parasitology lab notes


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parasitology lab notes

  1. 1. Lab 8: Blood Parasites
  2. 2. Trypanosoma cruzi <ul><li>Extracellular hemoprotozoan found circulating in peripheral blood </li></ul><ul><li>Primarily found in Central & South America but occasionally reported in the south half of US </li></ul><ul><li>Transmitted by the kissing/assassin bug (reduviid bug) </li></ul><ul><li>Swimming stage called trypomastigote , banana shaped w/ lateral undulating membrane & thin, whiplike flagellum (tail) </li></ul><ul><li>Also has a resting cyst stage ( amastigote ) that may be found encysted in cardiac muscle </li></ul>
  3. 3. Trypanosoma cruzi <ul><li>Zoonotic potential!!!! </li></ul><ul><li>In humans causes Chagas Disease, acute symptoms are mild, chronic disease causes multiple organ damage (heart diz, intestinal malformation) if untreated is fatal!!!! </li></ul><ul><li>In dogs, can cause “mega” syndromes (megasophagus/ </li></ul><ul><li>megacolon), heart failure & severe fatigue </li></ul><ul><li>Transmission: by posterior station – insect does not inject! Insect defecates while taking blood meal – animal/human scratches feces into open wound. </li></ul>
  4. 4. Babesia spp. <ul><li>Intracellular protozoan found w/in RBCs of dogs – destroys RBCs </li></ul><ul><li>Pear-shaped trophozoites in center of cell – side by side </li></ul><ul><li>B. canis: Transmitted by Rhipicephalus sanguinus (Brown dog tick) </li></ul>
  5. 5. Babesia spp. <ul><li>B. bigemina/bovis : Transmitted by Boophilus tick. </li></ul><ul><li>Destroys RBCs at such a rate that it looks like cattle are urinating blood due to hemoglobin in urine </li></ul><ul><li>Also called Red Water Fever or Texas Cattle Fever </li></ul><ul><li>Seen more in Mexico & South America after eradication efforts in US – REPORTABLE DISEASE!!!! </li></ul><ul><li>Cattle have immunity for 1 st 6mo. Then can cause severe anemia, anorexia, splenomegaly & fever. </li></ul><ul><li>Boophilus tick is one host tick – </li></ul><ul><li>Vertical transmission, female tick </li></ul><ul><li>passes Babesia transovarially to </li></ul><ul><li>baby ticks </li></ul>
  6. 6. Mycoplasma haemophilus: previously known as Hemobartonella felis/canis <ul><li>Bacterial cause of Feline Infectious Anemia </li></ul><ul><li>Rarely seen in healthy animals – seen commonly with immunosuppressed cats (FELV+ or FIV+) </li></ul><ul><li>Epicellular rods on RBCs and in plasma </li></ul><ul><li>Transmitted by blood sucking insects (fleas, ticks, lice & mosquitoes) </li></ul><ul><li>Causes severe anemia, jaudice/icterus, animal may eat dirt or litter in effort to supplement more iron </li></ul>
  7. 7. Mycoplasma haemophilus <ul><li>Rarely seen in dogs, unless immune system suppressed </li></ul><ul><li>Usually filtered by spleen </li></ul><ul><li>Can be diagnosed through blood smear or PCR (Coomb’s test) </li></ul><ul><li>Easily treated with Doxycycline </li></ul>
  8. 8. Eperythrozoans <ul><li>Rickettsial parasites of swine, cattle, llamas </li></ul><ul><li>Appearance similar to M. hemophilus (Hemobartonella) </li></ul><ul><li>Seen as small cocci or rings on RBCs or free in plasma </li></ul><ul><li>Hemolytic in stressed or immunosuppressed animals only </li></ul><ul><li>Otherwise animal will filter through spleen </li></ul><ul><li>Transmitted by tick vectors </li></ul>
  9. 9. Anaplasma marginale <ul><li>Anaplasmosis – dark staining cocci on periphery or margin of RBCs </li></ul><ul><li>Mostly affects cattle & other ruminants </li></ul><ul><li>More severe in adults when stressed or immunocompromised </li></ul><ul><li>Considerable economic damage in cattle esp. older cows </li></ul><ul><li>Seen most in SE US </li></ul><ul><li>Causes anemia, dehydration & hypoxia </li></ul><ul><li>Anaplasma + Babesia = Tick Fever </li></ul>
  10. 10. Cytauxzoon felis <ul><li>Seen naturally in wild cats – innocuous </li></ul><ul><li>Causes severe fatal hemolytic anemia in domestic cats </li></ul><ul><li>Quickly destroys RBCs until death </li></ul><ul><li>Rare </li></ul><ul><li>Transmitted by Dermacentor variabilis : American Dog Tick </li></ul><ul><li>Seen in RBCs, WBCs, Macrophages – small dark staining, irregular ring form in cell </li></ul>
  11. 11. Ehrlichia canis <ul><li>Rickettsial parasite of dogs </li></ul><ul><li>Lives in WBCs, monocytes & neutrophils </li></ul><ul><li>Clusters in cytoplasm in morulae </li></ul><ul><li>Transmitted by Rhipicephalus sanquinus : Brown dog tick </li></ul><ul><li>Causes anorexia, depression, stiffness, edema of limbs & scrotum, coughing, dyspnea </li></ul><ul><li>Will see thrombocytopenia, leukopenia & anemia </li></ul><ul><li>Dx: buffy coat smear or serologic testing </li></ul><ul><li>Incidence increasing recently!!! </li></ul>