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Flashcards in Parasites Deck (36):
1

Nematodes that live in human host

pinworm
whipworm
roundworm
hookworm
threadworm
Trichinella spiralis
filariasis

2

Aberrant nematodes - Can't complete life cycle in humans

Cutaneous larva migrans (Ancylostoma caninum , braziliensis)
Visceral larva migrans (Toxacara cati, canis)

3

Nematodes that cause Eosinophilic meningitis

Baylisascaris - raccoon ascaris
Angiostrongylus cantonensis

4

Round worm

Ascaris lumbricoides

5

Ascaris

- 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

6

Loffler's syndrome

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

- Ascaris
- Strongyloides stercoralis
- hookworm

7

Toxocariasis results from

Visceral larva migrans

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

Ocular toxocariasis

8

Visceral Larva Migrans


- 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

9

Whipworm

Trichuriasis

10

Trichuriasis

- 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

11

Capillariasis

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

12

Rat lungworm

Angiostrongyliasis

13

Angiostrongyliasis

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

14

Hookworm

Ancylostoma duodenale
Necator americanus

15

Ancylostoma duodenale
Necator americanus

- 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

16

Cutaneous Larva Migrans

non-human dog or cat hookworm

- Ancylostoma braziliense
- Ancyclostoma Caninum

17

Cutaneous Larva Migrans

- 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”

18

Threadworm

Strongyloides stercoralis

19

Strongyloidiasis

- 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

20

Pinworm

Enterobius vermicularis

21

Enterobius vermicularis

- 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

22

Trichinellosis


- 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

23

Scabies

- 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

24

Scabies Crustosa

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

25

Treatment for head lice? body lice?

Permethrin

Malation

26

Jigger flea

Tungiasis

27

Tungiasis

- 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

28

Botfly

Myiasis
Dermatobia hominis
Cordylobia anthropoghaga

29

Myiasis

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

30

Bed bugs

Cimex lectularius

31

Cimex lectularius

- bed bugs

bites in lines or cluster

bite at night - drawn to warmth and CO2

itching papules

dark specks on mattress seams

32

Chagas

American Trypanosomiasis
- T. cruzi

33

Sleeping sickness

African Trypanosomiasis

34

American Trypanosomiasis

- 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

35

African Trypanosomiasis

- 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

36

Leishmaniasis

- 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