parasitic infections

Question 1

define infection

Answer 1

invasion by and growth of pathogenic microorganisms within the body

Question 2

define disease

Answer 2

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

Question 3

define parasite

Answer 3

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

Question 4

2 types of parasite

Answer 4

endoparasite, ectoparasite

Question 5

2 types of endoparasite

Answer 5

protozoa, metazoa

Question 6

4 types of protozoa

Answer 6

amoeba, coccidiae, ciliate, flagellates

Question 7

3 types of metazoa

Answer 7

roundworms, flatworms, flukes

Question 8

features of protozoa

Answer 8

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

Question 9

features of metazoa

Answer 9

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

Question 10

2 examples of amoeba

Answer 10

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

Question 11

how does infection by amoeba occur

Answer 11

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

Question 12

describe time frame of amoeba infection

Answer 12

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

Question 13

describe spectrum of amoeba disease

Answer 13

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

Question 14

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

Answer 14

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

Question 15

describe laboratory diagnosis of amebiasis

Answer 15

wet mount of stools to look for mature cysts

Question 16

treatment of amebiasis

Answer 16

nitroimidazole derivatives (act on trophozoite, not cyst)

Question 17

in humans, what type of parasite are coccidial infections mostly

Answer 17

zoonoses, so via animals

Question 18

3 types of coccidia infection

Answer 18

Plasmodium species (5 species), Toxoplasma, Crytosporidium

Question 19

what disease is Plasmodium species responsible for

Answer 19

malaria

Question 20

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

Answer 20

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

Question 21

when do malaria symptoms appear

Answer 21

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

Question 22

symptoms of malaria

Answer 22

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

Question 23

treatments of uncomplicated malaria

Answer 23

chloroquine, tetracycline

Question 24

treatments of severe malaria

Answer 24

ACT

Question 25

diagnosis of malaria

Answer 25

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

Question 26

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

Answer 26

fever, swollen lymph nodes, headaches, sore throat

Question 27

infection routes by Toxoplasma gondii

Answer 27

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

Question 28

diagnosis of toxoplasmosis

Answer 28

serological test

Question 29

what can toxoplasmosis in immunocompromised patients cause

Answer 29

CNS disease, brain lesions, pneumonitis, retinochoroiditis

Question 30

disease caused by cryptosporidium, and major symptoms

Answer 30

cryptosporidiosis, causing diarrhoea (more severe in immunocompromised)

Question 31

transmission of cryptosporidium

Answer 31

faecal-oral

Question 32

diagnosis of cryptosporidiosis

Answer 32

stool examination

Question 33

treatment of cryptosporidiosis

Answer 33

fluid rehydration

Question 34

disease caused by ciliate protozoa Balantidum coli

Answer 34

balantidiasis

Question 35

reservoir hosts of Balantidum coli

Answer 35

pigs, rodents, primates

Question 36

symptoms of Balantidum coli

Answer 36

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

Question 37

diagnosis of Balantidum coli

Answer 37

stool examination

Question 38

problem of asymptomatic carriers

Answer 38

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

Question 39

disease caused by flagellate Giardia lamblia

Answer 39

giardiasis

Question 40

2 stages of giardiasis

Answer 40

trophozoites, cysts

Question 41

acute symptoms of giardiasis

Answer 41

diarrhoea, greasy floating stools, stomach cramps, dehydration

Question 42

diagnosis of giardiasis

Answer 42

stool examination

Question 43

treatment for giardiasis

Answer 43

metronidazole

Question 44

example of flagellate transmitted sexually

Answer 44

trichomonas

Question 45

symptoms of trichomoniasis

Answer 45

discharge, dysuria

Question 46

complications of trichomoniasis during pregnancy and for HIV

Answer 46

preterm delivery, low birth weight; enhances HIV transmission

Question 47

diagnosis of trichomoniasis

Answer 47

microscopy, rapid test

Question 48

treatment of trichomoniasis

Answer 48

metronidazole

Question 49

another type of flagellate

Answer 49

Leishmania

Question 50

features of Helminths (metazoa)

Answer 50

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

Question 51

4 examples of roundworms (nematodes)

Answer 51

Ascaris, hookworm, Filaria, Strongyloides

Question 52

Ascaris transmission

Answer 52

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

Question 53

symptoms of ascariasis

Answer 53

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

Question 54

diagnosis of ascariasis

Answer 54

stool examination

Question 55

treatment of ascariasis

Answer 55

mebendazole

Question 56

transmission of hookworm

Answer 56

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

Question 57

symptoms of hookworm

Answer 57

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

Question 58

diagnosis of hookworm and whipworm

Answer 58

stool examination

Question 59

treatment of hookworm and whipworm

Answer 59

mebendazole

Question 60

transmission of whipworm (Trichuris)

Answer 60

faecal-oral

Question 61

symptoms of whipworm

Answer 61

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

Question 62

what can roundworms (filaria) cause

Answer 62

elephantiasis due to obstruction of lymphatics

Question 63

2 types of roundworms

Answer 63

B. malayi, W. bancroft

Question 64

diagnosis of lymphatic filariasis

Answer 64

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

Question 65

treatment of lymphatic filariasis

Answer 65

albendazole

Question 66

what causes eye worm (loaiasis)

Answer 66

Lao Lao

Question 67

transmission of Loa Loa

Answer 67

fly vector and migrate through subcutaneous tissue, including under conjunctiva

Question 68

flatworms (cestode) species

Answer 68

Taenia spp.

Question 69

transmission of Taenia spp.

Answer 69

pig or cow

Question 70

symptoms of Taenia

Answer 70

asymptomatic, but can cause digestive problems if large worm

Question 71

diagnosis of Taenia

Answer 71

segment or eggs in stool

Question 72

treatment of Taenia

Answer 72

paziquantel

Question 73

what does Taenia solium cause

Answer 73

cysticercosis (causes acquired epilepsy)

Question 74

example of fluke (trematode)

Answer 74

Schistosoma

Question 75

Schistosomiasis transmission

Answer 75

requires water snail

Question 76

symptoms of Schistosomiasis

Answer 76

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

Question 77

diagnosis of Schistosomiasis

Answer 77

stool/urine samples

Question 78

treatment of Schistosomiasis

Answer 78

praziquantel

Question 79

what are ectoparasites

Answer 79

parasites living on skin

Question 80

examples of ectoparasites

Answer 80

scabies, headlice, body lice, pubic lice

Question 81

transmission of scabies

Answer 81

direct contact

Question 82

diagnosis of scabies

Answer 82

rash, burrows

Question 83

treatment of scabies

Answer 83

sabicides

Question 84

3 stages of louse life cycle

Answer 84

eggs, nymphs, adults

Question 85

transmission of lice

Answer 85

direct contact

Question 86

4 stages of life cycle of Leishmania protozoa endoparasites

Answer 86

inoculation, vertebrate host, ingestion, sandfly

Question 87

2 forms of Lieshmania

Answer 87

promastigote, amastigote

Question 88

Leishmania promastigotes

Answer 88

within sandfly vector, and can move in direction of flagellum

Question 89

Leishmania amastigotes

Answer 89

within human and have reabsorbed flagellum, so no longer motile

Question 90

distribution of sand flies

Answer 90

warm climates but due to global warming going further north

Question 91

appearance and behaviour of sand flies

Answer 91

small, hairy, hop around, silent attack

Question 92

why do only females feed on blood

Answer 92

for egg nutrition

Question 93

4 major forms of leishmaniases

Answer 93

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

Question 94

symptoms of visceral leishmaniases (fatal if untreated)

Answer 94

irregular fever, weight loss, hepatosplenomegaly, anaemia

Question 95

3 risk factors for visceral leishmaniases

Answer 95

malnutrition, immunosuppressives, HIV co-infections

Question 96

diagnosis of visceral leishmaniases

Answer 96

case definition, laboratory investigations (parasite and antibody detection)

Question 97

lesions in post Kala-azar dermal leishmaniases (PKDL)

Answer 97

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

Question 98

symptoms of cutaneous leishmaniases

Answer 98

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

Question 99

symptoms of diffuse cutaneous leishmaniases

Answer 99

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

Question 100

what happens in mucocutaneous/mucosal leishmaniases

Answer 100

destroys mucous membranes, causing disfigurement

Question 101

healing and relapse in mucosal leishmaniases

Answer 101

no spontaneous healing, relapses

Question 102

diagnosis of cutaneous leishmaniasis

Answer 102

microscopy/culture, skin test, serology, PCR