The number of overseas outbreaks involving people returning to Scotland halved in 2019 compared with the year before, according to a new report.

In 2019, there were 36 potential outbreaks of infectious intestinal disease in those going back to Scotland from abroad. This was down from the 75 potential overseas outbreaks reported in 2018 but was in line with the 35 recorded in 2017.

Data comes from the annual surveillance report on overseas outbreaks of infectious intestinal disease in 2019 published by Health Protection Scotland (HPS), part of Public Health Scotland (PHS).

HPS uses a surveillance system to collect information on potential outbreaks believed to be acquired by people returning to Scotland from outside the United Kingdom. Surveillance relies on voluntary reports from NHS Board Health Protection Teams but outbreaks can be identified by reference laboratories.

Such an outbreak is defined as two or more confirmed cases of the same infection, or at least one confirmed case wher others are alleged to have been ill, and who have visited or stayed at the same accommodation.

Top country and pathogen
Between 2003 and 2019 the average number of potential overseas outbreaks was 56 but it was as high as 100 in 2010 and as low as 20 in 2013.

In 2019, Turkey was the most frequently reported country from which people returned with 10 outbreaks. Spain, including the Balearic Islands, was second with nine outbreaks, then Cuba with four and Tunisia with three, while 10 countries were each associated with one potential outbreak.

The year before Spain had been top, reflecting the fact that it is the country with the most visitors, followed by Turkey, Mexico, Egypt and Cuba.

Salmonella was the most frequently identified pathogen linked to potential overseas outbreaks and was reported from 19 potential incidents. Since 2011, Salmonella has been the top pathogen each year except for 2015, when it was Cryptosporidium.

In 2019, Cryptosporidium was second with 11 outbreaks followed by Shiga toxin-producing E. coli (STEC) with three and one each for Shigella, Giardia and Cyclospora.

There were four outbreaks of Salmonella in Scotland in 2019 that were part of wider U.K. incidents. based on 2018 data, there were six domestic outbreaks of E. coli O157 and other STEC; three of E. coli O157, two of E. coli O145 and one of E. coli O26.