Parasites

Question 1

What are the 2 main classifications of parasites?

Answer 1

Protozoas and Helmiths

Question 2

What are the subclassifications of protozoas?

Answer 2

Amoebas, Flagellates, Ciliates and Sporozoas

Question 3

What are the subclassifications of helmiths

Answer 3

Platyhelminths (flatworms) and nematodes (roundworms)

Question 4

What are the subclassifications of platyhelminths?

Answer 4

Trematodes (flukes) and Cestodes (tapeworms)

Question 5

Give an example of a amoeba parasite, its transmission route and characteristic feature

Answer 5

Entamoeba Histolytica

Transmitted via faecal oral route

4 nucleus + 1 chromatid line

Question 6

List 2 flagellated parasites and their associated clinical disease

Answer 6

1. Giardia intestinalis: Giardianosis which refers to sudden onset of diarrhoea with foul smelling stools but no blood or mucus. Common cause of ‘Traveller’s Diarrhoea’
2. Trichomonas vaginalis:
   Trchomoniasis which is sexually transmitted and causes STI in females (~50% symp) and males (~mostly asymp)
   - characteristic feature is ‘STRAWBERRY CERVIX’

Question 7

List a sporozoan parasite

Answer 7

Plasmodium (malaria)

Question 8

List 2 cestodes (tapeworms) and their associated clinical disease

Answer 8

1. Taenia solium
   - Intestinal disease
   - ** Cysticercosis - worm infiltrates the brain, causing epilepsy, encephalitis and hydrocephalus
2. Echinococcus Granulosus: Hydatid disease where cysts develop in the liver

Question 9

List at least 2 different types of flukes (trematodes)

Answer 9

1. Liver
2. Lung
3. Intestinal
4. Blood

Question 10

List the blood fluke and its associated disease

Answer 10

Schistosome

Acute schistomiasis: ‘Swimmer’s itch’

Chronic schistomiasis:
1. S. mansoni and japonicum: HEPATOSPLENOMEGALY and liver failure

2. S. haematobium:
   RENAL FAILURE AND BLADDER CANCER

Question 11

What is the liver fluke?

Answer 11

Clonorchis sinensis - infected when humans ingest undercooked FRESHWATER FISH

Biliary tract infections and worse outcome: Biliary tract cancer (cholangiocarcinoma)

Question 12

What is the intestinal fluke?

Answer 12

Fascidopsis buski - found on water plants

Diarrhoea, intestinal obstruction

Question 13

What is the lung fluke?

Answer 13

Paragonimus Westermani - raw or undercooked CRAYFISH

Cough, haemoptysis, fever, night sweats (similar to TB)

Question 14

What is the main transmitter of Clonorchis sinensis?

Answer 14

FRESHWATER FISH with cercaria (free swimming larvae)

Question 15

What is the main transmitter of Paragonimus Westermani?

Answer 15

CRAYFISH

Question 16

What kind of infection route is trematodes commonly associated with?

Answer 16

WATER

Question 17

What is the feature commonly associated with helminths infection?

Answer 17

EOSINOPHILIA (raised eosinophil count)

Question 18

What does the nematode Onchocerca volvulus cause?

Answer 18

River blindness

Question 19

What does the nematode Dracunculus Medinesis cause?

Answer 19

Larvae replicates and mature in the gut.

Female adult migrate to skin, forming blister.

Blister ruptures -> high chance for secondary bacterial infection

Question 20

What does the nematode Angiostrongylus Cantonesis cause and which animal is it related to?

Answer 20

Eosinophilic Meningitis

LINKED TO CONSUMPTION OF SNAILS

Question 21

Name the mnemonic for intestinal nematodes

Answer 21

EAASTTT

E - Enterobius Vermicularis (Pinworm)
A - Ascaris Lumbicoides (GIANT roundworm)
A - Hookworms
S - Strongyloides stercoralis (threadworm)
T - Trichinella spiralis (‘pork’ worm)
T - Trichuris trichiura (whipworm)
T- Toxocara canis (adult worm)

Question 22

List at least 2 nematodes that are transmitted via faecal-oral route.

Answer 22

Enterobius
Ascaris
Trichuris
Toxocara

Question 23

List the 2 nematodes that enter via the penetration of the skin

Answer 23

Strongyloides
Hookworms

Question 24

Which nematode enters via ingestion of uncooked meat?

Answer 24

Trichinella spiralis

Question 25

Which nematode causes autoinfection and why?

Answer 25

Stronglyoides: it can complete its life cycle within the human host. Hence, the infection keeps perpetuating since the worms keep multiplying inside human host's intestines.

Question 26

What is the main clinical disease of hookworms?

Answer 26

Chronic anaemia and iron deficiency.

Question 27

Stronglyoides cause _ due to its autoinfection and _ in immunocompromised individuals.

Answer 27

Chronic GIT infections, Hyperinfection syndrome

Question 28

Which nematode invades the muscle cells?

Answer 28

Trichinella spiralis

Question 29

Which nematode causes bloody stools?

Answer 29

Trichuris trichiura Trichuris Dysentery Syndrome (Chronic diarrhoea + Growth/intellectual retardation)