Spatial and temporal analysis of Zika and chikungunya epidemics in Colombia

In 2014-2017, Latin America experienced back-to-back outbreaks of chikungunya virus followed by Zika virus. Both viruses are transmitted by Aedes mosquitoes and had not been previously reported in the Americas. People with symptoms typically experience fever, rash and joint pain. Additionally, Zika virus infection during pregnancy increases the risk of severe birth defects in newborns and chikungunya fever can cause chronic joint pain that lasts weeks or months.

Colombia was one of the most affected countries during the recent outbreaks with over 100,000 Zika virus and 400,000 chikungunya virus suspected and laboratory- confirmed cases. Using surveillance data from Colombia’s National Institute of Health, this study first estimated the week of invasion in each city (Figures 1-2). Next researchers fitted gravity models to study the invasion dynamics of both viruses between cities in Colombia. Gravity models describe movement from one location to another based on population size and distance.