Global infection outbreaks rising since 1980: Study

The number of outbreaks of infectious diseases and the number of unique illnesses causing them appear to be increasing around the globe, says a study co-authored by an Indian-American professor.

However, even though the globe faces more outbreaks from more pathogens, they tend to affect a lesser number of the global population, found the study.

The researchers found that 65 percent of diseases in the dataset were "zoonoses". In other words, they come from animals, revealed the analysis.

"We live in a world where human populations are increasingly interconnected with one another and with animals that host novel pathogens," said Katherine Smith, assistant professor of biology in Brown University.

"These connections create opportunities for pathogens to switch hosts, cross borders, and evolve new strains that are stronger than what we have seen in the past," said Smith.

Thus, Ebola may have come from bats.

Altogether, such diseases caused 56 percent of outbreaks since 1980, found the study.

By using Global Infectious Disease and Epidemiology Online Network (GIDEON) data, the team created a database comprising 12,102 outbreaks of 215 infectious diseases involving 44 million cases in 219 countries between 1980 and 2013.

"GIDEON defines an outbreak as an increase in the number of cases of disease beyond what would normally be expected in a defined community, geographical area, or season," said Sohini Ramachandran, assistant professor of biostatistics, Brown University.

Between 1980 and 1985, there were well under 1,000 such instances, but for 2005-10, the number surged to nearly 3,000, showed the analysis.

During the same period, the number of unique diseases causing the trouble went up from less than 140 to about 160.

"Our data suggest that, despite an increase in overall outbreaks, global improvements in prevention, early detection, control, and treatment are becoming more effective at reducing the number of people infected," concluded the authors.

The study appeared in the Journal of the Royal Society Interface.