Infectious Disease -- Parasite Packet #3 Flashcards
Five kinds of Helminths
Schistomiasis Trichinella Cistercicosis Filariasis Oncocerciasis
Death from Schistomiasis is usually caused by…
Hepatic granulomas and fibrosis
Unique symptom of Schistomiasis haematobium
hematuria and obstruction of the bladder
Predisposition to Squamous cell carcinoma of the bladder
Life cycle of Schistomiasis
Sporocysts in fresh water snails give rise to cercaria
Infection of humans by penetrating skin
Schistosomes migrate in peripheral vasculature
Arrive in portal and pelvic venous system and grow up
Eggs shed in feces, return to the river
Tissue reactions of Schistomiasis eggs?
Granulomas and Fibrosis
Cause of hepatic damage in Schistomiasis?
- IL3, 4, 5 result in IgE synthesis, mastocytosis, eosinophilia
- Eggs induce lymphocytes to secrete fibrinogenic factors, which leads to fibroblast prolif and portal fibrosis
Hepatic hallmark of Schistomiasis infection?
Hepatic fibrosis out of proportion to parasite injury
Describe the granulomas surrounding Schistosoma eggs
Calcified, pinhead granulomas
Macrophages, lymphocytes, neutrophils, eosinophils
How is Schistomiasis liver fibrosis described? It’s significance?
Pipestem potral fibrosis
Portal hypertension, Splenomegaly, Esophageal varices, ascites
How are people infected with Liver flukes?
Eating undercooked fish
Symptoms of infection with liver flukes?
Usually asymptomatic
Can cause biliary hyperplasia, fibrosis, portal cirrhosis
Two types of trematodes
Schistosomiasis
Liver Flukes
Other word used for cestodes
Tapeworms
Three main types of cestodes?
Taenia saginata - Beef
Taenia solium - Pork
Echinococcus - Dog
T. saginata or T. solium – who causes cysticercosus?
Solium
What is happening during cysticercosus?
When solium eggs are ingested, larvae hatch and penetrate gut wall. Hematogenous dissemination results in CNS cysts.
CNS symptoms of cysticercosus?
Convulsions, High Intercranial Pressure, Mental disturbances
What type of cysts are especially problematic in cysticercosus?
Degenerating cysts – cause local inflamm and focal scating, calcifications.
Intact cysts usually don’t evoke much of a reaction.
Echinococcus cysts tend to form in…
liver and lungs
Symptoms of Echinococcus?
Usually asymptomatic and chronic
Can cause liver disease
Cyst rupture can lead to anaphylaxis
Treatment for Echinococcus?
Mabendazole
Four most common types of nematodes (worms) in the US
Pinworms
Whipworms
Hookworms
Strongyloides
Pinworms – whats the official name
Enterobius vermicularis
Most common parasite in US
Pinworms
Life cycle of Pinworms?
Small worms of the intestine
Spread by oral ingestion of eggs extruded from the anus
Lifespan – 2 months
Most common symptoms of Pinworms
Anal pruritis
Reservoir of Pinworms?
ONLY HUMANS
Focus of Pinworm treatment?
Preventing Re-infection
The official name for whipworms?
Trichuris trichura
How big are whipworms?
about a half inch
Where do people tend to get whipworms?
Tropics
Warm, Moist Parts of the Southern US
Symptoms of whipworms?
Local hyperemia
Lesions of colonic mucosa
Official names of hookworms?
Necator amricanus
Ancylostoma duodenale
Hookworm infection is common in the “hookworm belt”
Where is the hookworm belt?
The southern US
What do hookworms do in the host?
Attach to upper levels of the SI
How are hookworms transmitted?
Infectious larvae (not eggs) Larvae penetrate between the toes
How to ascaris, hookworms, and strongyloides disseminate?
Ingest eggs/Penetrate host Bloodstream, Lungs Invasion by filariform larvae Esophagus Infective form --> Intestine
Symptoms of hookworms?
Small, itchy papule at penetration site
Mild pneumonitis from traveling through lungs
Blood loss + Anemia
Strongyloides is important because…
it can cause fatal disseminated disease in an IC host
Strongyloides is endemic where?
Appalachia+SE
Important reservoirs for Strongyloides?
Cats and Dogs
Symptoms of Strongyloides in an IC host?
Severe pneumonitis + Duodenitis
Scond most common parasite of humans
Ascaris lumbricoides
How big are Ascaris lumbricoides?
35 cm
Where do Ascaris lumbricoides live in the host?
They live unattached in the SI
Symptoms of Ascaris lumbricoides infection?
Eosinophilic pneumonitis - dyspnea, dry cough, fever, eosinophilia.
Colicky epigastric or periumbical pain
Malnutrition
Greatest danger of Ascaris lumbricoides infection?
abnormal migration in the body
Blockage of biliary ducts
Obstruction of SI
How to diagnose Ascaris lumbricoides?
Eggs in feces
Common SI parasites?
Hookworm, Ascaris, Strongyloides, Giardia
Trichanella spiralis is acquired by…
Ingestion of improperly cooked pork
What happens in the host in a Trichanella spiralis infection?
Larvae penetrate tissues
Disseminate hematogenously
Encyst in muscle cells
Symptoms of Trichanella spiralis infection?
Eosinophilia
Fever, Myalgia
Periorbital edema
Cardiac Failure
Relationship of Trichanella spiralis to the host heart?
Patchy interstitial myocarditis with eosinophila+ giant cells eventually cause scarring
Relationship of Trichanella spiralis and the lungs
Allergic eosinophilic infiltrate
Muscles especially influenced by Trichanella spiralis?
Diaphragm, Extraoccular, Laryngeal
Deltoid, Gastroc, Intercostal
Three types of Larval migrans syndromes
Cutaneous
Visceral
Neural
Cause of Cutaneous larval migrans
Ancylostoma
What occurs in cutaneous larval migrans
Larvae can’t mature in humans, but survive in SubQ for a long time.
Causes intense pruritis skin lesions
Who gets cutaneous larval migrans?
Plumbers, Construction workers, Duck hunters
What gives you visceral larval migrans?
Toxocara canis
T. cati
What happens in visceral larval migrans
Infection from pet
Hepatomegaly, hypereosinophillia, hypergammaglobulinemia, history of geophagia
What gives you neural larval migrans?
Balisascaris
Who gets Balisascaris?
Children with poor hygiene and geophagia
Symptoms to watch for in Balisascaris?
Eosinophilic meningioencephalitis
How is Balisascaris typically diagnosed?
Post mortem
Treatment for visceral larval migrans?
Steroids and anti-histamines
Filariasisis caused by
Wucheria bancrofti
Filariasisis symptoms
Larvae develop in lymphatic channels and damage them via granuloma formation. Causes lymphedema called elephantitis in the lover limb. Also influences scrotum, penus, vulva, leg, arm
How is Filariasisis transmitted?
Mosquito
How if Onchocerciasis transmitted?
Blackflies
Significance of Onchocerciasis?
Major cause of blindness in equatorial Africa
Symptoms of Onchocerciasis
Chronis pruritic dermatitis
Subcutaneous dermal nodules (onchocercoma)
Punctate keratitis
Damage to retina
Cause of retinal damage in Onchocerciasis?
Cross reaction between parasite and retinal pigment epithelial cell antigens
Three arthropods of significance as parasites
Scabies
Lice
Chiggers
