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Parasitology > GIT Helminths > Flashcards

GIT Helminths Flashcards

Necator americanus, Strongyloides stercolaris, Trichuris trichiura, Ascaris lumbroides, Enterobius vermicularis

1
Q

Anatomy of GIT

A 
Mouth
Oesophagus 
Stomach 
Small intestines - duodenum, jejenum
Large inestines - ascending, transverse, descending 
Rectum, anus
Liver, gall bladder, pancreas
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2
Q

Trematodes

A

Flukes

  • Classify depending on location found
  • – Blood flukes, liver flukes, lung flukes, intestinal flukes
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3
Q

Intestinal cestodes

A 
Tapeworms 
-- Species: 
Taenia solium 
T. saginata 
Diphyllobothrium 
Hymenolepis 
Dipylidium caninum 
Echinococcus 
Spirometra 
Taenia multiceps
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4
Q

Nematodes

A

Ascaris lumbricoides - ascariasis
Trichuris trichuria - whipworm - trichuriasis
Necator americanus + Ancylostoma duodenale - hookworms
Enterobius vermicularis - pinworm - entrobiasis
Strongyloides stercoralis - strongyloidiasis

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5
Q

Ascariasis - life cycle

A

Begins with eggs maturing in soil
human ingests eggs via food/drink/contaminated hands
Larvae burrow out of GI lumen into venous blood -> right heart -> lungs
Mature and live in lungs until coughed up
Then goes back to GIT

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6
Q

Why do ascaris prefer the lungs to develop?

A

Maybe higher O2 conc’n in lungs compared to GIT

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7
Q

Definitive host of acaris

A

humans; they mate there reaching final form

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8
Q

Why do they prefer hatching in soil?

A

Body temp too high

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9
Q

Risk factors - Ascariasis

A

Poor sanitation

Warm weather

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10
Q

Early illness ascariasis - symptoms due to

A
  • lung migration
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11
Q

Late illness ascariasis - symptoms due to

A
  • worm burden
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12
Q

Early infection - Eosinophils levels

A

When the body recognizes larvae moving in the blood, Eosinophilic levels rise in blood and lung tissue.

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13
Q

IgE - mediator of immune response causes what symptoms

A

–immune response causes transient cough, wheezing, chest pain, hemoptysis

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14
Q

Sputum sample

A

–Eosinophils in areas they shouldn’t be in
or
–Charcot-Leyden Crystals (sign of high burden of Eosinophils)

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15
Q

Late infection of ascaris is often asymptomatic (T/F)

A

True

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16
Q

Diagnosis of Ascariasis

A

Colonoscopy findings, feces observation (OAP)

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17
Q

Symptoms - Ascariasis

A

nausea
Abd pain
Diarrhoea

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18
Q

Ascariasis fertilized eggs distinguished from unfertilized eggs, how?

A

They are round rather than elongated and have a thicker cell wall.

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19
Q

Ascaris - fertilile egg

A

Round/ovoidal with thick shell; mammilated coat

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20
Q

Ascaris - infertile egg

A

Elongated, triangular, kidney shaped; thin shell; mammilated covering missing

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21
Q

Complications

A

Bowel blockage - heavy infection
Worms crawling to biliary tree - blocks biliary flow = biliary sepsis
Worms moving to peritoneum carrying fecal content - peritonitis

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22
Q

Treatment- Ascariasis

A

Albendazole, mebendazole, pyrantel

Surgery for obstruction

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23
Q

Trichuriasis - pathogen and egg shape

A

Trichuris trichiura

Long void, two clear bulbs on each end, football shaped

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24
Q

Trichuriasis transmission and complication

A

Soil; fecal oral

Rectal prolapse - occurs when rectum loses attachment to internal body and protrudes from anus

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25
Trichuriasis pathogenesis
1. eggs are ingested and travel to the intestines 2. the larvae emerge and take up residence 3. They become either male or female adults 4. Adult worm resembles a bull whip - one side thick and other thin - thin side burrows into gut - fat end remains out in gut 5. Eggs passed into stool
26
Eggs sit in soil for 3-5 wks for maturation to become fertile (T/F)
True
27
Risk factors and treatment - Trichuriasis
Poor sanitation Warm weather to nurture eggs -Mebendazole + Albendazole
28
Clinical presentation - Trichuriasis -Illness severity correlates with worm burden (T/F)
True
29
Light infection symptoms - Trichuriasis
-Asymptomatic
30
Moderate infection symptoms - Trichuriasis
- Nausea - Abd pain - Diarrhoea
31
Heavy infection - symptoms
- anemia, growth stunting, rectal prolapse (due to tenesmus-irritation of worms)
32
Host may/may not respond to infection (T/F)
True
33
Host may not respond to infection due to?
Heads of worm buried in mucosa
34
Antigen presentation occurs where?
Antigen persentation to gut associated lymphatic tissue (GALT)
35
Eosinophilia usually mild so immunization is unclear in Trichuriasis (T/F)
True
36
Life cycle - hookworms
Burrow into epidermis until they penetrate dermis Move to vascular supply -> heart -> lungs Maturation in lungs (same as ascaris) When coughed up -> stomach -> jejunum (SI) - reproduction Eggs must exit body to complete life cycle
37
Virulence factors - hookworms
Mouthparts to hold on to intestines - keeps from swept away with feces and sucks blood
38
Transmission - hookworms
Fecal, soil, skin; not oral
39
Anthroponosis in dogs
Related to dog hookworm
40
Unholy trinity - lung issues
- Overlaps Trichuris, Ascaris, hookworm
41
Human hookworm
Necator americanus
42
Risk factors - Necator
- poor sanitation - warm weather - bare skin - Impoverished persons affected
43
When does high worm burden occur in hookworm infections?
Penetration to GIT in late infection
44
Skin migration in hookworms referred to as?
Cutaneous Larva migrans
45
Larva migrans
Worms moving through the skin for a few days | IgE comes to respond to invaders - histamine released to local tissues, causes itchiness = secondary infection
46
IgE response in local tissues causes what symptoms in hookworm infection?
Transient cough, wheezing, chest pain, hemoptysis - increase in eosinophils
47
Clinical manifestations - hookworm infection
CLM rash Loeffler's GI upset Iron deficiency anemia
48
Dog hookworm species
Ancylostoma brazilliense
49
Ancylostoma life cycle
Dog poops depositing eggs | Walking by and larvae burrow in skin
50
Clinical manifestation - Ancylostoma
Creeping eruption - itchy response, IgE response | Won't penetrate - will remain under skin until death
51
Diagnosis of hookwoms
Ova and Parasite test - eggs are smooth, lobes of embryo inside
52
Treatment - Necator americanus
Albendazole Ivermectin Both oral and well absorbed - to tissues
53
Late infection treatment - hookworms
Antihistamines for itching | Iron repletion for growth restriction
54
Prevention - hookworms
Shoes
55
Are vaccines possible - hookworms?
Possible, since there is tissue migration can do humoral response
56
Strongyloidiasis etiology
Strongyloides stercoralis
57
Strongyloides stercolaris - life cycle
1. Enters via skin - dermis penetration 2. Moves to heart -> lungs -> respiratory tree -> oesophagus -> intestine 3. Maturation in duodenum/bronchus 4. Eggs hatch to larvae -> move to bowel lumen 5. Larvae metamorphose in bowel - feces - to filiform larvae (infectious larvae)
58
New host infection occurs via which route?
Larvae passed in feces
59
Autoinfection
primary host infection in away that completes life cycle
60
Autoinfection occurs in strongyloides how?
Stays on skin/rectal area when wiping | Infectious larvae in stool penetrates the rectal wall
61
How are strongyloides different from other roundworms?
They have a free living cycle in soil and can also complete their cycle in humans
62
Risk factors - strongyloides
Poor sanitation Warm weather Bare skin/ direct contact with feces - fatal in immunocompromised + newborns
63
Clinical features - early illness - Strongyloides
Skin and lung migration
64
Clinical features - late illness - Strongyloides
Immunosuppression = high worm burden
65
Skin migration
Rash (Larva currens) - pruritic, IgE mediated | Infection shorter than cutaneous migrans
66
Lung migration pathogenesis
Larvae reaches lungs IgE migration to lungs - causes immune response which leads to transient cough, wheezing, chest pain, hemoptysis ---Eosinophil in blood/ Charcot-Leyden
67
Late infection symptoms - Strongyloides
Nausea Abd pain Diarrhea
68
Hyperinfection - causation
- if autoinfection causes strongyloides to persist; can occur for yrs/decades - Causes decrease in T lymphocytes -depletion of T lymphocytes will cause lowered immunity which leads to hyperinfection
69
Hyperinfection risk factors
-immunosuppresion heavy - chemo, organ transplant
70
Hyperinfection - clinical features
(worms reproduce faster due to low immune response and migrate to ectopic sites carrying fecal bacteria from gut) - causes infection from bacteria in blood = sepsis - death
71
Chronic auto-infection symptoms
Larva currens on exam - butt cheeks | - blood test +ve high eosinophils
72
Diagnosis - Strongyloides early infection
- biopsy of bowel wall = worms - OAP - false negatives, worms few in num hard to find - Serology - ELISA - good if patient has good immune system (cause worms go to blood)
73
Hyperinfection - Diagnosis
GNR in blood, low eosinophils Larvae in sputum - lung migration Serology - too late to help - long waiting time
74
Treatment - early infection
Ivermectin preferred over albendazole | Treat patient before immunosuppression
75
Treatment - hyperinfection
Add ivermectin + albendazole Reduce immunesuppression Broad spectrum antibiotics for sepsis
76
Prevention - Strongyloides
Wear shoes
77
Good indicators of strongyloides hyperinfection - symptoms
Pneumonia + sepsis
78
Enterobius vermicularis
Pinworm
79
Transmission - Enterobius vermicularis
- Food contaminated with eggs - Eggs on skin/fingers - Eggs in bedding/underwear
80
Anthroponosis
Pathogen only lives in humans, includes enterobius
81
Eggs visualization
small, flat on one side, dome on the other
82
Life cycle - pinworm
1. when consumed stomach juices allow them to hatch 2. cecum - where they have reached maturiy 3. Female fertilized and moves to rectum = crawl out through anus along perianal skin and leave goo behind which is microscopic - sticky eggs are irritating so it becomes itchy
83
Pinworms must exit body to complete life cycle
Yes they move to perianal space
84
Children are affected by pinworm more often (T/F)
True
85
Symptoms
Often asymptomatic Itchy butt/pruritis ani in heavy infection Young kids symptoms Irritability, wet beds, insomnia
86
Perianal rash in kids can occur due to
Perianal rash, - can be due to eggs themsevles/ due to secondary infection /superinfection - on the superficial area
87
Vaginal discharge occurs why?
Migration of worms to vagina
88
Immune response - pinworms
None - since they dont invade tissue - hides from GALT | -Eosinophil - no response - no vaccine
89
Standard sign of pinworms
Pruritis ani
90
Diagnosis
Cellophane tape prep in morning Fingernail scrapings Adult female can be seen outside perianal area at night
91
Treatment - enterobius
Albendazole - penetrates tissue Pyrantel pamoate - stays in gut Both highly effective
92
Prevention - enterobius
Keep hands clean

Parasitology (10 decks)

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