Term
| What phylum do intestinal nematodes belong? |
|
Definition
|
|
Term
| What are the 2 classes in Nematoda and what are they based on? |
|
Definition
Based on phasmids (sensory organs on skin)
Secernentea (Phasmidia) and Adenophora (Aphasmidia) |
|
|
Term
| What two organisms did we study that belonged to Adenophora? |
|
Definition
| Trichuris trichura and Trichinella spiralis |
|
|
Term
| What is the common name for Trichuris trichura and why? |
|
Definition
| whipworm because it has a thin anterior and a wide posterior |
|
|
Term
| Describe the morphology of Trichuris trichura? |
|
Definition
| thin front and wider posterior (looks like a bull whip), 2" long (M and F size similar), Esophagus with stichocytes 3/5 of body) |
|
|
Term
|
Definition
| unicellular gland around the esophagus but not incorporated within the tissue |
|
|
Term
| How can you distinguish the male from the female? |
|
Definition
| really curved posterior with 1 spicule |
|
|
Term
| describe the life cycle of Trichuris trichura. |
|
Definition
| The female lays eggs-> unembryonated eggs in feces -> eggs develop in warm/moist SOIL -> the filariform (L3) after 3-6 wks-> humans ingest L3-> hatch in small intestine and burrow for 10 days ->go to lumen/LI and mature (3mos.)->Adults embed their anterior ends in mucosa of LI--> the posterior breaks free so fertilization occurs and eggs in feces |
|
|
Term
| how many eggs does the female T. trichura lay per day and how are they dispersed? |
|
Definition
In the LI the adults mature she produces 2000-6000 eggs/day
in the LI, the adults embed in the mucosa and the posterior end breaks off releasing eggs for fertilization and passage into the feces |
|
|
Term
| how long can Trichuris tricura survive? |
|
Definition
|
|
Term
| What are some of the clinical manisfestations of infection with Trichuris trichura? |
|
Definition
ANEMIA--because the parasite penetrates the intestinal walls
Abdominal pain, nausea and vomiting, diarrhea RECTAL PROLAPSE, secondary infection |
|
|
Term
| How do you diagnose infection with T. trichura? |
|
Definition
| ID eggs with the Brine floation |
|
|
Term
| Where is T. trichuris found? |
|
Definition
Worldwide (esp. tropical)
**2nd most common in the U.S. following Ascaris |
|
|
Term
| What chemotherapy is used to treat T. trichura infection |
|
Definition
|
|
Term
| What is the host immune response associated with T. trichura? |
|
Definition
| Elevated levels of IgE and IL-10 |
|
|
Term
| Why do you see elevated levels of Il-10? |
|
Definition
| Because Il-10 downregulated Th-1 cell mediated response (T-helper cell activated macrophages) so that Th-2 cell-mediated immunity can occur (activate B cells which make Ab) |
|
|
Term
| What is a the common name for Capillaria hepatica? |
|
Definition
| capillary liver worm (hepato = liver) |
|
|
Term
| what is the natural host for Capillaria hepatica? |
|
Definition
|
|
Term
| How is Capillaria hepatica transmitted? |
|
Definition
| eggs only out if the host dies and the embryonated eggs escape because the natural host is eaten by a suitable new host(man) or eat/drink something contaminated with the eggs |
|
|
Term
| where does Capillaria hepatica localize? |
|
Definition
| in the liver and the parenchyma around the liver |
|
|
Term
| What clinical manifestations arise with Capillaria hepatica and how do you diagnose this? |
|
Definition
| clinical symptoms depend on the amount of liver that is infiltrated by the parasite (ex: hepatitis and cirrhiosis); diagnose with liver biopsy or after death in an autopsy |
|
|
Term
| How do the eggs of T. trichura look? |
|
Definition
| cylindrical with 2 plugs in the ends |
|
|
Term
| What is the morphology of Trichinella spiralis? |
|
Definition
it is small and slender
Male-->posterior is curved with copulatory pseudobursae and papillae
Female->viviparous |
|
|
Term
| what does viviparous mean? |
|
Definition
| L1 larvae are in the uterus instead of eggs |
|
|
Term
| Describe the life cycle of Trichinella spiralis up to excystation in human S.I. |
|
Definition
| LARVAE AND ADULT ARE WITHIN DIFF ORGANS...adults in SI of pigs and rodents-->L1(rhabditiform) encyst in their skeletal muscle--> us humans go and eats infected pork-->in SI larvae excyst and go 4 molts to adults(4-5 days) |
|
|
Term
| What occurs after excystation of T. spiralis in the S.I. of humans? |
|
Definition
| they become adults...adults female produce 1500egg/day and L1 larvae develop-->L1 travel via the lymphatic and blood to the right side of heart, striated mucsle and encyst--> develop to L3 within nurse cells |
|
|
Term
What is the striated muscle that the L3 larvae travel to?
how long can a nurse cell survive? |
|
Definition
diaphragm, tongue, eyes, jaw
years but eventually it calcifies and dies |
|
|
Term
| What are the 3 stages of pathology for Trichinella spiralis and what do they correspond to with the parasite? |
|
Definition
| invasion (nausea vomiting similar to food poisoning because female penetratieng mucosa); migration (muscle pain, fever, hypereosinophilia b/c immune response to parasites); encystation/tissue (swelling, myocarditis, peritonitis, heart damage and death if encephalitis and brain tissue |
|
|
Term
| how do we diagnose T. spiralis? |
|
Definition
| biopsy, xenodiagnosis, skin diagnosis (Bachman intradermal reaction), slide presser, ELISA |
|
|
Term
| What is the Bachman intradermal reaction? |
|
Definition
| intradermally inject an extract of T. larvae suspended in saline...positive if there is an immediate or a delayed response |
|
|
Term
| What is the chemotherapy for T. spiralis? |
|
Definition
|
|
Term
| What is the host immune response to T. spiralis? |
|
Definition
| B cell response (in production of Ab) so if recover from initial infection you are resistant to reinfection |
|
|
Term
| What are the members of Phasmidia that we studied? |
|
Definition
| Strongyloides stercoralis, Hookworms, (creeping eruption causation: A. braziliense and A. caninum), Ascaris lumbricoides, and Enterobius vermicularis |
|
|
Term
| is the life cycle of Strongyloides stercoralis entirely parasitic? |
|
Definition
| no it can be free-living and parasitic (homogonic (only parasitic)) or (heterogonic (free-living with parasitic generations interrupting)) |
|
|
Term
| What is the morphology of Strongyloides stercoralis? |
|
Definition
| there is a free-living adult male but NO adult parasitic male; female is protandrogonous or parthenogentic; esophagus 1/3 of body, shallow buccal capsule, few eggs in uterus at once |
|
|
Term
| Describe the free-living morphology of S. stercoralis... |
|
Definition
| male:1mm and female:2mm with more eggs than the parasitic form |
|
|
Term
| What is the parasitic life cycle of S. stercoralis? |
|
Definition
| filariform penetrates host skin--> goes to R. heart via blood/lymph-->pulmonary arteries/lung/trachea/epiglottis/esophagus-->S.I where it 4th molt and is protandrogonous female-->burrow into mucose and lay embroyanted eggs-> hatch to rhabditiform and feed down to exit with feces (good conditions:SOIL; bad:autoinfection) |
|
|
Term
| What is the free-living life cycle of S. stercoralis? |
|
Definition
| rhabditiform establishes in the soil and 4 molts have adult female and male-->copulate-->eggs...(Good:ADULTS and continue free-living; BAD:L3 and infect) |
|
|
Term
| What is the pathology of S. stercoralis infection? |
|
Definition
| 3 phases: cutaneous (itch swell and L3 entrance); pulmonary (bronchial pneumonia/swelling b/c of migration); intestinal (nausea and vomiting as female embeds in mucosa) |
|
|
Term
| What is the epidemiology of S. stercoralis? |
|
Definition
| cosmopolitan; typically contract within the soil, primarily in warm climates but can be in temperate and cold |
|
|
Term
| How do you diagnose S. stercoralis? |
|
Definition
| rhabditiform or L3 are in the feces; zinc sulfate suspension; check spit for larvae |
|
|
Term
| How can you tell the difference between hookworm rhabditiform and S. stercoralis rhabditiform? |
|
Definition
S. stercoralis (short buccal capsule)
hookworm (long buccal capsule) |
|
|
Term
| What 2 hookworms cause human infection? |
|
Definition
Ancylostoma duodenale (OLD WORLD) and Necator americanus (NEW WORLD)
**eggs are indistinguishable |
|
|
Term
| What is the morphology of the hookworms? |
|
Definition
| anterior end dorsally curves; Ancylostoma have TEETH and Necator CUT PLATES |
|
|
Term
| What is the teeth arrangement of A. duodenale? A. braziliense? and A. caninum? |
|
Definition
2 pairs
1 pair
3 pairs (the CANINE has the most) |
|
|
Term
| Describe the life cycle of the hookworms |
|
Definition
| SOIL infections...sheathed L3 penetrate skin--> through blood/lymph go to right side heart/lungs/epiglottis/esophagus (3rd molt/buccal capsule)->S.I.(4th molt) adults burrow-->eggs in feces(eggs can mature in walls/autoinfection)-->SOIL rhabditiform hatches FEEDING w/long buccal capsule-->2 molts L3 |
|
|
Term
| What is the pathology of hookworms? |
|
Definition
| 3 phases: invasion(ground itch), migration(from lungs to throat hemorrhage and csue); establishment(intestinal holes--ANEMIA and loss of appetite (A. duodenale is the worst) |
|
|
Term
| How do you diagnose hookworm infection? |
|
Definition
| look at eggs in the feces |
|
|
Term
| What chemotherapy is prescribed and what is the immune response to hookworm infection? |
|
Definition
| Mebendazole for 3 days (if anemic treat anemia first); eosinophilia |
|
|
Term
| What 2 hookworms cause cutaneous larval migrans and why? |
|
Definition
| A. braziliense and A. caninum because their natural hosts are dogs and cats so they fail to pass stratum germinativum so ridges follow burrowing larvae |
|
|
Term
| how do you treat creeping eruption? |
|
Definition
| with topical ointment thiabendazole |
|
|
Term
| What is the largest nematode? |
|
Definition
| Ascaris lumbricoides (female is 40 cm and male is 30 cm) |
|
|
Term
| What is the metabolism of Ascaris lumbricoides? |
|
Definition
| anaerobic because in S.I.. has antiproteolytic enzyme to inhibit pepisn and trypsin |
|
|
Term
| What is the life cycle of Ascaris lumbricoides? |
|
Definition
| ingest the eggs->hatch in jejunem and burrow->go to LIVER (hepatic portal system), R. side of heart/lungs/epiglottis-->esophagus to SI 4th molt and sexually mature-->unfertilized (longer)and fertilized eggs(coat) in feces-> develop to infective in soil |
|
|
Term
| What is the pathology of A. lumbricoides? |
|
Definition
| 80% are asymptomatic and other symptoms follow the progression of the larvae; also affects the LIVER |
|
|
Term
| How do you diagnose A. lumbricoides? |
|
Definition
| Identify the eggs in the feces |
|
|
Term
| What 2 organisms cause visceral larval migrans and why? |
|
Definition
| Toxocara canis and Toxocara cati; because these are ascaroids with typical cat and dog hosts that accidentally infect humans (in normal host they display the life cycle of Ascaris) |
|
|
Term
| What its the life cycle of Toxocara canis and T. cati in man? |
|
Definition
| ingest egg-->hatch in S.I.->larvae in liver, lungs, eyes, brain DONT DEVELOP INTO ADULTS always rhabditiform |
|
|
Term
| So how do Toxocara spp. cause visceral migrans? |
|
Definition
| Although they typically eventually gravitate to one loaction, for weeks they migrate through the tissue and leave trail of inflammation and granulosa cells |
|
|
Term
| what are the symptoms a of visceral larval migrans? diagnose? treatment? |
|
Definition
| eosinophilia and hepatomegaly; ELISA and biopsy; infection self-limiting (corticosteroids if allergic response) |
|
|
Term
| What is the common name for Enterobius vermicularis? |
|
Definition
| the pinworm becasue the female which resides in the appendix and cecum has a long pointed tail...cosmopolitan |
|
|
Term
| What is the life cycle of the pinworm? |
|
Definition
| egg containing L3 larvae ingested-->hatches in S.I.-->mots twice and is adult in ileocecal region (MALE PASSES OUT after copulation)-->female migrates to perianal skin FULL OF EGGS--> unembryonated eggs on perianal area (STICKY)-->scratch and infect (retroinfection too) |
|
|
Term
| What is the pathology of pinworm infection? |
|
Definition
itchy butt; adult attachment in LI causes tickling sensation; appendicitis
TOXIC METABOLITES CAUSE FRETFULNESS, ANOREXIA...if females are in an abnormal area like vagina (Salpingitis) |
|
|
Term
| How do you diagnose Enterobiasis vermicularis infection? |
|
Definition
| adults in feces or swab perianal for eggs |
|
|
