Antihelminthic Flashcards
What are some unique characteristics of parasitic infections?
Worms multiply outside of their definitive host in contrast to other parasites
Evade immune system
Infections are chronic - last lifetime of the host
What parasite has the high infection rate in the world?
Ascaris
Where are anthropod-borne parasites endemic?
tropic and pets in the USA
What are the two phyla?
Flatworms (Platyhelminths) - Tapeworms (Cestodes), Flukes and Schistosomes (Trematodes)
Roundworms (Nematodes)
What are examples of tapeworm infections?
Beef Tapeworm (Taenia saginata) Pork Tapeworm (Taenia solium) Fish Tapeworm (Diphyllobothrium latum)
Facts about T. saginata - cestode
Global distribution
Transmitted by eating undercooked meat
Facts about T. solum - cestode
Global distribution
Bladder worms
Occasionally found in undercooked pork
Facts about D. latum - cestode
Largest tapeworm (10m)
Transmitted by eating undercooked fish
Northern hemisphere
Robs host of nutrients, especial vit. B12
Life cycle of Taenia
Eggs/proglottids pass into environment –> cattle or pig become infected by eating contaminated vegetation –> oncospheres hatch –> penetrate intestinal wall –> circulate to musculature –> oncospheres develop into cysticerci in muscle –> human infected by eating raw or undercooked meat –> taenia use scolex to attack to intestine –> mature into adults –> release proglottids into feces
What is cysticercosis
caused by autoinfection by ingesting eggs produced by T. solium
can go to the brain (instead of the muscle) and cause neurocysticercosis
What is Dwarf Tapeworm - cestode
Hymenolepis nana most common cestode infection can be transmitted directly between humans found in temperate regions worldwide children predominately infected infected by ingesting eggs generally not serious
What is schistosomiasis - trematode
Bloodflukes
3 species: S. hematobium; S. mansoni; S. japonicum
Caribbean, S. America, Africa, Middle East
Can live for 5-10 yrs
Sx due to immune reaction to eggs (headaches, fatigue, fever, GI problems, ascites, hepatic fibrosis, bladder cancer)
What is Praziquantel used for?
Highly effective against cestodes and trematodes
No activity against nematodes
MOA: disrupt calcium homeostasis, causes muscular contraction followed by spastic paralysis, immune response may be involved
Praziquantel therapeutic uses
Drug of choice for all schistosomiasis
dramatically reduces egg burden in those not cured
Single does kills 100% of saginata, solium, and latum
DOES NOT KILL EGGS OF SOLIUM
Toxicity: mild and transient, avoid in pregnancy, and avoid driving(dizziness/drowsiness)
Facts about Hookworms
American hookworm (Necator americanus)
Old world hookworm (Ancyclostoma duodenale)
Found in soil
Infect by penetrating through the skin or ingestion
feed on intestinal tissue and blood
Cause pulmonary lesions, skin reactions, intestinal ulcerations, and anemia
Prevalent in regions w/ temp around 23-33C