Parasites
Terms
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- Intermediate Host
- Houses intermediate stage of devpt
- Definitive Host
- houses adult/final stage of devpt (us. Human
- ECTOPARASITE
-
skin of host
INFESTATION - ENDOPARAISTE
-
digest tract/extraintest organs/intracell
INFECTION - 5 groups of parasitic disease
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1.Filth-borne/contaminative
2.Contracted from soil/water:
a.ingestion of infective stage
b.skin
3.Food-borne infection
a.raw flesh w/larval stage of parasite
b.encysted larvae on aquatic plant
4.Arthropod:intermediate host/vector (malaria)
5.Infestation by arthropods (lyse, scabies) - 2 Morphologies of Protozoa
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TROPHOZOITES: motile form in pts
CYSTS: under harsh envt conditions (soil,food,h20) - 3 types of Metazoa (helminth or worm)
-
oTrematodes/flukes (leaf-shaped flatworm)
oCestodes/tapeworks (ribbon-shaped flatworm)
oNematodes/roundworm -
3 types of PROTOZOAN
Flagellates -
1. Giardia lamblia:Giardiasis
Site: nonbloody diarrhea, intestines
Route: oral-fecal, cysts in food/water, from water, poor hygiene, sex
DX: TROPHOZOITES or cysts in stool
2. Trichomonas Vaginalis: Trichomoniasis
Site: Vagina, prostate, urethra
Route: Widespread- sex
DX: TROPHOZOITES in wet mount of vaginal exudates
3.Trypanosoma:Trypanosomiasis
Site: African:Blood-sleeping sickness, American:Visceral-Chagas disease
Route: African: Tsetse fly (dx:blood smear), American:Reduviid bugs (bone/marrow smear) - 3 types of PROTOZOAN Amoebae
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1.Entamoeba histolytica: Entamoebiasis
Site: Intestinal damage to mucosa, muscle, liver
Route: Oral-fecal vias cysts in h20/food, person-person contact
DX:TROPHOZOITES/cysts in stools
2. Acanthamoeba&Naegleria: Meningoencephalitis
Route: US, Europe, Australia, acquired by swimming in pond during bloom
3.Balantidium coli: Dysentery
Site: diarrhea, asymptomatic
Route: Oral-fecal, animal-person, p-p - 3 misc types of PROTOZOAN
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1. Toxoplasma gondii: Toxoplasmosis
Site: Systemic- lymph, blood, brain, most asymptomatic,immunosuppresed
Route:raw meat,cat/animal feces
DX:serology,tissues
2.Plasmodium Species(4): Malaria
Site: Infects RBC&liver- hemolytic disease, fever
Route: blood,vetor:mosquito
DX: Giesma stain
3.Cryptosporidium: Cryptosporidiosis
Site:Intestines- nausea, cramps,immunosuppresed
Route: Oral-fecal, cysts in food/h20, animal-person, p-p
DX: Oocysts by acid-fast stain of stool -
HELMINTHS/WORMS
Cestodes- Tapeworm -
1.Taenia Saginata: BEEF
Intestinal, asymptomatic, proglottids in feces
Ingested larvae attach to intestine and grow, gravid proglottids passed in feces, eaten by cattle (embryo from cow gut to skeletal muscle, develop into cysticerci—which is ingested
Microscopic ID of gravid proglottids in stool
2.Taenia solium: PORK
Intestinal, asymptomatic, proglottids in feces
3.Diphyllobothrium Latum: FISH
Intestinal, asymptomatic -
HELMINTHS/WORMS
Trematodes- Leaf-shaped flatworms -
1. Opisthorchis sinensis (Clonorchis: Clonorchiasis)=Chinese liver fluke
Liver disease
Oral-fecal,from raw fish
reservoir in dog/cat/human
2.Schistosoma species- Schistosomiasis: blood flukes **Common**
Live, spleen, bladder
From snails/h20 (pentration of skin)
Oral-fecal by contact w/h20-borne cercariae
Reservoir in pets/rodents/humans -
HELMINTHS/WORMS
Nematodes- Roundworms -
1.Trichuris trichiura: Whipworm: Trichuriasis
Intestinal. pers-pers
2.Enterobius vermicularis: Pinworm: Enterobiasis
Intestinal/perianal itching, pers-pers
3.Ascaris lumbricoides: Roundworm: Ascariasis
Intestina/bile ducts, pneumonitis- pers-pers
4.Ancylostoma duodenale & Necator americanus: Hookworms
Intestinal blood loss, pneumonitis, skin rash, pers-pers
5.Strongyloides stercoralis: Strongyloidiasis: pneumonitis
Inestinal in hyperinfection , pers-pers
6. Trichinella spiralis: Trichinosis
Systemic by migrating larvae, mild to severe, pig to human -
ECTOPARASITES
Lice -
-Pediculus humanus: vector for transmission of rickettsia of typhus and trench fever and spirochetes of relapsing fever
oHead lice: Pediculus humanus capitis
oBody lice: Pediculus humanus humanus
-Public Lice: Phthirus pubis -
ECTOPARASITES
Bugs -
-Bedbug: Cimex lectarius: hide in dark cracks and suck blood
-Triatomid bugs: in Americas
oLive in cracks/roofs
oVector for Chagas disease: Typanosoma cruzii -
ECTOPARASITES
FLeas - small, wingless, long legs for jumping, blood sucking, widespread, Xenopsylla cheopis vector for plague (Yersinia pestis) and murine typhus (Rickettsia
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ECTOPARASITES
Ticks -
-Hard Tick: Ixodidae
-Soft Tick: Argasidae -
ECTOPARASITES
Mites -
Scabies: Sarcoptes scabiei: human itch mite
o upper layer of epidermis
o may cause secondary infection from bacteria in broken skin
Dust mites: feed on dead skin, live in dust, people are allergic to their droppings⬦ asthma -
ECTOPARASITES
Mosquitos -
-Anopheles species:Malaria: Plasmodium species
-Aedes aegypti: Yellow fever (virus)