Helminths Flashcards
Three groups of Helminths
Cestodes (Tapeworms)
Nematodes (Roundworms)
Trematodes (Flukes)
Characteristics of Helminths
-Can be male/female or hermaphroditic
-Primary site of infestation is the intestinal tract: take nutrients, dispose wastes and cause blockages
-Multicellular and have complex life cycles
-Can be serious if disseminated and spread to vital organs
-Classified by egg, larva and adult stages
-Have well-developed organ systems and are active feeders
Mode of transmission
-Transmission through insect bite
-Transmission through direct skin penetration
-Transmission through ingestion of larvae from undercooked meats and fish
-Transmission through ingestion of eggs in faces
-Usually more common in areas that are unsanitary. Rare in US
Cestodes (Tapeworms) can be divided into
Taenia solium
Taenia saginata
Echinicoccus granulosus
Diphyllobothrium Tatum
Features of Cestodes
-Long, Segmented and hermaphroditic flatworms
-No intestinal and body cavity.
-Ingest through cuticles and absorb nutrients through microvilli
-Segments are called proglottids and they contain male and female organs
-Fertilized eggs are in posterior end of worms so they can break off and pass in faeces
Taeniasis (General info)
Taenia solium: Pork
Taenia saginata: Cow
Both infect intestines. Have hooks and suckers in scolex that helps attach to intestinal wall
Larvae of both species develop into adult tapeworms in intestine
Taeniasis treatment
Praziquantel and Niclosamide (kills worms on contact)
Taeniasis diagnosis
Proglottids in stool
Taeniasis clinical symptoms
Hunger pains, nausea, diarrhea, abdominal symptoms, chronic indigestion or constipation
Cysticercosis is caused by what organisms
Taenia soli larvae
Clinical presentation of Taniea coli
-If infestation occurs in the eye, disrupted vision and detached retina may occur
-If infestation occurs in muscle, you might feel lumps under skin
Cystercosis mode of transmission
-Infection occurs when eggs enter the body through ingestion of feces.
-Develop into larvae and form cysts or cysticerci in brain or eyes
Neurocysticercosis clinical presentation
Lead to seizures, vomitting, headaches
Neurocysticercosis diagnosis
MRI scans, biopsies, CT scans
Neurocysticercosis Treatment
Surgery or Praziquantel and Albendazole
Condition where cysts form in the brain and spinal cord is called
Neurocysticercosis
Echinococcus granulosis
Dog Tapeworm
Echinococcus granulosis cysts infects…
Liver, lung, brain
Clinical symptoms of Echinococcus granulosis
Jaundice, Bile duct obstruction, Abdominal discomfort, Chest pain and Cough if cysts in lung rupture
Echinococcus granulosis diagnosis
Chest x-ray, MRI, CT scan, Ultrasound, Eosinophilia, Biopsy of infected tissue, Serological tests (IHA) and ELISA
Echinococcus granulosis is transmitted by
Ingesting dog feces. If cysts ruptures, an anaphylactic reaction can occur to the worms Ags
Diphyllobothriasis
Fish Tapeworm, long
Diphyllobothriasis is transmitted by
Ingesting larvae from undercooked freshwater fish. Crustaceans are intermediate host
Diphyllobothriasis symptoms
-Most individuals are asymptomatic. However abdominal pain, vomiting, diarrhea, numbness in fingers and toes, fatigue
-Megaloblastic anemia due to uptake of B12 by the worm
-Eosinophilia in early stages
Diphyllobothriasis diagnosis
Detection of eggs in stool