Brainscape's Knowledge GenomeTM

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


See full index

Management of Infection > Lecture 3B - Worms > Flashcards

Lecture 3B - Worms Flashcards

1
Q

What are worms?

A

highly developed multicellular organisms which generally replicate outside of the human host (through the shedding of eggs typically in faeces)

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

What do worms that are parasitic in humans lead to?

A

great suffering on a global scale because they are hard to treat

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

Classes of worms?

A

roundworms (4,500 million infections globally)

tapeworms (175 million)

trematodes (250 million)

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

What do worms rely on the body for?

A

nutrition of the parasite at early stages of its life cycle

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

Where does the ascaris roundworm have an adult stage?

A

in the gut, which can shed eggs into the faeces

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

What happens to the ascaris worm eggs outside the gut?

A

they are fertilised and the embryonic form of the parasite is reingested

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

Where do the larvae of the ascaris worm go?

A

they hatch from the eggs inside the gut, they break through the gut wall and migrate through the blood stream to the lungs

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

What happens to the larvae once in the lungs?

A

the developing larvae are coughed up and swallowed, gain to reinfect the gut and grow to adult hood

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

Why do worms go to the lungs?

A

because of the very fine capillaries

they go via the hepatic portal vein because the blood from the gut goes there

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

What are roundworms known as?

A

nematodes

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

Intestinal nematodes?

A

often cause diarrhoea, itch and anaemia

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

How are intestinal nematodes acquired?

A

orally or through skin, transmitted by faeces

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

Strongyloids?

A

threadworm - can migrate to lungs

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

Trichuris?

A

whipworm - transmitted via the soil, if human faeces is used asa fertiliser and food isnt cleaned

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

Ascaris?

A

roundworm

migrates to liver, heart, lung and back to gut

some patients carry 1000+ worms, females worms can lay 200,000 eggs daily

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

Enterobius?

A

pinworm

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

Necator and ancylostoma?

A

hookworms - larvae can penetrate bare feet

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

Trichostrongylus?

A

mild intestinal symptoms but very common

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

Extraintestinal nematodes?

A

trichinella (trichinosis) and dracunulus (guinea worm)

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

Trichinella?

A

present in infectedmear, cysts in muscle

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

Dracunculus?

A

can grow up to one metre long in the skin

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

Larva migrans?

A

disease eruption can occur in a variety of tissues when invaded by larvae of roundworms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are nemathelminthes?

A

roundworms which include the nematodes - includes roundworms like ascaris

24
Q

What are platyhelminthes?

A

all flatworms

25
Q

What are platyhelminthes divided into?

A

the cestoda (tapeworms like taenia)

the trematodes (flukes like sheep liver fluke)

26
Q

What are extraintestinal nematodes?

A

thread like wormsn, 200-300microns long when adult and about one red blood cell wide when transmitted by an insect vector

27
Q

What stage do extraintesinal nematodes have?

A

an insect stage in which the larvae develops

28
Q

Where do injected larvae go

A

to specific tissues such as skin, lungs, lymphatics

- here they mature to adults (forming skin nodules)

29
Q

What happens once extraintestnal nematodes mature?

A

after a sexual stage they produce microfilariae

30
Q

What do the microfilariae do?

A

migrate to particular tissues depending upon the species involved, giving rise to pathogenesis as they mature to microlarval stage?

31
Q

Wucheria bancrofti?

A

microfilarial blockage of lymphatic ducts leading to elephantiases

affects over 120 million people throughout the tropics and subtropics

32
Q

Onchocerca volvulus?

A

larval migration to the eye causing river blindess

300 million at risk in sub saharan africa, parts of arabia and S america

27 million cases annually, 300,00 cases of permanent blindess

33
Q

Treatment for onchocerca?

A

Ivermectin, but needs to be continued for 10-15 years as it only kills the larvae and not adult worms

evidence that doxycycline can kill adult worms

34
Q

What is elephentiasis?

A

legs swell to a huge extent because the fluid cannot return due to blocked ducts

35
Q

Treatment for wucheria?

A

Diethylcarbamazine can kill all forms of the worms in around 2 weeks

treatment more effective when used with ivermectin

36
Q

Where do adult flukes mainly reside?

A

in blood (veins), gut or lungs

37
Q

Life cycle of flukes?

A

complex, but essentially adult flukes produce eggs which become encysted when present in the liver or other tissues (bladder, lung, CNS)

38
Q

What does reaction to presence of fluke eggs cause?

A

pathological changes in the infected tissue

39
Q

What happens in schistosomiasis?

A

eggs are released via faeces or urine into water, where the parasite is taken up by snails, the snail then releases a form of larva (cercaria) which can penetrate skin and infect persons coming into contact with water

40
Q

Schistostoma mansoni?

A

FLUKE

encysted eggs present in the liver can cause fatal cirrhosis

41
Q

Fasciola hepatica?

A

sheep liver fluke - can also infect humans

42
Q

Where is schistosomiasis most common?

A

transmitted by water

most prevalent in agriculture and fishing communities fro affected areas

43
Q

What can infestation with schistosomiasis cause?

A

a variety of complications, mainly gut and urinogenital - but also include seizures, anaemia and renal failure

praziquantel is the preferred treatment

44
Q

What can flukes penetrate?

A

the colon wall and make their way via the hepatic portal vein to the liver

45
Q

what does infestation with fasciola cause?

A

jaundice amongst a variety of complications

causes cirrhosis and liver damage = jaundice

46
Q

Tapeworms?

A

cestodes

flat segmented worms containing both male and female organs

47
Q

Taenia solium?

A

pork tapeworm

pigs become infected by swallowing eggs present in the human faeces

48
Q

What happens when humans ingest the uncooked pork?

A

the ingested eggs release larvae in the duodenum

the larvae are carried in the blood to muscle, CNS and the eye where get encysted and cause pain and neurological problems such as epilepsy

49
Q

Where is taenia a problem?

A

Mexico, latin america and other countries in the southern hemisphere with uncooked meat

50
Q

Epinococcus granulosus?

A

adult worms are found in the guts of dogs

they produce eggs (excreted in faeces) which can remain viable for up to a year

51
Q

Where can epinococcus eggs be found?

A

in dog fur, on dog leads and on the tongues of infected dogs

52
Q

What happens when epinococcus eggs are ingested?

A

they release larvae when in the gut and larval cysts can then be found in the liver and other tissues of humans and sheep

53
Q

Cysts of epinococcus?

A

can be quite large (litres of fluid) and contain many immature larvae, causing major problems when they burst

54
Q

How big are cestodes?

A

a few millimetres to 25 metres

55
Q

What can the larval form of cestodes penetrate?

A

the gut wall and migrate to any internal tissues

typicall they affect the lungs and liver but can also affect the CNS

56
Q

What can infected meat contain?

A

hundreds of larval cysts (taenia solium) which can infect consumers when eaten

the mouth of taenia solium hook into the gut wall so as to anchor the tapeworm

Management of Infection (36 decks)

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