450 likes | 2.07k Views
Case Study in Parasitology. 温锦娣 0456208 3 November 2006. Case 4: geohelminths. 36-year old woman History of travel to Puerto Rico Submitted routine stool specimen. Wet Mount Examination of the Concentrate from the Stool Specimen. Fertile (infective) Ascaris eggs bile stained
E N D
Case Study in Parasitology 温锦娣 0456208 3 November 2006
Case 4: geohelminths • 36-year old woman • History of travel to Puerto Rico • Submitted routine stool specimen
Wet Mount Examination of the Concentrate from the Stool Specimen • Fertile (infective) Ascaris eggs • bile stained • thick, warty, albuminous coat • thick transparent inner shell • Crescent-shaped spaces • 45~75 x 35~50 mm in length • Resistant: chemicals, temperature, pH, irradiation
Infertile egg • elongated and larger than fertile egg • thin shelled • shell ranges from irregular mammillations to smooth • internal contents: a mass of disorganized, highly refractive granules • 85-95 mm x 43-47 mm
Diagnosis Disease Ascariasis Transmission fecal-oral route (soil, water, foodborne) Occurrence 1.5 billion (25%) infections worldwide Detection direct microscopic observation
Symptoms • Vague intestinal pain, nausea, diarrhea, malnutrition • Intestinal obstruction • Larva migrans: allergic hypersensitivity reactions such as asthmatic attacks, pulmonary infiltration and urticaria and oedema of the lips
Wet Mount Examination of the Concentrate from the Stool Specimen • Trichuris trichiura (Whipworm) • characteristic opercular plugs at each end of the egg • Barrel-shaped • yellow-brown, thick smooth shell • 50-55 mm x 22-24 mm
Diagnosis Disease Trichuriasis Transmission fecal-oral route (soil-borne, contaminated vegetables) Diagnosis direct microscopic observation of the egg from stool specimen: smear, sedimentation
Symptoms • Chronic dysentery, bloody stools • Iron-deficiency anemia • Rectal prolapse
Wet Mount Examination of the Concentrate from the Stool Specimen • Enterobius vermicularis (Pinworm) • elongated and flattened on one side • thick colorless shell • 50-60 mm x 20-30 mm • Found in feces: unembryonated • Cellulose tape preparation: embryonated (infective)
Diagnosis Disease Enterobiasis Transmission anal-oral route, airborne Detection cellophane tape
Symptoms • majority of infections are asymptomatic • irritation of the perianal region • Appendicitis • Pelvic inflammation
Treatment • administration of an anti-helminthic drug • Mebendazole • Albendazole
Association between Multiple Geohelminth Species Infection • Infection intensities of different species were positively correlated • Individuals with single-species infections had generally lower species-specific egg counts than individuals with multiple-species infections.
Association between Multiple Geohelminth Species Infection • individuals with multiple species infections are likely to be at highest risk of geohelminth-related morbidity • number of infections they harbour • carry heavier infections of each species