Infection

Question 1

Endoparasite

Answer 1

Live inside body
Major cause of illness
Helminths (worms)
Protozoa

Question 2

Ectoparasite

Answer 2

Live outside body
Minor symptoms but can transmit other infections 
Fleas
Lice
Bed bugs
Ticks

Question 3

Helminths:

Cestodes (tapeworms)

Answer 3

Segmented, flat
Largely asymptomatic (abdominal pain, malnutrition)
Cattle are intermediate hosts
Intestinal parasite of human

Question 4

Trematodes (flukes)

Answer 4

unsegmented, flat
Human host: infection of veins around bladder
Causes bladder inflammation, bleeding into urine
Intermediate host fresh water snail

Question 5

Nematodes (round worms)

Answer 5

Cylindrical, have digestive tract with lips, teeth and anus

Question 6

Fungal infection: Tine pedis

Answer 6

Athlete’s foot

Question 7

Fungal infection: Tinea corporis

Answer 7

Ringworm

Question 8

Severe fungal infection: cryptococcus neoformans (yeast)

Answer 8

Infects patients with low resistance due to failing immune system e.g HIV
Causes meningitis (inflammation of membrane lining brain)
Headache, neck stiffness, confusion, coma, death

Question 9

Bacterial infections

Answer 9

Pneumonia
Urinary tract infection
Cellulitis
Cholecysitis
Diverticulitis
Appendicitis

Question 10

Viral infections

Answer 10

rhinovirus (common cold) (mild)
HIV (severe)
Ebola (life threatening)
Epstein-barr virus

Question 11

Prion diseases

Answer 11

CJD - Creutzfeldt-Jakob disease
Rare fatal, degenerative neurological disease

Variant CJD
Typically occurs in young adults
Thought to be derived from BSE (mad cow disease)

Kuru - similar to vCJD
Spread by cannibalism
Especially brains of diseased relatives

Question 12

2 infections by trauma/bites

Answer 12

Tetanus: bacterium present in soil, contaminates wounds, releases toxin causing muscle spasm, prevented by vaccination
Malaria: parasite infection, present in large areas of tropics, causes severe febrile illness affecting all body systems

Question 13

Cholera toxin

Answer 13

Cause: cholera toxin
Severe watery diarrhoea
Bacteria produce toxin
Binds to gut lining cells
Massive loss of fluid and electrolytes
Causes severe dehydration, kidney failure & death 
Cholera toxin enters cells of gut lumen
Activates adenyl cyclase increasing cAMP
Reduces Na+ absorption
Increases Cl- secretion
Water and other electrolytes drawn into bowel lumen = diarrhoea
Treatment: oral rehydration therapy (water, salts, glucose)

Question 14

Dengue fever

Answer 14

Virus infection
Transmitted by Aedes mosquito
Fever & rash & muscle pain
Severe form: bleeding, shock & multi organ failure