Over the last decades there is an increase in the numbers of mass mortalities observed in marine mammal populations related to infection by morbilliviruses. In general, disease is a major cause of death in stranded species in the ASCOBANS area, but there are very few recorded mass strandings that can be directly associated with disease.

The species most commonly affected by disease in the ASCOBANS area are the harbour porpoise, the common dolphin and the long finned pilot whale. In 2008 there were several strandings of Cuvier’s beaked whales, Sowerby’s beaked whales and long finned pilot whales in the UK and Ireland, but the causes of these mortalities remain undetermined since most carcasses were too decomposed for necropsy.