Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DTMH > Helminths > Flashcards

Helminths Flashcards

1
Q

Foodborne trematode (Fluke) lifecycle

A
  1. Eggs released in faeces
  2. Miracidia hatch and enter snail
  3. In snail Miracidia become sporocysts
  4. In snail - Sporocysts –> Rediae –> Cercariae
  5. Cercariae swim from snail and encyst on intermediate host
  6. Cercariae become metacercarie and are ingested by host
  7. Become adults in gut and migrate to specific organ to lay eggs (hemaphroditic reproduction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Adult trematode body parts

A

Leaf shaped
Tegument cover
oral sucker
ventral sucker
blind ending gut
reproductive organ.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name of liver flukes

A

Fasciola - hepatica/gigantica
Opisthorchis
Clonorchis - liver/biliary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name of lung fluke

A

Paragonimus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Name of gut fluke

A

Fasciolopsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which trematodes have pathogenic eggs?

A

Schistosomiasis only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Food associated with each foodborne trematode

A

Fasciola - Aquatic vegetables/ contaminated water
Opisthorchis/Clonorchis - Fish
Paragonimus - Crustaceans
Fasciolopsis - Aquatic vegetables

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Fasciola egg description

A

Egg: 120-150 um
Oval, yellow, operculum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fasciola snail

A

lymnaea truncatula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Opisthorchis egg description

A

Egg: 27-30um
Yellow, flask shaped, operculum with shoulders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Opisthorchis snail

A

Bithynia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Symptoms of foodborne trematode infection

A

Eosinophilia
GI symptoms
Urticaria
Fever
Hepatomegaly and abdominal pain
Weight loss/ malnutrition
Chronic → clinical syndrome from biliary obstruction → RUQ pain, nausea, jaundice.
Cholangiocarcinoma - more common in Opisthorchis/Clonorchis
Extra-heaptic infection → brain, lungs, heart, skin, gut.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Treatment for Trematode infections (including Schistosomiasis)

A

Praziquantel
(except Fasciola –> give Triclabendazole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Paragonimus egg description

A

Egg - 70-95um. Yellow, operculum with shoulders. Unsegmented ovum and mass of yolk cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Paragonimus snail

A

Potodoma/ Semisulcospira

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How to kill trematode eggs

A

cooking/ freezing
Temp >60, <20.
Schistosomiasis - leave water for 24hrs before use.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Schistosomiasis snails

A

Biomphalaria spp. - S. mansoni
Bulinus spp. - S. haematobium
Oncomelania spp. - S. japonicum (right)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which sex is more significantly affected by Schistosomiasis and why

A

Females due to effect on gynecological system, PID and malignancies. Increased risk of catching HIV.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Method of Schistosomiasis innoculation

A

Any water contact
- via skin
- bathing
- drinking contaminated water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

3 types of Schistosomiasis and their locations

A

S.masoni (GIT) - South America + Africa
S.haematobium (genitourinary) - Africa
S. Japanicum (GIT) - Japan/Asia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does Schistosomiasis cause disease?

A

Eggs are potents toxins which stimulate immune reaction and fibrosis. Lead to organ failures, micro-perforations and malignancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Schistosomiasis lifecycle

A
  1. Egg released in faeces (and urine in haematobium and japanicum)
  2. Eggs hatch in water releasing miracidia which enters snail
  3. In snail Sporocysts –>Cercariae
  4. Cercariae swim and penetrate human
  5. Become Schistosomulae in human and enter bloodstream
  6. Mature into adults in liver
  7. Adult worms migrate to venules of bowel/genitourinary tract and lay eggs (sexual reproduction).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Schistosomiasis lifespan

A

60 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Early Schistosomiasis symptoms

A

Cercarial dermatitis “Swimmers itch”
- Acute papular disease
- Occurs from cercariae penetration from skin
- Praziquantel not effective at this stage

Acute schistosomiasis - Katayama fever
- 2-4 weeks post exposure. A serum sickness type illness
- Urticaia, cough, abdo pain, fever.
- Need to treat with Praziquantel twice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

S. Haematobium signs/symptoms

A

Haematuria/ Haematospermia
obstructive uropathy
Increased risk of bladder cancer SCC
Cervical inflammation and cysts/papules
Vaginal bleeding/dyspaeunia
Subfertility and infertility
pulmonary granuloma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

S. mansoni signs/symptoms

A

Bowel changes
Bacteremia
Malignancies
portal hypertension
hepatosplenomegaly
Anaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Management of CNS Schistosomiasis

A

praziquantel and steroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Population management of Schistosomiasis

A
  1. population chemotherapy
  2. snail control (expensive, toxic)
  3. water and sanitation (difficult to implement – no def/urine in water).

WHO recommends in endemic countries (>10%) get annual preventative chemo from the age of 2. If the prevalence does not go down, you treat twice yearly. If the prevalence is reduced you can start to switch to a test and treat base.
→ praziquantel: very short half-life. Only adult worms are praziquantel sensitive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Schistosomiasis diagnostic techniques

A

Bladder US - characteristic appearance
Stool OCP
Urine filtration + concentration
Serology
Antigen testing - highly specific
Rectal biopsy for eggs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

S. Haematobium egg description

A

100 - 170um with terminal spine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

S. Mansoni egg description

A

100 - 170um with lateral spine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Cestode anatomy

A

Head (Scolex) - with 4 suckers and Rostellum (line of hooks)
Body segements (Proglottids) in a chain (Strobila) - with last proglottid containing the eggs
Excretory canal
Haemaphroditic reproductive organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Cestode lifecycle

A

Proglottids containing eggs
Eggs released in faeces
Ingested by intermediate host
Eggs change into onchospheres
Develops into metacestode in muscle (juvenile) (called cysterceri in taenia and plerocercoid in diphyllobothrium)
Metacestode consumed by definitive host
Metacestode matures to adult in intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Cyclophyllidea egg description (pork/beef/dwarf/hydatid tapeworms)

A

40um size. Round onchosphere containing hooks. Gelatinous outer ring with middle ring called an embryophore.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Difference between Taenia Solium and Taenia Saginata adult tape worms

A

Solium - more defined head, less uterine branches <15
Saginata - less defined head, more uterine branches 15-30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What organism causes Cysticercosis

A

The juvenile stage of Taenia Soilum (Pork Tapeworm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Cysticercosis symptoms

A

Seizure
Headaches
Visual disturbance
Confusion
Focal neurology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Cysticercosis imaging

A

rice grain calcification in thighs
hole punch brain (invaginated scolex creating a target shape is diagnostic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Neurocysticercosis treatment

A

Albendazole + Dexamethasone.
Add praziquantel in high helminth load.
Dexamethasone alone if raised ICP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Treatment/ Preventative Chemotherapy for Taenia

A

Praziquentel
Albendazole
Niclosamide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Taenia egg description

A

Round, 33 to 43 μm with a thick radially striated dark brown wall.
Inside each shell is an embryonated oncosphere with 3 pairs of hooks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Diagnostics for Taenia

A

Faecal OCP
Kato-Katz
Less used: PCR, Serology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Intermediate hosts for Diphyllobothrium

A

Copepod and Fish
(Note usually only single worm infection in human)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Treatment for Diphyllobothrium

A

Praziquentel
Niclosamide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Description of Diphyllobothrium egg

A

The egg is pale yellow
-brown and oval in shape, it measures about 65-70 μm.
There is an operculum at one end which can be difficult to see.
The egg contains a mass of granulated yolk cells surrounding an undeveloped ovum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Which Cestode does not require intermediate host

A

Dwarf Tapeworm (Hymenolepis nana) - However rodents can also be a host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Treatment for Dwarf Tapeworm (Hymenolepis nana)

A

Praziquantel

48
Q

Which Cestode is common in children

A

Dwarf Tapeworm (Hymenolepis nana)

49
Q

Description of Hymenolepis nana egg

A

Fried egg appearance with of hooks in the central oncosphere
and polar filaments within the space between the oncosphere and outer shell.

50
Q

Definitive host for Echinococcus (Hydatid)

A

Fox (multilocularis) and Dog (granulosus) (Humans are a dead-end accidental host)

51
Q

Hydatid symtpoms

A

Cysts form wherever eggs become stuck
Mainly large liver lesions. Hepatosplenomegaly.
Cysts form daughter cysts within - tumor like growth.

Pulmonary cysts (In multilocularis)
Can have fever, pain, coughing up salty liquid/haemoptysis.
Collapsed cyst have ‘water lily’ appearance on imaging.

52
Q

Hydatid treatment

A

Albendazole, Mebendazole
Praziquantel (first choice in dogs).
Surgical / PAIR.

53
Q

Hydatid subtypes

A

multilocularis (liver + pulmonary)
granulosus (liver)

54
Q

Echinococcus (Hydatid) egg description

A

round/oval shaped with thick wall and central onchosphere.

55
Q

Nematode anatomy

A

Cylindrical with a body cavity
Full GIT with anus
Lips
Teeth
Filariaeform extremeties

56
Q

Vector for Geohelminths

A

No vector

57
Q

Peak age of Trichuris infection

A

5-10 yr olds

58
Q

Peak age of Ascaris infection

A

5-10 yr olds

59
Q

Peak age of hookworm infection

A

> 30yrs old

60
Q

Ascaris life cycle

A
  1. Eggs ingested
  2. Larvae hatch and move from small intestine –> liver –> heart –> lungs –> swallowed in saliva –> small intestine
  3. Larvae mature into adults in small intestine
  4. Eggs pass in faeces

Ascaris CANNOT auto-infect –> eggs need to embryonate in soil

61
Q

Symptoms of Ascaris infection

A
  • Loefflers syndrome / Pulmonary eosinophillia - cause wheeze, dyspnoea and blood tinged sputum. Fluctuating infiltrates on CXR. Usually occurs in first infection.
  • Abdominal symptoms - associated with heavy worm burden. Can get bowel obstruction.
  • Malnutrition
  • Moving abdominal mass that changes in size.
  • Hepatobiliary and pancreatic obstruction/symptoms
  • Vit A deficiency
62
Q

Diagnostics for ascaris

A
  • Kato Katz
  • Stool OCP - need multiple
  • PCR
63
Q

What is the name if the eosinophillic lung disease caused by some Nematodes

A

Loefflers syndrome
(Ascaris and Hookworm as per their lifecycle)

64
Q

Treatment for common Geohelminths

A

All albendazole except strongyloides

Ascaris - Albendazole (or Ivermectin)
Trichuris - Albendazole (or Ivermectin) - repeat twice
Hookworm - Albendazole (NO Ivermectin unless it is a non-human species)
Strongyloides - Ivermectin (or Albendazole)

65
Q

Description of Ascaris Eggs

A

Fertile egg - oval in shape, brownish colour. 60
microns in length. Thick shell is rough/bumpy with dark staining
Decorticated egg - Occasionally the coat of the egg is not present and the egg instead has a thick smooth colourless shell.

66
Q

Trichuris lifecycle

A
  1. Eggs ingested
  2. Larvae hatch in small intestine and mature into adults
  3. Eggs passed in faeces and embryonate in soil

Cannot auto-infect - eggs embryonate in soil

67
Q

Mechanism of anaemia and GI damage in Trichuris

A

Head and neck burrows into intestines and releases enzymes - this dissolves that part of bowel which they then consume - can dissolve capillaries and cause anaemia.

68
Q

Trichuris symptoms

A

Rectal prolapse
IBD type symptoms
Bloody dysentery
Eosinophilia

69
Q

Trichuris egg description

A

light brown, lemon shaped, clear mucoid polar plugs at the end. 50um

70
Q

Hookworm lifecycle

A
  1. Eggs passed out in faeces
  2. Larvae quest (wave about) on blades of grass
  3. Cutaneous entrance into human (very itchy)
  4. bloodstream –> heart –> lungs –> sputum swallowed –> small intestine
  5. Larvae mature into adults in small intesting
71
Q

Hookworm symptoms

A

Itch + cutaneous larva migrans
Enteritis/ Abdominal pain
Eosinophillia
Anaemia, hypoproteinemia
Loeffers syndome/ pulmonary disease.

72
Q

Hookworm egg description

A

57 to 76 μm. Oval or ellipsoidal shape. Morulated appearance
Thin shell.

73
Q

Enterobius lifecycle

A
  1. Eggs ingested then hatch in small intestine
  2. Larve move to large bowel then mature into adults
  3. Adults lay eggs in perianum. Eggs also embryonate here

Can auto-infect

74
Q

Enterobius diagnostics

A

Peri-anal swab
Anal adhesive tape

75
Q

Enterobius egg description

A

Oval in shape, colourless with a clear shell and are slightly flattened on one side, eggs are about 55microns in length.

76
Q

Strongyloides lifecycle

A

Only females are parasitic - Could live their whole lives as a free living worm.

  1. Eggs hatch in soil –> Larve penetrate skin
  2. Blood –> lungs –> sputum –> intestine
  3. Larvae pass out in intestine or penetrate into bloodstream to auto infect

Adult only lives in soil - not found in human.
Asexual reproduction of larvae in body, sexual reproduction in soil.

77
Q

Disease which increases the risk of high burden Strongyloides infection

A

HTLV-1 –> due to TH2 pathology
Alcoholics
Malnutrition
High dose steroids

78
Q

Strongyloidiasis symptoms

A

Intensely itchy migratory paths - larvae currens
Sporadic diarrhoea, weight loss, abdo pain.
Pulmonary symptoms rare
Eosinophillia

79
Q

Strongyloides diagnostics

A

Multiple methods required due to poor diagnostics

Faeces (multiple techniques - formalin, baermann, koga agar, charcoal) sensitivity <50%
Sputum
Duodenal fluid
Larvae on mucosal biopsy
Serology - high false positives, false neg in immunocomprimised
Fluctuating infiltrates on CXR

80
Q

Strongyloides CXR findings

A

fluctuating infiltrates

81
Q

Strongyloides faecal findings

A

Nothing!
Larvae not seen unless specimen is fresh
Eggs not seen

82
Q

Coiled larvae in muscle

A

Trichinella

83
Q

Cause of Ocular Larva Migrans

A

Toxocara
- Human is wrong host. Dies in human body

84
Q

Strongyloides hyperinfection syndrome symptoms

A

Asthma like syndrome
Liver/biliary obstruction
Endocarditis and Endomyocardial fibrosis
Renal disease
CNS disease

85
Q

Types of Filarial Nematodes

A

Lymphatic filariasis - Wuchereria Bancrofti, Brugia Malayi, Brugia Timori
Mansonella Species
Onchocerca (river blindness)
Loa Loa (Eye worm)
Dracunculus (Guinea worm)

86
Q

Symptoms of Lymphatic filariasis

A

Develop lymphadenopathy, lymphoedema, lymphangitis and elephantitis
Acute dermatolymphangioadenitis (secondary bacterial infection)
Genital lymphoedema (chyluria, hydrocele, epididymitis, orchitis)
Chylous diarrhoea
Tropical pulmonary eosinophillia

87
Q

Lymphatic filariasis diagnostics

A

Thick blood smear
Concentration techniques
Membrane filtration
Staining techniques - identifies which species
CFA antigen detection
Brugia rapid dipstick
IgG4 test
Ultrasound of lymphatics

88
Q

Management and Treatment of lymphatic filariasis

A

Exercise, Elevation and inversion of hydroceles.

Triple therapy - Di-ethyl-Carbamazine (DEC) + Ivermectin + Albendazole.

EXCEPTION - Avoid DEC in Onchocerciasis or Loa Loa co-infection (in which case they should be treated first with doxy, or give regimen without DEC)

89
Q

Issues with Di-ethyl-Carbamazine (DEC) and Ivermectin in Filariasis

A

In onchocerciasis DEC can cause Mazotti reaction (sepsis like picture with swelling and urticaria) and eye damage

In Loa loa DEC and ivermectin can cause fatal encephalopathy

90
Q

Issue with CFA test for lymphatic filariasis

A

Highly cross reactive with Loa Loa

91
Q

Wuchereria Bancrofti mosquito vector

A

Anopheles (Africa)
Culex (S. America, Asia)
Aedes (Asia, Pacific)

92
Q

Brugia Malayi mosquito vector

A

Mansonia, Anopheles, Aedes

93
Q

Lymphatic filariasis larvae appearance (and how to tell each species apart)

A

Wuchereria Bancrofti - long empty sheath at tail, pink stained sheath
Brugia Malayi - kinked with 2 nuclei at tip, clear sheath
Mansonella - small and unsheathed
Loa loa - nuclei to top, kinked
Oncho - only found in skin snip

94
Q

Mansonella life cycle

A
  1. Bite by Culicoides (Biting Midge fly) and larvae enter
  2. Adults live in peritoneal or pleural cavity –> release microfilariae into blood stream
  3. midge takes blood meal –> Larvae mature L1 –> L3
95
Q

Mansonella larve appearance

A

small and unsheathed

96
Q

Onchocerciasis Vector

A

Black fly (Simulium)

96
Q

Onchocerciasis lifecycle

A
  1. Black fly takes blood meal - L3 larve enter
  2. Adult migrates to subcutaneous tissue and lymphnodes to live
  3. Release microfilariae to skin, lymph, tissue, blood, urine, sputum.
  4. Black fly takes blood meal - larvae mature L1 –> L3
97
Q

Symptoms of Onchocerciasis

A
  1. Ochodermatitis - itchy nodules from microfilariae
    - Highly pruritic
    - Depigmentation
    - Lizard skin
  2. Blindness from microfilariae in eye (occurs due to wolbachia secretion)
    - Sclerosing keratitis
    - Optic neuritis and optic atrophy
  3. CNS
    - nodding syndrome
    - hypopituitary
98
Q

Onchocerciasis diagnostics

A

Skin smear/ skin snip (must be bloodless to ensure you are not finding the lymphatic type)
DEC patch test
Rapid diagnostic test
Serology

99
Q

Onchocerciasis treatment

A

Doxycycline for 6 weeks followed by Ivermectin STAT (If Loa loa co-infection avoid Ivermectin)

Ivermectin also used as population control measure

100
Q

Loa Loa distrubution

A

Only found in Central Africa

101
Q

Loa Loa vector

A

Deer fly (lives in forest canopy)

102
Q

Loa loa lifecycle

A
  1. Blood meal by Deer fly –> larvae enter
  2. Adults live in subcut tissue
  3. Adults produce microfilariae which spread to all fluids (blood, urine, CSF, sputum)
  4. Fly takes blood meal, larvae mature L1–>L3
103
Q

Loa Loa Symptoms

A

Highly pruritic
Seen migrating across eye
Calabar swelling - transient migrating angioedema

Rare renal, cardiac and neuro pathology
Proteinuria and haematuria
Endomyocardial fibrosis
Meningoencephalitis
Hypereosinophilia

104
Q

Loa loa diagnostics

A

Thick film microscopy

105
Q

Loa Loa treatment

A

If <2000 microfilaria - DEC for 3 weeks
If 2000-8000 microfilaria - Ivermectin STAT then again in 1-3 months - then treat with DEC once microfilaria <2000 (beware risk of encephalopathy)
If >8000 microfilaria - Albendazole for 3 weeks then Ivermectin STAT - then treat with DEC once microfilaria <2000 (beware risk of encephalopathy)

106
Q

Loa Loa larvae description

A

sheathed and the nuclei extends to the tip of the tail, which is often bent to one side.

107
Q

Dracunculus (Guinea worm) lifecycle

A
  1. Human drinks water containing copepods
  2. Larvae released when copepods die in the stomach. Larvae mature into adults in the stomach.
  3. Female migrates to skin and discharges larvae through the skin via making a hole
  4. Larve consumed by copepod and matures

(Dog is also a host)

108
Q

Treatment/Diagnostics for Dracunculus (Guinea worm)

A

None!

Can manually extract female from the blister (submerge in water)

109
Q

What bacteria is symbiotic with filaria?

A

Wolbachia - is required by filaria to reproduce

110
Q

Concentration method for filariasis

A

Thick blood film
Membrane filtration
Knotts concentration - centrifuge blood + water

111
Q

Faecal concentration methods

A
  • direct wet mount
  • floatation technique (high specific gravity solution)
  • Kato Katz (for schistosomiasis)
  • sedimentation technique (low specific gravity solution)
112
Q

concentration technique for enterobius

A

sellotape on anus

113
Q

strongyloidiasis filtration techniques

A

Faecal charcoal
Agar plate
Filter paper

114
Q

Terms for different helminths and ova

A

All eggs are called ova

Trematodes (flukes) - larval forms are miracidia/cercariae
foodborne termatodes ova have operculum.
Cestodes (land) - eggs are oncoshperes. larval form is cyctercerci.
Cestodes (water) - eggs are granulated yolk cells, has an operculum, larvae are coracidia
Nematodes - larval form is filariae

115
Q

Which ova are embryonated in faecal sample?

A

Enterobius
Opisthorchis

DTMH (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions