Worms and Prions

Question 1

transmitted by larvae penetrating through the skin, usually the foot. larvae live in soil and eat bacteria and vegitation. FILIARIFORM LARVA can penetrate the human skin (normally on the toes). travel directly to the alveoli and are coughed up and swalloed. in the small intestine they become adults when they attach and release eggs into stool.
only differ in the path to the lungs. Nectar = foot and Ancyl = intestine to lung.
clinical symptoms: diarrhea, abdominal pain, weight loss, anemia (iron deficiency). intense inching at entrance site. local growth in the lung can result in cough, infiltrate on chest X ray and eosinophilia.
diagnosis: eggs in fresh fecal sample. treat iron deficiency.

Answer 1

Necator americanus (hook worm and Ancylostoma duodenale)

Question 2

transmitted by larvae penetrating through the skin, usually the foot. larval forms live in soil and then penetrate human skin to travel to the lungs to grow. coughed up and swallowed into the small intestine to develop adult worms and lay eggs. EGGS ARE NOT PASSED IN STOOLS.
hatch in three ways: (1) autoinfection - penetrate intestine and go back to the lungs. (2) Direct cycle - larvae pass out in feces, live in soil, and infect another person. (3) Indirect cycle - sexual cycle where larvae pass in stool and while in soil mate and re-infect a human.
clinical symptoms: may complain of vomitting, abdominal bloating, diarrhea, anemia, ad weight loss. (similar to hookworm = purititic rash, lung symptoms, and eosinophilia.
diagnosis: identifying larvae in feces. ENTEROTEST - long mylon sting in swallowed and later pulled out mouth with larvae.

Answer 2

Strongyloides stercoralis

Question 3

acquired by the ingestion of encysted larvae in the muscle (pork meat). cyst mature and male leave in feces. females penetrate into intestinal mucosa producing thousands of larvae. larvae can spread to organs and skeletal ms, where they can become encysted and stay for decades.
clinical manifestation: abdominal pain, diarrhea, fever. fever and muscles aches a week later when larve mature. can be fatal is larvae invade the heart ms.
diagnosis: serologic tests ro muscle biopsy. high WBC due to ms invasion. ince eosinophils. high CPK if muscle is invaded.
prevent by cooking and freezing pork.

Answer 3

Trichinella spiralis

Question 4

transmitted by ingestion of eggs. NO filariform larvae, NO transient cross across the intestinal wall, NO lung involvment, NO raise in Eosiniphils. Slow life cycle. ingest the eggs and they migrate to the cecum. mature adult releases eggs and there is no autoinfection. must incubate in soil 3-6 weeks to become infective.
clinical manifestations: abdominal pain, diarrhea.
diagnosis: eggs in stool that look like footballs with bumps on each end. adults look like a bull whip.

Answer 4

Trichuris trichiura (whip worm)

Question 5

transmitted by ingestion of eggs. SIMPLE LIFE CYCLE. eggs are ingested and mature in the cecum and ascending large intestine. female migrates to the perianal area (at night) and leave eggs that become infectious in 4-6 hrs. extreme perianal itching.
TAPE TEST or unaided crawling.

Answer 5

Enterobius vermicularis (hook-warm)

Question 6

describe round worms

Answer 6

Arthropod vectors

Filariae = round worm family. grow in lymphatics and give birth to microfilariae (dont lay eggs!).

Question 7

Location: Africa, central and south america, transmitted by BLACK FLIES. larvae are found coiled into fibrous nodules in the skin and subcutaneous tissue. then they migrate to the dermis and conective tissue.

clinical: pruritic skin rash with darkend pigmentation. skin is thicker with the formation of a papular rash = intraepithelial granulomas. they’re thick, scaly, and dry (“lizard skin”). can move to the eyes causing blindness - RIVER BLINDNESS.
diagnosis: microfilariae in superficial skin biopsies ro adult worms in nodules. microfilariae can be often seen in the eye (cornea and anterioir chamber) by slit lamp examination

Answer 7

Onchocerca volvulus

I VER with IVERmectin

Question 8

is endemic to the Malay Peninsula and is often seen in southwest Asis. transmitted by mosquito. microfilarie spread to lymph and cause obstruction when a mature male.
clinical: febrile episodes, headaches, inguinal lymph nodes swollen. swollon extremities with chronic disfiguration.
Diagnosis: blood should be drawn at night due to Nocternal periodicity. and can be made with pos titers via immunoflourescence.

Answer 8

Wuchereria bancrofti/Brugia malayi

Question 9

Africa = Ghana and Sudan. restict the use of public water. thats how they spread. prevention is the basic treatment. larvze move from the intestine to the subcutaneous tissue where adults grow and mate. female can be 100cm. migrates to the skin and exposes uterus and when in contact with water, larvae are released,
allergic symptoms, nauses, vomitting, hives ad breathlessness during larval release.
get ride of worms by wrapping them around a stick to twist it out.

Answer 9

Dracunculus medinesis (Guinea worm)

Question 10

creeping eruptions due to the intensely prutitis, migratory skin infection commonly occuring in the southeastern US. the larvae of dog and car hook worms penetrate the skin and migrate beneth the epidermis. they move a few centimeters per day. raised, red, itchy rach that moves with the advancing larvaer. diagnosis from biopsy of the advancing portion of the rash.

Answer 10

Cutaneous larval migrans

Question 11

pneumonic phase of nematodes in humans?

Answer 11

larvae develop in the lungs and then coughed up and swallowed

Question 12

Schistosomes (blood flukes)
-acquired from freshwater, very common worldwide (second only to malaria). Hosts are snails. Cercariae penetrate through intact skin.
Reside in veins associated with GI tract/liver or bladder. Geographic Considerations?

Answer 12

cercariae = larva.

Eastern Asia = S. Japonicum
South American and Africa = A. mansoni
S. haematobium = Africs

Question 13

porck tape worm. undercooked pork. ingestion of eggs = cysticercosis. heads with HOOK. 2-8 meters long. feces with eggs, CT scan or brain or muscle. Eosinophilia with cysticercosis. first adult seizure.

Answer 13

Taenia solium

Question 14

BEEF WORM. undercooked beef, heads with SUCKERS, NO HOOKS. fecal exam with eggs or gravid proglottids.

Answer 14

Taenia saginata

Question 15

FISH WORM. can growm to length in 45 min, WITHIN EYES or gravis proglottids. B12 deficiency leading to anemia.

Answer 15

Diphyllobothrium latum

Question 16

DWARF TAPEWORM - adults grow ito 15-55mm. eggs are infectious. fecal exam for eggs, proglottids are too small to see. AUTOINFECTION.

Answer 16

Hymenolepsis nana

Question 17

Hydatid cysts form most often in the liver and lung. enlarge over 1-20 years producing symptioms from the mass. CT or ultrasouns, serology.

PAIR
percutaneous
Aspiration
Infusion of sclocidal agent
Reaspiration

surgery to remove the cysts. must kill fluid first. leaking of the cyst can cause an allergic reaction.

Answer 17

Extraintestinal tapeworm
Echinococcus granulosus (hydatid disease)

Question 18

Characteristics of Prion disease?

Answer 18

Characterisitcs:
long incubation (months to years)
gradual increase in severity leading to death within months. no host immune responce. no inflammatory process within the brain.
Neuopathological findings may include:
Macro = normal,
Micro = spongiform changes (small, apparently empty, microscopic vacules of varing nueral tissue), neural loss, amyloid plaques, with accumulation og prion protin (PrP)

Question 19

Hypothesis with prion disease? etiologies?

Answer 19

Protein hypothesis and viral hypothesis. protein is more excepted. PRP is a normal gene on Chr 20. protien can activate that gene. PRPc (cellular) in the brain. PRPsc scrapie) is the diseased isoform.
post translationg change of PRPc to PRPsc.

etiologies:
inherited the PRP mutation
Infectious: exogenous PRPsc
Sporatic: unknown reason for rare de novo mutation leading to the conformational change.

eating contaiminated neural tissue (MAD COW) can cause the disease in humans.

Question 20

Clinical presentation: 
rapidly progressive dementia
psyuuchiatic symptoms
cerebellar symptoms (ataxia)
Involuntary movements
ultimatley a fatal disease.

Answer 20

Prion disease

Question 21

Diagnosis of prion disease

Answer 21

Diagnosis:
Gold standard = immunostaining for PRPsc in brain tissue
CSF is normal except elevated proteins. tau protein has high-sensitivity and specificity for vCJD
neuro imaging
serial EEG
PRPscin lymphoreticular tissue with vCJD. tonsil biopsy too.

Question 22

transmitted by ingestion of eggs. infection from the tropics and mountains in souther US. contaiminated food with eggs. larvae grow in alveoli, coughed up, and ingested to the stomach. when in the small intestine adults will produce eggs to be secreted in the stool. infection can be mild ot asymptomatic. heavy infections can cause abdominal cramping. adult worms can enter the bile ducts, gallbladder, appendix, and liver. children with heavy worm loads my suffer malnutrition due to competing for food. when in lung may have a deep cough, pulmonary infiltrates on chest X-ray, and high eosinophil count in the blood and sputum.
diagnosis is made from identification of eggs in feces. larvae in sputum, peripheral blood smear will have inc eosinophils.

Answer 22

Acaris Lumpricoides