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25 Cards in this Set
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Eimeria bovis
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Oocyst: 4 sporocysts with 2 sporozoites each
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Direct, single host, sporogony in environment. Immature oocyst in feces > sporulation in environment (2-3w, requires moisture, O2, proper temp 10-12C) > infective oocyst ingested > oocyst excysts in SI > asexual repro in SI > merozoites, infect more intestinal cells > asexual repro (schizogony or merogony) usually self-limiting > after several generations, oocysts produced via gametogony > oocysts produced. Organism is “all-in-all-out” – once oocyst is passed, the organism is gone. Continual reinfection à persistent infection.
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Eimeria zurneii
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Oocyst: 4 sporocysts with 2 sporozoites each
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Direct, single host, sporogony in environment. Immature oocyst in feces > sporulation in environment (2-3w, requires moisture, O2, proper temp 10-12C) > infective oocyst ingested > oocyst excysts in SI > asexual repro in SI > merozoites, infect more intestinal cells > asexual repro (schizogony or merogony) usually self-limiting > after several generations, oocysts produced via gametogony > oocysts produced. Organism is “all-in-all-out” – once oocyst is passed, the organism is gone. Continual reinfection à persistent infection.
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Eimeria orinoidalis
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Can get “giant meronts”, huge #s merozoites
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Crypto-sporidium parvum (C. hominis, C. bovis)
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Coccidia-like parasite, 4 sporozoites each; sporulated when passed, Smaller than RBCs, 5-8um
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Infection continuous; autoinfectious, 2 types of oocysts: (1) thick-walled: passed in stool, generally calves <6w, (2) thin-walled: ruptures within gut. Oocytes infectious when passed; resistant to common disinfectants. Meront/gamont are intracellular but extracytoplasmic = on top of cell, just within plasma membrane. From oocyst to oocyst: <2d, Specific immunity takes 6-7d
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Crypto-sporidium baileyi
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Coccidia-like parasite, 4 sporozoites each; sporulated when passed, Smaller than RBCs, 5-8um
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Crypto-sporidium meleagridis
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Eimeria tenella, necatrix, acervulina, maxima, mivati, brunette
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Disease of confinement, Mixed infections common, Each species has tissue-site specificity and differential age susceptibility
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Eimeria adenoeides, meleagridi.
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Disease of confinement, Mixed infections common, Each species has tissue-site specificity and differential age susceptibility
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Eimeria debliecki
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Unsporulated occyst in sow feces à develops in environment à ingested by piglet nursing on dirty teats. Affects NEONATAL pigs, older swine carriers. Often mixed with Isospora = worse
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Eimeria scabra
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Isospora suis
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Porcine neonatal coccidiosis (more sporocysts than Eimeria) = significant morbidity in nursing pigs; distinguish from viral/bacterial diarrheas of piglets. Sporulation time ~24hrs = favors explosive outbreaks
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Isospora canis
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Oocyst: 2 sporocytes w/ 4 sporozoites each
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Homoxenous or heteroxenous Sporulated oocysts passed in feces à ingested by rodents (paratenic) à rodents carry cystozoites = sporozoites encysted in mesenteric lnn à dog/cat ingests rodent à sporulation time 4d
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Isospora wallacei
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Heteroxenous: dog eats raw beef (oocysts fed to dogs do NOT infect)
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Isospora felis
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Homoxenous or heteroxenous, rodents can carry cystozoite
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Sarcocystis cruzi: Also: ovicanis, ovifelis, bovifelis, bovicanis
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Thin-walled oocysts, 2 sporocysts, 4 sporozoites each. Killed by UV light (keep moist, cool)
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Obligate heteroxenous. Asexual in prey (pathology). Sexual in predator (gametogeny in lamina propria of SI). Definitive host (predator): thin-walled oocysts sporulate in gut > shed infectious naked sporocysts containing sporozoites in feces (can survive in environment for months) > ingested by intermediate host (prey) > penetrate arterial endothelium (1st stage meront), then capillaries (2nd), meront in blood monocyte (3rd) > sarcocysts (bradyzoites) in muscle > eaten by predator > merozoites > gametocytes
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Sarcocystis neurona
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Horse is aberrant, dead-end host; only supports growth of rapidly-dividing meronts (not sarcocyst stage). Sporocysts passed in opossum feces à horses infected by eating/drinking materials contaminated by possum feces
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Toxoplasma gondii
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Oocyst 13-11 um x 11-9um
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Sexual cycle only in cat, in lamina propria; cat supports gametogenous infection ONCE. Asexual cycle in mammals (including cats) and birds, any nucleated cell. Cat ingests oocysts or tissues w cysts > merogony in intestinal epi > gametogony > unsporulated oocysts shed (3-5d PI, for 1-2w ONLY) > sporulation in environment (infectious for many months) > ingestion by intermediate host > sporozoites differentiate > tachyzoites (acute infection, rapidly-dividing) > conversion to bradyzoites in tissue cysts (chronic infection, slowly dividing). Weak IR: tachyzoites flare up, Strong IR: host clears infection. Intermediate host behavior: mice lose fear of cats, human risk-taking behavior. ALL STAGES INFECTIOUS; INFECTION IS FOR LIFE: Transmission: ingestion of sporulated occysts or tissue stages (tachyzoites, encysted bradyzoites); transplacental transmission (acute infection), rare in cats. Human mother to fetus: 30-40% women infected. Transmission ONLY occurs if mom acquires initial infection WHILE PREGNANT; otherwise maternal immune system protects fetus.
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Neospora caninum
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Oocysts similar to T. gondii
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Transmission: ingestion of sporulated occysts, tissue cysts (tachyzoite), , transplacental
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Babesia canis
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Piriform, round or amoeboid, 4-5um. LARGE (more than ½ of RBC). Paired, tear-drop shaped piroplasm in RBCs
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ONLY INFECTS RBCs. (don’t have MHCI = good hiding place. Hide there and change Ag). Infected RBCs can lodge in capillaries. Transmission: ticks (Rhipacephalus sanguinus), dogfights, blood transfusions, transplacental. Risk factors: ticks, kennels, fighting, transplacental, splenectomy/chemo, blood transfusion (often from pit bulls). Any age of dog; most severe in puppies or immunocompromised
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Babesia gibsoni
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SMALL (less than ½ of RBC); single, oval piroplasm
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B. gibsoni (Asia): Haemophysalis sp. B. gibsoni (CA): unknown vector. B. coco (new spp from splenectomized dog): unknown
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Cytauxzoon felis
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Infects MPs and RBCs. Transmission: Dermacentor variabilis ticks. Seasonal (April-September)
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Plasmodium gallinaceum
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Meronts and gamonts in RBCs; malaria pigment
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Gametocytes ingested by female mosquito > gametes > fertilization > zygote (ookinete) > sporocyst > sporozoites migrate to salivary gland, transmitted when mosquito feeds > sporozoites enter endothelial cells (liver, blood vessels) > merozoites > reinvade endothelium or RBCs > asexual repro > some gametocytes, circulate in blood awaiting mosquito
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Leuco-cytozoon simondi
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Gamonts in WBCs, no malaria pigment
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Mosquito Simulium > 2 kinds of schizonts: hepatic & and megaloschizonts (lymphoid cells or MPs) > gametocytes in lymphocytes, RBCs
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Leuco-cytozoon smithi
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Gamonts in WBCs, no malaria pigment
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Mosquito Simulium > 2 kinds of schizonts: hepatic & and megaloschizonts (lymphoid cells or MPs) > gametocytes in lymphocytes, RBCs
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Hemoproteus
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Gamonts in RBCs, malaria pigment
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Gametocytes only inRBCs
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