprehensive source of outbreak information, but the information was buried in paragraphs of prose, making it difficult to statistically analyze, Smith said.

The researchers hope people use the database “to help do a better job of predicting and preventing outbreaks in the future,” Smith said.

“The hope is that this data set can be used to try to really dig into the drivers of these big outbreaks,” said Samantha Rosenthal GS, a co-author of the paper who studies at the School of Public Health.

“Understanding those drivers can help us build robust prediction models, so that we can be more prepared for outbreaks like Ebola in the future,” she said.

The majority of the catalogued diseases are zoonotic diseases, which are transmitted between species, often from non-human species to humans, Smith said. Widely-known diseases such as Ebola, Lyme disease, West Nile virus and tuberculosis are all zoonotic diseases.

While Ebola is currently the focus of much media and medical attention, Smith said diseases like Lyme disease and West Nile virus are still prevalent in Rhode Island and the Northeast in general.

“Other research has shown that it’s the combination of high biological diversity existing in regions where there are already a lot of people, or the populations are very dense, that are the most likely predictors for zoonotic disease emergence and outbreaks,” Smith said, adding that this could be a reason why there are more outbreaks now than in the past.

The researchers hope to use the database to examine the factors that influence how far diseases spread and to attempt to answer why outbreaks are affecting fewer people today than they did in the past,  Rosenthal said.

The study is “particularly timely as the global community struggles to confront the global health security and humanitarian crises associated with Ebola,” wrote James Hughes, a professor of medicine and public health at Emory University who was not involved in the study, in an email to The Herald. The “results also remind us of the continuing need to further strengthen public health systems globally to enable early detection and rapid, effective response to disease emergence.”

The database’s creation marks the start of a journey Smith and her colleagues are embarking on to learn more about disease outbreak and prevention. Smith said she plans to start asking more specific questions in the next phase of her research, such as “Will a warmer world be a sicker world?” She also plans to explore the effects of climate and land-use change on infectious disease outbreaks.

“As a world, we need to be more cognizant of the fact that wildlife and livestock around us are likely to harbor pathogens that could spill over and infect us,” Smith said. In addition to research, “there’s a lot more we could do in terms of public outreach and education” in local communities, she added.

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