Helminthic, Lect 8 Flashcards
(60 cards)
1
Q
Describe the shape of nematodes. Is there only one sex?
A
- Nematode = roundworm
- elongated cylindrical body that tapes at either end
- male and female
2
Q
what is generalized life cycle of nematodes
A
- eggs become larvae in environment
- larvae become adult roundworms in humans
3
Q
What is the common name of Enterobius vermicularis
A
pinworm
4
Q
describe the Enterobius vermicularis worm
A
- small 8-12 mm
- whitish
5
Q
how is Enterobius vermicularis transmitted
A
- person to person
- Or indirectly from environment
6
Q
reservoir for Enterobius vermicularis
A
humans
7
Q
what is the most common helminthic disease in US
A
Enterobius vermicularis
8
Q
describe the life cycle of Enterobius vermicularis
A
- Eggs on perianal
- eggs and larvae hatch in Small intestine
- Adults mature in colon
- Gravid female migrates to perianal to deposit eggs
9
Q
clinical presentation
- itching in anal region (Pruritis ani)
- heavy infections can lead to secondary bacterial infections, disturbed sleep, abd pain
A
E. vermicularis
10
Q
how is E. vermicularis diagnosed
A
- presence of eggs on perianal skin
- cellophane tap method
11
Q
what is the most effective means to minimize the spread of E. vermicularis
A
handwashing
12
Q
what is the transmission of Ascaris lumbricoides
A
contaminated soil ingestion
13
Q
how is Trichuris trichiura transmitted
A
contaminated soil ingestion
14
Q
what is the common name of Trichuris trichiura
A
whipworm
15
Q
Trichuris trichiura causes what disease
A
Trichuriasis
16
Q
what is the common name of Ascaris lumbricoides
A
large intestinal roundworm
17
Q
what disease does Ascaris lumbricoides cause
A
Ascariasis
18
Q
describe the life cycle of Ascaris lumbricoides
A
- Eggs ingested and larvae released to duodenum
- Larvae penetrate mucosa and travel blood -> lungs, alveoli, trachea, then oropharynx.
- Once swallowed they mature in duodenum.
- Adult worms make eggs that are infective in soil
19
Q
clinical presentation
- often asymptomatic
- worm burden determines extent of disease
- due to blockage
- pulmonary-Loeffler’s syndrome
- abd pain
A
Ascaris lumbricoides
20
Q
how is Ascaris lumbricoides diagnosed
A
eggs in stool
21
Q
what makes the eggs of Trichuris trichiura different from other worm eggs
A
egg capsules (two ends taper off)
22
Q
what is the life cycle of Trichuris trichiura
A
- Infective eggs ingested
- larvae are released in duodenum
- maturation in colon
- released eggs can mature in soil
23
Q
clinical presentation
- can be asymptomatic
- heavy infections
- frequent painful passage of stool (with associated mucus and blood)
- rectal prolapse can occur
A
Trichuris trichiura
24
Q
how is Trichuris trichiura diagnosed
A
eggs in stool
25
Name the two clinically relevant species of hookworms
* Necator americanus
* Ancylostoma duodenale
26
what seperates hookworms from other worms in regards to thier feeding habits
hookworms feed on blood from intestinal mucosa
27
how do people get hookworm infections
* eggs from feces hatch in soil
* larvae can penetrate skin
28
describe the life cycle of hookworms
* eggs hatch in soil
* larvae penetrate skin go to blood to lungs, alveoli, trachea, and oropharynx
* swallowed and mature in duodenum
* adults worms produce eggs which mature and hatch in soil
29
clinical presentation
* blood-filled, pruritic lesions can occur at the site of larval penetration ("ground itch"
* continual blood loss occurs due to feeding by adult worms
* may observe anemia
hookworm
30
Strongyloides stercoralis causes what disease
strongyloidiasis
31
describe what the Strongyloides stercoralis worm looks like
* small, termed "threadworms"
32
Strongyloides stercoralis have what two multiplication cycles
* in host (parasitic)
* in soil (free living)
33
Strongyloides stercoralis is commonly found in what areas
* tropical and subtropical area
* related to poor sanitation
34
describe the life cycle of Strongyloides stercoralis
* Infective larvae in soil penetrate the skin to blood, lungs, alveoli, oropharynx
* swallowed, get in duodenum and mature
* following reproduction, release larvae in feces
35
clinical presentation
* intestinal-diarrea, pain, constipation, malabsorption
* chronic infection lasting for years
* life threatening in patients with a defect in cell mediated immunity
Strongyloides stercoralis
36
how is Strongyloides stercoralis diagnosed
* larvae in stool sample or duodenal aspirate
37
what is the common name for trematode
flukes
38
describe the trematode worm
* flattened, leaflike body
* presence of suckers
* hermaphroditic
39
What is the common name of Clonorchis sinensis
Chinese liver fluke
40
Clonorchis sinensis causes what disease
Clonorchoriasis
41
Clonorchis sinensis adults live where in the body
biliary ducts
42
where, globally, are Clonorchis sinensis common
Far East
43
how is Clonorchis sinensis transmitted
via ingestion of larvae in raw, smoked, pickled, salt-cured, and dried fish
44
describe the life cycle of Clonorchis sinensis
1. Fish w/ larvae are eaten
2. excystation in duodenum and larvae pass to bile ducts for maturation
3. eggs released in feces that is eaten by aquatic snails which release larvae that get on fish
45
What are the two intermediate hosts and 1 definitive host of trematodes
* 2 intermediate: fish and snails
* 1 definitive: humans
46
Name the two types of tapeworms and what each's reservoir is
* Taenia solium - pork
* Taenia saginata - beef
47
describe what tapeworms (T. solium, T. saginata) look life
* Large (3-9 meters)
* posses a scolex (head structure)
48
What are the only definitive hosts of tapeworms (T. solium, saginata)
humans
49
where are eggs kept in tapeworms (**T. solium (pork); T. saginata (beef)**
Proglottids
50
describe Taenia life cycle
* Eggs ingested by cattle or pigs
* hatch in duodenum and larvae penetrate wall
* cysticerci larvae develop in muscle which is ingested by humans and develops into an adult in jejunum
* Proglottids released in feces contain eggs
51
which Taenia, when ingested by humans can cause **cysticercosis**
T. solium
52
clinical presentation
* asymptomatic, involves only one worm
* mild GI symptoms
* can become serious if infected site is eye (blindness) or brain (seizures)
T. solium
53
how is T. solium diagnosed
* eggs or proglottids in stool sample
* CT scans -\> cysticercosis
54
what is the common name of Diphyllobothrium latum
fish tapeworm
55
describe the Diphyllo. latum worm
* very LONG (12 meters) and contain thousands of proglottids
56
how are eggs released in Diphyllo. latum
* eggs are released singly, not in proglottids
57
What is the reservoir of Diphyllo. latum
* fish
* humans and other fish eating mammals harbor the adult worms
58
what is the life cycle of Diphyllo. latum
* Larvae in muscle of fish which is eaten
* adult develops in jejunum and eggs -\> feces
* eggs hatch in fresh water and larva are ingested by crustaceans
* crustaceans are ingested by fish
59
clinical characteristics
* asymptomatic
* adult worm competes with human for vitamin B12
* anemia
D. latum
60
how is D. latum diagnosed
* anemia
* presence of eggs in stool
* ID of adult worm
