State of the art: public health and passenger ships

The purpose of this report is to describe issues relevant to public health and to review all passenger ship associated diseases and outbreaks. Moreover, legislation and practices on sanitation and diseases surveillance related to ships internationally were also reviewed. Some relevant historical information about infections on merchant ships is provided as well.

The methods used to develop the state-of-the-art report included a scientific literature review and an extensive and thorough search of the websites of organisations and government departments. A considerable effort was made to capitalise on previous experience in the field. In particular, for the literature review, a total of 158 scientific articles were used including 91 full papers and 67 abstracts, 7 guidelines published by the WHO, and 13 guideline documents published by other organisations. Moreover, 5 international conventions relevant to passenger ships were identified.

At the international level, public health issues related to ships are regulated by the revised International Health Regulations (2005). Other conventions of the International Maritime Organization regulate safety on board ships and waste and ballast water management, while conventions of the International Labour Organization regulates issues related to working conditions on board ships. Guidelines for preventing and controlling public health threats on board ships can be found in seven Guidelines published by the World Health Organization, including the WHO Guide to Ship Sanitation, which provides a framework for policy making and local decision making. The literature review results revealed that the infections/outbreaks that occur on passenger ships include Norovirus, Legionella spp., Salmonella spp., E. coli, Vibrio spp., and influenza A and B virus. The modes of transmission include person to person, waterborne, foodborne, airborne, and vector-borne, and shore excursions are responsible for some outbreaks.

The industry (especially the ferry industry) and sanitary organisations can enhance collaboration in order to implement integrated hygiene programmes and prevent the occurrence of communicable diseases aboard passenger ships.