Protozoa and Rickettsia

protozoa

• single celled organisms

• infect a variety of tissue sites (usually blood), also fecal material (intestinal protozoa)

• sexual or asexual reproduction

• simple or complex lifecycles

• ticks usually intermediate host

trophozoite

• vegetative form

• stage of feeding, movement, and reproduction

• very fragile stage

Organelles for locomotion

• flagella- long whiplike structures

• Cilia- short flagell arranged in rows or tufts

cyst stage

• metabolic functions suspended

• Happens under the conditions below

  • lack of nutrients, low oxygen tension, lack of water, low pH, accumulation of waste, overcrowing

Trypanosoma cruzi

• parasite of humans and dogs

• extracellular and swim in blood

• banana shaped

• swimming stage- trypomastigote

• cyst stage- amastigote

  • also found in cardiac muscle and other tissue

Chagas disease symptoms

lethargy, fever, decreased appetite, weight loss

how chagas disease is transmitted

• mexican kissing beetle carries it

  • beetle also sucks blood from dog and defecate around wound

  • dog licks feces from wound, eat beetle or eat contaminated stool

Leishmania

• hemoprotozoan that infects severak mammals- dog, cats,and humans

• transmitted by sandflies

• two forms of disease are recognized

  • mucocutaneous form

  • visceral form

mucocutaneous form of leishmania

• Leishmania braziliensis

• characterized by skin sores

Visceral form of leishmania

• affects internal organs (liver, spleen, and bone marrow)

• Leishmani donovani and leishmania infantum

Trichomonads

• long slender organism with a single flagellum (It looks like subnautica bladder fish with a little tail)

Tritrichomonas foetus

• reproductive tract of cattle

• causes infertility, spontaneous abortions and, pyometra

Trichomonas gallinae

• found in crop washings of pigeons, doves, and poultry

• transmitted through drinking water

• looks like subnautica bladder worm with a little tail and many antennae

what Trichomonas gallinae looks like in an affected bird

Cystoisospora

• protozoal parasite of small intestine of dogs and cats

• Cause Coccidiosis, one of most commonly diagnosed disease in puppies and kittens

• Oocyst is diagnostic stage in fecal float

Babesia

• babesia canis

• intracellular RBC parasite of dogs

• pear shaped body, tick is intermediate host

  • seen in a blood smear, trophozoite stage333