<P> Liver abscess: In addition to targeting organisms in solid tissue, primarily with drugs like metronidazole and chloroquine, treatment of liver abscess must include agents that act in the lumen of the intestine (as in the preceding paragraph) to avoid re-invasion . Surgical drainage is usually not necessary except when rupture is imminent . </P> <P> People without symptoms: For people without symptoms (otherwise known as carriers, with no symptoms), non endemic areas should be treated by paromomycin, and other treatments include diloxanide furoate and iodoquinol . There have been problems with the use of iodoquinol and iodochlorhydroxyquin, so their use is not recommended . Diloxanide furoate can also be used by mildly symptomatic persons who are just passing cysts . </P> <Table> <Tr> <Td> Genus and species </Td> <Td> Entamoeba histolytica </Td> </Tr> <Tr> <Td> Etiologic agent of: </Td> <Td> Amoebiasis; amoebic dysentery; extraintestinal amoebiasis, usually amoebic liver abscess; "anchovy sauce"); amoeba cutis; amoebic lung abscess ("liver - colored sputum") </Td> </Tr> <Tr> <Td> Infective stage </Td> <Td> Tetranucleated cyst (having 2 - 4 nuclei) </Td> </Tr> <Tr> <Td> Definitive host </Td> <Td> Human </Td> </Tr> <Tr> <Td> Portal of entry </Td> <Td> Mouth </Td> </Tr> <Tr> <Td> Mode of transmission </Td> <Td> Ingestion of mature cyst through contaminated food or water </Td> </Tr> <Tr> <Td> Habitat </Td> <Td> Colon and cecum </Td> </Tr> <Tr> <Td> Pathogenic stage </Td> <Td> Trophozoite </Td> </Tr> <Tr> <Td> Locomotive apparatus </Td> <Td> Pseudopodia ("false foot" ") </Td> </Tr> <Tr> <Td> Motility </Td> <Td> Active, progressive and directional </Td> </Tr> <Tr> <Td> Nucleus </Td> <Td>' Ring and dot' appearance: peripheral chromatin and central karyosome </Td> </Tr> <Tr> <Td> Mode of reproduction </Td> <Td> Binary fission </Td> </Tr> <Tr> <Td> Pathogenesis </Td> <Td> Lytic necrosis (it looks like "flask - shaped" holes in Gastrointestinal tract sections (GIT) </Td> </Tr> <Tr> <Td> Type of encystment </Td> <Td> Protective and Reproductive </Td> </Tr> <Tr> <Td> Lab diagnosis </Td> <Td> Most common is direct fecal smear (DFS) and staining (but does not allow identification to species level); enzyme immunoassay (EIA); indirect hemagglutination (IHA); Antigen detection--monoclonal antibody; PCR for species identification . Sometimes only the use of a fixative (formalin) is effective in detecting cysts . Culture: From faecal samples - Robinson's medium, Jones' medium </Td> </Tr> <Tr> <Td> Treatment </Td> <Td> Metronidazole for the invasive trophozoites PLUS a lumenal amoebicide for those still in the intestine . Paromomycin (Humatin) is the luminal drug of choice, since Diloxanide furoate (Furamide) is not commercially available in the United States or Canada (being available only from the Centers for Disease Control and Prevention). A direct comparison of efficacy showed that Paromomycin had a higher cure rate . Paromomycin (Humatin) should be used with caution in patients with colitis, as it is both nephrotoxic and ototoxic . Absorption through the damaged wall of the intestinal tract can result in permanent hearing loss and kidney damage . Recommended dosage: metronidazole 750 mg three times a day orally, for 5 to 10 days followed by paromomycin 30 mg / kg / day orally in 3 equal doses for 5 to 10 days or Diloxanide furoate 500 mg 3 times a day orally for 10 days, to eradicate lumenal amoebae and prevent relapse . </Td> </Tr> <Tr> <Td_colspan="2"> Trophozoite stage </Td> </Tr> <Tr> <Td> Pathognomonic / diagnostic feature </Td> <Td> Ingested RBC; distinctive nucleus </Td> </Tr> <Tr> <Td_colspan="2"> Cyst Stage </Td> </Tr> <Tr> <Td> Chromatoidal body </Td> <Td>' Cigar' shaped bodies (made up of crystalline ribosomes) </Td> </Tr> <Tr> <Td> Number of nuclei </Td> <Td> 1 in early stages, 4 when mature </Td> </Tr> <Tr> <Td> Pathognomonic / diagnostic feature </Td> <Td>' Ring and dot' nucleus and chromatoid bodies </Td> </Tr> </Table> <Tr> <Td> Genus and species </Td> <Td> Entamoeba histolytica </Td> </Tr>

What is the infective stage of entamoeba histolytica