Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
124 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
This is commonly seen in worm infections in tissue
|
Eosinophilia
|
|
|
|
These play a major role in the immune response against worms
|
Eosinophils
|
|
|
|
These types of parasitic infections are notable for *not* eliciting eosinophilia
|
Worms in the intestine, protozoan infections
|
|
|
|
Description of the anatomy of round worms
|
Outer tube: impermeable cuticle
Inner tubes: tubular gonads, intestines |
|
|
|
T/F: Most round worms release live larvae
|
False. Most worms release eggs
|
|
|
|
This worm causes an asymptomatic or minor intestinal worm infection
|
Enterobius (pinworm)
|
|
|
|
What are the definitive and intermediate hosts of pinworm?
|
Humans are the only hosts
|
|
|
|
What is the infective stage of Enterobius?
|
Embryonated eggs
|
|
|
|
Where do eggs of Enterobius hatch?
|
Small intestine
|
|
|
|
Where do Enterobius larvae mature?
|
Cecum
|
|
|
|
Number of eggs produced by female Enterobius
|
10,000
|
|
|
|
Describe Enterobius egg-laying.
|
Female crawls from cecum through colon to anal sphincter where she released UNEMBRYONATED eggs, then dies
|
|
|
|
How long does it take for Enterobius eggs to become infectious?
|
They become embryonated incredibly fast--within 6 hours--thus this disease is not eradicated by santiary revolution.
|
|
|
|
How long do Enterobius eggs remain infectious?
|
Less than 2 weeks
|
|
|
|
How long does it take for Enterobius to mature after hatching?
|
5-6 weeks.
|
|
|
|
Diagnostic stage of Enterobius
|
Eggs on perianal folds
|
|
|
|
How is Enterobius diagnosed?
|
Scotch tape preparation of perianal eggs.
|
|
|
|
Describe the Enterobius egg.
|
Thick-walled, colorless shell (since it is not excreted with feces) with developing larva inside, flattened on one side.
|
|
|
|
Clinical signs and symptoms of pinworm
|
Anal itch
|
|
|
|
How many worms does a child with pinworm typically have?
|
50 on average
|
|
|
|
What is the most common worm infection?
|
Pinworm. 30% of children and 15% of adults worldwide.
|
|
|
|
Complications of pinworm
|
Pinworm neurosis (mother or father paranoid about worms, spend 8 hours/day cleaning, etc.)
|
|
|
|
Treatment of pinworm
|
Bendazole. It is important to treat the entire family since eggs get everywhere, and re-treat about three weeks later.
|
|
|
|
T/F: good sanitary measures can prevent reinfection by pinworm
|
False. Reinfection is almost inevitable. Pinworm is the one worm infection that is not eradicated in the santitary revolution of developed countries.
|
|
|
|
Infective stage of Trichuris
|
Embryonated eggs
|
|
|
|
Diagnostic stage of Trichuris
|
Eggs in feces
|
|
|
|
Transmission of Trichuris (Whipworm)
|
Humans ingest embryonated eggs from human fecal contamination
|
|
|
|
Where do eggs of Trichuris (whipworm) hatch?
|
Small intestine
|
|
|
|
Where do Trichuris larvae mature?
|
Cecum
|
|
|
|
How long does it take for Trichuris to mature after hatching?
|
2 months
|
|
|
|
How long does it take for Trichuris eggs to become infective?
|
3 weeks (thus this disease is eradicated by sanitation revolution)
|
|
|
|
Describe Trichuris (whipworm) egg-laying
|
Female releases eggs from within the cecum, which are then excreted out in the feces of the host
|
|
|
|
Describe the Trichuris (Whipworm) egg
|
Brown egg shell (stained by bile), underdeveloped embryo (older eggs have larval worm)
|
|
|
|
These worms anchor themselves to the intestinal mucosa
|
Trichuris (Whipworm); Ancylostoma, Necator (Hookworm)
|
|
|
|
The female of this worm type grows to 4 cm long
|
Trichuris (Whipworm)
|
|
|
|
This worm lives for several years and produces 8,000 eggs each day
|
Trichuris (Whipworm)
|
|
|
|
Clinical signs and symptoms of whipworm
|
Mild or subclinical; lots of worms can cause diarrhea
|
|
|
|
Geographic distribution of Trichuris (Whipworm)
|
Southeastern rural USA; tropical regions around the world
|
|
|
|
Geographic distribution of Enterobius
|
Global
|
|
|
|
Complications of whipworm
|
Anemia, abdominal pain, severe diarrhea, rectal prolapse in exceedingly heavy infections
|
|
|
|
Recal prolapse is a complication of this worm infection
|
Trichuris (Whipworm)
|
|
|
|
Anemia can result from infection by these worms
|
Trichuris (Whipworm); Ancylostoma, Necator (Hookworm)
|
|
|
|
The female of this worm type grows to 35 cm long
|
Ascaris, Onchocerca
|
|
|
|
These two worms have a relatively simple life cycle, whereas these worms have a relatively complex life cycle
|
Enterobius (pinworm), Trichuris (whipworm); Ascaris, Hookworm, Strongyloides
|
|
|
|
Infective stage of Ascaris
|
Embryonated eggs
|
|
|
|
Where do eggs of Ascaris hatch?
|
Small intestine
|
|
|
|
Where do Ascaris larvae mature?
|
Partially mature in the alveoli, fully mature in the small intestine after being re-swallowed
|
|
|
|
Migration of Ascaris larvae
|
Larvae are tiny after hatching and penetrate into portal circulation, then travel to lung capillaries where they break out into alveoli, and then make their way up the respiratory tree and are re-swallowed
|
|
|
|
When do Ascaris worms begin to produce eggs?
|
2 months after infection
|
|
|
|
How long does it take for Ascaris eggs to become embryonated and therefore infective?
|
3 weeks (thus this disease is eradicated by sanitation revolution)
|
|
|
|
Diagnostic stage of Ascaris
|
Egg in feces
|
|
|
|
Unmated females of this worm species will lay non-fertilized eggs
|
Ascaris
|
|
|
|
Describe the Ascaris egg
|
Lumpy-bumpy surface; thick, yellow-brown shell (bile-stained).
|
|
|
|
Clinical signs and symptoms of Ascaris
|
Usually asymptomatic, but may include: exit of adult worm through anus; abdominal pain, n/v; fever; eosinophilia (during larval migration through lung); pneumonitis (only in heavy infection, during larval migration); OBSTRUCTION due to balling up of worms
|
|
|
|
Complications of Ascaris
|
Malabsorption, intestinal obstruction (knotted mass of worms), biliary obstruction (worms in bile duct), pancreatic obstruction, hemorrhagic pneumonitis (during larval migration phase)
|
Obstruction since the balls curl up, like a giant asterisk "*"
|
|
|
This worm affects mainly children
|
Ascaris
|
|
|
|
Hemorrhagic pneumonitis is a complication of this worm infection
|
Ascaris
|
|
|
|
This worm infection is very common in the tropics and occasionally seen in the USA, especially in the southeast, and pig versions seen in New England
|
Ascariasis
|
|
|
|
How many eggs does an Ascaris female lay per day?
|
A lot: 200,000
|
|
|
|
How long do Ascaris eggs remain infective?
|
Months, though they are destroyed by sunlight or drying, but stable to feezing
|
|
|
|
Most infections by this worm in New England are by the pig version of the worm via pig fecal contamination
|
Ascaris
|
|
|
|
Prevention of Ascaris, Trichuris, Hookworm
|
Sanitary disposal of feces
|
|
|
|
These worms can cause severe anemia
|
Ancylostoma, Necator (Hookworm spp.)
|
|
|
|
Diagnostic stage of Hookworms
|
Eggs in feces
|
|
|
|
Describe Hookworm egg
|
Thin shell
|
|
|
|
This roundworm enters the human host by penetrating the skin and entering the blood
|
Hookworm
|
|
|
|
The larval development of these three roundworms is similar
|
Ascaris, Hookworm, Strongyloides (into lungs, then re-swallowed)
|
|
|
|
Migration of Hookworm larvae
|
Enter through the skin into circulation, then leave via lung capillaries into the alveoli, climb the respiratory tree and are swallowed, then complete maturation in the small intestine
|
|
|
|
Survival time of infectious Hookworm larvae outside of host
|
Less than 6 weeks
|
|
|
|
Clinical signs and symptoms of Hookworm
|
Papule and erythema at site of entry ("ground itch/dew itch"), transient pulmonary sx with eosinophilia in heavy infection
|
|
|
|
Ground itch/dew itch
|
Caused by Hookworm and Strongyloides infections
|
|
|
|
The female of this worm type grows to 1 cm long
|
Hookworm
|
|
|
|
This worm secretes anticoagulant and sucks blood
|
Hookworm
|
|
|
|
Lifespan of Hookworms in hosts
|
5 years
|
|
|
|
Number of eggs produced by female Hookworm
|
10,000 eggs/day
|
|
|
|
Complications of hookworm
|
Anemia with marginal iron deficiency, mental retardation in children with chronic anemia on account of hookworm infection
|
|
|
|
Great improvement in the infection of children in rural southeastern USA by this worm has been seen over the course of the last century
|
Hookworm
|
|
|
|
Patients with this worm infection may require iron supplements or even transfusion
|
Hookworm (due to severe anemia)
|
|
|
|
Prevention of these diseases is mainly by the wearing of shoes
|
Hookworm, Strongyloides
|
|
|
|
This worm is notable for being able to multiply extensively in humans and produce life-threatening disease
|
Strongyloides
|
|
|
|
This worm has three interrelated life cycles
|
Strongyloides
|
|
|
|
These are the three life cycles of Strongyloides
|
Parasitic (hookworm-like), Free-living, Autoinfective (hyperinfection)
|
|
|
|
The eggs of this worm are laid in the host, and then hatch in the host without being excreted
|
Strongyloides
|
|
|
|
Duration of infection until egg-laying begins in Strongyloides
|
1 month
|
|
|
|
This worm burrows into small intestine mucosa and lays eggs there
|
Strongyloides
|
|
|
|
Diagnostic stage of Strongyloides
|
Larva in feces
|
|
|
|
Infective stage of Strongyloides
|
Larva
|
|
|
|
Infective stage of Hookworm
|
Larva
|
|
|
|
Hatching site of Stronglyloides
|
Intestine
|
|
|
|
Hatching site of Hookworm
|
Outside of host
|
|
|
|
Free-living larvae are seen in these two worms' lifecycles
|
Hookworm, Strongyloides
|
|
|
|
Newly hatched larvae of this worm are excreted in the feces
|
Strongyloides
|
|
|
|
The free-living forms of this worm are able to mate and lay eggs
|
Strongyloides (not Hookworm)
|
|
|
|
T/F: free-living, reproducing Strongyloides are able to infect hosts
|
False. They must differentiate into infectious larvae to infect humans
|
|
|
|
Define autoinfection in Strongyloides infection
|
Larvae that hatch in the host mature into infectious larvae that penetrate intestinal wall or perianal skin and eventually reach lungs via circulatory system
|
|
|
|
Infection by this worm is usually lifelong
|
Strongyloides (due to autoinfection)
|
|
|
|
Describe Strongyloides larva
|
Short buccal cavity, hour-glass shaped esophagus, genital promordium, anus
|
|
|
|
The female of this worm type grows to 2 mm long
|
Strongyloides
|
|
|
|
Clinical signs and symptoms of Strongyloides
|
Usually asymptomatic, but may include: mild cutaneous and pulmonary sx, diarrhea, nausea, abdominal pain, eosinphilia
|
|
|
|
Infection by this worm may result in a long-term (decades), low-grade infection
|
Strongyloides
|
|
|
|
Recurrent gram-negative bacteremia is a feature of this worm infection
|
Strongyloides (E.coli is carried by penetrating worm into the intestinal mucosa)
|
|
|
|
Hyperinfection may result in immunocompromised patients with this worm
|
Strongyloides
|
|
|
|
Complications of Strongyloides
|
Diarrhea, nausea, abdominal pain, pulmonary and cutaneous symptoms, hyperinfection
|
|
|
|
Features of hyperinfection seen in Strongyloides
|
High fever, dyspnea, gram negative septicemia
|
|
|
|
Geographic distribution of Stronglyoides and Hookworm
|
Tropical and warm temperate climates (previously including southeastern USA)
|
|
|
|
This disease is caused by infection of a human by a roundworm species that does not recognize humans as natural hosts
|
Larva migrans
|
|
|
|
The intestinal phase is not seen in infections with these roundworms in humans
|
Larva migrans
|
|
|
|
This disease is caused by an Ascaris-like intestinal round worm of dogs (or, less commonly, cats)
|
Visceral larva migrans
|
|
|
|
This infection is most common in children under 4 years old
|
Visceral larva migrans (4 year olds playing near dog feces)
|
|
|
|
T/F: Most visceral larva migrans infections are asymptomatic
|
True
|
|
|
|
This disease may mimic retinoblastoma
|
Retinal involvement in visceral larva migrans
|
|
|
|
Fever and hepatomegaly may be seen in this round worm infection
|
Visceral larva migrans
|
|
|
|
A history of pica or dog contact suggests this diagnosis
|
Visceral larva migrans
|
|
|
|
Liver biopsy can be diagnostic in patients with this infection
|
Visceral larva migrans (migrating larvae seen on bx)
|
|
|
|
Most infections by this worm are self-limiting in less than 1 year
|
Visceral larva migrans (larvae become enclosed in granulomata)
|
|
|
|
Prevention of visceral larva migrans
|
Treat dogs to eliminate their round worms, avoid dog feces
|
|
|
|
Cause of cutaneous larva migrans
|
Dog and cat hookworm
|
|
|
|
Cause of visceral larva migrans
|
Ascaris-like worm of dog (and, less commonly, cats)
|
|
|
|
This infection causes local itching and inflammatory response
|
Cutaneous larva migrans
|
|
|
|
Rate of movement of worms in cutaneous larva migrans
|
1 cm/day (or less)
|
|
|
|
Most infections by this worm are self-limiting in less than 2 months
|
Cutaneous larva migrans
|
|
|
|
T/F: The larval track in cutaneous larva migrans leaves a scar
|
True
|
|
|
|
The geographical distribution of this worm is southeastern USA
|
Cutaneous larva migrans
|
|
|
|
How is cutaneous larva migrans diagnosed?
|
Observation of the characteristic lesion
|
|
