Intestinal Parasites

Intestinal protozoa

• Rhaizopode:

Entamoeba histolytica,

Entamoeba coli Flagellate:

Giardia lamblia.

Entamoeba histolytica

• Pathogenic (amoebic dysentery).

• Central endosome (karyosome).

• Regular distribution of peripheral chromatin.

• Trophozoite stage : amoeboid shape, metabolically active

Entamoeba histolytica

• Presence of RBC inside E. histolytica.

 Amoebic Dysentery penetrates the intestinal mucosa so cause bloody diarrhea.

extra intestinal involvement ( abscesses in liver , lungs & rarely in brain).

Entamoeba histolyticacyst

cyst stage: round shape , metabolically inactive, infective

stage .

Entamoeba histolyticaLife cycle

Entamoeba coli

• Non pathogenic.• Eccentric

karyosomes.• Irregular peripheral

chromatin.• Cyst contain 8

nucleus.

Giardia lamblia

• Trophozoite pear shape, tennis rickets.

• 2 nuclei without peripheral chromatin.

• Pathogenic Giardiasis.

Giardia lamblia

• Trophozoite contain 4 pairs of flagella.

• 2 sucking disc in the ventral part.

Giardia lamblia cyst

    Cyst stage:         Oval shape ( in

amoeba it was round)

         (1-4) nuclei. Mature cysts have 4 nuclei. Either 2 anterior & 2 posterior OR the 4 on the same side.

Multicellular / worms   

3 Types of worms :• A.    Cestodes• B.      Trematodes C. Nematodes

Platyhelminthes

Cestodes :

• Taenia saginata

(Beef tapworm)• Taenia solium

(Pork tapworm)• Diphylobothrium

latum.

(fish worm)

Taenia saginata• Cestode worm is

composed of 3 parts:     • 1- scolex : responsible

for the attachment to intestinal mucosa by suckers.

• 2- Neck: responsible for strobilization / production of body segments.

• 3- Body : compose of segments (proglottids)

•     

It has 3 types of proglottids (segments) :

1-Immature: near the neck,          

2- Mature : developing of sex organs occur.

3- Gravid : the segment is mature & uterus is filled with eggs.

Taenia solium

 • 4 sucker with

rostellum and hooks

Taenia eggs        

• # Eggs have embryo called :

hexacanth embryo

Diphyllobothrium latum

• Intermediate host is fish infected with larva

    Scolex of D.latum:• Has no suckers /

instead it has 2 grooves called bothria ( di-phyllo-bothria )

D. latum gravid proglottides

• Gravid segment of D.latum

• Can appear in stool(like taenia)

• Width is more than the length

• Uterus has rossete shape ( no longitudinal branches like tinea)

    Central genital pore (lateral in taenia)

D.latum Eggs:

• Like trematode eggs

• Oval shape• Transparent,

hasn’t thick wall• Operculated:

( has a cap , the cap open so embryo will be released from egg.

Comparison of Cestodes

  

   

Taenia saginata 

 

Taenia solium

 

Diphyllobothrium latum

 Scolex 

 Sucking Disks Only

 Sucking Disks Plus a Rostellum with Hooklets

 Sucking Grooves (Bothria)

 Proglottid 

 Longer than it is Wide

 Longer than it is Wide

 Wider than it is Long

 Uterus

 Lateral Branching > 13 Branches (About 16) 

 Lateral Branching< 13 Branches (About 8)

 Rosette in Shape

 Genital Pore 

 Located on the Lateral Margin 

 Located on the Lateral Margin

 Located Centrally

 

Trematodes

• 1. Clonorchis sinensis:

• Distinctive membrane        

• Shouldered operculum

• Has posterior projection

Heterophyes heterophyes

• Same characteristics of C.sinesis eggs but NOT shouldered operculum

Fasciolopsis buski found in intestine

3.5 cm in length• Fasciola hepatica • found in the liver or

bilary duct. 3 cm in length.

     Schistosoma mansoni

•    Separate sexes• Lateral

spine

Nematodes

Enterobius vermicularis.

• *intestinal worm, small size, cause anal itching at night (mostly in children ).

•  *Transparent egg: Presence of larva stage inside egg

     Trichuris trichura

•   *  Lemon shape

•    * 2 mucus blugs one at each side of egg.

    Ascaris lumbricoides

• The egg :•    When fertilized ,

it will form mucus membrane ( vitelline membrane ) at the outer surface.

    Hookworms

( Ancylostoma duodenale, Necator americana)

      Hook worm egg (found in stool):

         It has cell stage embryo (form multiple cells

     Strongyloides stercoralis

•        

• the larva stage NO EGG

• Male : smaller than female, has pointed curved end

•        Female : larger,straight tail

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