[4] After completing his medical studies, Colebunders spent his early career as a general practitioner in Bougaa, Algeria, from 1974 to 1975, where he gained experience treating patients in rural, resource-constrained environments.

[9][11] Colebunders furthered his research in this area as a visiting scientist at the Centers for Disease Control (CDC) International Activities HIV/AIDS programme in Atlanta, USA, in 1988.

In 2004, he took a sabbatical to serve as a senior clinical investigator at the Infectious Diseases Institute in Kampala, Uganda, assisting with the rollout of antiretroviral therapy (ART) for HIV patients.

This partnership, part of the VLIR-IUC (Flemish Inter-universities Council -Institutional University Cooperation) programme, aimed to strengthen research capacity and address healthcare challenges, including infectious diseases like HIV, in rural African communities.

[19] In 2014, Colebunders received an advanced European Research Council (ERC) grant to investigate the cause of nodding syndrome and other forms of epilepsy in onchocerciasis-endemic regions.