Roundworms Flashcards
What is pinworm?
Enterobius vermicularis
Describe the life cycle of Enterobius vermicularis
Embryonated eggs swallowed
Larvae hatch in small intestine
Adults in lumen of caecum
Female crawls out of anus at night to lay eggs at perianal region
What are the symptoms of pinworm infection?
Asymptomatic
Perianal/vaginal itch
How is pinworm treated?
Anti-helminthics
What are the 3 types of roundworms?
Pinworms
Ascaris
Strongyloides
Describe the life cycle of Ascaris lumbricoides
Fertilised egg ingested from contaminated food/water
Invade intestinal wall, enter circulation
Travel to lungs, penetrate alveolar spaces
Climbs up trachea and pharynx, swallowed, re-enters GIT
Describe some of the possible sequelae of Ascaris infection
Pneumonitis
Intestinal obstruction
Pancreatitis (via obstruction)
Cholangitis (via obstruction)
How is Ascaris infection diagnosed?
Eggs in faeces on wet mount
Imaging of obstructions
How is Ascaris infection treated?
Antihelminthic
What kind of immune response is mounted to Ascaris?
Weak (chronic and repeated infections can occur)
How can Ascaris infection be prevented?
Sanitary sewage disposal
How does Ascaris cause obstruction of lumens?
Large worms (can be 30-40cm)
Describe the life cycle of Strongyloides stercoralis
Larvae penetrate skin and enter circulation
Transported to the lungs, penetrate the alveoli
Climb up trachea and pharynx, swallowed into GIT
Larvae can be excreted in the stool or penetrate the mucosal skin to cause auto-infection
What are some possible sequelae of Strongyloides stercoralis?
Often asymptomatic
Pneumonitis
Can cause Gram- sepsis during mucosal penetration
How is Strongyloidosis diagnosed?
Eggs in faeces on wet mount
Serology
