Ports have always been the gateway through which goods, people and ideas could leave or enter a country, but they also allow the movement of less welcome visitors.
For thousands of years before rail, road or air travel became possible, diseases moved most swiftly by sea. Ships containing infected people or goods travelled long distances, carrying diseases to countries where they had never been known before.
The quarantine guard ship Rhin at Standgate Creek near Sheerness. © NMM