Amoebiasis by dr najeeb
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Transcript of Amoebiasis by dr najeeb
ByDR: MUHAMMED NAJEEB Faculty Of
Community Medicine & Public Health Sciences LUMHS, Jamshoro,Sind, PAKISTAN [email protected]
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 shelter and nourishment on or within other living organisms.
ENTOMOLOGY – science that deals with
arthropods of medical importance
• Helmintology: – helminths / worms
Microorganism
Prokaryotes
Bacteria
Euokaryotes
Parasite
Fungi
Non –cellular
Viruses
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)
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium falciparum
SPOROZOA
Plasmodium
AMOEBA
Entamoeba Histolytica
(Eat tissue)
FLAGELLETS
1. Leishmenia
L .Donovani
L. Tropica
L. Mexicana
L. Brasiliensis
2. Intest: Flagellets
Giardia Lamblia
3. Ciliate:
Balantadium coli
B. METOZOA ( Multicellular organism )PlatyhelminthsPlate helminthes Nemathelminths
T. saginata(Beef)
T. solium(Pork)
Hymenolepis nana
E. Granulosus
Diphylobothriumlatum (Fish)
Cestodes
Schist soma mansoni
Schist soma japonicum
Schist soma haematobium
TrematodesTrematodes/ Flukes
Ancylostoma duodenale
Ascaris lumbricoids
Enterobius
Vermiculus
(Anal irritation)
Intes: Nematodes
-W.Bancrofti
-Loa Loa
-Dranculus
medinesis
(Guinia .W)
-Strangloides Stercoralis
Somatic Nematodes
Tap worm R.Worm Skin worm
Hook.w
R. worm
Pin / Thread .w
STAGES IN LIFE CYCLE OF PROTOZOA
Infective stage: – Cysts, Oocysts, Sporozoites,
Spores- dormant stages and Resistant
Vegetative stage: – Trophozoites – take
nourishment from 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 Organism 4 species of
Entamoeba:
Nonpathogenic: - E. dispar, – E. coli, – E. hartmanni
Pathogenic: - E.histolytica
Amoebiasis
Parasitic infection caused by the protozoan Entamoeba histolytica
2nd 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 Deaths
Africa 85 millions 10 millions 10-30thousands
Asia 300 millions 20-30millions
25-50thousands
Europe 20 millions 100thousands
Minimum
America 95 millions 10 millions 10-30thousands
Totals 650 millions 45-50millions
40-110thousands
2. Causative Agent
Entamoeba 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
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
LIFE CYCLE
The Pathogenesis• Area most commonly
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.
• Flask-shaped ulcers
3. ReservoirInfected Person OR
Carrier
4. Mode of TransmissionIngestion of mature cyst through
contaminated food or waterTRANSMISSION: Faecal ---- oral routeContaminated waterContaminated meals
Street vendors of mealanal-oral contact
5. SUSCEPTIBILITY
– Poor education
– Poverty and overcrowding
– Unsanitary conditions
– HIV infection 5
1. 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:
6. Incubation Period
-Variable-Probably varies from few days
--- weeks.
7.Period of Communicability
Varies from several days or months to
several years
INTESTINAL AMOEBIASIS:
Mild Abdominal discomfort
Pain
Irregular bouts of diarrhoea (With or without blood & mucus)
Fever may be present
Abdomen tenderLiver slightly enlarged & tender
In Fulminant colitis- All features are Sudden & severe
AMOEBIC LIVER ABSCESS:
Onset- Insidious
Pain & tenderness in Rt: hypochondrium
Fever High grade (with Nausea, Anorexia & Vomiting
Usually there is single abscessIn case of Rupture going to Peritoneum, Pleural cavity & pericardial cavity.
CLINICAL FEATURES
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 daysIdoquinol &
Paramomycin
(B) Tissue Amoebic ides:Metronidazole
TinidazoleSecnidazole
followed 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
