Entamoeba histolytica/E. dispar
A. Haghighi, Tuesday, March 05, 2019 Classification of Protozoa ? • The protozoa are generally unicellular and may be divided for convenience, into four distinct ﺣﺮﮐﺖ :groups based on method of locomotion 1. Mastigophora (Flagella)/Metamonada
2. Sarcodina (Pseudophora)/ Amoebazoa
3. Apicomplexa (microtubule complex)
4. Ciliophora (Ciliates) Human species of Amoebae The important intestinal amoeba in human Phylum: Sarcomastigophora / Amoebazoa Genus: 1- Entamoeba Species: - Entamoeba histolytica - Entamoeba dispar - Entamoeba moshkovskii - Entamoeba coli - Entaomeba hartmanni - Entamoeba gingivalis Genus: 2- Endolimax Species: Endolimax nana Genus: 3- Iodamoeba Species: Iodamoeba butschlii Classification based on number of nuclei in the mature cyst: 1. Octonucleate cyst group: - E. coli 2. Quadrinucleate cyst group: - E. histolytica - E. dispar - E. hartmanni - E. moshkovskii - Endolimax nana 3. Uninucleate cyst group: - Iodamoeba buetschlii 4. No cyst - E. gingivalis General characteristics of amoebas
1- Active form (Trophozoite) has no cell wall 2- The cytoplasm of active form consists of two parts, Ectoplasm and Endoplasmic 3- Movement is performed by forming a pseudopod in the active form Amoeba = Variable 4- There is no particular way to get food (No mouth) 5- They do not have a fixed shape, because they create pseudopod for locomotion and to get food. 6- They are Anaerobic, Therefore, Lack of mitochondria, endoplasmic network and Golgi apparatus. (New molecular findings suggest traces of these organelles) Entamoeba histolytica << HISTORY>> • 1875 Fedor Aleksandrovich Losch Amoeba coli • 1903 Fritz Schaudinn Entamoeba histolytica • 1925 Emile Brumpt E. dysenteriae (Craig 1905) E. dispar (= different) • 1912 Von Prowazek E. dispar (= different) Small Race (E. hartmanni) • 1957, 1959 Burrows • 1973 Martinez-Palomo Two species?
E. histolytica pathogen • 1978-1988 Peter Sargeant and … E. histolytica nonpathogen E. histolytica • 1993 Louis Diamond & C.G. Clark E. dispar
• 1997 WHO meeting in Mexicocity E. histolytica E. histolytica/E. disbar prevalence (Schoudinn 1903/ Brumt 1925) 20 to 30% in the tropics area And 5% 10% of world population in temperature (about 500-700 millions) climate nations
10% E. histolytica 90% E. dispar (50-70,000,000) (450-650,000,000)
5-10% 90-95% About 10% 45-65,000,000 (5-7,000,000) (700,000) asymptomatic Extra intestinal With symptoms Cyst passers Amebiasis
5-7,000,000 About 90% 45 - 65,000,000 Intestinal and Extra intestinal Cyst passers ? (4.500,000-6.500,000) Amebiasis Intestinal amebiasis
Great geographical virulence and symptomes in the world, ranging from 1% in Greece to 21% in Egypt, average 10% of infected patients)
* Up to 100,000 deaths, second after malaria in protozoan parasites Transmission routes
Feces (Person to person by the oro-fecal route) .1
Agent of transmission Finger .2 Food .3 Trophozoit Cyst Fluid (Water) .4 Flies .5 E. histolytica and E. dispar << Morphology and life cycle>> (10-20m) Ch. body Nucleus
Trophozoite Oral infection Brain Cell wall Karyosome Metacystic development Cyst Lung Encystation
Clumps of glycogen
Galactose/N-acetylgalactoseamine (Gal/GalNAc) lectin protein Large intestine Endoplasm
Ectoplasm Liver Trophozoite (Haematophge) 15-60 m Pathogenicity
A- (Intestinal diseases) or << Intestinal amoebiasis>>
B- (Extraintestinal diseases) << Extraintestinal amoebiasis>> Intestinal amoebiasis ? Frequently: - Anti-amoebic Ab is + - and Stool Ag test is + • Asymptomatic infection
Diarrhea, Dysentery, weight • Symptomatic noninvasive infection loss, fever, tenterness, Heme + • Acute rectocolitis (dysentery) • Fulminant colitis with perforation • Ameboma • Chronic nondysenteric colitis • Perianal ulceration Flask form ulcers
Familiarity with these diverse manifestations and epidemiologic risk factors greatly facilitates A rapid , correct diagnosis Extraintestinal amoebiasis ?
• Amoebic Liver Abscess (ALA) Brain • Lung abscess
• Brain abscess Lung • Splenic abscess
• Subdiaphragmatic
• .Large intestine ab
• Amebiasis cutis Liver • Genitourinary abscess Diagnosis methods • Intesinal amoebiasis • Extraintestinal amoebiasis Based on : 1- Doctor: Pay attention to clinical findings, geographical location, history of illness and findings Epidemiologic
2- Parasitological methods: Detection of trophozoite or cysts in feces or abscesses by: - Wet mount stool exam - Stool concentration (Formalin-ether technique) (Three alternate stool tests are recommended) . Cultivation Staining 3. Serologically tests: * IFA * ELISA (Sensitive tests) * IHA * CIE or GD : Non sensitive for acute diseases * Antigen capture (TechLab) 4. Bichemical or Biological methods: -PCR - Zymoden analysis Diagnosis of amebic liver abscess
Cinical symptoms
Lesion in the liver Positive amebic serology ***** Medical recommendation for diagnosis and treatment
WHO News and activities Bulletin of the WHO, 1997, 75 (3); 291-292 When diagnosis is made by light microscopy, the cysts of two species (10-20 um in diameter) are indistinguishable and should be reported as: E. histolytica/E. dispar Trophozoites with ingested red blood cells in fresh stool or other specimens and trophozoites in tissue biopsies are both strongly correlated with the presence of E. histolytica and invasive disease. In symptyomatic individuals the presence of high titers of specific antibody is also strongly correlated with invasive amoebiasis. Optimally, E. histolytica should be specifically identified, and infections, if present, treated is recommended. If only E. dispar is identified, no treatment is
necessary. If the infected individual has
gastrointestinal symptoms, other causes
should be sought. If E. histolytica/E. dispar has been detected in symptomatic patients, it should not be assumed that E. histolytica is the cause of symptoms and
other explanations should also be considered. Treatment • There are two classes of antiamoebic drugs:
a) Tissue amoebicies (Such as 5-nitoimidazole; e.g. Metronidazole)
b) and luminal amoebicides (such as diloxanide furoate and paromomaycine).
Invasive disease should be treated with a tissue amoebiside followed by a luminal amoebicide. Tissue amoebicides are not appropriate for treatment of asymptomatic individuals, unless there is other evidence for invasive amoebiasis.
• Chemoprophylaxis is never appropriate.
24 Treatment
Luminal agents : Diloxanide furoate A: In E. histolytica cyst passers Paromomycine (Asymptomatic intestinal colonization) Iodoquinol B: Invasive rectocolitis Tissue agents : Bowel wall only (Amoebic colitis) - Tetracycline -Erythromycine C- Extraintesinal diseases All tissues -Metronidazile (Amoebic liver abscess) -Tinidazole -Emetine hydrochloride -Dehydroemetine A: In E. histolytica cyst passers
1. Diloxanid foroate
- 500 mg orally 3 times a day for 10 days 2 . Paromomycine
- 30 mg/kg/days in 3 divided doses for 5-10 days 3. Tetracycline
- 250 mg qid for 10 days then Iodoquinol, 650 mg tid for 20 days 4. Metronidazol
- 750 mg tid for 10 days. B: Invasive rectocolitis
1. Metronidasol
2. Tetracycline,
3. Dehydroemetine C- Extraintesinalis treatment 1. Metronidasol
2. Tinidazol
3. Dehydroemetine
Treatment should be follow with one of the effective medicines on the cyst Prevention
1- Individual health (hand wash with soap, Destroying the flies and cockroaches, Using healthy food and especially vegetables)
2- Public Health (Proper disposal of waste, Environmental improvement, Health improvement, Proper disposal of sewage)
3- Health Education (Use of Mothers' Breastfeeds, Health Education in Schools, Health education through radio and television)
Vaccination: Researching on 3 genes