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Flashcards in Helminth Infections Deck (52)
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1
Q

What are helminths?

A

Worms

2
Q

What can helminths be divided into?

A
  • Roundworms (nematodes)
  • Flatworms (platyhelminths)
3
Q

How can the helminth life cycle be generalised?

A
  1. Ova
  2. Larvae
  3. Adults which then produce ova
4
Q

Which stage of the helminth life cycle is environmentally resistant?

A

Ova

5
Q

How are ova able to infect humans?

A

Through ingestion of food contaminated by excrement, direct contant, or ingestion of contaminated meat

6
Q

What might ova infection result in?

A

Inflammatory response

7
Q

What is the migratory part of the helminth life cycle?

A

Larvae

8
Q

What do larvae allow?

A

Helminths to travel around the human to the correct area

9
Q

What do adult helminths produce?

A

Eggs

10
Q

How long can helminths persist for?

A

Many years

11
Q

What shape are round-worms in cross-section?

A

Circular

12
Q

How can flatworms be further classified?

A
  • Tapeworms
  • Flukes
13
Q

How do tapeworms and flukes differ?

A

Tapeworms are segmented, flukes are not

14
Q

Give 4 types of helminths that can cause gut or tissue infections

A
  • Ascaris
  • Schistosomiasis
  • Echinococcus
  • Enterobius vermicularis
15
Q

What kind of helminths are ascaris?

A

Roundworms

16
Q

What do ascaris cause?

A

Intestinal infection in humans

17
Q

How are ascaris ova passed?

A

In human faeces

18
Q

How long can ascaris survive in human faeces?

A

Weeks

19
Q

Where do ascaris ova hatch once ingested in contaminated foods?

A

In the gut

20
Q

What happens to ascaris once hatched in the gut?

A

Its larvae migrate to the intestine, or can enter the lung or liver

21
Q

What is the main pathology of ascaris?

A

Cause bowel obstruction

Can also cause anaemia

22
Q

How can ascaris cause anaemia?

A

From when they take blood

23
Q

How is ascaris diagnosed?

A

Stool sample containing the ova

24
Q

What is schistosomiasis caused by?

A

Schistosoma

25
Q

What kind of helminths are schistosomas?

A

Flukes

26
Q

What do schistosomas cause?

A

Chronic infections in the hepatic, intestinal, and vesicle venous system

27
Q

How is schistosoma transmitted?

A

Its ova are passed out of the intestines of infected humans in stool before its larvae infect snails. After development of the snail, the larvae penetrate human skin and travel to the mesenteric, vesical plexus etc., depending on the species

28
Q

What happens once the schistosoma larvae are in their desired location?

A

The adult will lay her eggs

29
Q

What does schistosomiasis cause?

A
  • Fever
  • Hepatospleenomegaly
  • Skin rashes
  • Dysentry
  • Can affect lungs, bladder, or brain
30
Q

How is schistosomiasis diagnosed?

A

Ova in a stool sample

31
Q

What kind of helminths are echinococcus?

A

Tapeworms

32
Q

What is the normal host for enchinococcus?

A

Dogs and sheep, but can infect humans as accidental hosts

33
Q

How is enchinococcus transmitted?

A

The ova are passed in the animal faeces and ingested accidentally by the individual

34
Q

What does enchinococcus cause?

A

Cysts to develop in the liver and lung, causing hydatid disease

35
Q

What animals are enterobius vermicularis found in?

A

Only humans

36
Q

Where do enterobius vermicularis live?

A

In the large intestine

37
Q

How does enterobius vermicularis persist?

A

The females pass out of the anus at night to lay eggs on the perianal skin. The subsequent perianal itching will result in contamination of the fingers with the larvae, which can then cause spread to other individuals and ingested to develop in the intestine, starting a new life cycle

38
Q

What can insects act as?

A

Vectors for some disease causing organisms

39
Q

What is African sleeping sickness caused by

A

The Trypanosoma bruceigambiense

40
Q

What kind of organism is the Trypanosoma bruceigrambiense?

A

A protozoa

41
Q

What is African sleeping sickness transmitted by?

A

The tsetse fly

42
Q

What happens once the Trypanosoma bruceigambiense enters the blood?

A

It causes an immune response

43
Q

Why isn’t the immune reponse against Trypanosoma bruceigambiense effective?

A

The surface antigens are constantly changing

44
Q

What does Trypanosoma bruceigambiense cause?

A
  • Generalised lymphadenopathy
  • Hypergammaglobulinaemia
45
Q

What causes Chagas’ disease?

A

Trypanosoma cruzi

46
Q

How is Chagas’ disease transmitted?

A

The reduviid bug

47
Q

What does Chagas’ disease produce?

A
  • Acute cutaneous oedema
  • Intermittent fever
  • Shock with significant mortality
48
Q

What is scabies caused by?

A

The mite Sarcoptes scabei

49
Q

What kind of organism is Sarcoptes scabei?

A

Parasite

50
Q

What does Sarcoptes scabei do?

A

Burrows under the skin

51
Q

What is responsible for the symptoms of scabies?

A

Both the eggs and the mites cause an allergic response

52
Q

What does scabies produce?

A
  • Itching
  • Symmetrical inflammation of the body