Entamoeba histolytica and Balantidium coli PDF

Entamoeba histolytica by Dr. Shaimaa Helmy Ass. Professor of Medical parasitology Faculty of Medicine Helwan University  Parasites of Large Intestine Nematoda of Large Intestine: Enterobius vermicularis Trichuris trichiura...

Entamoeba histolytica by Dr. Shaimaa Helmy Ass. Professor of Medical parasitology Faculty of Medicine Helwan University  Parasites of Large Intestine Nematoda of Large Intestine: Enterobius vermicularis Trichuris trichiura Commensal Protozoa: Entamoeba coli Entamoeba disbar Entamoeba hartmani Endolimax nana Iodamoeba butschlii Pathogenic protozoa: Blastocystis hominis Entamoeba histolytica Balantidium coli Parasites of Large Intestine Dysentery Painful frequent evacuation of small quantities of stool containing mucus tinged with blood & tenesmus Parasites of Small Intestine Diarrhoea ± Malabsorption Diarrhoea: Increase in frequency, fluidity or volume of bowel motions Malabsorption: poor intestinal absorption of nutrients due to defects occurring during the digestion and absorption of food nutrients.  Objectives By the end of this lecture, you will be able to recognize Entamoeba histolytica & Balantidium coli regarding their: Geographical distribution Life cycle Mode of infection Pathogenesis Clinical picture Diagnosis Treatment Epidemiology Prevention and control Entamoeba histolytica  Entamoeba histolytica An ameboid pathogenic intestinal protozoan parasite. Causes Amoebiasis Trophozoite Cyst Geographical Distribution: cosmopolitan, warm climate  Entamoeba histolytica Life Cycle Mode of infection Ingestion of Entamoeba histolytica Infective stage cyst: Quadrinucleate cyst 1- In contaminated food or water 2- Through flies & food handlers 3- Faeco-oral route (hand to Definitive host mouth) Infected Man External Autoinfection Diagnostic stages Habitat Cyst & Trophozoite caecum and sigmoido- rectal region Binary fission  Pathogenesis The severity of infection depends on: - Parasite virulence. Non-pathogenic: in the lumen. - Host resistance. OR - Condition of the intestinal tract. Pathogenic: trophozoites invade intestinal mucosa. Attachment of trophozoites to the epithelial cells of caecum and sigmoido-rectal region leading to hyperaemia and inflammation Trophozoites produce histolytic enzyme that produce necrosis of mucosa leading to the formation of flask-shaped ulcer. Proliferation of connective tissue, thickening of intestinal wall & Intensive ulcerations. Extra-intestinal invasion to brain, liver, lung or skin Abscesses  Clinical picture I) Asymptomatic amebiasis (85-95%): parasite in lumen and cysts pass in stool (Cyst Passer) II) Symptomatic amebiasis (5-15%): 1. Acute intestinal amoebiasis ( amebic dysentery): fever, abdominal cramps, tenderness, anorexia and chronic fatigue, painful spasm of anal sphincter, tenesmus (painful difficult defecation) with passage of blood and mucus in stool. 2. Chronic intestinal amebiasis: recurrent attacks of dysentery with intervening periods of constipation, localized tenderness, weight loss and cachexia. 3. intestinal amebic perforation (perforated ulcer): peritoneal irritation, abdominal rigidity, distension, ileus and gases. 4. Amebic granuloma (ameboma): chronic granulomatous lesion. 5. Hemorrhage: erosion of large blood vessel in the wall of the ulcer 6. Stricture of the colon: healing by fibrosis 7. Appendicitis  Clinical picture I) Extraintestinal amebiasis (rare): 1. Hepatic amebiasis: Amebic hepatitis: liver tenderness and enlargement with fever, sweating Amebic liver abscesses: liver tender, sever persistent fever. Taping of abscess revealed thick anchovy-sauce or chocolate-colored pus with trophozoites. 2. Pulmonary amebiasis: fever, dyspnea, cough with sputum may contain trophozoites 3. Brain, pericardium, spleen and skin amebic abscesses  Diagnosis Clinically Laboratory ‫بحث الصور عن‬histolytica entamoeba ‫نتيجة‬ trophozoite Direct stool examination: Trophozoites are detected in diarrhoeic stool Cysts are detected in formed stool Serological tests: Copro-antegin detection Antibodies detection  Diagnosis Sigmoidoscopy: to visualize the ulcer, scrap, aspirate or take biopsy to see the trophozoites. Molecular techniques. DNA Radiological examination: using barium enema.  Diagnosis of Extraintestinal Amoebiasis Clinically: according to the organ affected. Laboratory: 1-Examination of aspirate from lung or liver abscesses for trophozoites. 2-Liver & Lung scanning. 3-Serology. 4-Leucocytosis due to 2ry bacterial infection. Differences between Amoebic & Bacillary Dysentery Typical amoebic dysentery: Gradual onset with no or mild fever Stool: Bulky, Acidic with Scanty exudate. Pus cells (+), Blood (+), Charcot Leyden Crystals with presence of Amoebae trophozoites. Typical bacillary dysentery: Acute onset with severe fever Stool: Scanty, Alkaline with Massive exudate. Pus cells (+++), Blood (+), No Charcot Leyden Crystals and no Amoebae trophozoites  Treatment Drugs: Tissue amoebicides: Metronidazole, Tinidazole. Very effective in killing amoebas in the wall of the intestine, in blood and in liver abscesses. Luminal amoebicides: Diluxanide furoate. kills trophozoites and cysts in the lumen of the intestine. ✓ Asymptomatic patients: are given luminal amoebicide as Diluxanide furoate. ✓ Symptomatic patients: are given tissue amoebicide as Metronidazole followed by luminal amoebicide as Diluxanide furoate. ✓ Treatment of Amoebic abscesses: Aspiration or open surgical drainage  Epidemiology Cyst passers are the main source of infection. Cysts remain viable in faeces for few days, in water for longer periods. Cysts are killed by dryness, heat (over 55ºC) and by chlorine.  Prevention and Control Treatment of patients. Examination and treatment of food handlers. Environmental sanitation. Personal prophylaxis. Human faeces should not be used as fertilizers. Balantidium coli  Balantidium coli A ciliated pathogenic intestinal protozoan parasite. Largest intestinal protozoan of man Causes Balantidiasis Trophozoite Cyst Geographical Distribution: cosmopolitan, warm climate Reservoir hosts: Pigs  Life Cycle of Balantidium coli Mode of infection Ingestion of cyst Balantidium coli: Infective stage 1- In contaminated food or water cyst 2- Through flies & food handlers 3- Faeco-oral route (hand to mouth) Definitive host Infected Man External Autoinfection Diagnostic stages Habitat Cyst & Trophozoite large intestine spicially the caecum. Transverse Binary fission  Pathogenesis & clinical picture Attachment of trophozoites to the mucosal lining of large intestine inflammation Secretion of hyaluronidaze enzyme and the boring action of cilia tissue invasion Necrosis of mucosa leading to the formation of flask-shaped ulcer. Secondary bacterial infection. Symptoms of dysentery. Complications: Haemorrhage. Perforation. Peritonitis. Appendicitis.  Diagnosis Stool examination several times. Pass in diarrhoeic stool Pass in formed stool Treatment Metronidazole OR Oxytetracycline Control As Amoeba + Care in disposal of pig’s excreta