s4 l2 Nematodes i

Nina Ian John “G” Rachel Mark Jocelle Edo Gienah Jho Kath Aynz Je Glad Nickay Ricobear Teacher Dadang Niňa Arlene Vivs Paulfie Rico Ren Mai Revs Mavis Jepay Yana Mayi Serge Hung Tope Ag Bien

JJaannuuaarryy 1111,,22001111

S4 L2: NEMATODES I by Dr. Mary Antonette Madrid *** Note: For consolidation purposes (naks!!), please refer to the table at the last 2 pages. Intense na talaga tayo! 

Ascaris lumbricoides GIANT ROUNDWORM Most common intestinal nematode of man Occurs most frequently in the tropics A soil-transmitted helminth (moist, shady soil) Can cause varying degrees of pathology: o Tissue reaction to invading larvae o Intestinal irritation to the adult worms due to its mechanical and toxic action o Complications due to extraintestinal migration Parasite Biology Has a polymyarian type of somatic muscle arrangement, in which cells are numerous and project well into the body cavity Worms are large and whitish or pinkish, with smooth striated cuticles Have a terminal mouth with 3 lips and sensory papillae Female: 22- 35 cm in length; contain paired reproductive organs in posterior 2/3; lays 200, 000 eggs per day Male: 10- 31 cm in length; has a ventrally curved posterior end with 2 spicules and a single long tortuous tubule adults reside but do not attach to mucosa of small intestine INFERTILE OVUM longer and narrower than fertile eggs has a thin shell and irregular mammilated coating filled with refractile granules

During migration: larvae may cause sensitization resulting in allergic manifestations such as lung infiltration, asthmatic attacks and edema of lips symptoms similar to pneumonia may result due to penetration of lung capillaries Diagnosis  finding ova in feces using the following techniques: 1. 2.

3.

DIRECT FECAL SMEAR (DFS) 2 mg feces emulsified in a drop of NSS on a glass slide and examined under LPO KATO TECHNIQUE OR CELLOPHANE THICK SMEAR METHOD qualitative method; recommended for mass examination of feces KATO-KATZ TECHNIQUE (QUANTITATIVE) o modified Kato technique o amount of feces is measured in grams o quantify number of eggs per gram (EPG) o determines egg reduction rate after treatment o determines intensity of Ascaris infection

Treatment Drug of Choice = ALBENDAZOLE Alternative Drugs: Mebendazole; Pyrantel pamoate Ivermectin = as effective as albendazole if given at a dose of 20 micrograms/kg single dose Prevention and Control  sanitation  health education  mass chemotherapy, done periodically Life Cycle of Ascaris lumbricoides

FERTILE OVUM has an outer, coarsely mammilated albuminous covering (may be absent or lost in “decorticated” ovum) has a thick transparent, hyaline shell, immediately after the albumin layer, and a delicate vitelline, lipoidal, inner membrane which is highly impermeable INFECTIVE STAGE  

fully embryonated ovum when these eggs are ingested, the larvae hatch in the lumen of the small intestine and penetrate the intestinal walllarvae enter the venulesgo to the liver through the portal veinheart and pulmonary vesselsbreak out of the capillary vesselsair sacsundergo motlingmigrate to larynx and oropharnyxswallowed into digestive tract

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Adult worms live in the lumen of the small intestine. A female may produce approximately 200,000 eggs per day, which are passed with the feces . Unfertilized eggs may be ingested but are not infective. Fertile eggs embryonate and become infective after 18 days to several weeks , depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed , the larvae hatch , invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs . The larvae mature further in the lungs (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed . Upon reaching the small intestine, they d;evelop into adult worms . Between 2 and 3 months are required from ingestion of the infective eggs ;to oviposition by the adult female. ;Adult worms can live 1 to 2 years.

Prevention and Control personal hygiene fingernails should be cut short frequent handwashing Life Cycle of Enterobius vermicularis

.Enterobius vermicularis HUMAN PINWORM causes ENTEROBIASIS or OXYURIASIS characterized by perianal itching or pruritus ani classified as “meromyarian” based on arrangement of somatic muscles where there are 2 to 5 cells per dorsal or ventral half Parasite Biology adult worms have cuticular alar expansions at the anterior end (cephalic alae used for migration) and a prominent posterior esophageal bulb Female: 8-13 mm x 0.4 mm and has a pointed tail; uteri of gravid female are distended with eggs Male: 2- 5 mm x 0.1 to 0.2 mm and has a curved tail and single spicule; rarely seen, usually die after copulation Rhabditiform larvae has the esophageal bulb but has no cuticular expansion Ovum 11, 105 eggs per day asymmetrical, with one side flattened and the other side convex translucent shell consist of an outer triple albuminous layer covering for mechanical protection and an inner embryonic lipoidal membrane for chemical protection resistant to disinfectants susceptible to dehydration in dry air within a day may remain viable for 13 days in moist conditions Clinical Manifestations innocuous parasite rarely produce serious lesions mild catarrhal inflammation of intestinal mucosa migration of egg laying females to anus causes irritation of perianal region children affected may suffer from insomnia due to pruritus easily spread within the family Diagnosis GRAHAM’S SCOTCH ADHESIVE TAPE SWAB/ PERIANAL CELLULOSE TAPE SWAB/ SCOTCH TAPE METHOD Treament Drug of Choice = PYRANTEL PAMOATE Alternative Drugs = Albendazole, Mebendazole

Eggs are deposited on perianal folds . Self-infection occurs by transferring infective eggs to the mouth with hands that have scratched the perianal area . Person-to-person transmission can also occur through handling of contaminated clothes or bed linens. Enterobiasis may also be acquired through surfaces in the environment that are contaminated with pinworm eggs (e.g., curtains, carpeting). Some small number of eggs may become airborne and inhaled. These would be swallowed and follow the same development as ingested eggs. Following ingestion of infective eggs, the larvae hatch in the small intestine and the adults establish themselves in the colon . The time interval from ingestion of infective eggs to oviposition by the adult females is about one month. The life span of the adults is about two months. Gravid females migrate nocturnally outside the anus and oviposit while crawling on the skin of the perianal area

. The larvae contained inside the eggs develop (the

eggs become infective) in 4 to 6 hours under optimal conditions . Retroinfection, or the migration of newly hatched larvae from the anal skin back into the rectum, may occur but the frequency with which this happens is unknown. Capillariasis philippinensis Female: 2.3-3.2 mm Male: 2.5 – 4.3 mm Currently considered a parasite of fish eating birds (natural definitive host) Endemic in the Phil, Thailand Rare cases: other Asian countries, Middle East, Colombia Clinical Features Abdominal pain, diarrhea Protein losing enteropathy  cachexia and diarrhea

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 Smaller, 1mm  Short and stout (i’m a little teapot? Hehehe )  Double bulbed, muscular esophageal pharynx Free living form (male)  broadly fusiform tail pointed and curved ventrad Clinical Features

Life Cycle of Capillaria philippinensis

Frequently asymptomatic 3 phases of Infection o invasion of skin  filariform o migration of larvae thru the body o penetration of intestinal mucosa by adult female worms Light infection : no intestinal symptom Moderate infection : diarrhea alternating with constipation Heavy infection : intractable, painless intermittent diarrhea (numerous, thin, watery bloody) Complication : edema, emaciation, loss of appetite, anemia, lobar pneumonia, malabsorption Frequently asymptomatic GIT symptoms : epigastric pain, diarrhea Pulmonary symptoms : Loeffler’s syndrome pulmonary migration of filariform larvae Dermatology : urticarial rash in buttocks or waist area Massive hyperinfection /Disseminated strongyloidiasis immunosuppressed patient : Severe enterocolitis and widespread dissemination to heart, lungs and CNS abdominal pain, distention, shock, pulmonary and neurologic complication; septicemia Blood eosinophilia: acute/chronic stage ; (-) in dissemination Life cycle of Strongyloidiasis stercoralis

Diagnosis Stool exam intestinal biopsy eggs larva or adult worm Capillaria philippinensis eggs: Unembryonated eggs: 1. peanut shaped 2. measures 36-45 um x 21 um Treatment Mebendazole Albendazole Strongyloides stercoralis Smallest of intestinal nematodes Rural areas, institutional settings, lower socioeconomic group Acquired thru: direct contact of skin with soil dwelling larvae; ingestion of filariform contaminated food Facultative parasite Parasitic form (female)  delicate filariform 2.2 mm  esophagus: 1/3 or 2/5 of the anterior part of the body  parthenogenetic parasitic form (male)  none Free living form (female)

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Diagnosis

Life cycle of Trichuris trichiura Derived from S. stercoralis filariform larva Antibody detection Immunodiagnostic test : indicated when infection is suspected and organism cannot be demonstrated by duodenal aspiration, string test or stool exam EIA : 90% sensitivity (+) in immunocompromised with disseminated strongyloidiasis Cross reaction with filariasis and some nematode infection Ab levels decrease within 6 mos post treatment Peptic-ulcer like pain associated with peripheral eosinophilia strongly suggest diagnosis of strongyloidiasis

Laboratory tests Microscopy: larvae ( rhabditiform, filariform) Stool or duodenal fluid Wet mounts: Baermann funnel technique Harada Mori filter paper technique Culture: agar plate Enterotest string ; duodenal aspiration Larva : sputum : patient with disseminated strongyloidiasis Clinical features Morphology Parasitic of Filariform larvae o Long esophagus o No constriction of the esophagus o Long intestine o Esophagus equal in length to the intestine o Longer and more slender than rhabditoid o Nonsheathed Rhabditiform larva in wet mount after fixation in 10% formalin Diagnostic characteristic : o Length 200-250µm o Short buccal cavity o Prominent genital primordium o Rhabditiform esophagus clearly visible in the larva o Consists of a club shaped anterior portion, a post median constriction and a posterior bulb Treatment Ivermectin Albendazole

Most frequently asymptomatic Heavy Infection: GIT problem: o Abdominal pain, diarrhea, rectal prolapsed, growth retardation Diagnosis Stool concentration methods to recover the eggs Moderate eosinophilia Rectal mucosa: proctoscopy Trichuris eggs (wet prep) Diagnostic characteristics: o Typical BARREL-shaped o 2 polar plugs that are unstained o Size: 50-54 µm x 22-23 µm o The external layer of the shell of the eggs is yellow brown in contrast to clear polar plugs o Eggs: unembryonated eggs are when passed in the stool Treatment

Prevention Medical personnel caring for patients with hyperinfection syndromes should wear gowns and gloves as stool, saliva, vomitus and body fluids may contain infectious filariform larvae Patients who have resided in an endemic area should be examined for presence of this parasite before and during steroid treatment or immunosuppressive therapy Trichuris trichiura Human WHIPWORM Adult : 0.50 mm in length Anterior 2/3 is thin and threadlike Posterior end is bulbous Tail: Male – Coiled; Female – straight Tropical weather and poor sanitation practices

Mebendazole Albendazole Hookworm Infect > 900 M Moist warm cimate Local distribution: agricultural areas, rice fields, vegetable garden Prevalence: 40-45% Criteria Common name Female Male Transmission Temperature

Ancylostoma duodenale Old world hookworm

Necator americanus New world hookworm

10-13 mm 8-11 mm Oral:percutaneous Eggs and developmental stages more tolerant of low temp

9-11 mm 7-9 mm Percutaneous Sensitive to low temp

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Factors that contribute to transmission Suitable environment o Damp, sandy or friable soil with decaying vegetation T 2432° C Mode and extent of fecal pollution of the soil unsanitary disposal of human feces. Use of night soil for fertilizer Mode and extent of contact between infected soil and skin or mouth Clinical Features Iron deficiency Anemia: Microcytic, hypochromic moderate or heavy chronic infection. Blood loss at the site of intestinal attachment of adult worm with cardiac complication Blood eosinophilia: 30-60% GIT, Nutritional, metabolic symptom, abdominal pain, steatorrhea, bloody/mucoid stools, edema, albuminuria Skin manifestation: ground itch/dew itch: penetration of filariform (L3) larvae (+) itching, edema, erythema  papulovesicular eruption for 2 weeks Respiratory symptom: pulmonary migration of larvae bronchitis or pneumonitis (+) minute hemorrhage with eosinophilic and leukocytic infiltration

o Determine species Hookworm eggs on wet mount: o Egg, advanced cleavage. (Iodine) Diagnostic characteristic: Size: 57-76 µm x 35-47 µm Oval or ellipsoid shape Thin shells The embryo has begun cellular division and is at an early developmental stage – gastrula Hookworm rhabditiform larvae on wet preparation Long buccal cavity Small genital primordium Constriction of esophagus Larger than Strongyloides rhabditoid More attenuated posteriorly than Strongyloides rhabditoid Non-sheated Hookwork filariform larva (wet prep)

Life cycle of hookworm

Short esophagus No constriction of the esophagus Long intestine Ratio:: esophagus: intestine: 1:4 Longer and more slender than rhabditoid stage (+) striations on the surface sheath Adult worm: o

o

A. duodenale: anterior end depicted showing cutting teeth

N. americanus: anterior end depicted showing mouth parts with cutting plates

Diagnosis Adults: pinkish white Head often curved in a direction opposite that of the body Males: unique fan shaped copulatory bursa Oral cavity: o A. duodenale: 4 sharp toothlike structure o N. americanus: dorsal and ventral cutting plates DFS (Direct Fecal Smear): o Only when infection is heavy o May not detect parasite in light infection (400 eggs/gm feces) Concentration methods: detect presence of egg o Zinc sulfate centrifugal flotation o Formalin ether method Culture (Harada Mori)

Treatment Prioritize: pregnant women, children and patients with malnutrition, pulmonary TB and anemia Albendazole Mebendazole Pyrantel pamoate Correct anemia: Iron therapy Prevention Sanitary disposal of human feces Wear shoes, slippers, boots Health education: o Personal, family and community hygiene

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Treatment of affected individual Mass chemotherapy when incidence >50% Protection of susceptible individual Natural food preservative substances:: salt, sugar, acetic acid, onion garlic, mustard, pepper, spices: lethal to eggs and larvae ------------------------------------------end of trans-----------------------------------------------

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CRITERIA Common name Habitat Classification based on the presence or absence of caudal chemoreceptors Classification of adult female based on life stages Infective stage Mode of transmission Life cycle Pathogenesis

Laboratory diagnosis

Ova/ egg

Adult worms

Ascaris lumbricoides Giant intestinal roundworm/ eelworm Upper end of the small intestine Phasmid

Whipworm Large intestine Aphasmid

Enterobius vermicularis Pinworm/ seatworm Large intestine Phasmid

Oviparous

Oviparous

Ovoviparous/ oviviparous

Embryonated egg Ingestion of fully embryonated egg Egg embryonates on soil and larva undergoes lung migration Intestinal Ascariasis and Ascaris Pneumonitis Larva can cause allergy, and eosinophilia. Occasionally, ectopic larva are found in other organs with local inflammation and necrosis. Adult worms can cause obstruction of the small intestine, bile duct and trachea. Also, appendicitis and pancreatitis. Children may vomit up a bolus of adult worms! (eeeeew!!) For intestinal ascariasis:  Direct fecal smear  Concentration technique  Kato-Thick smear  Kato-Katz For Ascaris pneumonitis:  Rarely, embryos can be found in sputum Female adults produce 2 types of egg:

Embryonated egg Ingestion of fully embryonated egg Egg embryonates on soil but larval form do not undergo lung migration Trichuriasis/ Whipworm Infection Generally, there are few or no symptoms but in the cases of a very heavy infection, there may be local inflammation with abdominal discomfort and diarrhea and in some cases, rectal prolapse.

Embryonated egg Ingestion of fully embryonated egg` Eggs do not embryonates on soil and larval form do not undergo lung migration Enterobiasis/ Pinworn Infection The main symptom is pruritus ani which is caused by female migration. Itching results in insomnia and restlessness. In some cases, gastrointestinal signs like pain, nausea and vomiting may develop

Finding ova in the stool through:  Direct fecal smear  Concentration technique  Kato-Thick smear  Kato-Katz

Ova are found in perianal and fingernail scrapings

Eggs measure 50-60 um x 20-30 um. Eggs are ovoid with one side flattened. Shell is transparent and with 2 layers and with a coiled occasionally motile embryo/ Lop sided or D shaped.

Egg measure 50-54 um x 23 um. Eggs are barrel/ football/ lemon/ lantern shaped with polar prominences. Egg has a yellowish outer and a transparent inner shell. Commonly known as Japanese Lantern ova. Eggs are more susceptible to desiccation than eggs of Ascaris

Whitish. With cuticular alar expansion at the anterior end and a prominent esophageal bulb. Adult female is 3-8mm x 0.4mm long and with am pointed tail end. Adult male is 2-5 mm x 0.1-2 mm. Has a curved tail.

Pinkish gray. Anterior 2/3 of the worm is slender, giving it a whipworm appearance. Adult male is 3045 mm and are slightly shorter than females. Long and with a coiled posterior end Adult female is 35-50 mm long and it has a bluntly rounded posterior end.

Fertilized Unfertilized - 45-70 um x 35- 50 um - 88- 94 um x 39-44 um - regularly ovoid with - irregularly ovoid with thick shell thin shell - cytoplasm contains - disorganized germ organized germ cells cells are coarsely that are finely granular granular - shell with 3 layers: - longer and narrower outer mamillary coat, than fertilized egg middle glycogen layers and inner lipoidal vitelline membrane Male or female adult worms are usually pink or white, both with terminal mouth provided with 3 lips (trilobite lip). Males are 10-31 cm long with s curved posterior end. Females are 22-35 cm long. They may superficially resemble an earthworm.

Trichuris trichura

Larva stimulate the morphology of adult worms

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Criteria Common name

Habitat Classification based on the presence or absence of caudal chemoreceptors Classification of adult female based on life stages Infective stage Mode of transmission Life cycle

Pathogenesis

Laboratory diagnosis

Hookworms Ancylostoma duodenale- Old world Hookworm Necator americanus- new world hookworm A. caninum- dog hookworm A. braziliense- cat hookworm Small intestine Phasmid

Rhabditiform Larva Filariform Larva Adult worm

Small intestine Phasmid

Oviparous

Ovoviparous

Filariform larva Larval skin penetration Egg embryonates and hatch on soil, larva undergoes lung migration

Filariform larva Larval skin penetration Undergo 3 different life cycles:  Direct  Indirect  Autoinfection Cochin china diarrhea/ Vietnam diarrhea/ Strongyloidiasis

Hookworm infection (Ancylostomiasis/ Uncinariasis)  Skin at the site of entry: There is a general allergic reaction known as ground itch  Lungs during larval migration: localized pneumonitis and eosinophilia may develop  Small intestine which is the habitat of adult worms. Parasites start to ingest blood. There can be occult bleeding from intestinal mucosa Finding the characteristic egg in the feces through:  Direct fecal smear  Concentration technique Culture methods to identify the species

Ova

Strongyloides stercoralis Threadworm

All hookworm eggs are alike. Ovoid with thin hyaline transparent shell contains 2-8 germ cells 250 um in length. Resembles those of Strongyloides but larger. Characterized by a long buccal cavity and has a small genital primordium 700 um in length. With short esophagus and with pointed tail. Sheathed. Grayish white. Females are generally larger than males. A. duodenale is slightly larger than N. americanus. Anterior end has a buccal cavity with a dental pattern. N. americanus has semi lunar teeth. A. duodenale has two pairs of buccal teeth. A. caninum has three pairs and A. braziliense has one pair. Male posterior end is expanded due to copulatory bursa. Female posterior end is pointed. In A. duodenale, head continues in the same direction as the curvature of the body. In N. americanus, head is curved opposite to the curvature of the body which is like a hook at the anterior end.

In the direct cycle, this can cause local dermatitis. Local migration can cause localized pneumonitis in the viscera and ectopic larva can sometimes be found in the brain and other viscera. There is a genral allergic reactions and eosinophilia. Adult worms can cause inflammation of the intestinal mucosa producing diarrhea and occasionally, pneumonitis Finding the motile rhabditiform larva rarely; the egg in feces through:  Concentration technique  Beale’s string test  Serologic tests (ELISA) Larva can be found in feces and occasionally in the sputum Eggs have thin clear shell and are similar to those of hookworms except that they measure only about 5-=58 um x 30-34 um. Commonly referred as Chinese :Lantern Ova With short buccal cavity and has a large genital primordium Long esophagus and with distinct cleft at the tip of the tail (notched tail end) Free living male and female measures 1 mm x 0.06 mm, found in the soil. Smaller than filariform larva Parasitic female measures 2.2 mm x 0.04 mm. colorless semi transparent with slender tapering anterior end and a short conical pointed tail. Has a short buccal cavity with 4 indistinct lips. Parasitic male is indistinguishable from the free living ma,le since both measures 0.7 mm x 0.04 mm Male worm is smaller than female

Source: CEU College of Medical Technology Parasitology Review Notes by Ma. Cristina Liwanag

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