Although virologists are not in agreement on the origins of the 1918-19 influenza pandemic, it has long been associated with the virulent type A virus.

At least 21 million people died from the disease over a 12-month period, becoming one of the world's worst short-term demographic disasters.

The disease was introduced into Nigeria by passengers and crews who arrived via ship from overseas.

Thus, coastal ports were the primary focus of the diffusion of the disease.

Its spread to the hinterland mwas facilitated by improvements in transportation technology.