Infestation is the state of being invaded or overrun by pests or parasites . It can also refer to the actual organisms living on or within a host .
5-397: In general, the term "infestation" refers to parasitic diseases caused by animals such as arthropods (i.e. mites , ticks , and lice ) and worms , but excluding (except) conditions caused by protozoa , fungi , bacteria , and viruses , which are called infections . Infestations can be classified as either external or internal with regards to the parasites' location in relation to
10-403: Is known as parasitology . Medical parasitology is concerned with three major groups of parasites: parasitic protozoa , helminths , and parasitic arthropods . Parasitic diseases are thus considered those diseases that are caused by pathogens belonging taxonomically to either the animal kingdom , or the protozoan kingdom . Although organisms such as bacteria function as parasites,
15-427: The host. External or ectoparasitic infestation is a condition in which organisms live primarily on the surface of the host (though porocephaliasis can penetrate viscerally) and includes those involving mites , ticks , head lice and bed bugs . An internal (or endoparasitic ) infestation is a condition in which organisms live within the host and includes those involving worms (though swimmer's itch stays near
20-453: The surface). Medically, the term "infestation" is often reserved only for external ectoparasitic infestations while the term infection refers to internal endoparasitic conditions. Parasitic disease A parasitic disease , also known as parasitosis , is an infectious disease caused by parasites . Parasites are organisms which derive sustenance from its host while causing it harm. The study of parasites and parasitic diseases
25-450: The usage of the term "parasitic disease" is usually more restricted. The three main types of organisms causing these conditions are protozoa (causing protozoan infection ), helminths ( helminthiasis ), and ectoparasites . Protozoa and helminths are usually endoparasites (usually living inside the body of the host), while ectoparasites usually live on the surface of the host. Protozoa are single-celled, microscopic organisms that belong to
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