Protozoa and fungi are simple organisms, capable of living in many different habitats. Some protozoa and fungi are parasites of humans. They acquire all their food from our bodies and often cause disease. One protozoal infection, malaria, affects hundreds of millions of people worldwide each year and is often fatal.
Protozoal infections are discussed first, starting with malaria, the most important health hazard for visitors to the tropics. Further articles deal with other protozoal infections, including diseases that are common causes of diarrhoea, such as amoebiasis and cryptosporidiosis. The protozoal infection trichomoniasis, which is transmitted sexually, is covered with other such sexually transmitted infections (see Trichomoniasis). Fungal infections are discussed next. Like most protozoal infections, fungal infections may be serious in people with reduced immunity, such as those who have AIDS. The types of fungi described in this section can spread around the body from the initial site of infection, sometimes causing long-term illness. Common fungal infections that affect particular areas of the body, such as the skin and vagina, are covered in the sections on specific body systems.
For more information on the structure of protozoa and fungi.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.