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Y2 MCD Microbiology > parasitic infections > Flashcards

Flashcards in parasitic infections Deck (102)
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1
Q

define infection

A

invasion by and growth of pathogenic microorganisms within the body

2
Q

define disease

A

disordered or incorrectly functioning organ, part, structure, or system of
the body resulting from effect of genetic or developmental errors, infection, poisons, nutritional deficiency or imbalance, toxicity, or unfavourable environmental factors; illness; sickness; ailment

3
Q

define parasite

A

organism living in/on host and dependent on it for nutrition, causing damage

4
Q

2 types of parasite

A

endoparasite, ectoparasite

5
Q

2 types of endoparasite

A

protozoa, metazoa

6
Q

4 types of protozoa

A

amoeba, coccidiae, ciliate, flagellates

7
Q

3 types of metazoa

A

roundworms, flatworms, flukes

8
Q

features of protozoa

A

single celled organisms, eukaryotes, varied pathogenesis, some have insect vectors, no eosinophilia

9
Q

features of metazoa

A

multicellular organisms, free living, intermediate hosts and vectors, some just inhabit gut while others invade tissues, eosinophilia if invade blood

10
Q

2 examples of amoeba

A

E. histolyica (invasive), E. dispar (normal GI commensal)

11
Q

how does infection by amoeba occur

A

ingestion of mature cysts in food or water, or on hands contaminated by faeces

12
Q

describe time frame of amoeba infection

A

incubation period as short as 7 days, tissue invasion after first 4 months

13
Q

describe spectrum of amoeba disease

A

asymptomatic -> dysentry -> amoebic liver abscess (3rs most common cause of death of parasitic infections)

14
Q

describe how humans, E. histolyica’s only reservoir, are infected

A

cysts enter small intestine -> release active amoebic parasites (trophozoites) -> invade epithelial cells of large intestines -> cause flask-shaped ulcers -> spread ot other organs via venous system

15
Q

describe laboratory diagnosis of amebiasis

A

wet mount of stools to look for mature cysts

16
Q

treatment of amebiasis

A

nitroimidazole derivatives (act on trophozoite, not cyst)

17
Q

in humans, what type of parasite are coccidial infections mostly

A

zoonoses, so via animals

18
Q

3 types of coccidia infection

A

Plasmodium species (5 species), Toxoplasma, Crytosporidium

19
Q

what disease is Plasmodium species responsible for

A

malaria

20
Q

describe life cycle of malaria: types of host and stages in human

A

different types of plasmodium, 2 types of host (human and female Anopheles mosquito), 2 stages in human (liver and blood)

21
Q

when do malaria symptoms appear

A

as early as 7 days, but can be as long as one year

22
Q

symptoms of malaria

A

fever, headache, chills, vomiting, muscle pain, paroxysm, severe anaemia, cerebral malaria, liver and kidney failure, shock, pulmonary oedema, hypoglycaemia, rupture of spleen

23
Q

treatments of uncomplicated malaria

A

chloroquine, tetracycline

24
Q

treatments of severe malaria

A

ACT

25
Q

diagnosis of malaria

A

blood film, Giema stained (rapid antigen detection tests are more expensive and less sensitive)

26
Q

symptoms of toxoplasmosis in immunocompetent individuals (serious danger to foetus)

A

fever, swollen lymph nodes, headaches, sore throat

27
Q

infection routes by Toxoplasma gondii

A

undercooked meat with tissue cysts, food/water contaminated by cat faeces, contaminated environmental samples, blood transfusion, organ transplantation, transplacentally

28
Q

diagnosis of toxoplasmosis

A

serological test

29
Q

what can toxoplasmosis in immunocompromised patients cause

A

CNS disease, brain lesions, pneumonitis, retinochoroiditis

30
Q

disease caused by cryptosporidium, and major symptoms

A

cryptosporidiosis, causing diarrhoea (more severe in immunocompromised)

31
Q

transmission of cryptosporidium

A

faecal-oral

32
Q

diagnosis of cryptosporidiosis

A

stool examination

33
Q

treatment of cryptosporidiosis

A

fluid rehydration

34
Q

disease caused by ciliate protozoa Balantidum coli

A

balantidiasis

35
Q

reservoir hosts of Balantidum coli

A

pigs, rodents, primates

36
Q

symptoms of Balantidum coli

A

persistent diarrhea, dysentery, abdominal pain, weight loss, nausea, and vomiting (left untreated, perforation of colon)

37
Q

diagnosis of Balantidum coli

A

stool examination

38
Q

problem of asymptomatic carriers

A

don’t get treated as no symptoms, but still spread disease

39
Q

disease caused by flagellate Giardia lamblia

A

giardiasis

40
Q

2 stages of giardiasis

A

trophozoites, cysts

41
Q

acute symptoms of giardiasis

A

diarrhoea, greasy floating stools, stomach cramps, dehydration

42
Q

diagnosis of giardiasis

A

stool examination

43
Q

treatment for giardiasis

A

metronidazole

44
Q

example of flagellate transmitted sexually

A

trichomonas

45
Q

symptoms of trichomoniasis

A

discharge, dysuria

46
Q

complications of trichomoniasis during pregnancy and for HIV

A

preterm delivery, low birth weight; enhances HIV transmission

47
Q

diagnosis of trichomoniasis

A

microscopy, rapid test

48
Q

treatment of trichomoniasis

A

metronidazole

49
Q

another type of flagellate

A

Leishmania

50
Q

features of Helminths (metazoa)

A

complex multicellular parasites, cycles may involve insect vectors and intermediate hosts, humans are definitive host for most, adult worms can’t multiple in humans, number of adults related to infection, lay eggs, microfilaria, larvae

51
Q

4 examples of roundworms (nematodes)

A

Ascaris, hookworm, Filaria, Strongyloides

52
Q

Ascaris transmission

A

eggs transmitted by faeces (faecal-oral transmission and carried to lung by portal system)

53
Q

symptoms of ascariasis

A

usually asymptomatic but if many worms will cause abdominal pain and intestinal obstruction; feeding on contents can cause malnourishment, and penetration of larvae from capillaries into lungs can lead to Loeffler’s pneumonia

54
Q

diagnosis of ascariasis

A

stool examination

55
Q

treatment of ascariasis

A

mebendazole

56
Q

transmission of hookworm

A

larvae go through skin and into blood vessels, lungs then GI

57
Q

symptoms of hookworm

A

iron deficiency anaemia (blood loss due to GI attachment), GI and nutritional/metabolic symptoms, respiratory symptoms

58
Q

diagnosis of hookworm and whipworm

A

stool examination

59
Q

treatment of hookworm and whipworm

A

mebendazole

60
Q

transmission of whipworm (Trichuris)

A

faecal-oral

61
Q

symptoms of whipworm

A

asymptomatic, but if many worms cause blood diarrhoea, anaemia and inflammation of intestinal wall (-> rectal prolapse)

62
Q

what can roundworms (filaria) cause

A

elephantiasis due to obstruction of lymphatics

63
Q

2 types of roundworms

A

B. malayi, W. bancroft

64
Q

diagnosis of lymphatic filariasis

A

blood smear or antigen detection for peripheral blood microfilariae (during night as in day present in deep veins)

65
Q

treatment of lymphatic filariasis

A

albendazole

66
Q

what causes eye worm (loaiasis)

A

Lao Lao

67
Q

transmission of Loa Loa

A

fly vector and migrate through subcutaneous tissue, including under conjunctiva

68
Q

flatworms (cestode) species

A

Taenia spp.

69
Q

transmission of Taenia spp.

A

pig or cow

70
Q

symptoms of Taenia

A

asymptomatic, but can cause digestive problems if large worm

71
Q

diagnosis of Taenia

A

segment or eggs in stool

72
Q

treatment of Taenia

A

paziquantel

73
Q

what does Taenia solium cause

A

cysticercosis (causes acquired epilepsy)

74
Q

example of fluke (trematode)

A

Schistosoma

75
Q

Schistosomiasis transmission

A

requires water snail

76
Q

symptoms of Schistosomiasis

A

rash, itchy skin, fever, chills, cough, muscle aches, inflammation, scarring, anaemia, malnutrition, organ damage

77
Q

diagnosis of Schistosomiasis

A

stool/urine samples

78
Q

treatment of Schistosomiasis

A

praziquantel

79
Q

what are ectoparasites

A

parasites living on skin

80
Q

examples of ectoparasites

A

scabies, headlice, body lice, pubic lice

81
Q

transmission of scabies

A

direct contact

82
Q

diagnosis of scabies

A

rash, burrows

83
Q

treatment of scabies

A

sabicides

84
Q

3 stages of louse life cycle

A

eggs, nymphs, adults

85
Q

transmission of lice

A

direct contact

86
Q

4 stages of life cycle of Leishmania protozoa endoparasites

A

inoculation, vertebrate host, ingestion, sandfly

87
Q

2 forms of Lieshmania

A

promastigote, amastigote

88
Q

Leishmania promastigotes

A

within sandfly vector, and can move in direction of flagellum

89
Q

Leishmania amastigotes

A

within human and have reabsorbed flagellum, so no longer motile

90
Q

distribution of sand flies

A

warm climates but due to global warming going further north

91
Q

appearance and behaviour of sand flies

A

small, hairy, hop around, silent attack

92
Q

why do only females feed on blood

A

for egg nutrition

93
Q

4 major forms of leishmaniases

A

visceral (Kala-azar), cutaneous, diffuse, mucocutaneous/mucosal

94
Q

symptoms of visceral leishmaniases (fatal if untreated)

A

irregular fever, weight loss, hepatosplenomegaly, anaemia

95
Q

3 risk factors for visceral leishmaniases

A

malnutrition, immunosuppressives, HIV co-infections

96
Q

diagnosis of visceral leishmaniases

A

case definition, laboratory investigations (parasite and antibody detection)

97
Q

lesions in post Kala-azar dermal leishmaniases (PKDL)

A

lesions on face around mouth -> become nodular -> spread to trunk and limbs

98
Q

symptoms of cutaneous leishmaniases

A

self-healing skin lesions on exposed body parts, creating serious disability and scars (immune to reinfection)

99
Q

symptoms of diffuse cutaneous leishmaniases

A

disseminated lesions (resembles leprosy), difficult to treat, no spontaneous healing, frequent relapses

100
Q

what happens in mucocutaneous/mucosal leishmaniases

A

destroys mucous membranes, causing disfigurement

101
Q

healing and relapse in mucosal leishmaniases

A

no spontaneous healing, relapses

102
Q

diagnosis of cutaneous leishmaniasis

A

microscopy/culture, skin test, serology, PCR