ABSTRACT
Many important human and animal diseases are caused by protozoan pathogens (Table 1.1). These diseases impact humans directly in terms of morbidity and mortality as well as having a major impact on agriculture. In addition to being known parasites, some protozoa are considered opportunistic pathogens that primarily affect immunocompromised individuals. In many parts of the world diseases caused by protozoa are on the rise and thus considered as emerging or re-emerging diseases. In addition, these diseases are often neglected because they are found predominantly in developing countries. A wide range of disease manifestations are exhibited by protozoan pathogens reflecting the variety of organs and tissues affected. Most protozoan infections are acquired through the ingestion of specialized infective stages and several protozoan species are transmitted by arthropod vectors.
