The widening range of sports and the ever increasing number of participants have meant that almost every type of infection may be acquired, directly or indirectly, in the pursuit of sport.

Though few if any of the more traditional sport associated infections, such as septic cuts, athletes foot, herpes gladiatorum, etc, have decreased in their occurrence, some new ones have recently emerged. Herpes has acquired an entirely new importance. There is also considerable concern regarding the possible risks of HIV infection while participating in sport, particularly in combat and contact sports where blood may be spilt.

Increased attention has also been given to viral infections and their effect on athletic performance, and in particular to the debilitating effects of the Epstein-Barr virus (glandular fever) and coxsackievirus B infections, both of which have been associated with the chronic fatigue syndrome. In addition, premature return to active physical activity after influenza or similar feverish viral illnesses can have irreversible damaging effects on cardiac muscle.

In recent times sport has also become increasingly international as world travel has speeded up. In consequence more and more athletes (and officials) become exposed to a wider range of environmentally acquired infections such as “travellers' diarrhoea” in its various guises, viral haemorrhagic fever, malaria, etc.

Infection may be acquired during sporting activities either direct by person to person spread (for example “scrumpox,” hepatitis B, respiratory infections) or from contact with a contaminated field or pool (for example, sepsis, tetanus, leptospirosis, giardiasis) - with contact sports, water sports and field sports posing most risks. Indirect spread (for example, herpes, fungal infections) may also occur through sharing contaminated equipment, towels, or clothing.