Ogwell did not give details about his alleged mistreatment. Germany's federal police, which is in charge of passport controls at the country's airports, did not immediately respond to requests for comment. An email to the Africa CDC was also left unanswered.
Ogwell's tweets generated an inquiry and an apology from Frankfurt Airport's Twitter account.
"As an international airport, we welcome all passengers and do not tolerate any form of discrimination or racism. We would like to have more information about this incident," it said.
Ogwell's tweets were liked and retweeted by thousands of Twitter users, among them World Health Organization Director-General Tedros Adhanom Ghebreyesus. Tedros replied directly to Ogwell that "it is absolutely critical that all World Health Summit participants from Africa and all other countries are treated with respect."
- Associated Press