During the 7 year period between 1975–81, a total of 2081 cases of infection were reported to the Communicable Diseases (Scotland) Unit, concerning persons with a history of recent overseas travel. The most frequently reported diseases were salmonellosis (829 cases), bacillary dysentery (345), malaria (236), campylobacter enteritis (219), giardiasis (125), enteric fever (82) and viral hepatitis (74).

Holidaymakers, particularly those who had visited the Mediterranean area, were most frequently affected, comprising more than two-thirds (67·8%) of the total, followed by business travellers and immigrants. Nearly three-quarters (72·7%) of infections were reported between June and November. Young adults, particularly males between 15 and 34 years, were responsible for almost one-half (48·l%) of cases.

Secondary spread of infection after arrival in Scotland was uncommon, occurring in less than 3% of cases. One unusual episode occurred in the North of Scotland when an imported rare salmonella serotype (S. zanzibar) subsequently contaminated milk at a dairy farm and later caused disease among young calves on another farm with seagulls being the apparent vehicle of secondary infection.