MCBoM- Parasitic Diseases

Question 1

Schistosomiasis

Answer 1

By Platyhelminthes
Adult worms live in hepatic portal/mesenteric vessels around bladder
Eggs deposited in vessels, acute local inflammation, tissue damage, vessel wall ruptured, egg to lumen of intestine or bladder, inflammation and granuloma, fibrosis

Question 2

Lymphatic filariasis

Answer 2

Elephantiasis
By nematode worms transmitted by mosquitoes
Live in afferent lymph vessels of nodes
Larvae in blood
Repeated infection- accumulate and obstruct lymph flow, inflammation, lymphoedema

Question 3

Geohelminths

Answer 3

Nematode worms
Transmitted faeco-orally
Roundworm, whipworm from infected food, hookworms from soil and burrow into skin
Large burden affects growth and development of children
1/2 of global population have

Question 4

Amoebiasis/ Amoebiac dysentry

Answer 4

Caused by parasitic protist in gut
Transmitted via cysts in faeces
-> severe bloody diarrhoea, liver abscess, death

Question 5

Malaria

Answer 5

Caused by plasmodium protist
Transmitted via female mosquitoes
Into erythrocytes, burst, malaria antigens and metabolic byproducts released
-> fever and chills, mortality in children and pregnant women, or cerebral

Question 6

Toxoplasmosis

Answer 6

Protists cause
Life cycle in cats, transmitted by ingestion of cysts from cat faeces or uncooked meat
Infects any nucleated cell type, mainly neural and muscular
Can remain for life with no problems, only an issue in immunocompromised

Question 7

Giardiasis

Answer 7

Flagellate protist
Lives in gut, transmitted via cysts in faeces
Often asymptomatic, may -> diarrhoea, flatulence, malabsorption syndrome

Question 8

Trichomoniasis

Answer 8

Flagellate protist

Often asymptomatic, but linked with increased HIV transmission, premature birth and decreased birthweight

Question 9

Dermatophytosis

Answer 9

Superficial mould infection
Infection of skin, hair and nails caused by keratinophilic moulds
Causes tinea pedis (athlete’s foot), tinea capitis (scalp), tinea corporis (body, ringworm)
Can be anthropophilic, zoophilic, geophilic transmission
Skin lesions respond to topical therapy, scalp/ nails need oral therapy

Question 10

Subcutaneous mycoses

Answer 10

Subcutaneous mould infection
From traumatic implantation of fungal spores of various moulds
Mycetoma- chronic localised destructive infection of skin and subcutaneous tissues
Mostly in arid tropical or sub-tropical regions
Often refractory to treatment
If bone involvement, amputation

Question 11

Aspergillosis

Answer 11

Deep mould infection
Ubiquitous in soil, dust, food, air (inhalation common transmission)
Potent allergens
-> localised infection in lungs or sinuses, widespread growth in lungs then spread to other organs
Mortality 40-90%

Question 12

Mucormycosis

Answer 12

Deep mould infection
Often from food spoilage
Mainly in those with uncontrolled diabetes mellitus or neutropenia
Cutaneous infection following contamination of wounds
Rapid progression to necrotic infarction
Needs aggressive treatment

Question 13

Candidosis

Answer 13

Deep yeast infection
Candida yeast commensal of mouth and GI tract in 30-50%
Opportunistic pathogens, usually endogenous origin
-> mucosal (thrush), cutaneous or nail infection
Oral candidosis in 80% AIDS patients, also infants and elderly and diabetes
Caused by IV lines, abdominal surgery, broad spectrum antibiotics

Question 14

Cryptococcosis

Answer 14

Deep yeast infection
Often from soil and bird droppings, or inhalation
-> cryptococcal meningitis
Often in CSF and AIDS patients
Fatal in 6 weeks if untreated