parasitology for nursing 1

8/12/2019 Parasitology for Nursing 1

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PARASITOLOGY 1Ebenezer Daryl P. Manzano, RMT


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INTRODUCTIONPROTOZOAFLAGELLATESAMOEBASPOROZOACILIATES


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PARASITOLOGYarea of biology concerned with the

phenomenon of dependence of oneliving organism on another


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Parasitea living organism which receives

nourishment and shelter from another

organism where it lives o ectoparasiteo endoparasiteo obligate parasiteso facultative or opportunist parasites


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Host an organism that harbors the parasite o DEFINITIVE HOST - harbors the adult stage of the

parasite or where the parasite utilizes the sexual method

of reproduction *man is the definitive host in majority of infections, in

malaria man acts as the intermediate host o INTERMEDIATE HOST harbors the larval stages

of the parasite *in some cases, developments are completed into two

different intermediate hosts first and second IH


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Infection-relationship of an endoparasite to its

hosto super in fec t ion- an ind iv idua lharboring the parasite is reinfected with

the same species of parasiteo autoinfection- when the infectedperson is his own source of the

reexposure


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Infestation

ectoparasites attach to the skin ortemporarily invade the superficial tissuesof the hosts body

! most frequently applied to arthropods


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Sources of Exposure! contaminated soil or water! soil polluted with human excreta Ascaris, hookworm! water cysts of parasitic amoeba and intestinal flagellates ! food containing the immature infective stage of the

parasite

! a domestic or wild animal harboring the parasite !

another person, his clothing, bedding, or the immediateenvironment that he has contaminated pin worm ! ones self- Strongyloides stercoralis


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Portals of Entry! mouth most common

! skin penetration hookworms,Schistosoma! bite of arthropods or blood-suckinginsects malaria, filariasis ! inha lat ion of a irborne eggs Enterobius vermicularis! transplacental infection! transmammary infection! sexual intercourse Trichomonas vaginalis


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PROTOZOOLOGYParasitology 1


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PROTOZOA

are unicellular organisms protozoan cells are covered with a cell membrane;

has a nucleus covered with nuclear membrane specialized organelles- contractile vacuoles,

cystosomes, mitochondria, ribosomes, flagella, cilia most protozoans produce cysts which are resistant

dormant stages that enable them to survive

drought, heat and freezing they reproduce asexually by cell division (binaryfission) and exhibit various degrees of sexual

multiplication


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(insert flagellates, amoebae, and sporozoa)


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Cryptosporidium sp Cryptosporidiosis Structure ! oocyst mature oocysts have 4 naked sporozoites Mode of Transmission ! ingestion of contaminated food and water with oocysts Habitat ! the developmental stages are located characteristically in avacuole at the surface of the microvilli of enterocytes or surfaces

of ciliated epithelium of respiratory tract


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Cryptosporidium spLife cycle! The oocysts of Cryptosporidium are ingested withcontaminated food or water. The oocysts releasesporozoites that invade the brush border of small

intestinal epithelium where they develop into

trophozoites. Oocysts may develop and pass into stool. Clinical Manifestation! Many infections are asymptomatic, or there may be amild watery diarrhea. Immunocompromised hosts (such

as persons with AIDS) may be more severely affected,

with many loose watery stools per dayDiagnosis! Examination of stool or duodenal aspirate foroocysts is required for diagnosis. Biopsy may reveal the

organisms in the brush border


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CILIATES Parasitology 1


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Balantidium coli Balantidiasis largest protozoa parasitizing man, sometimes visible

to the naked eye Mode of Transmission ! ingestion of contaminated food and drinks

with the cystic stage

! common in hogs, thus man gets infected fromthese animals especially piggery workers or slaughterhouse workers

Habitat ! large intestine


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Balantidium coli! has 2 stages:o trophozoite found in diarrheic stool ovoidal and covered with short cilia of uniform length has 2 nuclei a bean-shaped macronucleus and a smaller

micronucleus o cyst round in shape and covered with a tough cystic wall

found in formed or semi-formed stool


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Balantidium coliLife Cycle! Cysts of the parasite are ingested and excysts in the small intestine.The trophozoite then goes down to the large bowels and colonizes, As

the fecal material in which the trophozoite is transported down the

bowel dehydrates, encystation occurs.

Clinical Manifestation

! diarrhea! may disappear spontaneously in healthy individuals but may be fatal indebilitated personsDiagnosis! demonstration of parasites in feces Prevention and Control! environmental and personal hygiene


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Pneumocystis carinii fever, cough, dyspnea high risk groups

premature or debilitated infants

congenital immunodeficiency disease steroid or immunosuppressive therapy cancer of the lymphoid system AIDS - most common opportunistic infection


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Pneumocystis carinii

TROPHOZOITE CYSTIC stage

characteristic octonucleated cystbelieved to be sporozoites


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Pneumocystis carinii

DIAGNOSIS aspirates from lungs imprints from lungs tissue sections for autopsy and biopsy


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Pneumocystis carinii fever, cough, dyspnea high risk groups

premature or debilitated infants

congenital immunodeficiency disease steroid or immunosuppressive therapy cancer of the lymphoid system AIDS - most common opportunistic infection

parasitology for nursing 1

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