Two people are treated in Scotland for potentially fatal diphtheria infection.
NHS Lothian has confirmed that the two cases are related and that both patients are believed to be in hospital in Edinburgh.
had recently returned from overseas.
Public health experts said the likelihood of further cases was very low as most people were protected by childhood vaccines.
In Lothian, 98% of children are vaccinated against diphtheria at the age of 24 months.
Alison McCallum, director of public health at NHS Lothian, said: "All these patients' close contacts have been identified, contacted and followed according to nationally agreed guidelines.
" We encourage people traveling abroad to Fit for Travel
What is Diphtheria?
Diphtheria is a highly contagious and potentially fatal infection that can affect the nose, throat and sometimes the skin.
This can lead to breathing difficulties, heart failure and paralysis.
The infection is transmitted by coughing and sneezing or by sharing items such as cups, cutlery, clothing or bedding with an infected person.
This is the case in the UK In rare cases, babies and children are routinely vaccinated.
In some parts of the world, however, there is a low risk of getting the disease traveling.