Non-pathogenic commensal parasite in human gastrointestinal tract. Can be mistaken for pathogenic Entamoeba histolytica in stool examination. Moves slowly using pseudopod, maintains round shape. Contains eight nuclei in mature cysts, unlike E. histolytica's four. Cysts can survive three to four months outside host's body
Echinococcus is a parasitic flatworm with three layers and no digestive system. Body consists of scolex, neck, and 3-6 proglottids. Incubation period can reach up to 50 years
Fish have both specific and non-specific defenses against diseases. Non-specific defenses include skin, scales, and mucus layer. Vaccines are widely used in aquaculture and ornamental fish
Lice are wingless parasitic insects belonging to the Phthiraptera clade. Nearly 5,000 species exist, with 4,000 on birds and 800 on mammals. Lice live on warm-blooded hosts, except monotremes and bats. They are vectors of diseases like typhus
Cestoda is a class of parasitic worms in the flatworm phylum. Most species are tapeworms, with 6,000 described species. Adult tapeworms have scolex, neck, and segmented body called strobila. They are hermaphrodites with both male and female reproductive organs
Fleas are wingless insects, 1.5-3.3mm long, feeding on blood of mammals and birds. They have specialized jumping abilities, capable of jumping up to 50 times their body length. Adult fleas are brown, flattened, and covered with hard plates called sclerites