Protozoa Flashcards
1
Q
Terminology
A
Zoite–functional unit of protozoan development
- Prefixes are added to the term “zoite” to denote a life-cycle stage.
- Sporozoite–infective form found in a sporulated oocyst
- Trophozoites–form which feeds and grows
- Tachyzoites–form which divides rapidly
- Bradyzoites–form which divides slowly
2
Q
Life cycles
A
Oocysts to Sporulation to Sporulated oocyst
Cyst to Trophozoite
Asexual reproduction
- Binary fission, budding, schizogony (merogony)
- Protozoa that divide asexually have a short generation time, Exponential increase in the number of zoites, Destruction of host cells in proportion to the infection, Stops after a fixed number of repetitions
Sexual reproduction
- Gametogonyor sporogony
- Merozoite becomes either a Macrogametocyte(macrogamont) and then a macrogamete OR Microgametocyte (microgamont) and then several microgametes, When a microgamete fertilizes a macrogamete a zygote forms; then a wall forms around this and it becomes an oocyst
3
Q
Phyla
A
- Ciliophora: locomotion by cilia
- Sarcomastigophora: locomotion by pseudopodia and/or flagella
- Apicomplexa: locomotion by gliding, largely intracellular with sexual and asexual phases
4
Q
Balantidium coli
A
- Pigs, rodents, primates, zoonotic
- Ciliophora
- Trophozoites and cysts, largest protozoan
- Large intestine
- Mild to severe enteritis and dysentery
- Tetracycline
5
Q
Giardia intestinalis
A
- Dogs, cat, cattle etc., zoonotic
- Assemblages host specific (Zoonotic are A and B)
- Sarcomastigophora
- Trophozoites, Cysts (infective)
- Small intestine
- Acute or chronic diarrhea
- Fecal smear, fecal flotation (zinc sulphate); ELISA (SANP)
- No approved treatments for dogs and cats, Benzimidazole for cattle, Filters with 10um aperture
6
Q
Sprionucleus (Hexamita) spp.
A
- Domesticandwildfowl, S. melegridis in Turkeys and S. columbrae in Pigeons
- Chickensarenotaffected
- Sarcomastigophora
- Largeintestine
- Youngbirdsaffected (3-5wk)
- Infectiouscatarrhalenteritis, Listlessness, Watery/foamy diarrhea, Rapid weight loss
7
Q
Tritrichomonas foetus
A
- Cattle
- Sarcomastigophora
- Transmitted by coitus
- Bulls long time carriers
- Early abortion
- No treatment
- PCR & culture for diagnosis
- Prevention-cull +bull, AI
- Reportable disease
8
Q
Feline trichomonosis
A
- Tritrichomonas foetus
- Sarcomastigophora
- All breeds are susceptible
- ≤ one year old
- Fecal-oral route
- Diarrhea –cow pie-like stools
- PCR & culture
9
Q
Trichomonas spp.
A
- Canker(pigeons);Frounce (hawks)
- Domesticandwildfowl
- Sarcomastigophora
- “Pigeonmilk”;water;raptorpreying
- Trophozoites only
10
Q
Histomonas spp.
A
- Blackhead
- Fowl,primarilyturkeys
- Heterakis isthevector
- Sarcomastigophora
- Cecumandliver
- Infectiousenterohepatitis, Hemorrhagic/necroticliver lesions
- Separatedby>2yearsraisingchicken& turkeyinsamefacility
11
Q
Trypanosoma cruzi
A
- Dogs, cats, humans & many reservoirs
- Sarcomastigophora
- Amastigotes in muscle cells
- Chagas disease, Acute and chronic cardiac disease
- Elongated trypomastigote in blood smear, Xenodiagnosis or serological test
12
Q
Leishmania spp.
A
- Common name: Kala-azar (visceral), Oriental sore (cutaneous)
- Dogs, humans & many reservoirs
- Sarcomastigophora
- Skin, liver, spleen, bone marrow & lymph node
- Leishmaniasis (Cutaneous, Mucocutaneous, Visceral)
- Amastigotes in macrophages, ELISA, PCR
13
Q
Isospora canis
A
- Dogs
- PH: Rodents
- Big oocyst, 50 μm
- Small intestine
- Young animals most susceptible
- Diarrhea can be severe, watery, profuse and bloody
14
Q
Isospora suis
A
- Infects 1-2 week old piglets
- High morbidity; low mortality
- Diarrhea
15
Q
Eimeria spp.
A
- Multiple species (Pigs- 8, Cattle - 12, Sheep- 11, Goats- 9, Birds, Horses- 1)
- Life cycle: 1. Sporulation; 2. Asexual reproduction: infection and schizogony; 3. Sexual reproduction: gametogony and oocyst formation
- Small & large intestine
- Young animals (ex: Foals, 1-3mo lambs)
- Enteritis and diarrhea
- McMaster flotation for oocysts, Unsporulated oocysts excreted then sporulate, Sugar flotation or specific sedimentation for E. leukarti (Horses)
- Treatment: Avoid overcrowding, Sanitation, Immunity develops, Antiprotozoals, Coccidiostats, Supportive therapy, reduce stress
16
Q
Eimeria tenella
A
- Parasite in cecum of chickens
- Infection: Infective stage is sporulated oocysts, Through contaminated food and/or water
- Cycle: Has 1st and 2nd generation merozoites
- Clinical: bloody diarrhea, often result in death of young birds, plugged cecum due to clotted blood and sloughed cells
- Diagnosis: Necropsy (cecum)
- Prevention: Coccidiostats in food or water, Vaccine (species specific effectiveness)
17
Q
Toxoplasma gondii
A
- FH: Cat, other felids
- IH: Warm blooded animals, zoonotic
- Human infection –oocysts, tissue cysts, transplacental
- SOI: Intestinal and extraintestinal cells
- Signs: Cats asymptomatic but acute toxoplasmosis with FIV, Abortion in IH animals, Necrosis of IH organs
- Diagnosis: Oocysts in feces, Serological using direct agglutination, ELISA, IFA, Aborted fetus and placenta of IH, Necropsy
- Prevention: Avoid contaminated feces, Avoid undercooked meat from IH, Pregnant women should avoid sources
- Treatment: Nonsulfonamides and sulfonamides
18
Q
Sarcocystis spp.
A
- FH: Dogs, cats, humans, carnivores and birds
- IH: Cattle, herbivores, omnivores, birds; several species are zoonotic
- Sporulated oocysts with 2 sporocysts each with 4 sporozoites
- PPP: 1-2wk, sporocysts released 1wk-several mo
- SOI: Sarcocysts in muscles of IH, Sporocysts in GI Tract of FH
- Signs: None in FH, Abortion late gestation in IH
- Diagnosis: Sporocysts
- Prevention: Avoid raw meat and prevent fecal contamination
19
Q
Sarcocystis neurona
A
- Equine protozoal myeloencephalitis (EPM), the most commonly diagnosed infectious equine neurologic disease in America
- DH: Opossum
- IH: Cats, striped skunks, armadillos, fishers, raccoons, etc
- AH: Horse
- PPP: 1-2wk
- SOI: Gametogony in FH, Schizogony in IH (muscle), Schizonts in neurons of AH
- Signs: Non-pathogenic (FH); Pathogenesis in vascular endothelium from 2nd stage (IH); Affects the CNS, brain, brainstem, and spinal cord of AH (Lameness, Seizures, Difficulty standing, walking, or swallowing)
- Antemortem diagnosis challenging (Western blot, PCR), Necropsy (Histopathology of CNS)
- Treatment: Opossum control, Antiprotozoals
20
Q
Neospora spp.
A
- FH: Dogs
- IH: Dogs, cattle, sheep, goats, horses
- SOI: Gametogony in intestine of dog, Sporulated oocysts ingested by IH often go to CNS
- Transmission: Transplacental typical in dogs and cattle
- Signs: Abortion (mainly middle gestation), Fetus brain most consistently affected with encephalitis most common lesion
- Diagnosis: Serology (serum and CSF), Necropsy, Differentiate from T. gondii and Sarcocystis spp.
- Treatment: None effective in cattle, Prevent fecal contact, Hygiene, Dispose fetuses, Vaccinate cows 1st trimester
21
Q
Cryptosporidium spp.
A
- AKA: “Crypto”
- FH: wide range of vertebrate hosts; C. parvum infects calves (<3 wk) and humans; C. andersoni infects older calves & adults
- Oocysts: small; immediately infectious
- Transmission:ingestion (often water borne) & inhalation
- SOI: Epithelial cells of digestive tract, Respiratory tract
- Signs: Diarrhea, Immunocompromised patients high risk
- Diagnosis: Oocysts in fecal slides (Direct smear with stain; Concentrated sugar flotation), ELISA for Ag, IFA, acid fast stains such as Ziehl-Neelsen stains parasite red
- Treatment: None, Supportive treatment, Use filters with 4um aperture, Sanitation
22
Q
Hepatozoon spp.
A
- FH: Dogs
- Vector: Amblyomma spp.
- Identification: Gamonts in blood cells
- SOI: Schizonts in various tissues, Gamonts in WBCs
- Signs: H. canis- subclinical infection; H. americanum- severe disease; joint pain, myositis
- Diagnosis: Parasites in peripheral blood, Examine muscle tissue at biopsy or necropsy
- Treatment: No satisfactory treatment, Use tick control
23
Q
Babesia canis
A
- FH: Dogs
- Vector: Rhipicephalus sanguineus
- Identification: Trophozoites or merozoites in RBCs (Giemsa stain)
- SOI: Erythrocytes
- Signs: Depression, anorexia, anemia, splenomegaly
- Treatment: Antiprotozoal therapy effective but not approved in USA, Tick control
24
Q
Babesia gibsoni
A
- Similar to B. canis, but smaller
- Piroplasms in RBC only 1-2um vs. 4-5um
25
Q
Babesia bigemina
A
- Texas cattle fever
- FH: Cattle (older more susceptible and have chronic infection)
- Vector: Rhipicephalus (Boophilus) spp. (Cattle fever tick)
- Identification: Trophozoites or merozoites in RBCs
- SOI: Erythrocytes
- Signs: Arise from destruction of RBCs
- Diagnosis: Stained blood smears, Serology (chronic infections)
- Treatment: Antiprotozoal remedies, Tick control
26
Q
Cytauxzoon felis
A
- FH: Cats, Bobcats
- Vector: Amblyomma spp.
- Identification: Merozoites (1-2um) in RBCs
- SOI: Blood
- Signs: Fever, Anemia, Icterus, Developing schizonts cause enlargement of infected cells, Occlusion of blood vessels (heart, liver, lungs), Rapid and fatal disease in south central USA
- Diagnosis: Peripheral blood smear (Giemsa, Wright’s stain)
- Treatment: Tick control, Atovaquane(15mg/kg, PO,q8h) + Azithromycin (10mg/kg, PO,q24h) for 10D, Supportive care
27
Q
Leucocytozoon spp.
A
- FH:Domesticandwildfowl
- Vectors:Blackflies&bitingmidges
- Identification: Organismsinbloodortissues, Sphericaltoovaltospindle‐shaped massescontaining1‐4elongate,deeply stainedstructures
- SOI: Brain,heart,lung,kidney,gizzard, intestine,lymphoidtissue,bloodcells
- Signs: Pathogenicforyoungducksandgeese, Listless,anemic,laboredbreathing, CNSsymptoms,death
- Diagnosis: Organisms in blood or tissues
