A new study from the School of Public Health shows bacterial meningitis cases vary by season and peak during the winter months around the world. Bacterial meningitis, which is highly fatal and caused by common bacterial infections like streptococcus, has an estimated 1.2 million cases annually.

The study, which is the first world-wide analysis of the seasonal dynamics of bacterial meningitis, was recently published in the journal The Lancet Global Health.

To gather the results, the research team from the University of Minnesota, Princeton University, and the Institut de recherche pour le développement created the first-ever bacterial meningitis global database, which was compiled from more than 700,000 cases reported by surveillance systems in 66 countries.

“We found a strong seasonal trend in nearly all countries analyzed,” says study senior author and Assistant Professor Nicole Basta. “We also observed a strong latitudinal gradient in the timing of the seasonal peak, with bacterial meningitis seasons peaking during the dry, winter months in countries in both the northern and southern hemispheres.”

Interest in the seasonality of meningitis outbreaks stems from the previously observed annual dry season outbreaks of the disease occurring in the sub-Saharan area of Africa known as the “Meningitis Belt.”

“Our analysis of the seasonal dynamics of meningitis across diverse geographic settings is the first step towards understanding what factors drive these trends,” says Basta.

The researchers believe their findings provide key insight into the global epidemiology of meningitis and can be used to develop hypotheses about the host, environment, and pathogen characteristics that may be driving these patterns. They also argue that understanding global seasonal trends in meningitis could be used to design more effective disease prevention and control strategies.