Parasitic Helminths (Nematodes i.e roundworms) Flashcards
1
Q
What is the common name for Enterobiasis?
A
Pinworm disease
2
Q
What is the prevalence of enterobiasis?
A
greater than 500 million cases worldwide
3
Q
What is the most common helminth in the U.S.
A
Enterobiasis (pinworm disease)
4
Q
What is the geographic distribution of enterobiasis (pinworm disease)?
A
world-wide
5
Q
What is the most common nematode infection in temperate zone?
A
enterobiasis (pinworm disease)
6
Q
What is the life cycle of enterobiasis (pinworm disease)?
A
- humans ingest embryonated eggs that hatch in small intestine.
- Larvae migrate to colon, mature to adult male and female worms
- After copulation females migrate to perianal region and lay 10,000 fertilized eggs and then die.
- eggs embryonate on perianum
7
Q
Are enterobiasis suceptible to drying out?
A
no they are very resistant to dessication
8
Q
If you have enterobiasis in the colon what are the symptoms?
A
no symptoms
9
Q
What will a heavy enterobiasis infection cause?
A
pruritis ani. scratching may lead to cellulitis; occasional aberrant infection of vagina; probability of reinfection is extremely high
10
Q
(blank) can result from egg hatching and larval migration back into the colon in enterobiasis
A
autoinfection
11
Q
How does your immune system respond to enterobiasis?
A
IgE and mast cells involved in worm expulsion
12
Q
What is the treatment fr enterobiasis?
A
pyrantel pamoate (retreat after 2 weeks to kill new worms)
13
Q
How do you prevent and control enterobiasis?
A
drug treatment; difficult to eliminate through hygiene; NO Vaccine
14
Q
WHat is the common name for trichuriasis?
A
whipworm disease
15
Q
What is the prevalence of trichuriasis?
A
greater than one billion human cases worldwide
16
Q
What is the parasite that causes trichuriasis?
A
trichuris trichuria
17
Q
What is the geographic distribution of trichuriasis?
A
worldwide
18
Q
WHat is the life cycle of trichuriasis?
A
humans ingest embryonated eggs that hatch in small intestine
larvae migrate to colon where adult female and male worms mature and copulate. Adults embedded in columnar epithelium wher they lay fertilized eggs (3-5,000 eggs/day) that pass (unembryonates) in feces.
19
Q
What do light trichuriasis infections look like?
A
asymptomatic
20
Q
What do heavy trichuriasis infections look like?
A
may present as acute dysentery or a chronic colitis that resembles inflammatory bowel disease (e.g chrons disease); children develop chronic malnutrition, anemia, short stature
can cause tenesums which causes rectal prolapse
21
Q
How does your immune system handle trichuriasis (whipworm disease)?
A
IgA, mast cells and IgE
22
Q
How do you diagnose trichuriasis?
A
identification of characteristic bipolar eggs in stool sample; eosinophilia
23
Q
How do you treat trichuriasis?
A
mebendazole or albendazole; surgical intervention for rectal prolapse
24
Q
How do you prevent trichuriasis?
A
sanitary disposal of feces; NO vaccine
25
What is this:
Aberrant infections caused by the dog and cat ascarids Toxocara canis, T. felis and others (>10,000 cases/year in the U.S.; 40% prevalence in regions of Southern U.S.)
Visceral Larva Migrana
26
if a worm picture has teeth what is it?
ancylostoma duodenale
27
If a worm picture has a big toothless mouth?
necator americanus
28
What is the prevlance of hookworm disease?
greater than one billion human cases worldwie
29
What parasites cause hookworm disease?
```
ancylostoma dodenal (most virulent)
necator americanus (less virulent)
```
30
What is the geographic distribution of hookworm disease?
A. duodenale is found in the mediterranean region, N. asia and part of s. America.
N. americanus previals in the W. hempsiphere but is also found in Africa, S. America and the pacific region
31
What is the life cycle of hookworm disease?
- Humans are infected by 3rd stage filariform larvae that penetrate skin
- Larvae migrate to lung, enter alveoli, then migrate up to trachea and are swallowed
- Adult male and female copulate in small intestine and unembryonated eggs are passed in feces (egg production: A. duodenal>>N. americanus)
- Rhabditiform larvae in soil become infectious filiariform larvae.
32
What type of hookworm parasite produces more eggs, A. duodenal or N. americanus?
A duodenale
33
What is the clinical manifestation of hookworm disease?
pneumonitis
pruitic, papular, vesicular dermatitis
IN intestins-> severe infections cause blood loss, epigastric pain and nausea
34
What is the est. its of blood lost per day from humans infected with severe case of hookworm?
7 million liters
35
How does your immune system respond to hookworm disease?
IgA, mast cells, IgE
36
How do you diagnose hookworm disease?
eggs in stool; must find adults or larvae to sepciate hookworms
37
How do you treat hookworm disease?
albendazole; oral iron sulfate supplementation for anemia
38
What are the lab and clinical findings in hookworm disease?
- eosinophilia
- anemia
- iron deficiency anemia (CHF and death)
- edema and ascites (caused by protein malnutrition; common in children)
39
How do you prevent and control hookworm disease?
sanitary disposal of human feces?
40
What is this:
| Aberant infections caused by the dog hookworm Ancylostoma caninum and others
cutaneous larva migrans
41
What is the prevalence of strongyloidiasis?
greater than 200 milion human cases worldwide
42
What is the parasite that causes strongyloidiasis?
strongyloides stercoralis
43
What is the geographic distribution of stronyloidiasis?
tropical, subtropical and temperate (southeastern U.S); animal reservoirs
44
What is the life cycle/biology of strongyloidiasis?
both parasitic and free-living phase
- 3rd stage filariform larvae go to human skin->blood-> lungs.
- get swallowed and go to small intestine
- adult parthenogentic lay eggs
- larvae molt twice
- 2nd stage rhabditiform larvae pass in feces
- S. stercoralis can have free-living cycle
45
What are the clinical manifestations of strongyloidiasis?
skin- seroiginous, creepingm urticarial eruptions
lungs- pneumonitis
GI- water, mucous-laden diarrhea
Autoinfection or hyperinfection in colon can lead to disseminated disease and death
46
How does your immune system respond to strogyloidiasis?
T cell function critical, but exact mechanism is unknown
47
How do you diagnose strongyloidiasis?
stool examination for 2nd stage rhabditifom larvae; eosinophilia
48
How do you treat strongyloidiasis?
ivermectin or albendazole
49
How do you prevent or control strongyoidiasis?
sanitary disposal of human/animal feces; no vaccine
50
What is the prevalence of trichinellosis?
1.5 million harbor parasites in US
51
What is the parasite that causes trichenellosis?
trichinella spiralis
52
What is the geographic distribution of trichinellosis?
worldwide (infects any mammal)
53
What is the life cycle/biology of trichinellosis?
- Humans acquire T spiralis by consuming poorly cooked meat bearing encysted larvae.
- -the larvae are liberated by digestive enzymes, penetrate columnar epithelial cells, molt four times, become female and male within columnar epithelium of s. intestine
- After cpulation, females deposite living larvae that spread via blood or lymph an must penetrate striated muscle cells to survive.
54
What do you call muscle cells that are infected with trichinellosis?
nurse cells
55
Humans often acquire trichinellosis by consuming improperly cooked (blank); humans are usually (blank) hosts (nurse cells calcify)
pork
| dead end
56
What is the clinical manifestations of trichenellosis?
- severe gastroenteritis (diarrhea, vomiting, abdominal pain)
- larvae penetrate and kill cell types before death (myocarditis and encephalitis)
- larvae in striated muscle cells survive but cause a myositis (fever, myagia, periorbital edema)
- in extremly heavy infections-> muscles may become dysfunction (paralysis of diaphragm can be fatal)
57
What will the lab findings be like in trichinellosis?
eosinophils
| elevated muscle enzymes (CPK, LDH)
58
How does your immune system respond to trichinellosis?
ADCC against free larvae; mast cell-mediated expulsion of adult worms)
59
How do you diagnose trichinellosis?
enzyme immunoassay to detect anti-Trichinella antibodies; definitive by muscle biopsy, squash prep and histopathology
60
How do you treat trichinellosis?
Prednisone for muscle inflammation; albendazoe to kill adults
61
How do you prevent and control trichinellosis?
cook or freeze pork; prevent pigs from eating meat scraps; no vaccine
62
What is this:
- female mosquito vector deposits 3rd stage filariform larvae on skin while biting
- larvae enter bite wound and go to lymphatics
- long, slender adult female and male worms mature and couplate in lymphatic vessels, then females produce microfiaria that circulate in bloodstream.
- Female mosquitos acquires microfilaria with blood meal. -Microfilariae penetrat gut, migrate to flight muscles then molt twice, migrate to probiscus.
Filariasis
63
What are the parasites that cause filariasis?
Wuchereria bancrofti and Brugia malavi
64
What is the geographic distributon of filariasis?
tropics and subtropics (pacific islands)
65
What is the prevalence of filariasis?
greater than 120 million human cases worldwide
66
In some strains of filariasis, microfilaria are found in the blood only during the (bank), while other strains only exhibit (blank)
day (diurnal periodicity)
| nocturnal peridicity
67
What are the vector mosquitos of filariasis?
Aedes, Culex, Anopheles
68
For filariasis, biting habits must coincide with (blank)
microfilarial periodicity
69
What is the clinical manifestations of filriasis (not chronic)?
- filarial fever
- lymphangitis
- lymphadenitis
- cellulitis
- dermatitis (inguinal lymph nodes and tested often affected).
70
What are the clinical manifestations of chronic filariasis?
lymphatic blockage by adult worms leads to lymphedema; elephantiasis (most profound late stage sequella)
71
What wil filariasis laboratory findings show?
elevated IgE; eosinophilia
72
How do you diagnose Filariasis?
microfilaria on Giemsa-stained blood film (consider periodicity);
blood concentration techniques
73
How do you treat Filiariasis?
diethylcarbamzine to kill microfilariae; no effective therapy for adult worms; surgery to relieve lymphedema
74
How do you prevent and control filariasis?
mosquito contro; mass chemotherapy for microfilaria; NO VACCINE
75
What are some other filarids of minor medical importance?
Loa loa; Mnsonela perstans
76
What is this:
- blackfly vector deposits 3rd stage filariform larvae on skin while biting
- larvae enter bite wound and develop to adults in subcutaneous tissues
- Long slender worms copulate
- produce microfilaria that enter bloodstream and tissue (eye)
- backfly acquires microfilaria with bloodmeal, larvae penetrat gut and migrate to flight muscles where they molt twice before migrating to probosciscerciasis?
Onchocerciasis (river blindness)
77
What is the parasite that caues onchocerciasis?
Onchocerca volvulus
78
What is the geographic distribution of onchocerciasis?
subsaharan africa and latin america
79
What is the vector for onchocerciasis?
black fly vector
80
What are the clinical manifestations of Onchocerciasis (river blindness)?
Living microfillaria-no problem
Dead microfillaria- intest host inflammatory response
-lympatic obstruction and edema
81
What is the prevalence of ochocerciasis (river blindness)?
120 million at risk, greater than 20 million human cases, 270,000 blind
82
How does your immune response react to onchocerciasis?
immunopathologic response to microfilariae, little response to adult worms
83
How do you diagnose Onchocerciasis?
find microfilaria on Giemsa-stained blood film; identification of adults or microfilaria from skin snip near nodules
84
How do you treat onchocerciasis?
ivermectin, nodulectomy
85
How do you prevent Onchocerciasis?
blackfly control, mass chemotherapy NO VACCINE
86
What is this:
human swallows copepod with infective 3rd stage larvae. Larvae are freed from copepod in small intestine. Penetrate mucosa and migrate w/in CT for up to 1 year. Worms copulated and migrate to skin of lower extremities where they make a vesicle in skin. Vesicle ruptures on contact with water and uterine prolapse releases living larvae.
Dracunculiasis (guinea worm disease)
87
If you see a string coming out of a foot, what is it?
dracunculiasis
88
What is the parasite that causes dracunculiasis?
dracunculus medinensis
89
Where do you find dracunuculiasis?
central africa, yemen, pakistan
90
What does the worm of dracunculiasis look like?
very long an thin (100 cm X 1.5 mm)
91
What is the clinical manifestations of Dracunculiasis disease?
worm secretes toxin that induces vesicle local inflammation and ulceration; secondary bacterial infections; allergic reactions (urticaria and pruritus) to worm products
92
What does your immune system do in response to Dracunculiaiss?
has no acquired immunity
| inflammatory response to adult worms
93
How do you diagnose dracunculiasis?
identify head of female worm in skin lesion, identify larvae
94
How do you treat dracunculiasis?
slow winding of adult worm on a thin stick; surgery, mebendazole with corticosteroids to reduce inflammation
95
How do you prevent and control dracunculiasis?
boil or filter drinking water, eliminate copepods; NO VACCINE
96
What is this:
Cercariae penetrate skin and become schistosomules that migrate to lungs-> portal veins near liver.
Adults travel to mesenteric vessels (mansni and japonicum) or to the venous plexus of urinary bladder (haernatobium). After copulation, produces eggs that pass through blood vessel walls and gain access to colon or bladder and are passed in feces or urine. Eggs hatch on contact w/ water and release motile miracidia that penetrate food process of intermediate host snail. Asexual reproduction in snail yields fork-tailed cercariae that exit snail and find human definitive host.
Schistosomiasis (Blood fluke)
97
What are the parasites that cause Schistosomiasis?
Schistosoma mansoni; S. japonicum. S, haernatobium
98
What is the geographic distribution of schistosomiasis (blood fluke)?
tropics and subtropics
99
What are the clinical manifestations of schistosomiasis?
```
transient dermatitis
pneumonitis
cercarial dermatitis
Katayama fever
Liver granulomas
portal hypertension
pipestern fibrosis
```
100
What are the cinica and lab findings of schistosomiasis (blood fluke)?
hepatosplenomegaly, eosinophilia, hyperimmunoglobulenimia
101
How does the immune system respond to schistosomiasis?
T-cell mediated delayed hypersensitivity reaction to eggs; antibody-dependent cell mediated cytotoxicity against schistosomules (IgE and eosinophils)
102
How do you diagnose Schistosomiasis?
identification of chracterstic eggs in feces or urine
103
How do you treat schistosomiasis?
praziquantel
104
How do you prevent/control shicstosomiasis?
sanitary disposal of feces/urine; snail control NO VACINe
105
What are these:
Clonorchis sinensis;
Paragonimus westermanni; Opisthorchis spp.;
Fasciola hepatica;
Fasciolopsis buski;
Heterophyes heterophyes; Metagonimus yokogawi;
Echinostoma spp.
Related Food and Water-borne Trematode Species:
106
This parasite is caused by eating undercooked beef or pork product with cysticercus larva that matures to adult tapeworm in small intestine. Tapeworm attached to mucosal lining via its scolex (suckers and hooks) and produces eggs taht pass in feces. Eggs embryonate on soil and are consumed by intermediate host cow or pig. Eggs hatch and releases onchospheres in small intestine that penetrate intestinal lining to blood stream and are carried to various organs (muscle) Cystericercus larvea develop in muscle
Taeniasis (cattle and pork tapeworms)
107
What are the parasites taht cause Taeniasis?
```
Taenia saginata (cows)
T soilum (swine)
```
108
Where do you find taeniasis?
tropics and subtropics
109
What is teh clinical disease and pathology of taeniasis?
adult tapeworm infections (up to 40 ft long) usually asymptomatic; abdominal discomfort and mild diarrhea
110
How does your body respond to taeniasis?
worm produced may engage IgE and mast cells
111
How do you diagnose Taeniasis?
identification of eggs or proglottids in fecal sample
112
How do you treat Taeniasis?
Praziquantel, psychological support
113
HOw do you prevent/ control taeniasis?
proper cooking of beef and pork; freezing kills cystericercerci; NO VACCINE
114
What are some related tapeworm species to Taeniasis?
Diphyllobothrium latum (broad fish tapeworm…60 ft. long!);
Hymenolepis nana
(dwarf tapeworm); Hymenolepis diminuta (rat tapeworm);
Dipylidium caninum (dog tapeworm)
115
What is this:
humans consume embryonated eggs that hatch in s. intestine to release oncospheres. Oncosphere penertates intestines and migrates via blood to any organ or tissue where it grows into a cystericerus (bladder worm) enclosed in a produced by the host.
Cystericercosis
116
If you see a worm in the eye what is it?
cysticercosis (taenia solium larvae)
117
What is the parasite that cauess cysticercosis?
T. solium larvae
118
Where do you find cystericerosis?
Worldwide (especiallly prevalent in central and south america)
119
What are the clinical manifestations of cystericerosis?
-painless subcutaneous nodules
-larvea die and calcify
-neurocysticercosis (central america)
-retinitis or uveitis
(may present as a brain tumor or epilepsy)
120
What is the immune response to cysticercosis?
inflammation and fibrosis
121
How do you diagnose cysticercosis?
radiography
MRI and CT
serology
eosinophilia
122
How do you treat cysticercosis?
albendazole, add corticosteroids; surgical removal in certain cases; no vaccine
123
how do yo prevent cysticercosis?
sanitary disposal of human feces
124
If you see a CT with hole in it what is it?
cysticercus
125
What is this:
can have human or animal host that consumes embryonated eggs that hatch is s. intestine to release oncospheres.
Oncospheres penetrate intestine and migrate through blood stream to liver, lungs, and other organs.
Oncospheres develop into hydatid cyst. Canine carnivore consumes sheep (rarely human) host bearing hydatid cysts that rupture in small intestine releasing tapeworm heads (scolices) that attach to mucosal epithelium. Small adult tapeworms develop in canine, eggs are produced that pass in feces.
Echinococcosis (hydatid disease)
126
What does echinococcosis look like
fish eggs
127
Where do you find echinococcosis (hydatid disease)?
widespread in regions of world with sheep raising
128
What parasite causes echinococcosis?
Echinococcus granulosus. E multilocularis
129
What host do you most commonly see echinococcosis granulosus in?
domestic sheep> dog > sheep cycles
130
Where do you most commonly see e. multilocularis?
in wild animals (sylvatic cycles);
| in both cases, human interrupt these zoonotic cycles and serve as "dead end" hosts
131
In echinococcosis, do humans harbor adult tapeworms?
| What is disease due to then?
no
| presents of larval tapeworms
132
What do the clinical manifestations of echinococcosis depend upon?
where the unilocular hydatid cyst is growing, most commonly, liver cysts cause serious liver destruction; hydatid cysts in other organs can cause organ destruction and symptomology.
133
What can rupture of a hydatid cysts (caused by Echnococosis) cause?
anaphylactic shock and death
134
E. multicularis infections cause (blank) or (blank) cysts; moer severe tissue destruction seen in these destructions
multilocular or alveolar cysts
135
How does your immune system respond to echinococcosis?
non-protective immune response, host attempts to wall of hydatid cyst
136
How do you diagnose echinococcosis?
serologic tests are available, radiography
137
How do you treat echinococcosis?
alendazole is marginally effecive; surgical removal is indicated
138
How do you prevent and control echinococcosis?
avoid contact with dogs; prevent dogs from consuming offal; no vaccine
139
(blank) is a parasite, such as a flea, that lives on the outside of its host.
ectoparasite
140
What kind of parasites are ectoparasites?
arthropods
141
Name 4 insects that are ectoparasites?
lice
flies (myiasis)
bedbugs
fleas
142
Name 2 arachnids that are ectoparasites
mites
| ticks
143
What is the fancy name for lice and tell me the common features?
1. pediculus humanus (head or body lice)- pruritis of scalp or trunk; nits seen on hair shaft
2. phthirus pubis (pubic louse)-pruiritis in pubic area; nits seen on hair shaft
144
What is the fancy name for flies and what are the common features of disease?
Dermatobia hominis (botfly)-> pruitic, painful, and erythematous nodule; larva may be seen emerging from nodule
145
What is the fancy name for bedbugs and what are the common features of disease?
cimex letularius-> pruritic, erythematous wheal
146
What is the fancy name for fleas and what is the common feature of the disease?
Ctenocephalides felis (cat flea)-> pruritic; erythematous wheal
147
What is the fancy name for mites and what are the common features of disease?
sarcoptes scabiei (itch mite)-> pruiritic, erythematous papules, and linear tracks
148
What is the fancy name for ticks and what are the common features of disease?
dermacentor species-> ascending paralysis
149
How do you treat lice?
permethrin
150
How does pubic lice (crabs) spread?
sexual intercourse
151
What is this:
| reaction causes skin to turn bluish-gray in color, sores in the genital area
crabs!
152
How do you treat crabs?
permethrin cream
153
(blank) is an ectoparasitic infestation of viable or necrotic tissues by the dipterous larvae of higher flies
Myiasis
154
In (blank) myiasis burrowing larvae cause pustular lesions that resemble boils or furuncles
furuncular
155
Furuncular myiasis may be treated conservatively by coaxing embedded larvae from furuncles by smothering their respiratory spiracles with occlusive coatings of (blank)
petrolatum (Vaseline)
156
Myiasis wounds should be cleansed and débrided, (blank) should be administered, and bacterial secondary infections treated with antibiotics
tetanus prophylaxis
157
What is the most common bedbug found in the US?
cimex lectularius
158
What bug has an oval, brownish body?
bedbugs
159
The main symptom of a bedbug bite is a (blank) caused by a hypersensitivity reaction to proteins in the bug saliva
pruritic wheal
160
How do you treat a bed bug?
calamine lotion for itching
| malation or lindane for mattresses and beds
161
Scabies is an infestation by the itch or scabies mite called (blank)
Sarcoptes scabiei
162
The human scabies mite is an (blank) parasite and completes its entire life cycle on its human hosts as females burrow intradermally to lay eggs and larvae emerge and mature to reinfest the same or new hosts
obligate
163
TIck (blank) is a worlwide disease that is caused by ticks, but only a handful of species can cause this. It is caused by a neurotoxin secreted by the salivary glans of the arachnid/
paralysis
164
In tick paralysis what happens?
The patient develops ascending symmetrical flaccid paralysis and weakness in the lower extremities.
(death may follow if you get paralysis of respiratory muscles)
165
How do you treat tick paralysis?
removal of tick
