Box 1.

Hazards on military deployment

Dangerous equipment (e.g. weapons, ammunition)

Transport (heavy vehicles, aviation)

Environment (extreme temperature, humidity, altitudinal hypoxia)

Physical stress (mechanical load, protective clothing, lack of air conditioning)

Remote location (distance from medical facilities, difficult medical resupply)

Lack of adequate physiological reserve in new environment (genetic)

Medical evacuation (extraction under fire from forward locations)

Novel pathogens (malaria, viral illnesses)

Enemy action (includes unconventional weapons)