Helminthes Flashcards
2 phylum of helminths
Nemathelminthes
Platyhelminthes
Class of nemathelminths
Nematoda ( round worms )
Class of platyhelminthes ( flat worms)
Trematoda
Cestoda
Intestinal worms that enter body through the skin
Necator americanus- hookworm
Ancylostoma duodenale- hookwork
Strongyloides stercoralis
Intestinal worms that enter body through the oral cavity
Ancylostoma duodenale
ascaris lumbricoides
Trichuris trichuria
Enterobius vermicularis
Where do you find mostly ascaris lumbricoides
Africa
Asia
Tropical America
ascaris lumbricoides reservoir
Human
Transmission ascaris lumbricoides
Fecal oral
People more at risk of ascaris lumbricoides
Children
Life cycle ascaris lumbricoides
Eggs in soil -> become infective through embryo-> swallowed -> become larvae-> liver -> lung -> coughed up -> swallowed -> adult worms in intestines in 60-80daya
Symptoms of ascaris lumbricoides

Symptomless
Cough
Mild abdominal pain
Vomiting
Intestinal obstruction
Ascaris pneumonitis
PEM
Areas of the world where hookworms aka ankylostoma duodenale & necator Americanus Are found
Tropical areas of Africa, Asia, and South America
Reservoir of ankylostoma duodenale & necator Americanus
Humans
Transmission route of ankylostoma duodenale & necator Americanus
Lifecycle ankylostoma duodenale & necator Americanus
Eggs in soil-> rhabditiform larvae in one to two days-> a larvae becomes infective filariform in 5 to 10 days-> infective and penetrate skin-> goes to lungs-> get swallowed-> form adult worm in the small intestine
Symptoms of hookworms aka ankylostoma duodenale & necator Americanus
Iron deficiency anemia (hookworm withdraw blood from small intestine)
Hookworm dermatitis ( usually on the feet )
pneumonitis
Abdominal discomfort
Reservoir of Strongyloides stercoralis
Humans main host
Dogs
Cats
Mammals
Areas where Strongyloides stercoralis is common
Africa
South east Asia
Latin America
Transmission of Strongyloides stercoralis
Skin
Treatment of hookworm
Albendazole
Strongyloides stercoralis life cycle
Larvae passed in faeces -> infective filariform larvae in soil -> penetrate human skin -> develop like hookworm -> gets to intestine and become adult worm and hatch eggs
Some larvae in intestine become filariform larvae -> penetrate perianal skin mucosa -> auto-infection and persistent infection
Strongyloides stercoralis clinical features
Itchy rash (Penetration of skin by infective larvae)
Abdominal pain, diarrhoea, steatorrhoea, weight loss (Presence of worms in gut)
Urticarial plaques and papules, wheezing, arthralgia
Transient itchy, linear, urticarial weals across abdomen and buttocks due to auto infection.
Diarrhoea, pneumonia, meningoencephalitis, death (Systemic (super-)infection)
Investigations threadworm ( Strongyloides stercoralis)
eosinophilia - Serology (ELISA)
faeces microscopic motile larvae; Larvae - jejunal aspirates or string test
Larvae cultured from faeces
Management Strongyloides stercoralis
Ivermectin or Albendazole
Enterobius vermicularis (pinworm) reservoir
Humans
Transmission route Enterobius vermicularis (pinworm)
Fecooral