5-Parasitology Branch Lecture in microbiology

5-Parasitology Branch Lecture in microbiology

1. PARASITOLOGY
Dr. Mohammed Elkady
Clinical Pathology Consultant,
M.B.B.CH, EFCpath

2. PARASITE
•Parasite is a living organism, which lives inor
uponanother organism (host) and derives
nutrients directly from it, withoutgiving any
benefitto the host, but harmsthe host

3. HOST
•An organism, which harbors the parasite and
provides nourishmentand shelter.

4. •Definitive host: The host in which the adultparasites
replicate sexually(e.g., anopheles species), is called
as definitive host. The definitive hosts may be human
or nonhuman living things
•Intermediate host: The host in which the parasite
under goes asexualmultiplication.

5. VECTORS
•Vector is an agent, usually an arthropod that
transmitsthe infection from one infected
human-being to another.
•An infected blood sucking insect can
transmit the parasite directly into the blood
during its blood meal.

6. TAXONOMY
•Eukaryotes:
•Unicellular:
•Protozoa
•Multicellular:
•Helminthes
•Arthropods

7. PROTOZOA
•protozoa are unicellular parasites
•Stages :
•Trophozoite: motile, multiplies, colonizes ..
•Cyst: Non-motile, survive the environment ..

8. AMOEBA
•Amoeba is a single-celledprotozoa
•changesits shape. (the Greek word
“amoibe” = “change”).
•They constantly change their shape due to
presence of an organ of locomotioncalled
as “ pseudopodium”

9. CLASSIFICATION
•Intestinal amoebae: They inhabitatin the
large intestine of humans and animals.
•Entamoeba histolytica is the onlypathogenic
species.
•Others are nonpathogenic such as—E.
dispar, E. coli,

10. ENTAMOEBA HISTOLYTICA
•Pathogenecity:
•amoebic dysentery
•amoebic liver abscess

11. MORPHOLOGY
•Trophozoite
•It is the invasiveform as well as the feeding and replicatingform of the
parasite found in the feces of patients with activedisease.
•Pseudopodia
•Nucleus is single
•Precyst
•Cyst (immature and mature)
•infectiveform as well as the diagnosticform

14. •Mode of transmission :
•Feco-oral route
•Vector : NO

15. •Asymptomaticamoebiasis = carriers
•About 90% of infected persons are
asymptomatic carriers and excrete
cysts in their feces.

16. LABORATORY DIAGNOSIS
•Stool microscopy
•wet mount, detects cystsand trophozoites
•Stool culture
•Serology
•Amoebic antigen—ELISA
•Molecular diagnosis
•PCR

17. GIARDIA LAMBLIA

18. TRICHOMONAS VAGINALIS

19. PLASMODIUM

20. MICROSCOPIC DIAGNOSIS

23. HELMINTHS
•Trematodes: (Flukes)
•Schistosoma
•Fasciola
•Cestodes (Tapeworms):
•Hymenolepis
•Echinococcus
•Nematodes (roundworms):
•Ascaris lumbricoides
•Ancylostoma

28. WORKSHOP

29. IN A PATIENT WITH DIARRHEA, OCCASIONALLY
ENTAMOEBA HISTOLYTICA/E. DISPAR(FOUR
NUCLEATED CYSTS, NO CHROMATOIDAL BARS) ARE
IDENTIFIED AS BEING PRESENT; HOWEVER, THESE
CELLS, WHICH ARE MISDIAGNOSED AS PROTOZOA, ARE
REALLY:
•A. Macrophages
•B. Polymorphonuclear leukocytes
•C. Epithelial cells
•D. Eosinophils

30. WHICH SPECIMEN IS THE LEAST LIKELY TO PROVIDE
RECOVERY OF TRICHOMONAS VAGINALIS?
•A. Urine
•B. Urethral discharge
•C. Vaginal discharge
•D. Feces

31. PARASITIC ORGANISMS THAT ARE MOST OFTEN
TRANSMITTED SEXUALLY INCLUDE:
•A. Entamoeba gingivalis
•B. Dientamoebafragilis
•C. Trichomonas vaginalis
•D. Diphyllobothrium latum

32. THERE ARE FEW PROCEDURES CONSIDERED STAT IN
PARASITOLOGY. THE MOST OBVIOUS SITUATION
WOULD BE:
•A. Ova and parasite examination for
giardiasis
•B. Baermann’s concentration for
strongyloidiasis
•C. Blood films for malaria
•D. Culture of amoebic keratitis

33. WHICH OF THE FOLLOWING IS A KEY
CHARACTERISTIC OF THE THICK BLOOD FILM?
•A. The ability to see the parasite within the
RBCs
•B. The ability to identify the parasites to the
species level
•C. The examination of less blood than the thin
blood film
•D. The necessity to lake the RBCs during or
prior to staining

34. Good luck