The definition of “maritime medicine” covers a large number of issues, as: the environment of seafaring (effects of microclimate and macroclimate, noise and vibration aboard ship on seafarers, other work related exposures); conditions of work and life on merchant, passenger and fishing ships and on oil rigs; sanitary problems on ships; nutrition and food hygiene aboard ship; pathology of workers employed on ships (diseases, accidents and injuries); toxicology of seafaring; exotic diseases; health problems of navy personnel; personal hygiene of seafarers; vaccinations of ship’s crew members and other preventive interventions as their health education; training of seafarers in providing basic medical services on board ship during voyages; health standards for work at sea and medical examinations of seafarers and radio medical advice for ships.

Also diving and underwater medicine problems are included in this definition. However, this field has separately developed and a number of specialized centers all over the world employ specialists in this area.

These care not only for professionals, but also for recreational divers and they treat not only decompression sickness but also other cases of accidents and diseases.

Special training of medical doctors who take care of seafarers may be covered by this definition, and international postgraduate training courses in maritime occupational health for doctors have already been conducted.

Journals on maritime medicine or health have been published in a number of countries.

The field of interest of Maritime medicine partly overlaps with occupational medicine, tropical medicine, and travel medicine. The studies of health problems of shipyard workers and dockers may also be included in this chapter of medical science.

Another useful definition might be “maritime occupational health”. This term is widely used. For instance has WHO designated several maritime medicine centres specializing in this field as reference with the name of “WHO Collaborating Centres on Maritime Occupational Health”.
Another definition used by some authors is “nautical medicine”.

Seafaring has always been considered a dangerous occupation. Crews of merchant ships are exposed to extremes of weather, hazards connected with the operation of mechanical equipment, toxic cargoes and toxic substances used aboard. Seamen are swept overboard by heavy seas, and die as a result of vessel casualties (such as foundering, capsizing, explosions, fires).

Their health is affected by noise, vibration, smoke inhalation, fatigue, overwork and other exposures.

Travel to the tropics is connected with exposure to exotic diseases including malaria.

In case of sudden illness or an accident and injury during the ship’s voyage, the chances of receiving proper and effective treatment is not as good for seafarers as for workers on shore because of lack of direct and prompt access to qualified medical assistance. Seafaring is therefore a dangerous occupation with a higher morbidity and mortality rate than in most occupations onshore.

Numerous papers have been published on this subject in the medical literature.
A good source of information is data published by the International Labour Organization (ILO).

Even more dangerous is the occupation of fishermen.

Regarding the accidents and injuries of seafarers, they have generally been recorded more frequently on older than on newly constructed ships, on smaller than on large ships; on general cargo than on tanker ships.

Regarding the work-related mortality among fishermen in various countries, published data from Denmark indicated that it was 25-30 times higher than in workers on shore.

The liberalization of the labour market, also in the shipping industry, was found to weaken collective bargaining, minimum wages and safety of work.

Ship owners were the beneficiaries of the process of globalization; they are now able to operate their ships at lower labour costs than before. But for seafarers in many countries, globalization was a mixed blessing. They can now look for employment on ships operated under various flags. But for many of them, conditions and safety of work and the care for their health have generally deteriorated.

On ships flying flags of industrialized countries, there is job security for crews and the health care for them is fairly well organized. Seafarers are regularly examined by doctors, their medical expenses are fully covered by insurance, and strong trade unions protect their social security and fight for honest wages.

Yet, during the last two decades, a large number of ships of industrialized countries have been re-flagged and operated under so called “flags of convenience” (FOC).
Seafarers of any nationality can be employed on such ships. They come from developing countries or from newly independent countries, in which the previously efficient government operated health services have disintegrated.
Their contracts are usually for short periods of time, often for one or two voyages only.

Low registration fees, low or no taxes, and freedom to employ cheap labour are the motivating factors behind a ship owner’s decision to “flag out”. FOC registers have poor safety and training standards.
In 2000, there were 30 FOC countries, including Bolivia (having no access to sea), Bahamas, Cambodia, Cyprus, Lebanon, Liberia, Malta, Panama etc.

The international organizations as ILO, WHO, IMO, and the ITF have done much to introduce legislation protecting the safety of work, health and wellbeing of international seafarers, fishermen and other maritime workers. More about that is written in the next two chapters of this book.

Particularly WHO has done a lot, supporting many initiatives and activities of maritime health services in various countries, training and disseminating knowledge of health problems of seafarers.

In 1972, WHO designated one research centre (Institute of Maritime Medicine in Gdynia) as their global reference centre for maritime medicine. Since that time, several WHO Collaborating Centers were designated, in Hamburg, Esbjerg, Bergen. Similar centers in other countries (Ukraine, Russia, Vietnam, Japan, Lithuania, Spain) joined in these activities. International Symposia on Maritime Medicine have been conducted since the first one organized in 1963, and the health care workers from many countries who belong to the International Maritime Health Association (IMHA) regularly exchange experiences. Scientific maritime medicine journals are published in Poland, Japan, Spain, China and Ukraine.