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Amoebiasis by dr najeeb
 

Amoebiasis by dr najeeb

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    Amoebiasis by dr najeeb Amoebiasis by dr najeeb Presentation Transcript

    • ByDR: MUHAMMED NAJEEB Faculty OfCommunity Medicine & Public Health Sciences LUMHS,Jamshoro,Sind, PAKISTAN mnajeeb80@gmail.com
    • Microbiology• Branch of Biology dealing especially with Microscopic forms of life
    • • Micro organism• An organism too tiny to be seen by naked eye.
    • Parasitology science that deals with organisms that seek shelterand nourishment on or within other living organisms.
    • ENTOMOLOGY – science that deals witharthropods of medical importance• Helmintology: – helminths / worms
    • MicroorganismProkaryotes Euokaryotes Non –cellularBacteria Parasite Viruses Fungi Prion Proteins
    • • A. PROTOZOA (Unicellular organism) 4 types according types of organs for locomotion Amoebae - pseudopodia; Flagellates - flagella; Ciliates - cilia and Sporozoa – absence of locomototion B. METOZOA ( Multicellular organism )
    • A. PROTOZOA (Unicellular organism) AMOEBA SPOROZOA FLAGELLETS PlasmodiumEntamoeba Histolytica 1. Leishmenia Plasmodium vivax(Eat tissue) L .Donovani Plasmodium ovale L. Tropica L. Mexicana Plasmodium malariae L. Brasiliensis Plasmodium falciparum 2. Intest: Flagellets Giardia Lamblia 3. Ciliate: Balantadium coli
    • B. METOZOA ( Multicellular organism ) Platyhelminths Nemathelminths Plate helminthesTap worm R.Worm Skin worm Cestodes Trematodes Trematodes Intes: Nematodes Somatic / Flukes Nematodes T. saginata (Beef) Schist soma Ancylostoma Hook.w T. solium mansoni duodenale -W.Bancrofti (Pork) Schist soma Hymenolepis nana japonicum -Loa Loa R. worm Ascaris lumbricoids -Dranculus E. Granulosus Schist soma haematobium Enterobius medinesis Pin / Diphylobothrium Thread .w Vermiculus (Guinia .W) latum (Fish) (Anal irritation) -Strangloides Stercoralis
    • STAGES IN LIFE CYCLE OF PROTOZOAInfective stage: – Cysts, Oocysts, Sporozoites, Spores- dormant stages and ResistantVegetative stage: – Trophozoites – take nourishmentfrom the hosts; invasive causing pathology; most are motile.
    • LUMINAL PROTOZOA- COLONIZE THE LUMINAL ORGANS- intestinal tract and the urogenital tract- TWO STAGES – I ) Trophozoite (vegetatative / invasive) II) Cyst (infective)
    • Entamoeba histolytica (AMOEBIASIS)AMEBIC DYSENTRY;AMOEBIC LIVER ABSCESS
    • Life cycle:inhabit the large intestine; the cyst is the infective stage. On ingestion – excyst into amoebulae –trophozoites which is the vegitative stage – invade the mucosa to absorb nourishment from tissues dissolved by its cytolytic enzymes and also ingest RBCs.
    • Helminthes Eggs / Ova• Ancylostoma duodenale Hymenolopis Nana• Ascaris lumbricoids Trichus Trichuria• Enterobius Vermiculus• T. saginata• T. solium• Cysticercosis• E. Granulosus• Diphylobothrium latum
    • Cysts• Entamoeba histolytica ( single cell)• Giardia lamblia• Giardia Intestinals• Entameba Coli ( Non pathogenic )• Endolimax Nana ( = = )• Chilomastix Mesnili• Iodamoeba Butschli ( non pathog )
    • AMOEBIASIS
    • • Amebic Dysentery Amebic hepatitis• ( Amoebic Liver Abscess )
    • AMOEBIASIS
    • The Organism4 species of Entamoeba: Nonpathogenic: Pathogenic: - E. dispar, - E.histolytica – E. coli, – E. hartmanni
    • Amoebiasis Parasitic infection caused by the protozoan Entamoeba histolytica2nd to Malaria as protozoan cause of death worldwide 1
    • Epidemiology Helminthes, or parasitic worms, including• Nematodes,• Flukes and• Tapeworms, collectively infect approximately 2 billion people worldwide, or about a third of the world population. The majority of infected people reside in developing countries in tropical & temperate climate zones,where helminthes constitute a significant public health concern
    • Epidemiology. Increased prevalence in developing countries (up to 25%)• Principal frequency in countries with a deficiency in sanitary conditions• Poorest areasMost infected people.• perhaps 90%, are asymptomatic, but this disease has the potential to make the sufferer dangerously ill.
    • FrequencyRegion Infection Diasease DeathsAfrica 85 millions 10 millions 10-30 thousandsAsia 300 millions 20-30 25-50 millions thousandsEurope 20 millions 100 Minimum thousandsAmerica 95 millions 10 millions 10-30 thousandsTotals 650 millions 45-50 40-110 millions thousands
    • 2. Causative AgentEntamoeba histolytica 2
    • The Life Cycle• 1. Cyst Stage• Infective stage• Survive from –4 to 40 Celsius• Size – 12mm• Quadrinucleated• Ingested by contact with fecally contaminated food• Passes through stomach, excysts in lower small bowel.• Metacystic amoeba with four cystic nuclei from each cyst• 8 Small trophozoites from each metacystic amoeba• Trophozoites carried to cecum
    • LIFE CYCLE Amebiasis is an infection of the intestine, liver, or other tissues by pathogenic amebas (protozoan parasites).E. histolytica is found primarily in the colon where it can live as a non-pathogenic commensal or invade the intestinal mucosa (green).The ameba can metastasize to other organs via a hematogenous route (purple); primarily involving the portal vein and liver. The ameba can also spread via a direct expansion (blue) causing a pulmonary infection, cutaneous lesions or perianal ulcers
    • The Pathogenesis• Area most commonly • Flask-shaped ulcers involved = Cecum, then Recto-sigmoid area• May invade blood vessels causing thrombosis, infarction and dissemination via portal circulation to liver and• extra-intestinal sites eg. brain, pleura, pericardium and genito-urinary system.
    • 3. ReservoirInfected Person OR Carrier
    • 4. Mode of TransmissionIngestion of mature cyst through contaminated food or water TRANSMISSION: Faecal ---- oral route Contaminated water Contaminated meals Street vendors of meal anal-oral contact
    • 5. SUSCEPTIBILITY1. Age: Any age (Young Adults, rarely below the age of 5 Years.)2. Sex : Both 3. Immunity: An attack of the dis: does not confer immunity. (Relapses are common)4. Env: Factors: – Poor education – Poverty and overcrowding – Unsanitary conditions – HIV infection 5
    • 6. Incubation Period -Variable-Probably varies from few days --- weeks.
    • 7.Period of CommunicabilityVaries from several days or months to several years
    • CLINICAL FEATURESINTESTINAL AMOEBIASIS: AMOEBIC LIVER ABSCESS:Mild Abdominal discomfort Onset- InsidiousPain Pain & tenderness in Rt: hypochondriumIrregular bouts of diarrhoea (Withor without blood & mucus)Fever may be present Fever High grade (with Nausea, Anorexia & VomitingAbdomen tenderLiver slightly enlarged & tender Usually there is single abscess In case of Rupture going toIn Fulminant colitis- All features Peritoneum, Pleural cavity &are Sudden & severe pericardial cavity.
    • METHODS OF DIAGNOSIS• fresh or suitably preserved faecal specimens• smears of aspirates or scrapings obtained by proctoscopy• aspirates of abscesses or other tissue specimens 1. Exam: of Stool: (confirmed by trophozoites or cysts)• Macroscopic: offensive, dark brown semi fluid, mixed• with blood & mucus• Microscopic Exam: ( Fresh sample, 3 types of mounts)• (Trophozoites & cyst)• 1. With Normal saline- motile Trophozoites• 2. With Iodine + saline – Helps to distinguish from other parasites• 3. With Methylene blue – only stain leukocytes.
    • 2. Exam: of Blood: moderate Leukocytosis Serological Tests: (often Negative) (when stool exam: -ve) (IHA indirect haemagglutination & EIA enzyme immunoassays Positive in extra-intestinal disease such as liver abscesses) 3. X-ray, ultrasound and CT scans (also useful in the identification of amoebic abscesses) 4. Liver Aspirate:• Chocolate color, thick in consistency Trophozoites from material from wall of abscess (after 4-5 days)
    • TREATMENT(A) Luminal Amoebic ides: Diloxanide Furoate 500 mg tid x 10 days Idoquinol & Paramomycin(B) Tissue Amoebic ides: Metronidazole Tinidazole Secnidazolefollowed by diloxanide furoate
    • Prevention & ControlA. HEALTH EDUCATION:-reduce fecal-oral transmissionB. SANITATION:- Clean measures in & around the houses. Sate disposal of human excreta. Hand washing after defecation and before meals. Use of sanitary latrines.C. WATER SUPPLY:- Safe water supply. Protection of water from faecal contamination. Water filtration or boiling (more effective than chlorination)D. FOOD HYGIENE:- Protection of food against faecal contamination. Thorough washing of raw vegetables. (By full strength of vinegar)Vaccination: – None available currently – Prototype subunit vaccines based on the Gal/Gal Nac - lectin under study
    • The Complications• Complications of Intestinal amoebiasis: – Fulminant Amoebic Colitis with Perforation • May have a mortality rate of up to 50% • Children less than 2 yrs at increased risk of perforation – Massive Haemorrhage – amoeboma – amoebic Stricture • Resulting from fibrosis of intestinal wall
    • • END