Parasites

Question 1

Nematodes that live in human host

Answer 1

pinworm
whipworm
roundworm
hookworm 
threadworm 
Trichinella spiralis 
filariasis

Question 2

Aberrant nematodes - Can’t complete life cycle in humans

Answer 2

Cutaneous larva migrans (Ancylostoma caninum , braziliensis)

Visceral larva migrans (Toxacara cati, canis)

Question 3

Nematodes that cause Eosinophilic meningitis

Answer 3

Baylisascaris - raccoon ascaris

Angiostrongylus cantonensis

Question 4

Round worm

Answer 4

Ascaris lumbricoides

Question 5

Ascaris

Answer 5

• no animal reservoir
• Ingest → hatch in SI, penetrate lining into bloodstream → heart then to lung → trachea to larynx → swallowed - esophagus → develop in SI
• Loffler’s syndrome
• pulmonary infiltrates
• aberrant migration
• Dientamoeba flagilis
• inc in blood eosinophils seen - bc seen in the blood
• Ova n Parasite x3 - stool samples for 3 days
• eggs seen after 2 - 3 months
• Albendazole

Question 6

Loffler’s syndrome

Answer 6

Pneumonitis-like condition with transient pulmonary infiltrates, cough, occasional fever and peripheral blood eosinophilia

• Ascaris
• Strongyloides stercoralis
• hookworm

Question 7

Toxocariasis results from

Answer 7

Visceral larva migrans

Toxocara canis - dog
Toxocara cati - cat
ascarid Baylisascaris procyonis - raccoon

Ocular toxocariasis

Question 8

Visceral Larva Migrans

Answer 8

• Dog/cat feces contains eggs- incubation in soil - ingested by dirt eating children
• hatch in SI → liver → lung → pulmonary veins → throughout body to organs
• eggs don’t mature in humans - larvae
• Asthma-like attacks, Urticarial rashes, Enlarged liver
• Ocular toxocariasis - vision loss - use serum Elisa test to avoid INcorrect diagnosis of Retinoblastoma
• ~80% eosinophila

Question 9

Whipworm

Answer 9

Trichuriasis

Question 10

Trichuriasis

Answer 10

• Whipworm
• ingesting eggs in soil contaminated by human feces
• Larvae hatch in SI - stays in large intestine (attach to mucosa)
• Asymptomatic infections - usually diarrhea
  Rectal prolapse
• NO eosinophilia - stays in the mucosa
• Barrel shaped eggs in stool

Question 11

Capillariasis

Answer 11

• eggs confused with Trichuris
• it has striations - trichuris is smooth
• Northern philippines
• autoinfection
• death from heart failure

Question 12

Rat lungworm

Answer 12

Angiostrongyliasis

Question 13

Angiostrongyliasis

Answer 13

• rat lungworm
• Snails - intermediate hosts
• Hawaii
• Eosinophilic meningitis
• GI symptoms - mimics appendicitis
• Inc eosinophils in blood and CSF
• Patients recover completely

Question 14

Hookworm

Answer 14

Ancylostoma duodenale

Necator americanus

Question 15

Ancylostoma duodenale

Necator americanus

Answer 15

• Hookworm
• penetration of bare skin - feet - by filariform larvae (infective) in contaminated soil
• travels from venous system to the right side of the heart and then to the lungs → trachea → esophagus → SI
• mature + proliferate in SI - eggs produced – deposited to soil and forms rhabditiform (noninfective) → filariform larvae
• Loffer’s syndrome
• palpitations of the heart
• check stool for eggs
• hypochromic anemia - Oral iron therapy

Question 16

Cutaneous Larva Migrans

Answer 16

non-human dog or cat hookworm

• Ancylostoma braziliense
• Ancyclostoma Caninum

Question 17

Cutaneous Larva Migrans

Answer 17

• Ancylostoma braziliense
• Ancyclostoma Caninum
• eggs in feces - diagnostic stage
• Adults in SI of animals
• animal larvae cannot complete their normal life-cycle in the accidental human host - persists without developing further
• serpinginous, slightly elevated red track as the larvae migrate - creeping eruptions
• Moves slowly - few mm each day
• itchy papulo-pustules (eosinophil rich) in butt/back (nude sunbathers)
• “hookworm folliculitis”

Question 18

Threadworm

Answer 18

Strongyloides stercoralis

Question 19

Strongyloidiasis

Answer 19

• threadworm
• fecally transmitted - larvae (not eggs) in stool
• entry through skin - feet (cycle similar to hookworm)
• “autoinfection” - re-infection - adult in SI → egg → circulation via endogenous reinfection or skin penetration of buttocks after defecation → lungs
• Hyperinfection with dissemination - high eosinophil count
• Urticarial rash - itchy with hives
• Larva currens - diagnostic - hours to days - the rash moves rapidly: 1-2 cm/hr
• use PCR
• Ivermectin - drug of choice
• seen in patient taking high corticosteroids (in WV) has asthma

Question 20

Pinworm

Answer 20

Enterobius vermicularis

Question 21

Enterobius vermicularis

Answer 21

• pinworm
• Humans are the only host - can be transferred from fomites
• Scotch tape test
• Adolescent females - vaginal itch and UTI
• Insomnia
• Dientamoeba fragilis - flagellate - can be transmitted in eggs
• retroinfection
• if one person has it, everyone in family should be treated
• nothing to do with cleanliness
• convex/flat shape
• Pyrantel pamoate - treatment

Question 22

Trichinellosis

Answer 22

• larva ingested - uncooked pig meat/bear
• cook at 77°C ; freeze at -15°C for 30 days (arctic animals may be resistant to freezing)
• goes from stomach → SI → bloodstream → muscle, heart, CNS
• degree of illness reflects number of larva ingested
• intestinal phase - mucosal irritation
• muscle phase, larva complexes with nurse cells: Masseters, diaphragm, gastrocnemius
• muscle biopsy
• some neuro, cardiac problems
• Splinter hemorrhage under nails, bilateral periorbital edema
• Therapy: steroids + mebendazole

Question 23

Scabies

Answer 23

• found between fingers/wrists, flexor surface
• Human reservoir
• skin-skin contact; transferred from undergarments, bedclothes
• Diagnostic: two or more people in the same household complaining of nocturnal itching
• Treat family members simultaneously
• wash clothes with HOT water, dryer
• 5% permethrin, ivermectin

Question 24

Scabies Crustosa

Answer 24

• highly contagious
• immunodeficient patients in nursing homes
• misdiagnosed as psoriasis
• itching may be absent

Question 25

Treatment for head lice? body lice?

Answer 25

Permethrin Malation

Question 26

Jigger flea

Answer 26

Tungiasis

Question 27

Tungiasis

Answer 27

- Jigger flea - Central, South America, Africa, India - soles of feet, around toenails - white papule with a central black dot - prevention: wear shoes - Scratching helps expel eggs from jigger (avoid) - use scalpel/pluck out the jigger intact so no rupture occurs

Question 28

Botfly

Answer 28

Myiasis Dermatobia hominis Cordylobia anthropoghaga

Question 29

Myiasis

Answer 29

Cordylobia anthropophaga: - Africa - eggs on soil contaminated with urine, clothes laid out on ground to dry - iron clothes Dermatobia hominis: - central, south america - fly --> mosquito --> egg drops on skin - penetrates skin and burrows into the subcutaneous tissues - larvae of the “higher flies” - use petroleum jelly - helps pull the maggot out - greater risk in: demented, homeless, alcoholics, pre-existing wounds from diabetic ulcers/stasis ulcers

Question 30

Bed bugs

Answer 30

Cimex lectularius

Question 31

Cimex lectularius

Answer 31

- bed bugs bites in lines or cluster bite at night - drawn to warmth and CO2 itching papules dark specks on mattress seams

Question 32

Chagas

Answer 32

American Trypanosomiasis | - T. cruzi

Question 33

Sleeping sickness

Answer 33

African Trypanosomiasis

Question 34

American Trypanosomiasis

Answer 34

- Chagas - Mexico, Central and South America, some in US - sudden death in brazilian athletes - imported into US by visitors, immigrants from south america - T. cruzi carried by “kissing bugs” Reduviid bug - bug bites → takes dump on skin of man. Man rubs the feces with bug/infective parasite “Contamination” - Transmission via placenta, blood transfusion, organ transplant - Kissing bug lives in thatch roof, mud walls - Romana sign: UNILATERAL swelling of eyelid on one eye - Swollen nodule of the skin - Chagoma - T. cruzi - parasite in blood. T. rangeli is non-pathogenic look alike - Megacolon/esophagus/cardio (right bundle branch block) - Xenodiagnosis - Nifurtimox and benznidazole

Question 35

African Trypanosomiasis

Answer 35

- Sleeping sickness - Tsetse fly - bites - neurologic sequelae - Gambian (tropical, west/central africa, man as reservoir) vs Rhodesian (drier, east/southern africa, bushbuck, nagana) Nagana variety - Hyperexcitability → Insomnia → sleeping sickness - Winterbottom sign - nodes in the back of the neck - Gambian - Parasite found on blood/lymph from aspirated gland juice or lumbar puncture - Mott cells (eosinophilic plasma cells) in CSF - pathognomonic - Trypanosomal chancre - boil - Trypanosomal rash - skin eruption - Kerandel sign - delayed sensation to pain - Xeno-diagnosis - Treatment: early: iv suramin, iv melarsoprol

Question 36

Leishmaniasis

Answer 36

- bite of the Sand fly (phlembotomus, Lutzomyia) - Cutaneous, Mucocutaneous, Visceral - chiclero ulcer - eats away the ear: new world, cutaneous - Cutaneous: diagnosis: scrapings/needle aspiration - under the margin of the ulcer, NOT the center of the lesion - in Central, south Americas: wet. all three seen - Cutaneous seen in US - mediterranean and middle east: dry. only cutaneous and visceral - Mucocutaneous - central, south ameria: ulcerative lesions on/in nose or mouth. Tapir nose - Visceral - asia, africa, south america, mediterranean - us soldiers from gulf war: Black fever - Spleen and liver enlarge, grayish skin, lower than normal wbc - Treatment: injections of pentavalent antimonials, Amphotericin B