5 Parasites Flashcards

1
Q

Define: parasite.

A

An organism which lives in or on another organism and benefits by deriving nutrients at the other’ s expense.

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2
Q

Differentiate between symbiosis, mutualism and commensalism.

A

S: Close, long term interaction.
M: Both species benefit.
C: Parasite derives benefit without harming host.

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3
Q

What are the three classes of host?

A

Definitive: harbours adult stage/parasite sexually reproduces
Intermediate: harbours laval/asexual stages of parasite
Paratenic: parasite remains viable without further development

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4
Q

What are the four types of protozoa (micro-parasites)?

A

Flagellates.
Amoeboid’s.
Sporozoa.
Trypanosomes.

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5
Q

What are the two types of helminths (macro parasites)? What are the two subdivisions of these?

A

Platyhelminths (flatworms): cestodes (tapeworms), trematodes (flukes).
Nematodes (round worms): intestinal and tissue.

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6
Q

Which parasite causes ascariasis? How is it acquired and where is it found? What type of host is the human?

A

Ascaris lumbricoides.
Ingestion of eggs (faeces).
S.E. Asia
Definitive.

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7
Q

Ascariasis migrates to two places in the body - where? What does it cause there?

A

Eggs to Lung: Loefflers syndrome - cough, wheeze, heamoptysis, eosinophilic pneumonitis
Worms to Intestines: malnutrition, obstruction

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8
Q

How is ascariasis diagnosed, treated and controlled?

A

Observation in stool.
Albendazole (prevents glucose absorption - starves+detaches).
Control: sanitation, edu, deworming

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9
Q

What is schistosomiasis caused by? Where is it found? What is the intermediate host?

A

aka bilharzia
Schistosoma.
Fresh water lakes in Africa.
Snails.

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10
Q

What does schistosomiasis cause in the body?

A

Swimmers itch, Katayama fever.

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11
Q

Schistosome haematobium migrates to the urinary system - what does it cause there?

A

Haematuria. Bladder fibrosis. Squamous cell CA.

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12
Q

Which types of Schistosoma cause portal hypertension and liver cirrhosis?

A

S. mansoni
S. intercallatum
S. japonicum
S. mekongi

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13
Q

How is schistosomiasis diagnosed, treated and controlled?

A

Urinary + stool microscopy.
Praziquantel (increases worm ionic permeability + dies).
Kill snails, chemoprophylaxis, avoidance, sanitation.

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14
Q

What is hydatid disease caused by? Where is it found? What is the usual host (we are accidental)?

A

Echinococcus.
All over the world
Sheep and dogs.

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15
Q

Echoinococcus granulosus.
E multilocularis.
What type of hydatid disease does each cause?

A

Cystic.

Alveolar.

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16
Q

What does hydatid disease do to the body?

A
Cysts -70% liver, 20% lungs.
May remain asymptomatic.
Mass effect.
Secondary bacterial infection.
Rupture - hypersensitivity.
17
Q

How is hydatid disease diagnosed and controlled?

A

Imaging, serology.

Deworming, hand hygiene, safe carcass disposal.

18
Q

What is malaria caused by? Where is it found? What type of host is the human?

A

Plasmodium: falciparum, vivax, ovale, malariae.
Equatorial areas.
Definitive.

19
Q

What are the clinical complications of malaria? (9).

A
Fever, rigors. 
Cerebral malaria. 
Renal failure. 
Hypoglycaemia. 
Pulmonary oedema.
Circulatory collapse. 
Anaemia.
DIC.
20
Q

How does malaria cause its clinical effects?

A

Ruptures red cells, blocks capillaries and causes inflammatory reaction.

21
Q

How is malaria diagnosed and controlled?

A

Microscopy, serology, PCR.

Insecticide in homes, larvicide and filling in of breeding pools. Bed nets. Chemoprophylaxis.

22
Q

What is cryptosporidiosis caused by? Where is it found? Which animals act as a reservoir?
How is it spread?

A

Cryptosporidium: parvum and hominis.
Worldwide.
Cattle, sheep, goats.
Faecal-oral route.

23
Q

What does cryptosporidiosis cause?

A

Watery diarrhoea with mucus.

Bloating, cramps, fever vomiting.

24
Q

How does cryptosopridiosis affect different people?

A

Usually self-limiting (2wks).

Severe in young, old, immunocompromised.

25
Q

How is cryptosopridiosis diagnosed and controlled?

A

Faeces acid fast staining.

Hygiene, isolation, filter/boil water. Pasteurisation.

26
Q

How is cryptosopridiosis treated in most patients?

A

Rehydration and nitazoxanide.

27
Q

What are the commonly used anti-protozoal treatments?

A

Metronidazole.
Pentamidine.
Nitazoxanide.
Pyrimethamine.

28
Q

What are the commonly used anti-helminthic treatments?

A

Albendazole.
Mebendazole.
Ivermectin.
Praziquantel.

29
Q

Name a flagellate:

A

Giardia.

30
Q

Name an ameboid:

A

Entamoeba.

31
Q

Name three sporozoa:

A

Plasmodium.
Toxoplasma.
Cryptosporidium.

32
Q

Name a trypanosome:

A

Leishmania.

33
Q

Name two cestodes:

A

Taenia.

Echinococcus.

34
Q

Name a trematode:

A

Schistosoma.

35
Q

Name a intestinal nematode:

A

Ascaris.

36
Q

Name 3 tissue nematodes:

A

Wucheria.
Onchocerca.
Loa loa.

37
Q

How is cryptosporidiosis treated in the immunocompromised (4).

A

Puromycin (kills parasite).
Nitazoxanide.
Octreotide (reduce cramps + freq).
HAART if HIV +ve.