Nematodes PDF - Clinical Parasitology Past Paper

BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA INTESTINAL NEMATODES (RO...

BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA INTESTINAL NEMATODES (ROUNDWORMS) Somatic Lymphatic System: Body Cavity: 1. Ascaris lumbricoides W. bancrofti Mansonella perstans 2. Enterobius Vermicularis B. Malayi M. ozzardi 3. Ancylostoma duodenale 4. Necator americanus Subcutaneous Tissue: Conjunctiva: 5. Stronglyloides stercoralis Loa loa Loa loa 6. Trichuris trichiura O. volvulus 7. Capillaria philippinensis D. medinensis Tissue Roundworms: ASCARIS LUMBRICOIDES 1. Trichinella spiralis 2. Dracunculus medinensis common roundworm or giant Common Name roundworm GENERAL CHARACTERISTICS worldwide distribution; prevalent Distribution in the tropics males smaller than females and have a curved tail adult worms: small intestine unsegmented Habitat (jejunum) length varies from few millimeters to meters an adult worm: complete digestive tract (mouth to anus) large, broad, light, pinkish, worldwide distribution whitish Phylum Nematoda (“threadlike”) body: cylindrical, tapering at sexes are separate = diecious the anterior end and female nematodes: somewhat less at the o oviparous – lays eggs posterior end o viviparous – give birth to larvae mouth opens at the anterior o ovo-viviparous – lays eggs containing larvae end with 3 finely toothed lips which are immediately hatched out Oviparous Viviparous Ovo-viviparous A. lumbricoides D. medinensis S. tercoralis T. trichiura W. bancrofti A. duodenale B. malayi N. americanus – T. spiralis Morphology (eggs contain larvae) E. vermicularis CLASSIFICATION ACCORDING TO HABITAT OF ADULT WORM body cavity contains ascaron Intestinal (toxic fluid) Small Intestine: Large Intestine: produce PI3-pepsin inhibitor A. lumbricoides E. vermicularis 3, protecting the worm from A. duodenale T. trichiura digestion N. americanus produce phosphorylcholine S. stercoralis which suppresses T. spiralis lymphocyte proliferation C. philippinensis MANYLL REIGNE MAGANA 1 BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA male: of nonpermeable innermost measures 15-30 cm in length lipoidal vitelline membrane; measures 2-4 mm in a thick transparent middle diameter layer and an outermost posterior end is curved coarsely mamillated ventrally to form a hook albumoid layer presence of a pair of floats in unsaturated copulatory spicules of equal solution of common salts size female: measures 25-40 cm in length measures 5 mm in diameter longer and stouter than males tail is straight and conical mature females lay eggs (nearly 200,000 eggs daily) fertilized egg: fertilized egg with double shell: broadly oval, golden brown 2 shells are distinct: single cell stage when passed the external shell is rough, out with feces brown, covered with little 3 layers of eggshell: lumps (mamillated) inner nonpermeable, lipoidal the internal shell is smooth, vitelline membrane thick, and colorless thick transparent middle layer or glycogen membrane outermost coarsely mamillated, albuminoid layer unfertilized egg: never undergoes further Types of Ova unfertilized: development content of egg is irregular narrower and longer and disorganized measures 90 um in length larger than fertile egg measures 55 um in breadth mammilation (cortication) small atrophied ovum and a may be irregular or absent thin shell within an irregular coating of albumin fertilized: innermost lipoidal vitelline round or oval measures 60- membrane of the shell is 75 um in length absent measures 40 – 50 um in heaviest of all the eggs thus, breadth they do not float in surrounded by a thick, saturated solution of transparent shell consisting common salt MANYLL REIGNE MAGANA 2 BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA decorticated fertilized egg: the egg is single, smooth, thick, and colorless (or very pale yellow) without the external shell, presence of a single round colorless granular mass the egg has a single smooth Life Cycle thin colorless shell (double line), the inside contains large roundish colorless refractile granules ascariasis caused by both adult worms and migrating larvae affect the nutritional status of the host leading to malnutrition (retardation of Pathogenicity growth) and night blindness (vitamin A deficiency) lead to loss of appetite and obstruction of the intestinal tract worms are restless wanderers MANYLL REIGNE MAGANA 3 BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA release toxic body fluid hair-like and the posterior two-fifth (ascaron) leading to various is thick and stout resembling the allergic manifestations handle of the whip male: with coiled posterior end female: with comma or arc-shaped posterior; 3-5 cm demonstration of adult worm demonstration of larvae: detected in the sputum during the stage of migration Laboratory demonstration of both Diagnosis fertilized and unfertilized eggs (DFS, Kato-katz) serodiagnosis barrel-shaped with eosinophilia: seen in larval protruding mucous plug at invasion stage each pole pyrantel pamoate unsegmented ovum albendazole color: yellow to brown (bile- mebendazole stained) and plugs are piperazine citrate Ova colorless floats in saturated solution of prophylaxis: salt proper disposal of human secretion of TT47 allowing Treatment feces parasite to embed its entire avoidance of eating raw whip-like portion into the vegetables and salads intestinal wall periodic treatment with an effective anti-helminthic WASHED (water, sanitation, hygiene, education, deworming) TRICHURIS TRICHIURA Life Cycle Common Name whipworm Habitat large intestine adult worms: whip-shaped; Morphology anterior three-fifth is very thin and infective stage: embryonated ova MANYLL REIGNE MAGANA 4 BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA diagnostic stage: demonstration of small intestine of man, particularly ova in stool Habitat in the jejunum, less often in the rectal prolapse duodenum and rarely in the ileum rectal bleeding (whipworm infective stage: filariform larvae dysentery) with abdominal cramps, blood-streaked reservoir host: dogs, cats, hogs, Pathogenicity diarrhea, and severe rectal lions, tigers, gorillas tenesmus iron deficiency anemia intermediate host: none (malnutrition and blood loss) demonstration of egg in the Man is the only host; no Laboratory intermediate host is required. patient’s feces (DFS, Kato-katz, Diagnosis FECT) oral administration of When a person walks barefoot on mebendazole soil containing the filariform larvae, penetrate the skin reaches prophylaxis: subcutaneous tissue, then enters Treatment sanitary disposal of feces lymphatics or small venules, then avoiding consumption of raw into the circulation. The larvae vegetables migrate up the bronchi, trachea & treatment of infection larynx, epiglottis to the pharynx & persons are swallowed. Life Cycle HOOKWORM Undergoes 3rd molting & reaches the small intestine, undergoes 4th Important Species: molting & develop into adult Ancylostoma duodenale worms. Six weeks later, male o tends to occur in cooler and drier regions fertilizes female & the latter lays Necator americanus eggs which are passed in the feces o occurs in tropical and subtropical & the cycle is repeated. regions Less Important: A. braziliense o hookworm of wild and domestic dogs and cts A. caninum o dog hookworm A. ceylanicum o one of the smaller species of the genus o occurs in the intestine of cats and their wild relatives in Southeast Asia adult worms: small, pinkish and fusiform in ANCYLOSTOMA DUODENALE Morphology shape anterior end is curved Common Name old world hookworm dorsally (hookworm) MANYLL REIGNE MAGANA 5 BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA oral cavity provided with 4 consists of 3 lobes: 1 dorsal and 2 hook-like teeth on ventral lateral surface and 2 knob-like teeth on dorsal surface rhabditiform larvae long buccal canal, small rarely seen since they remain genital primordium firmly attached to the usually not found in stool but intestinal mucosa by means may be found if there is delay of well-developed mouth in processing parts 250-300 um long, 15-20 um wide males: measure: 5-11 mm by 0.4-0.5 mm posterior end expanded in an umbrella-like fashion (copulatory bursa) genital opening opens filariform larvae: posteriorly with cloaca 500-600 um long pointed tail females: sheated measure: 9-13 mm by 0.6 mm posterior end is tapering genital opening opens at the junction of the middle and posterior thirds of the body oval or elliptical measuring 60 um in length and 40 um in width colorless (not bile-stained) and surrounded by a thin transparent hyaline shell Eggs possess segmented ovum with 4 copulatory bursa: blastomeres; a clear space present in the male worm for between the segmented ovum and attachment with the female the egg shell during copulation MANYLL REIGNE MAGANA 6 BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA the eggs float in saturated salt solution indirect methods: through blood examination (anemia and eosinophilia) and stool exam showing positive occult blood and Charcot-Leyden crystals NECATOR AMERICANUS Common Name new world hookworm adult worms are slightly smaller ovoidal, thin- shelled, and thinner than A. duodenale colorless 4-8 cell stage in the feces no teeth and semi-lunar cutting in delayed transit time, plate embryo may develop inside Morphology the shell differentiation of Necator egg from Ancylostoma egg is difficult causes 3 types of lesions: indistinguishable from A. 1. Ancylostoma dermatitis Ova duodenale (ground itch; dew itch) when filariform larvae enter the skin and Life Cycle same as A. duodenale may lead to dermatitis Laboratory same as A. duodenale Diagnosis 2. creeping eruption Pathogenicity same as A. duodenale (cutaneous larva migrants) a mebendazole parasitic skin infection caused by hookworm larvae prophylaxis: improved living conditions Pathogenicity Treatment and sanitation 3. pulmonary lesions occurs when the filariform larvae sanitary disposal of human break through the pulmonary feces capillaries and enter the alveoli, wearing of shoes and gloves they may lead to bronchitis and for personal protection bronchopneumonia other: hypoalbuminemia – low level of albumin due to loss of blood, lymph, and CHON (carbon, hydrogen, oxygen, and nitrogen) direct methods: demonstration of eggs and adult Laboratory worms in feces and aspiration of Diagnosis duodenal contents (DFS, Kato-katz, Concentration techniques, Culture) MANYLL REIGNE MAGANA 7 BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA STRONGYLOIDES STERCORALIS filariform larvae: highly infectious threadworm long slender possess short mouth (characterized as free-living long cylindrical esophagus rhabditiform and parasitic occupying half the length of Common Name filariform stages) the larvae forked or notched tail (opportunistic pathogen in immunocompromised host) mucosa of the small intestine Habitat especially the duodenum and jejunum males: shorter, broader and do not have penetrating power (do not invade intestinal wall); presence of copulatory specules females: small, thing 2-3 mm in length and 30-50 um in width thin-shelled, transparent, and oval Egg containing larvae ready to hatch rhabditiform larvae: Morphology commonly seen in stool specimens shorter mouth or buccal canal double-bulb elongated esophagus large genital primordium mouth is open (feeding stage) Life Cycle Pathogenicity Strongyloidiasis MANYLL REIGNE MAGANA 8 BSML – 2211 | CLINICAL PARASITOLOGY Unit #2: Nematodes 2nd SEMESTER | S.Y 2022 – 2023 BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE LECTURED BY: MARILOU HONCULADA TRANSCRIBED BY: MANYLL REIGNE A. MAGANA skin lesions: invading the skin, the serology filariform larvae produce petechial thiabendazole hemorrhage at each site of prophylaxis: invasion (larva currens racing proper disposal of human larva”) waste Treatment avoidance of contact with pulmonary lesions: larvae migrate fecally contaminated soil through the lungs, breaks out of treatment of all diagnosed the pulmonary capillaries into the cases alveoli causing hemorrhages in the lung alveoli & bronchopneumonia Harada-Mori Culture: allows the hatching of larvae from eggs on strips intestinal lesions: patients develop for filter paper with 1 end immersed in water intermittent abdominal pain, recommended for specie identification distension, bloating & diarrhea; the duodenal & jejunal mucosa shows small tunnels through which parasitic females have burrowed their ways hyper infection: filariform larva enters the arterial circulation & lodge in various organs; seen with underlying immune defects, autoimmune diseases, protein malnutrition & patients with immunosuppressive therapy basic technique: stool exam (microscopic exam for rhabditiform larvae) - direct fecal smear (saline or fresh or preserved stool) - concentration technique (Kato-katz or thick technique, FECT) Laboratory other specialized techniques: Diagnosis stool culture (Harada-Mori) to demonstrate larvae; Harada-Mori culture should be examined after 5 days for Strongyloides and after 10 days for hookworm direct examination of sputum MANYLL REIGNE MAGANA 9