Nematodes Lab Discussion Slides PDF

NEMATODES CHRISTINE JOYCE M. JAVIER, RMT, MLS(ASCPI)CM 2024 Jul 11 – 13 MICRO PARA LAB  HELMINTHS ❑ also known as parasitic worms ❑ three stages of life cycle o EGG/OVUM: produced by adult worms o LARVA: hatch from eggs/ova o ADULT WO...

NEMATODES CHRISTINE JOYCE M. JAVIER, RMT, MLS(ASCPI)CM 2024 Jul 11 – 13 MICRO PARA LAB  HELMINTHS ❑ also known as parasitic worms ❑ three stages of life cycle o EGG/OVUM: produced by adult worms o LARVA: hatch from eggs/ova o ADULT WORM: male, female, or hermaphrodite ❑ diagnosis via observation of either of the three stages in a fecal specimen ❑ two typical hosts o INTERMEDIATE HOST: harbors larval stage o DEFINITIVE HOST: harbors adult worm  HELMINTHS flatworms roundworms or tapeworms or flukes or NEMATODES CESTODES TREMATODES  NEMATODES or ROUNDWORMS ❑ adult morphology: separate orifice for food intake (mouth) and waste excrement (anus); pseudocoelom, cuticle ❑ egg morphology: embryonated or unembryonated ❑ reproduction: usually sexual; males are smaller than females; males often have characteristically bent tail for holding the female for copulation ❑ infection: by eating uncooked meat with larvae in it, entrance into cuts in the skin or directly through the skin, via arthropod vectors ❑ diagnosis: microscopic identification of eggs in stool, or presence of adult worms in stool  INTESTINAL NEMATODES ❑ Ascaris lumbricoides ❑ Trichuris trichiura ❑ Ancylostoma duodenale ❑ Necator americanus ❑ Strongyloides stercoralis ❑ Enterobius vermicularis ❑ Capillaria philippinensis  Ascaris lumbricoides ❑ other name: giant round worm ❑ most common human helminthic infection globally ❑ highest burden in tropical and subtropical regions, especially in areas with inadequate sanitation ❑ infective stage o embryonated egg: ingestion of contaminated food/water ❑ clinical presentation o heavy infections in children = stunted growth o high worm burdens = abdominal pain, intestinal obstruction or nasopharyngeal expulsion o migrating adult worms = occlusion of the biliary tract, appendicitis ❑ treatment: albendazole  Ascaris lumbricoides A. unembryonated egg B. embryonated with L2 larva worm C. fertilized egg lumpy or mamillated A C D D. fertilized egg decorticated E. adult worm showing the anterior end with three lips B E Ascaris lumbricoides  Trichuris trichiura ❑ other name: whip worm ❑ third most common roundworm infection in humans ❑ infective stage o embryonated egg: ingestion of contaminated food/water ❑ clinical presentation o most frequently asymptomatic. o heavy infections, especially in small children, can cause gastrointestinal problems (abdominal pain, diarrhea, rectal prolapse) and possibly growth retardation ❑ treatment: mebendazole  Trichuris trichiura A. unembryonated egg with bipolar plugs; barrel-shaped and thick-shelled B. adult anterior end A C. adult posterior end with prominent spicule B C Trichuris trichiura  Ancylostoma duodenale ❑ other name: old world hookworm ❑ one of the two primary intestinal hookworm species worldwide that attach to the mucosa of small intestines and suck blood (0.15 mL to 0.26 mL blood per day) ❑ infective stage o L3 filariform larva: skin penetration ❑ clinical presentation o commonly asymptomatic; abdominal pain, nausea, and anorexia; other symptoms related to the blood-sucking ability of the species ❑ treatment: albendazole  Ancylostoma duodenaleGo to fullsize image A. egg that is thin-shelled and colorless with two to eight-cell stage of division B. filariform larva A C C. adult worm showing the buccal capsule with four ventral teeth D. rhabditiform larva B D  Necator americanus ❑ other name: new world hookworm ❑ one of the two primary intestinal hookworm species worldwide that attach to the mucosa of small intestines and suck blood (0.03 mL blood per day) ❑ infective stage o L3 filariform larva: skin penetration ❑ clinical presentation o commonly asymptomatic; abdominal pain, nausea, and anorexia; other symptoms related to the blood-sucking ability of the species ❑ treatment: albendazole  Necator americanus A. egg that is thin-shelled and colorless with two to eight-cell stage of division B. filariform larva A C C. adult worm showing the buccal capsule with two ventral semilunar cutting plates D. rhabditiform larva B D HOOKWORMS  Strongyloides stercoralis ❑ other name: threadworm ❑ infective stage o L3 filariform larva: skin penetration ❑ clinical presentation o acute strongyloidiasis: has three phase of infection ✓ cutaneous phase: skin penetration of L3 larva worm ✓ lung phase: lung migration of L3 larva worm ✓ intestinal phase: mild watery diarrhea, duodenitis o chronic strongyloidiasis: autoinfection but asymptomatic o disseminated strongyloidiasis: hyperinfection syndrome especially in immunocompromised AIDS patients ❑ treatment: albendazole, thiabendazole, ivermectin  Strongyloides stercoralis A. adult male B. adult female C. L1 rhabditiform larva D. L3 filariform larva A C B D Strongyloides stercoralis  Enterobius vermicularis ❑ other name: pinworm or seatworm ❑ causes enterobiasis or oxyuriasis ❑ infective stage o embryonated egg: ingestion or inhalation of contaminated food/water ❑ clinical presentation o pruritus ani: perianal itching o enterocolitis, vulvovaginitis, salpingitis, appendicitis ❑ treatment: mebendazole and pyrantel pamoate  Enterobius vermicularis A. egg that is D-shaped in wet-mount B. egg that is D-shaped in Graham’s scotch or cellulose tape test A B Enterobius vermicularis  Capillaria philippinensis ❑ other name: Pudoc worm ❑ discovered in Pudoc West Village, Tagudin, Ilocos Sur ❑ endemic in the Philippines and epidemics have occurred in the Northern Luzon region ❑ infective stage o embryonated egg: ingestion of raw fish ❑ clinical presentation o fever, abdominal pain, edema o chronic watery diarrhea o protein-losing enteropathy or wasting ❑ treatment: albendazole  Capillaria philippinensis A. egg that is peanut- shaped with flattened bipolar plugs A Capillaria philippinensis  Enterobius vermicularis ❑ other name: pinworm or seatworm ❑ causes enterobiasis or oxyuriasis ❑ infective stage o embryonated egg: ingestion or inhalation of contaminated food/water ❑ clinical presentation o pruritus ani: perianal itching o enterocolitis, vulvovaginitis, salpingitis, appendicitis ❑ treatment: mebendazole and pyrantel pamoate  Enterobius vermicularis A. egg that is D-shaped in wet-mount B. egg that is D-shaped in Graham’s scotch or cellulose tape test A B Enterobius vermicularis  BLOOD AND TISSUE NEMATODES ❑ Wuchereria bancrofti ❑ Brugia malayi ❑ Trichenella spiralis ❑ Onchocerca volvulus ❑ Loa loa ❑ Dracunculus medinensis ❑ Parastrongylus cantonensis ❑ Toxocara cani ❑ Toxocara cati ❑ Anisakis spp.  Wuchereria bancrofti ❑ other name: Bancroft’s filaria ❑ infective stage o L3 larva: injection of larva through mosquito bite ❑ clinical presentation o elephanthiasis: severe lymphedema of the limbs o hydrocele: swelling of scrotum ❑ treatment: diethylcarbamazine or DEC  Wuchereria bancrofti A. L1 microfilariae larva showing a tail that is tapered to a point B. adult worm B A  Brugia malayi ❑ other name: Brugian filariasis ❑ infective stage o L3 larva: injection of larva through mosquito bite ❑ clinical presentation o elephanthiasis: severe lymphedema of the limbs o hydrocele: swelling of scrotum ❑ treatment: diethylcarbamazine or DEC  Brugia malayi A. L1 microfilariae larva showing a tail that is tapered A FILIARIAL WORMS  Trichenella spiralis ❑ other name: pork worm ❑ infective stage o encysted larva: ingestion of undercooked pork ❑ clinical presentation o intestinal stage: gastric juices release larva from pork and can go with diarrhea, abdominal pain or vomiting o muscle stage: blood transfers larva to muscles and encysts within nurse cells; myocarditis or respiratory myositis o trichinellosis: severe myalgia, periorbital edema, eosinophilia ❑ treatment: mebendazole  Trichenella spiralis A. stained muscle tissue with encysted larvae B. unstained muscle tissue with encysted larvae C. liberated larvae A C B Trichenella spiralis  Onchocerca volvulus ❑ other name: blinding worm ❑ causes onchocerciasis or river blindness ❑ infective stage o L3 larva: injection of larva through blackfly bite ❑ clinical presentation o pruritus, dermatitis, lymphadenopathies o onchocercomata: subcutaneous nodules o ocular lesions to blindness: most serious manifestation  Onchocerca volvulus A. stained L1 microfilariae B. adult worm from patient’s scalp nodule A B  Loa loa ❑ other name: eye worm ❑ infective stage o L3 larva: injection of larva through deer fly or mango fly bite ❑ clinical presentation o often asymptomatic o subconjunctival migration  Loa loa A. stained L1 microfilariae B. adult worm from patient’s eye A B  Dracunculus medinensis ❑ other name: guinea worm ❑ infective stage o L3 larva: ingestion of contaminated food/water o L3 larva: ingestion of undercooked crustaceans ❑ clinical presentation o painful ulcers in skin  Dracunculus medinensis A. adult worm in stable blister B. adult worm from ruptured blister C. adult worm from A C patient’s skin ulcer B  MINOR NEMATODES ❑ Anisakis spp. ❑ other name: herring worm ❑ Toxocara cani ❑ other name: dog roundworm ❑ Toxocara cati ❑ other name: cat worm ❑ Parastrongylus catonensis ❑ other name: rat lung worm  LA FIN Thank you.