I have heard that during the refueling stop in Dakar, health officials come on board and spray everyone. Then on the return flight to Dulles, they both spray and replace all the chair cushions. Any truth to that rumor?

We were on a SAA flight from Dulles to JNB in September and the plane got sprayed both times when we departed Dakar (both on the outbound and return flights). I believe crew members walked the full length of the plane in both aisles and sprayed as they walked. They didn't spray anyone per se but I think some of the spray got on passengers sitting in aisle seats. They announced the spraying before they began and did not spray or replaced the chair cushions on our flight.