Pathophysiology of parasitic infections

Parasites can have a wide range of pathophysiological effects on the host. This review describes those associated with some parasites of major importance in man and animals. Haemoprotozoan diseases such as trypanosomiasis and malaria are primarily associated with anaemia. Such anaemias have a complex aetiology involving various mechanisms responsible for red cell destruction as well as possible defects in red cell production. In addition to these haematological effects these diseases are associated with marked disturbances in heart function and the nervous, immune and urinary systems. The other major groups of parasitic diseases are those associated with the gastrointestinal tract. The most advanced studies have been conducted on the pathophysiology of gastrointestinal nematode parasites of sheep and have revealed significant effects on feed intake, gastrointestinal function, and protein and energy metabolism. Similar studies have yet to be conducted in other hosts and parasitic diseases. There is also a need to examine in greater detail the factors which can modulate pathophysiological responses by the host to parasitic infections.