When the native steals Colonel Rawling's file from Steed's Bentley, a folder marked 'PZEV' from the episode "Two's a Crowd" can clearly be seen to be part of the file.
Mrs. Peel says the tsetse fly is Glossida trypanosoma. Actually it is genus Glossina; species morsitans, or fusca, or papalis. All three species cary the sleeping sickness parasite, Trypanosoma brucei.
In one scene, Steed briefly swaps his whangee-handled umbrella for a sword stick.
Both Peter Burton and James Villiers have both appeared as MI6 officers in the James Bond franchise.