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198 Cards in this Set
- Front
- Back
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Nematode
general facts |
biggest class helminths
"wandering" parasites - don't cause symptoms until they die strongyles - only nematode infection exacerbated in immunosuppression |
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Nematode
appearance |
tubular worm
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Nematode transmission
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oral intake
by skin (hookworm) via vector |
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Nematode life cycle
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5 stages:
L1 - newborn L2 - often in vector *L3 - infective form* L4 - developing form in host* L5 - adult* * = in human host |
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Nematode disease process
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mature nematodes DO NOT cause inflammation
dying larvae cause pathology |
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Diseases caused by nematodes
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Ascaris
Enterobiasis Onchocerciasis Dracunculiasis |
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Cestodes
appearance |
ribbon-like, segmented, very long with hooks on end
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Cestodes
life cycle |
worm and cyst stages
characteristic eggs/cysts (problematic) larvae often cause serious or fatal pathology |
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Diseases caused by cestodes
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Taenia Saginata (beef tapeworm - not problmetatic)
Taenia Solium (pork tapeworm - serious problems) |
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Trematodes
appearance |
flatworms
"leaf-like" shape have suckers |
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Trematodes
transmission |
snails
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Forms/Diseases of Trematodes
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Liver flukes - Fasciola
Lung flukes - Paragonimus Blood flukes - Shistosoma |
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Sarcodina
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unicellular, simple structure
tough, cystic wall pseudopod movement most important = entamoeba |
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Sarcodina genera
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Entamoeba coli - benign, colonic normal flora, cyst transmission
Isopora --> ds in immunocompromised (persistent diarrhea and peripheral eosinophilia) Microsporidium - silkworms, bees Cyclospora - outbreak from strawberries in MI |
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Intestinal diseases and parasites
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Giardia
Cryptosporidia Amebiasis Ascaris Trichuris Stronguloides Chagas' disease Tape worms Visceral Lesimaniasis |
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Giardiasis
general facts |
caused by Giardia
most important waterborne pathogen in U.S. world wide disease |
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Giardia appearance
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flagellate protozoan parasite - "trophozite"
pear-shaped |
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Giardia transmission
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fecal-oral (ingestion of viable cysts)
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Giardia life cycle
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lives in small intestine of humans and animals (not host specific)
trophozites develop into oval cysts - passed in feces 10 cyst minimum to produce infection |
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Giardiasis
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many asymptomatic
some with sever diarrhea (offensive, frequent, yellow stools) UNCOMMON persist several weeks NO INFLAMMATORY RESPONSE |
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Diagnosisng Giardiasis
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find the parasite
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Treatment for giardiasis
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Flagyl (metronidazole)
cyst excretion stops 2 days after initiation of tx |
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control of giardiasis
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use clean drinking water
boiling water to 50*C kills encysted trophocytes use approved water filters |
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immunity to giardia
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IgA targeted to surface antigens (giardins)
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predisposition to giardia
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malnourished children
contact-contract (day care centers) surgery (immunosuppression) NOT thought to be important in HIV diarrhea |
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Cryptosporidiosis
general facts |
caused by cryptosporidia
destroys enterocytes --> waterborne enteritis (mostly in jejunum) important cause of acute diarrhea in infants of developing countries |
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Cryptosporidia
appearance |
no cilia/flagella
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Cryptosporidia
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fecal-oral route
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Cyrptosporidia life cycle
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zoonotic potential via infective oocyst - not host specific
multiple cycles of replication oocysts exreted up to 2 weeks after cessation of diarrhea |
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Cryptosporidiosis
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major problem in immunocompromised (no recovery)
enterotoxic effect w/ weight loss self-limiting torrential diarrhea inflammatory response!! more systemic illness findings |
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diagnosis of cyrptosporidiosis
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find the oocytes
serum antibody |
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cryptosporidiosis treatment
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with intact immune system - NO Rx - use oral rehydration ONLY
AIDS pts - Spriramycin |
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control of cryptosporidiosis
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control cysts (resistant to common disinfectants like chlorine, but iodine solution effective)
destroyed by mix of NH3, HClO- and formol saline |
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immunity to cryptosporidia
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CMI and Ab
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predisposition to cryptosporidiosis
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cattle (vet students!)
day-care centers |
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extraintestinal pathogenicity of cryptosporidia
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biliary tract disease
mixed cryptosporidium/CMV infections respiratory tract involvement |
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Amoebiasis
general facts |
caused by Entamoeba Histolytica
rare in U.S. - imported from Middle East, South America Colonic parasite |
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Amoebiasis
transmission |
fecal-oral route
recovered from faces of cockroaches and flies |
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entamoeba histolytica life cycle
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parasitic cysts
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amoebiasis
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intestinal diarrhea, lower bowel hemorrhage
invasive form in immunosuppressed --> systemic systemic: liver abscesses - with tx, liver heals s/ scarring |
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diagnosis of amoebiasis
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fecal microscopy
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treatment of amoebiasis
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iodoquinol
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control of amoebiasis
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boiling water kills cysts
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Ascaris
general facts |
caused by human roundworms (tinea)
largest parasitic NEMATODE (1 foot long) |
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transmission of human roundworms
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ingestion of mature eggs
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life cycle of human roundworms
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female lays 200,000 eggs a day
eggs present in soil and mature there infective eggs release larvae on ingestion |
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ascaris
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larvae penetrate bowel, go to liver, lungs, are coughed up and returned to gut (continual reinfection)
causes death b/c of duodenal obstruction |
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diagnosis of ascaris
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fecal microscopy - look for eggs
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treatment of ascaris
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albendazole
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trichuris
general facts |
caused by whipworms
blood sucking parasite of large bowel uneven distribution in community of "wormy people" |
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Two types of dermal parasites
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ectoparasites
endoparasites |
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ectoparasites
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lice
mites fleas bugs ticks flies related pathologies: delusory parasitosis, allergy |
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endoparasites
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Tungiasis
Myiasis |
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Pediculosis
general facts |
lice
blood suckers on head transmits infectious disease |
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Transmission of lice
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contact
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life cycle of lice
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MUST feed daily to survivie
lice move fast on hairs nits are glued to hair for some time |
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Pediculosis
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pinpoint macules (red spots)
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treatment of pediculosis
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insecticides
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control of pediculosis
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daily combing and changing pillowcases
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phthirius
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crab lice
no zoonotic lice crab-like shape veneral treat clothes with dry cleaning/dryer 20 minutes |
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Sarcoptes
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mites
burrowing mites --> cause mange (scabies in humans) transmitted by contact eggs laid in burrowed tunnels |
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Sarcoptes
disease treatment other |
allertic sensitization (itchiness)
regional preference (hands, elbows, knees) feeding on stratum corneum tx = ivermectin HIV/AIDS pts get "Norwegian scabies" w/ extensivive darkened, scaling skin |
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Demodex
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hair follicle mite
common on human face (hair follicle, sebaceous glands) diagnosis by scraping |
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Fleas
general facts |
blood suckers
carrier of major dieases (plage, rickettsia, tape worms) jumps from host to host |
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Flease transmission
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contact (esp. w/ cat flea) on animal, furniture, carpet
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Fleas disease
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bite hypersensitivity - sensitization to salivary allergens --> pathology
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control of fleas
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vacuuming, insecticides, growth regulators
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Ticks
general facts |
periodic blood suckers
want to get rid of tick w/in 24 hours - after this, they can start to transmit disese most populous in summer |
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transmission of ticks
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contact
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disease caused by ticks
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irritating skin lesions
spread of infectious disease (e.g.: Lyme disease) |
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treatment of ticks
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removal
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control of ticks
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vaccine for cattle (destroys tick's gut)
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Bugs
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insects, blood suckers
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Cimex
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bed bug - irritating bites, sensitization to salivary antigens
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Triatoma
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kissing bugs - drop from ceiling and suck blood from host while pooping out back end on to host
can transmit Chagas' disease |
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Romano's sign
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associated with Chagas' disease
swollen eye b/c of allergy to bug's droppings/bug entering eye disease doesn't appear until 10 years later when there's an autoimmune interaction btw parasite and heart |
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Myiasis
general facts |
jiggers, chiggers
larvae of flies (e.g.: Housefly) in tissues secondary infections common |
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myiasis disease
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causes lumps on on the skin that contain the larvae
black spot in center of lump is entry site |
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treatment for myiasis
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bacon therapy - lay bacon over site and larvae emerge
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Enterobiasis
general facts |
pinworms
nematodes greatest prevalence in children |
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Enterobiasis transmission
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fecal-oral route
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Enterobiasis disease
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sticky eggs causes itchiness (perianal irritation)
vulvo-vaginitis in females |
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Diagnosing enterobiasis
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fecal microscopy - ova or adult worms
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Treatment of enterobiasis (pinworms)
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albendazole
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predisposition to enterobiasis (pinworms)
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handling kids' bedding and clothes who have the worms
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Onchocerciasis
general facts |
caused by onchocera
nematode causes river blindness |
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transmission of onchocera
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black fly
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life cycle of onchocera
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microfilaria in skin, eyes
adults under skin in nodules |
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onchocerciasis disease
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causes blindness and sever dermatitis when worm dies
chronic - atrophy of skin (very thin, scaly) |
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Treatment of onchocerciasis
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ivermectin
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dracunculiasis
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Guinea Worm
waterborne filarial nematode |
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transmission of Guinea worm
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ingestion of contaminated water
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Life cycle of the guinea worm
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adult under skin, female sheds larvae into water
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Dracucculiasis
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blister caused by allergic reaction to worm fluid
adult causes chronic debilitating ulcer on skin (site where female releases larvae) 2* infections from ulceration |
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Treatment of dracunculiasis
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wind worm around a stick as it emerges
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control of guinea worm
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proper filtration
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Loiasis
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Loa Loa
in itself, does not cause disease insect vector |
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Leishmaniasis
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caused by leishmania
protozoa - flagellate arthropod transmitted |
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transmission of leismania
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sand fly vector
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Lesishmania transmission
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sand fly is vector
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Leishmania life cycle
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lives and replicates in macrophages
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Leishmaniasis - disease
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cutaneous - characteristic ulcer (raised, hardened edge; parasites at edge, not at center)
visceral mucocutaneous - severely debilitating/disfiguring |
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Diagnosing lesimaniasis
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biopsy
culture |
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GU tract parasites
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trichomonas
schistosomiasis STDs of various sorts |
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trichomoniasis
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caused by trichomonas vaginalis
highly site specific pathogen worldwide distribution high prevalence (80%) among sex workers |
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trichomonias appearance
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flagellate with twitching motion
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trichmonas tranmission
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ONLY venereal
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trichomonas life cycle
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can survive several hours in moist environment
infects squamous cells no cystic forms occur (NOT in environment) |
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trichomoniasis - disease
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symptomatic in females
usually asymptomatic in males symptomatic = allergic inflammation, yellow vaginal discharge, erythmatous vulva discharge contains large numbers of PMNs |
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Diagnosis of trichomoniasis
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microscopy to identify the parasite
DDX with candidiasis (does NOT have a pungent odor) large numbers of PMNs in discharge Giema stain, PAP NOT gram stain or serological diagnosis |
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Treatment of trichomoniasis
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metronidazole
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immunity to trichomoniasis
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PMNs and macrophages capable of killing trichomonads
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Schistosomiasis "bilharzia"
general facts |
caused by schistosoma
TREMATODES: blood flukes |
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schistosoma
appearance |
flat worms - "leaf shaped"
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transmission of schistosomas
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freshwater snails, birds (skin penetration on water contact)
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life cycle of schistosoma
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adults in visceral blood vessels
eggs shed in feces/urine |
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Schistosomiasis disease
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Hepatic, urinary stages
acute phase - antigen Ab complexes chronic phase (granulomas in liver/bladder, bladder cancer) |
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Diagnosing Schistosomiasis
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eggs in feces/urine
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treatment for schistosomiasis
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praziquantel
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Pulmonary parasites
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Malaria
Paragonomiasis Trichinella Nematodes Filiariasis |
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Pneumocystis carinii/jirovecii
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protozoal organism
aerosol transmission opportunistic proliferation in T cell deficient immunocompromised diagnose by silver stain tx: aerosolized petamindine |
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Paragonamiasis
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trematode: lung flukes
transmission by house dust mites, cockroaches disease: allergies, asthma leads to lung fibrosis |
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Trichinella
general facts |
a worm
pigs get infected by eating infected meat --> humans that eat pork |
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Trichinella
transmission |
eating poorly cooked pork or other carnivores
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Trichinella life cycle
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invade muscle cells (nurse cells) - lives there for years
larvae live for years, then die and calcify |
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Trichinella disease
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enteritis symptoms
attacks diaphragm, intercostals (hard to breathe), also eyelids (periorbital edema), and tongue muscle --> severe muscle pain allergic reactions disease severity proportional to number of larvae ingested |
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Diagnosing trichinella
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biopsy
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Treating trichinella
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Albendazole
anti-inflammatory agents (b/c killing worm in muscle and muscle breakdown --> inflammation) |
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control of trichinella
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pork surveillance and meat inspection
cook pork to 170*F |
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Central nervous system parasites
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toxoplasma
Cysticercosis Acanthamoeba Naegleria |
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Toxoplasma
general facts |
Coccidian parasite
need to be concerned about if pregnant - may contact from cats common infection, BUT uncommon disease uncontrolled proliferation occurs in immunocompromised |
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toxoplasma appearance
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cysts form in tissues
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transmission of toxoplasma
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from cats
transplacental oral ingestion of tissue cysts (eg: cattle meat) |
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toxoplasma life cycle
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fecal oocysts in cats
all cells can be infected (including macrophages and neurocytes) intracellular replication in enterocytes --> resistant oocysts predator/prey keeps organism going everywhere rapid proliferation until immunity sets in |
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Toxoplasma disease
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rupturing cyst --> inflammation
primary infection --> flu-like symptoms, swollen cervical LNs invasion of maternal tissues during pregnancy leads to invasion of fetus --> consequent congenital abnormalities (esp. of eye) some puberty-onset |
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Diagnosing toxoplasma
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serological tests, immunostaining
biopsy |
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Treatment of toxoplasma
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not simple
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Control of toxoplasma
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good hygiene
proper cooking pregnant women avoid changing litter boxes/contact with cat feces |
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immunity of toxoplasma
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antibodies against it (b/c of previous infection)
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Naegleria
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free-living amoeba
flagellate; thermophilic, tough cysts warm fresh water, swimming hole invades via olfactory epithlium --> olfactory nerve --> brain induces purulent meningitis in brain fatal no tx |
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Acanthamoeba
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free-living in water as trophs or cysts
affects CNS contaminated contact lens solution invasive to cornea perivascular location leads to amoebic keratitis - can close eyes tremendous abscesses in the brain without treatment, is fatal in all cases |
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Taenia Saginata
general facts |
beef tapeworm
NOT problematic zoonotic infection |
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appearance of taenia saginata
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ribbon-like segmented
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transmission of taenia saginata
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ingesting infected beef
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life cycle of taenia saginata
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multiple tapeworm cysts (intermediate stage) - very problematic
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taenia saginata disease
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NO symptoms in cattle
no serious signs in infected humnas |
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treatment for taenia saginata
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praziquantel or albendazole
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control of taenia saginata
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freeze carcasses
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Taenia solium
general facts |
pork tapeworm
causes serious problems |
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Taenia solium appearance
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ribbon-like segmented
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Taenia solium transmission
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ingesting infected pig
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Taenia solium life cycle
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multiple tapeworm cysts (intermediate stage) in pork muscles
very problematic |
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Taenia solium disease
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larvae invade eye, CNS, muscle, skin
neuocysticercosis = serious CNS problem |
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Diagnosis of taenia solium
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space occupying CNS lesion
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Treatement of taenia solium
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surgery (for larger lesions - need to be careful of inflammatory worm fluid)
albendazole |
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Control of taenia solium
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vaccine for pigs
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Trypanosoma brucei
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causes one form of trypanosomiasis
-African sleeping sickness zoonotic - cattle and humans tsetse fly vector replication in CNS --> death |
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Trypanosoma cruzi
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causes one type of traypanosomiasis
native South America triatomid bug (kissing bug) vectors replication in HEART muscles - develop autoantibodes chronic - cause Chagas disease - may develop autoantibodes against heart and colon distention |
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Vascular parasites
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malaria
schistosomiasis lymphatic filariasis |
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Filariasis
general facts |
nematode
1 in every 15 people on earth are infected |
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Transmission of filariasis
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mosquito borne
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life cycle of filariasis
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adult in lymphatics (does NOT block them)
microfilaria in blood |
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Diseases of filariasis
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Elephatiastis = skin changes
Lymphedema = accumulation of lymph fluid in tissues of limbs Hydrocele - accumulation of lymph fluid in scrotal sacs chronic condition - frequent, acute fevers get 2* infectinos b/c parasite is immunosuppressive sometimes lymph drains over to urine |
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Systemic parasites
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Hookworm
Malaria Strongyloides Toxoplasma Schistosoma in liver |
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Parasites associated with anemia
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hookworm
malaria |
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Hookworms
general facts |
blood suckers - major cause of ANEMIA, iron deficiency
worst nematode to have in gut |
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transmission of hookworms
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skin penetration by larvae
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life cycle of hookworms
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skin --> venules --> lungs --> then gut
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hookworms
diseases |
skin penetration
intestinal events - blood loss! |
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Diagnosing hookworms
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fecal microscopy
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Hookworms treatment
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albendazole
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Malaria
general facts |
Plasmodium falciparum
one of greatest causes of mortality and morbidity in the world today |
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transmission of malaria parasite (plasmodium falciparum)
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mosquito borne
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Life cycle of malaria
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1st stage in LN --> liver --> RBCs --> mosquitos
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Malaria
disease |
periodic fevers
cerebral syndrome (ring hemorrhage) - can be fatal anemia renal complications hepatosplenomegaly |
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Malaria diagnosis
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blood stages (may contain no parasites b/c they stick to endothelial cells)
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treatment of malaria
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artemesin
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control of malaria
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insectiside-coated nets
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immunity to malaria
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no vaccine available
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predisposition to malaria
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children and travelers (have no immunity)
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General multi-organ parasites
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Lesimaniasis
Amoebiasis Ecchinococcus Cysticercosis |
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Toxocara
general facts |
ascarids
dog and cats roundworms (all puppies infected) zoonotic problem |
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transmission of toxocara
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fecal-oral route
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toxocara (Ascarids) life cycle
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eggs present/mature in moist soil
can't complete cycle in humans |
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Toxocara disease
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ocular and CNS problems in children
visceral larva migrans (VLM) - larvae migrating in body tissues ocular larva migrans (OLM) - larvae migrating in eye and CNS |
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diagnosing toxocara
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clinical signs, serology
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treatment of toxocara
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anhelmintics
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Echinococcus granulosus
general facts |
small tapeworms of dog gut
causes "Hydatid disease" |
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Echinococcus granulosus
transmission |
dog feces
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Life cycle of echinococcus granulosus
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cystic larvae eaten by dog to complete life cycle
dog feces eaten by herbivores (Eggs hatch here and invade viscera) |
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echinococcus granulosus
disease |
space occupying lesions - grow massively
can go anywhere in body - lung, bone, brain, etc. |
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Treatment of echinococcus granulosus
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surgery
anhelmintics |
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Strongyloides
general facts |
threadworms
free living, non-pathogenic soil nematodes less common than hookworm more severe than hookworm - can be life threatening (esp. in immunocompromised b/c of autoinfection) |
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Strongyloides transmission
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skin penetration
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Strongyloides life cycle
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soil maturation can produce free living cycle
penetrate skin and travel via venule, right heart and lungs coughed up and sallowed (autoinfection) mature into adults quickly in gut tiny intestine dweller |
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Strongyloides disease
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hemorrhage due to invasion (not b/c of eating like hookworms)
death of parasites --> inflammation |
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Diagnosisng strongyloides
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larvae in feces
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Treating strongyloides
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albendazole
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