Nematodes, Cestodes, Trematodes, Arthropods Flashcards
Trichuris trichura
Life cycle - direct
Route of infection - ingested eggs
Geo. -ww
Lab diagnosis – formalin-ethyl acetate conc. stool
adults – females 35 - 50 mm, males 30-45 mm
eggs – 50 - 54 micrometers by 20 micrometers - barrel shape; Count the number of eggs
Pathology - asymptomatic, hypochromic anemia - malnutrition and blood loss, bloody diarrhea (dysentery)
Common name: whipworm
Taenia saginata
Clonorchis sinensis
(Liver fluke)
Life cycle-eggs-miracidia-sporocysts-rediae cercariae-metacercariae-adults
Route-ingestion of metacercariae infected uncooked freshwater fish
Geo.-China, Taiwan, Japan, Korea, Vietnam
Lab diagnosis-wet prep of formalin-ethyl acetate concentrated stool
adult-1-2.5 cm by 3.5 mm
egg-similar to Heterophyes, Opistorchis viverrini and Metagonimus, 28-35 micrometers, operculated
Pathology-jaundice, eosinophils, liver damage
Ascaris lumbricoides
hookworm
rhabditaform larva
Loa loa
Schistosoma japonicum
Life cycle-eggs-miracidia-sporocysts-cercariae-adults
Route of infection-cercariae penetrate skin
Geo.-China, Indonesia, Japan, Philippines
Lab diagnosis-wet prep of conc. stool, Kato – Katz smear – 50 mg stool, glycerin soaked cellulose coverslip, ELISA, enzyme-linked immunoelectro transfer blot test (EIBT)
egg- 70-100 micrometers by ~50 micrometers, small lateral spine,s acid fast positive
adult-similar to S. mansoni, found in mesenteric vessels of bowel/rectum
Pathology-Similar to S. mansoni -fever, headache, dysentery/bloody diarrhea, hepatomegaly
but S. japonicum has a higher egg production-more severe
potential, Katayama fever, weight loss
Hymenopelis nana
Diphyllbothrium latum
Life cycle-larvae-intestine-adults
Route of infection-ingestion infected raw, poorly cooked or pickled freshwater fish
Geo.-freshwater lakes
Lab diagnosis-wet prep of formalin ethyl-acetate concentration of stool
adults-scolex,strobila ( Chain of proglottids)
eggs-operculated, 58 – 75 micrometers
Pathology- diarrhea, obstruction, B12 deficiency, macrocytic anemia
Taenia solium
Trichuris trichura ova
Schistosoma mekongi
Life cycle-eggs-miracidia-sporocysts-cercariae-adults
Route of infection-cercariae penetrate skin
Geo.-Mekong river valley-Laos, Thailand
Lab diagnosis-wet prep of formalin-ethyl acetate concentrated stool
egg-similar to S. japonicum, but smaller, 50 - 65 micrometers by 30-55 micrometers, acid fast ?
adult- similar to S. japonicum
Pathology-Similar to S. japonicum
hepatosplenomegaly, portal venous hypertension
Life cycle-eggs-miracidia-sporocysts-cercariae-adults
Route of infection-cercariae penetrate skin
Geo.-Mekong river valley-Laos, Thailand
Lab diagnosis-wet prep of formalin-ethyl acetate concentrated stool
egg-similar to S. japonicum, but smaller, 50 - 65 micrometers by 30-55 micrometers, acid fast ?
adult- similar to S. japonicum
Pathology-Similar to S. japonicum
hepatosplenomegaly, portal venous hypertension
Taenia solium
Life cycle-cysticerci-intestine-adults
Route of infection-ingestion infected raw or poorly cooked pork; cysticercosis- ingestion of egg
Geo. – ww; Hispanic population – US Southwest
Lab diagnosis-wet prep, formalin ethyl-acetate concentration of stool; ELISA – coproantigen test
adults-scolex, strobila-proglottids; gravid proglottids = 7-13 uterine branches
eggs-thick, striated shell,6 hooked embryo, 31-43 micrometers
Pathology-diarrhea, weight loss; cysticercosis: ingestion of egg- pseudo-brain tumor, Immunoblot test,CDC
Hookworm ova
Echinostoma ilocanum
Capillaria philippinensis
Life cycle – See next slide, autoreinfection possible
route of infection – may be ingestion raw fish, raw shrimp, crabs and snails
Geo. – Philippines, Taiwan, Japan, Egypt, Iran
Lab diagnosis – formalin-ethyl acetate conc. stool
adults - 2.5 – 4.3 mm female,2.3-3.2 mm male
eggs - like Trichuris- less prominent polar plugs, striated, 36-45 micrometers
Pathology - large numbers -malabsorption, watery stools, pneumonia, heart failure
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Schistosoma intercalatum
Life cycle-eggs-miracidia-sporocysts-cercariae-adults
Route of infection-cercariae penetrate skin
Geo.-Central and Western Africa
Lab diagnosis-wet prep, of conc. stool
eggs- 140-240 micrometers, morphology similar to S. haematobium, acid fast positive- spine
adults - similar to the other schistosomes, adults in intestinal vessel walls
Pathology-Similar to S. mansoni infections
pathology confined to mesenteric-portal system – rectal bleeding, anorexia, nausea, diarrhea
Paragominus westermani ova
Heterophyes heterophyes
Life cycle-eggs-miracidia-sporocysts-rediae-cercariae-metacercariae-adults
Route of infection-ingestion of metacercariae infected raw, pickled or poorly cooked freshwater fish
Geo.-Egypt, Israel, Philippines, Japan
Lab diagnosis-wet prep of formalin ethyl acetate concentrate, stool
adult-1.5 mm by 0.4 mm ( 3 suckers-oral, ventral, genital),egg-brownish yellow, 27-30 micrometers, operculated
Pathology-abdominal pain, mucous in stool
Ascaris lumbricoides
Life cycle - direct Route of infection -contaminated soil Geo. - ww Lab diagnosis – formalin-ethyl acetate concentrate stool adults - 20 – 35 cm female, 15-31 cm male eggs – Fertilized 45-75 micrometers by 50 micrometers, unfertilized 85-95 micrometers (mcm) Pathology - asymptomatic, pneumonitis – Loeffler’s syndrome, eosinophilia, malabsorption, bowel obstruction
Opisthorchis viverini
Life cycle-eggs-miracidia-sporocysts-rediae-cercariae-metacercariae-adults
Route of infection-ingestion of metacercariae infected freshwater fish
Geo.- northern Thailand and Laos
Lab diagnosis-wet prep, conc. stool
egg-like C. sinensis, and ones listed previously, 19-29 mcm (um)
Pathology-abdominal pain, hepatomegaly, cholangitis – inflammation of bile ducts, cholecystitis – inflammation of gall bladder, obstructive jaundice
Toxocara canis
Life cycle-eggs-larvae-tissue migration
Route of infection –infective embryonated eggs in dog or cat feces
Geo. - ww
Lab diagnosis - biopsy or autopsy
larvae 0.5 mm by 20 micrometers
ELISA - serological tests
Pathology - visceral larva migrans
occular larva migrans, eosinophilia, fever
Enterobius vermicularis ova
Schistosoma mansonii
Life cycle -eggs-miracidia-( find a snail host) -sporocysts-cercariae-adults
Route of infection-cercariae penetrate skin
Geo.-West and Central Africa, Egypt, Brazil, Venezuela, West Indies, Puerto Rico
lab diagnosis-wet prep of conc. stool, Kato-Katz- 50 mg stool, glycerin soaked cellulose coverslip; hatching test – stool in water, watch for eggs hatching to miracidia, ELISA and EITB (enzyme linked immunoelectro transfer blot), acid fast positive
eggs-114-180 micrometers by 55 micrometers, large lateral spine
adults-male 1.2 cm, female 1.6 cm, in mesenteric vessels of rectum
Pathology- Acute schistosomiasis ( Katayama’s fever) : fever, headache, dysentery/bloody diarrhea, hepatomegaly
Paragominus westermani
Lung Fluke
Life cycle-eggs-miracidia-sporocysts-rediae-cercariae-metacercariae-adults
Route-ingestion of metacercariae infected uncooked crabs or crayfish
Geo.-Far East, Africa
Lab Diagnosis-sputum, wet prep of formalin-ethyl acetate conc. stool; adult-reddish brown in lungs or intestine; egg-similar to D. latum -operculated shoulders, lack knob, size 80-120 micrometers, ELISA for confirmation
Pathology-cough, chronic bronchitis, cerebral complications
Brugia malayi
Strongyloides stercoralis
rhabditaform larva
Schistosoma japonicum (S. mekongii = smaller)
Schistosoma mansonii
Dipulidium caninum
Life cycle-cysticercoid larva-intestine-adult
Route of infection-ingestion of infected dog or cat flea
Geo. - ww
Lab diagnosis-wet prep conc. stool
adults-10-70 cm. long, scolex-4 suckers, proglottids-barrel shaped
eggs-25-40 micrometers often in egg packet
Pathology-indigestion, appetite loss
Fasciolopsis buski
Life cycle-eggs-miracida-sporocysts-rediae-cercariae-metacercariae-adults
Route of infection-ingestion of metacercariae contaminated raw or undercooked plants (water chestnuts, water bamboo, water caltrops)
Geo.- South China, Taiwan, Thailand,
Vietnam, Indonesia, Malaysia
Lab diagnosis- adult, 2-7.5 cm, no nose cone, for dx-egg – large 130-140 mcm (um) ( See egg chart handout), wet prep of formalin-ethyl acetate conc.
Pathology- inflammation, mucous, hemorrhage, ulcerations - intestine
Echinococcus
Life cycle-eggs-hydatid cysts, lung, liver
Route of infection-ingestion eggs from dogs. Humans are accidental intermediate hosts
Geo. -Australia, New Zealand, Alaska, Canada, Continental U.S.
Diagnosis-history, X-rays or scans
Variety of immunoassay tests: Mayo does a IgG Ab test and reflex to Western blot test; Enzyme-linked immunoelectrotransfer blot ( ELIB), ELISA, Arc-5 double diffusion assay (DD5)
Pathology-abdomen discomfort, anaphylactic rxn, HYDATID DISEASE
Hymenolepis diminuta
Life cycle-cysticercoids-intestine-adults
Route of infection-ingestion infected arthropods (various beetles, larval fleas)
Geo.- ww
Lab diagnosis-wet prep conc. stool
adults- 20 -60 cm. long
eggs-like H. nana, except no polar filaments, 70-85/ 60-79 micrometers
Pathology-few symptoms-nausea, anorexia, diarrhea, headache
Schistosoma haemotobium (intercalatum)
Taenia ova
Hymenopelis nana
Life cycle-eggs-larvae-adults
Route of infection-ingestion of eggs; rarely infected grain beetles
Geo.-ww
Lab diagnosis-wet prep conc. stool
adults- 25 - 40 mm. ( 8- 100 mm) long,scolex-4 suckers, short rostellum with hooks, proglottids-broad
eggs- 30-47 micrometers long, oval to round, polar filaments, polar thickening
Pathology-asymptomatic, dizziness, nausea, autoinfection possible
Hookworms
Life cycle - larvae -heart, lungs, intestine
Route of infection - skin penetration by filariform larvae
Lab diagnosis – formalin-ethyl acetate conc. stool
adults - 7- 11 mm male, 10-13 mm female, 2 pair teeth (AD), 9-11 mm female (NA) cutting plates
eggs – 56-75 micrometers by 36-40 micrometers, thin shell
rhabditiform larvae - long buccal cavity, small genital primordium
Pathology:
pruritis, vesicles from erythematous papulae is called ground itch
lg. # larvae -pneumonitis
adults, intestine - diarrhea, nausea, blood loss ( stools – red to black)
chronic infections - iron deficiency
Hymenopelis dinimuta
Diphyllbothrium latum
Trichostrongylus spp.
Life cycle - larvae - intestine - adults
Route of infection -
infected larvae contaminating plant material
Geo. - ww
Lab diagnosis – formalin-ethyl acetate conc. stool
adults - like hookworm, except no distinct buccal capsule with special mouth parts
Rhabditiform larva – long buccal cavity, small genital primordium
eggs - like hookworm, 75-95 micrometers, oval, pointed ends
Pathology - asymptomatic, diarrhea, anorexia, nausea, headache, hemorrhage in intestinal tract
Taenia saginata
Life cycle-cysticerci-intestine-adults
Route of infection-ingestion infected raw or poorly cooked beef
Geo.-ww
Lab Diagnosis-wet prep, formalin ethyl-acetate concentration of stool
adults-scolex, strobila-proglottids; gravid proglottids = 15-20 uterine branches
eggs-like Taenia solium, 31-43 micrometers
Pathology-diarrhea, weight loss, appendicitis
Fasciolopsis buski
Dracunculus medinensis
Life cycle-larvae-duodenal mucosa- connective tissue
Route of infection-
ingesting infected copopods ( water fleas)
Geo. – Sudan, Ghana, and Nigeria
2017, only 20 villages have D. medinensis now according to Carter Foundation: Chad and Ethiopia, Angola and South Sudan added (2018)
Lab diagnosis - subcutaneous tissue (feet)
female - 1 meter in length, male - 2 cm.
Pathology-erythema, blister formation
Clonorchis sinensis
Enterobius vermicularis
Life cycle -direct
Route of infection – ingestion eggs: fingers, airborne eggs, fomites-soiled nightclothes, soiled bed linens
Geo. - ww
Lab diagnosis
adults - females 8 - 13 mm, males 2 - 5 mm
eggs - 50 - 60 micrometers flattened on one side
scotch tape/cellulose/cellophane method, when to take specimen- early morning/ just after waking up
can be infective to lab personnel
Pathology - pruritis, nervousness, may have eosinophilia/ Common name: pinworm
Metagonimus yokogawai
Life cycle-eggs-miracidia-sporocysts-rediae-cercariae-metacercariae-adults
Route-ingestion of infected metacercariae uncooked or pickled freshwater fish
Geo.-Japan, Indonesia, Israel, Spain, “USSR”
Lab diagnosis-wet prep of conc. stool
adult-similar to Heterophyes, Clonorchis and Opistorchis viverrini
Egg:26-28 by 16 micrometers, brown yellow, operculated
Pathology-abdominal pain, mucous, diarrhea
Brugia malayi
Life cycle-larvae-lymphatics-adults
Route of infection- Mansonia-night feeder, Anopheline ( Anopheles)-day or night feeder
Geo. - Far East, Malaysia, India, Vietnam/ B. timori –Indonesia, Timor islands
Lab diagnosis - Knott technique ( 1 mL blood + 10 mL formalin and centrifuge), thick and thin preps, take blood samples 10 PM- 4 AM
Pathology- involvement lymphatics, fever, chills,chronic condition– Elephantiasis: chronic infection, obstructed lymph node system
Trichenella spiralis
Life cycle-larvae-intestine- muscles
Route of infection - ingestion raw or undercooked pork or other infected meat ( bear, cougar, wild-boar, walrus)wild pigs in Oklahoma
Geo. - ww
Lab diagnosis
Muscle biopsy morphology: characteristic 2 ½ turn, EIA, bentonite flocculation test, IFAT(immunofluorescent antibody test), ELISA - pigs
Pathology - diarrhea, nausea, abdominal pain, general malaise, eosinophilia, muscle invasion, periorbital edema, myocarditis, death
Strongyloides stercoalis
Life cycle-larvae-vessels-lungs-intestine
Route of infection - skin penetration by filariform larvace
Geo. - ww
Lab diagnosis - formalin-ethyl acetate conc. stool
Entero-test, Baermann concentration technique, Harada – Mori filter paper ( “Mini Baermann”), Agar plate culture, IgM,IgG antibody test, ELISA
rhabditiform larvae - short and sexy
Filariform larvae can develop in intestinal tract and be infective to lab personnel
Pathology -
Asymptomatic to cutaneous -pruritis, lung- pneumonia, intestinal infections,diarrhea; super-infections -death
autoinfection - filariform larvae,
Echinostoma ilocanum
Life cycle
eggs-miracidia-sporocysts- rediae-cercariae-metacercariae-adults
Route of infection- ingestion of metacercariae infected mollusks (octopus, mussels, snails, slugs)
Geo.- Philippines, China, Thailand, Celebes
Lab diagnosis- find eggs, wet prep of formalin and ethyl acetate concentrated stool
adult-< 1 cm (10 mm) by 0.2 cm (2 mm), reddish gray
Egg: 86-116 mcm (um), morphology oval egg, operculated, yellow-brown
Pathology-asymptomatic, inflammation
Onchocerca volvulus
Life cycle-larvae-adults-subcutaneous tissue
Route of infection - Simulium spp., blackfly or buffalo gnat ( SBB mnemonic)
Geo. - Africa, Mexico, Central America, S.A.
Lab diagnosis- multiple skin snips- H and E stain, microfilariae, 220-360 mcm
Pathology- itchy nodules, may cause blindness
Wucheria bancrofti
Schistosoma haematobium
Life cycle-eggs-miracidia-sporocysts (snail host)-cercariae-adults
Route of infection-cercariae penetrate skin
Geo.-Africa, Asia minor, Cyprus- island of Turkey, South Portugal
Lab diagnosis-wet prep of urine
Egg:112-170 micrometers by 55 micrometers, acid fast negative
ELISA, enzyme-linked immunoelectro Transfer blot test (EIBT) testing
Adults- similar to other schistosomes, female in bladder vessel walls ( venous plexus)
Pathology- dysuria, hematuria, granulomas, fibrosis, ulcerations, bladder cancer
Loa loa
Life cycle-larvae-adults-skin-microfilariae
Route of infection - Chrysops spp. -mango flies or deer flies (DMC mnemonic)
Geo. - Africa
Diagnosis -
Knott technique (1 mL blood + 10 mL formalin and centrifuge), thick ( Giemsa) and thin films ( Wright-Giemsa)
Pathology - calabar swelling, eosinophilia
Fasciola hepatica
Life cycle-eggs-miracidia-sporocysts-rediae-cercariae-metacercariae-adults
Route of infection-ingestion of metacercariae infected aquatic vegetation ( watercress)
Geo.-ww, only a few cases in the U.S.
Lab diagnosis-wet prep of formalin-ethyl acetate concentrated stool
egg-similar to F. buski and E. ilocanum, 130-150 micrometers, adult, ~ 2 cm ( < 1 inch) and nose cone
ELISA test sensitive to both hepatic and intestinal infection
Pathology-biliary obstruction, cholangitis, pruritis, jaundice, hepatomegaly, eosinophils
Wucheria bancrofti
Life cycle-lymphatics-adults; blood –larvae/microfilariae
Route of infection-Culex - night feeder, Aedes - day feeder, Anopheles ( Anopheline) - day or night feeder
Geo. Africa – Culex; Pacific - Aedes , Anopheles
Lab diagnosis - Knott technique, if Africa; thick: Giemsa, thin: Wright-Giemsa, or hematoxylin stains; microfilariae size 244-296 mcm
Pathology – high fever, lymphangitis, lymphadenitis, eosinophilia
Chronic infection, obstructed lymph node system– elephantiasis;
