Helminths

Question 1

Types of Helminths

Answer 1

Nematodes (roundworms)
Cestodes (tapeworms)
Trematodes (flukes)

Question 2

Strongyloides stercoralis

Answer 2

Larvae which penetrate the skin

Clinical Features:
- diarrhoea
- abdo pain
- skin lesions where larvae have penetrated

Question 3

Enterobius vermicularis (pinworm)

Answer 3

asymptomatic ~90%

Symptoms:
- perianal itching
- vulval symptoms

Question 4

Ancylostoma duodenale, Necator americanus (hookworms)

Answer 4

Larvae which penetrate skin of feet

GI infection → anaemia

Question 5

Loa loa

Answer 5

Transmission by deer fly and mango fly

Symptoms:
- red itchy swellings below the skin (‘Calabar swellings’)

Question 6

Trichinella spiralis

Answer 6

Develops after eating raw pork

Features include:
- fever
- periorbital oedema
- myositis

Question 6

Onchocerca volvulus

Answer 6

Causes ‘river blindness’
Spread by female blackflies

Features include:
- blindness
- hyperpigmented skin
- allergic reaction to microfilaria

Question 7

Wuchereria bancrofti

Answer 7

Transmission by female mosquito

Causes blockage of lymphatics → elephantiasis

Question 8

Toxocara canis (dog roundworm)

Answer 8

Transmitted through ingestion of infective eggs.

Features include:
- visceral larva migrans
- retinal granulomas

Question 9

Ascaris lumbricoides (giant roundworm)

Answer 9

Eggs visible in faeces

May cause intestinal obstruction

Occasional migrate to lung (Loffler’s syndrome)

Question 10

Echinococcus granulosus

Answer 10

• ingestion of eggs in dog faeces. - host is dog, which ingests hydatid cysts from sheep

Features include:
- liver cysts
- anaphylaxis if cyst ruptures

Question 11

Taenia Solium

Answer 11

Transmitted after eating undercooked pork

• cysticercosis
• neurocysticercosis
• mass lesions in the brain ‘swiss cheese appearance’

Question 12

Schistosoma haematobium

Answer 12

Hosted by snails

• ‘swimmer’s itch’
• frequency
• haematuria
  Risk factor for squamous cell bladder cancer

Question 13

Paragonimus westermani

Answer 13

undercooked crabmeat,

Causes secondary bacterial infection of lungs

Question 14

Clonorchis sinensis

Answer 14

undercooked fish

Features include:
- biliary tract inflammation
Risk factor for cholangiocarcinoma

Question 15

Fasciola hepatica (the liver fluke)

Answer 15

May cause biliary obstructionT

Question 16

Treatment for roundworms and tapeworms

Answer 16

-bendazoles

sometimes Ivermectin

Question 17

Treatment of flukes

Answer 17

Praziquantel