MEDICAL PARASITOLOGY&ENTOMOLOGY Prepared by: Sr. norazsida
CLASSIFICATION OF PARASITES • Phylum Sarcomastigophora • Phylum Ciliophora • Phylum Apicomplexa • Phylum Microspora • Phylum Aschelminthes • Phylum Platyhelminthes
Phylum Sarcomastigophora • Subphylum Sarcodina (amebae) • Subphylum Mastighopora (flagellates) Characteristics: • Amebae move by means of cytoplasmic protrusions called pseudopods (false feet). • Flagellates move by means of whiplike appendages known as flagella. • Asexual
PHYLUM CILIOPHORA • Move by means of cilia, threadlike extensions which are shorter and more numerous than flagella- arise from small basal granules. • Most are free-living and nonpathogenic. • The sole human pathogen: Balantidium coli, the largest intestinal protozoan known to infect man.
PHYLUM APICOMPLEXA • Class Sporozoa. • Having complex life cycles with alternating sexual and asexual generations. • Pathogens include the Coccidia: parasites found in the intestinal mucosa. • Found in blood and tissues.
PHYLUM MICROSPORA • Tiny intracellular parasites. • Cause infections in vertebrate and invertebrate. • In human- Immunocompetent individuals are rarely infected.
PHYLUM ASCHELMINTHES • Roundworms (nematodes). • round, elongated bodies with coiled tails. • Sexes separated. • Male usually being smaller than the female. • Most are free living. • Life cycle involve intermediate as well as definitive hosts. • Class Nematoda
PHYLUM PLATYHELMINTHESE • Flatworms with flattened shape of the adult worm. • Hermaphroditic : having male and female reproductive structures • Found in class: 1)Trematoda (flukes) • 2) Cestoda (tapeworms). • Complex life cycle. • Tapeworms: elongated, ribbonlike bodies, consisting of a scolex, an organelle of attachment, anteriorly, a neck region and segmented called proglottids.
Protozoa • Are unicellular animals that occur singly or in colony formation. • A complete unit capable of performing the physiologic functions that in higher organisms are carried out on by specialized cells. • For the most part they are free-living, but some are parasitic, having adapted themselves to an altered existence inside the host.
Amoeba parasite in human • Entamoeba histolytica (pathogenic) • E. hartmanni (commensal) • E. coli (commensal) • E. gingivalis (commensal) • Iodomoeoba buetschili (commensal) • Endolimax nana ( commensal)
Entamoeba histolytica • Diseases: amebiasis, amebic dysentery, amebic hepatitis. • Also known as E. dispar (non pathogenic strain) • Life cycle consist of: 1) trophozoite 2) Cyst (infective stage) -wide geographical distribution.
Mode of transmission -usually acquired by ingestion of contaminated water or food containing amebic cyst (oral), -male homosexual.
Symptoms • Abdominal pain • Diarrhea or bloody diarrhea • Ulcers in appendix, cecum and other parts of colon. • Flask-shaped ulcer- with a small mucosal opening and an eroded area beneath the surface.
Laboratory diagnosis • Concentration technique – permenant smears stained by trichrome method • Serological procedures: -Indirect hemagglutination assay (IHA) -enzyme linked immunosorbent assay (ELISA) -Indirect immunofluorescent (IFA)
Treatment • Using amebicidial agents: • Luminal amebicides: iodoquinol, diloxanide furoate • Tissue amebicides: metronidazole, chloroquine, dehydroemetine
Prevention • Filtration and chemical treatment – bcoz- resistant to chlorination • Avoidance of contaminated water