Worms Flashcards
1
Q
What are three types of worms
A
- Nematodes (roundworms)
- Trematodes (flatworms)
- Cestodes (tapeworms)
2
Q
Where are nematodes found
A
- Intestines
2. Tissues
3
Q
Where are trematodes found
A
- Blood
- Liver
- Lung
- Intestinal
4
Q
Where are cestodes found
A
- Non invasive
2. Invasive
5
Q
Can adults worms reproduce outside the body
A
No, they require specific environmental conditions of the host
6
Q
What is the pre-patent period
A
Interval between infection and appearance of eggs in the stool
7
Q
Where are intestinal nematodes transmitted
A
From human to human via eggs or larvae
Faecal-oral spread
8
Q
Why is the egg or larva no infectious when first passed
A
Because it needs to undergo a period of development in the soil
9
Q
What is ascariasis
A
Infection of the intestines with nematodes
10
Q
How long is the ascaris lumbricoid
A
15-30 cm long
11
Q
How long does the ascaris lumbricoid live for
A
A year or more
12
Q
Pre-patent period of ascaris lumbricoid
A
60-75 days
13
Q
Sundrome is associated with larval migration through the lung
A
Loeffler’s syndrom e
14
Q
How long does it take for Loeffler’s syndrome to occur
A
10-14 days after infection commenced
15
Q
What is the effect of adult worm migration through the body
A
Asymptomatic
Leads to malnutrition
16
Q
How do diagnose for, infection
A
Stool microscopy for eggs
17
Q
How is worm infection treated
A
Piperazine, pyrantel
Levasimole
Mebendazole
18
Q
What does Hookworm cause
A
Ancyclostoma Duodenal
Nectar Americanus
19
Q
How does Hookworm enter the body
A
Through the soil if you’re barefooted
20
Q
Life-expectancy of hookworm
A
1-5 years
21
Q
Pre-patent period of the hookworm
A
40-100 days
22
Q
What is the most common reason for iron deficiency
A
Infection by hookworm
23
Q
Life cycle of the hookworm
A
- Filiform larvae penetrate exposed skin and migrate to the lungs
- Break out into alveoli are swallowed and develop into adults at the small intestines
- Adults attach to mucosa of duodenum and jejunum
- Females produce eggs that are passed into the soil with faeces and hatch within 24 hours
- Infectious filariform larvae develop after 5-10 days in moist soils
24
Q
Clinical features of hookworm
A
- Ground itch (At site of entry of larvae)
- Mild pulmonary symptoms due to migration
- Iron-deficiency
25
How is Hookworm treated
Iron supplements (Pyrantel, mebendazole)
26
PPP of Enterobius Vermicularis
40 days
27
Lifespan of Enterbius
56 days
28
Lifecycle of Enterobius
1. Females emerge from anus at night
2. Lays eggs around the anus and dies
3. Eggs embryonate within 4-6 hours causing scratching and eggs under fingernails
4. Formites contaminated with infective eggs
5. Ingested eggs move to duodenum where they hatch
6. Mature adults migrate to caecum
29
Four clinical features of Enterobius
1. Prunitis ani
2. Appendicitis
3. Vaginal penetration
4. Paranasal sinuses
30
Diagnosis of enterobius
Microscopy sellotape strip from perineal region
31
Treatment of enterobius
Iron supplements
32
PPP of whipworms
70-90 days
33
How long are whipworms
2-5 cm long
34
Life cycle of whipworms (Trichuris Trichuria)
1. Eggs are ingested by a suitable host
2. Immature larvae hatch from eggs when they arrive at small intestine
3. Larvae pass into large intestines
4. Larvae embedded in the mucosa via thin anterior ends, reach sexual maturity and mate
5. Trichuris app are found in the caecum, ascending colon and throughout the colon
6. Eggs passed into environment in host faeces
7. Embryonation in moist soil takes 21 days
35
Where is whipworm found
Large bowel
36
`Clinical features of whipworms
```
Asymptomatic
Co-ecists with ascaris lumbricoides
Trichuriasis
Bloody diarrhoea
Reactal prolapse
Anaemia
```
37
What does Stronglyloides stercoarlis cause
Strongyloidiasis
38
Length of Strongyloid
2mm
39
PPP of strongyloid
17-28 days
40
Life cycle of strongyloides stercoarlis
1. Filariform larvae penetrate the host's skin and migrate to lungs via blood
2. Larvae break out into alveoli, crawl over glottis and swallowed
3. Development in Jejunum
4. Eggs laid after ingestion
5. Small no. eggs laid be females whose head is burrowed in sub-mucosa of small intestines
6. Eggs hatch immediately in intestines and rhabditiform larvae passed into faces
7. Infectious filariform larvae develop in the intestines and penetrate tract or perianal skin.
41
Clinical features of Strongyloides
1. Pruritis at larval entry
2. Larval migration into lungs
3. Malabsorption with eosinophilia
4. Skin rashes due to auto-infection
5. Hyperinfection syndrome
42
What type of worm is larva migrans caused by
Toxocara canis and T cati
43
Life cycle of larva migrant
Eggs ingested and develop into larva
44
Clinical features of larva migrant
1. Children effected
| 2. Pyrexia, eosinophilia and hepatomegaly
45
How do we diagnose larva mirgans
Serology
46
How is larva migrant treated
Mebendazole
| Albendazole
47
What is Ocular Toxocariasis
1. Larvae trapped in retina
2. Granulomatous reaction takes place
3. Causes blindness and increased retinal mass
48
What condition can we accidentally diagnose a patient with ocular toxocariasis with
Retinoblastoma
49
Diagnosis of ocular toxocariasis
Serology and antigen detection in aqueous humour
50
What causes cutaneous larva migrant
1. Dog hookworms and ancyclostoma canine
51
Clinical feature so cutaneous larva migrant
Lesions at sites where larvae penetrate
52
How is cutaneous larva migrant spread
Contact with dog faeces
53
How is cutaneous larva migrant treated
Topical.systemic thiabendazole and topical cryotherapy
54
Life cycle of anisakiasis
1. Definitive host is infected when eating food
2. Adult ascarides found in stomach
3. Passed through host faeces
4. Eaten by marine animals
5. Migrates into tissues of fish, squid
55
PPP of Dracunculus medinesnsis
1 year
56
Length of Dracunculus
100 cm
57
Life cycle of Dracunculus medinesnsis
Man swallows cyclops sp in contaminated water
2. Infected larvae liberated digestive juices and penetrate the gut wall
3. Larvae develop and occupy subcutaneous tissues
4. After one year, female's head approach skin where a blister forms
5. Blister bursts and larvae leaves through discharge
58
Clinical feature of Dracunculus
1. Localised pain and urticaria at site where worm protrudes
2. Tetanus
3. Blisters
59
Diagnosis of dracunculus
Drop of water on ulcer promotes egg release
60
Treatment of Dracunculus
1. Wind out worm
| 2. Mebendazole
61
Why do we use mebendazole
Eases extraction
62
How do we prevent further infection by dracunculus
Sieve of water
63
What worm causes elephantiasis
Wuchereria Bancroftii
64
How is Wuchereria Bancroftii diagnosed
Demonstration of microfilaria in blood taken between 11 and 1 am
Serology
65
How is Wuchereria Bancroftii treated
DEC and Ivermectin
66
What is Onchocerciasis
Hanging groin, river blindness
67
Where are worms found in Loa Loa
Retina
68
Life cycle of Trichina Spirals
1. Larvae digested from muscle enter epithelial lining and becomes sexually mature
2. Male and female worms in intestinal wall mate and produce larvae
3. Newborn larvae pass through lymphatic system into the blood
4. Larvae encyst ini striated muscle
5. Infected meat is ingested by humans and carnivorous or omnivorous animals
69
What causes Trichinosis
Trichiniella Spiralis
70
Clinical features of Trichinella in muscles
1. Asymptomatic
2. GI disturbance as worms develop
3. Fever, headache, cough at 8 weeks
4. Periorbital oedema, haemorrhage
5. Splinter haemorrhage
6. Neurological signs (deafness)
7. Myocarditis
8. Pneumonitis
71
What meat is Tania Saginatum found
Beef
72
Length of Tania Saginatum
5-10 metres
73
Lifespan of tania saginatum
30 years
74
PPP of tania saginatum
12 weeks
75
Life cycle of Tania Saginatum
Caught by eating undercooked beef containing cysts
76
Clinical features of tania saginatum
Asymptomatic
| Proglottids may emerge from human anus
77
Diagnosis of tania saginatum
Stools of eggs and proglottids
78
Treatment of taenia saginatum
Niclosamide
| Praziquantel
79
Life cycle of Taenia Solium
1. Solex attaches to intetsine
2. Adult tapeworm
3. Gravid proglottid in faeces or environment
4. Onchosphere hatches and penetrates intestine wall
5. Cystercus in lungs, brain, eye or connective tissue
80
What worm causes neurocysticercosis
Pork tapeworm
81
What tapeworm causes HYDATID DISEASE
Echinococcua Granulosus - DOG
82
What is caused by Echinococcus Multilocularis
Alveococcosis
83
How can we get Diphyllobothrium latum
Fish
84
What is sparganosis
An infection caused by Diphyllobothrium Latum
85
What is the intermediate host used by flukes to spread
Snail
86
Where are flukes found
Blood
Liver
Lung
Bowel
87
Name an adult fluke
Schistosoma
88
Normal life span of a fluke
3-5 years
89
How long is an adult fluke
12 cm
90
What does Schistosoma infection cause
Katayama fever
91
What is Katayama fever
An initial immune-complex mediated illness 2-4 weeks after exposure
92
What proportion of patients infected with Schistosomia have Katayama fever
50%
93
Why is Katayama physiologically caused
T-cell mediated immune response to egg surfaces leads to cytokine release
IL-12 can suppress egg-induce pathology (mediated by INF-gamma)
Granuloma development
Fibrosis if egg laying continues
94
Where do adult S haematobium reside
Liver
95
Where do S haematobium egg migrate to
Bladder
96
What damage can S haematobium do in the bladder
1. Pseudopapillomata (granulomatous lesions)
2. Obstructive uropathy (reversible if short duration and treated)
3. Calcified bladder
4. Squamous cell bladder cancer
5. Kidney stones
97
Clinical features of S mansoni
1. Asymptomatic
2. Iron deficiency
3. Hepatosplenomegaly
4. Pseudopolyposis
5. Fibrosis of liver
6. Portal vein hypertension
98
How is Schistosomia caused
1. Serology
2. Urine (time-consuming)
3. Stool (67% positive)
4. Rectal Biopsy
5. Ultrasound
99
How is Schistosomia-caused infection treated
1. Praziquantel
2. Isoquinoline
3. Metriphonate
4. Oxamniquine
