Protozoa Flashcards
(44 cards)
1
Q
sporozoite
A
infective form found in a sporulated oocyst
2
Q
trophozoites
A
form which feeds and grows
- the stage that often causes clinical signs
- does not survive well in the environment or in the host GI environment
- reproduce
3
Q
tachyzoites
A
form which divides rapidly
4
Q
bradyzoites
A
form which divides slowly
5
Q
oocysts
A
formed after sexual reproduction
- sporulation - fertilization
- sporulated oocyst - prior to fertilization, oocysts are not infective
6
Q
cyst
A
infectious stage
- contain a cyst wall that helps them survive in the environment and in the animals intestine
- do not reproduce
7
Q
asexual reproduction
A
- binary fission: nucleus divides first, followed by two equal size daughter cells
- budding: produce on large and one smaller cell
- Schizogony: nucleus divides first, followed by the formation of schizont which contains many different individuals and then eventually it will break apart and release many protozoa
- 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
8
Q
sexual reproduction
A
- gametogony or sporogony
- merozoite becomes either a macro gametocyte and then a macrogamete OR micro gametocyte and then several microgametes
- when a microgamete fertilizes a macrogamete a zygote forms, then a wall forms around this and it becomes an oocyts
9
Q
Sarcomastigophora
locomotion by pseudopodia and/or flagella
A
Kinetoplastorida
- trypanosoma
- leishmania
Diplomonadorida / Trichomonadorida
- giardia
- spironucleus
- histomonas
- tritrichomonas
- trichomonas
10
Q
Kinetoplastorida
- trypanosoma
- leishmania
A
- haemoflagellates
- parasites of the blood
- generally transmitted by biting insects
11
Q
Diplomonadorida/ Trichomonadorida
- giardia
- spironucleus
- tritrichomonas
- trichomonas
A
- flagellates
- predominately of the intestines
12
Q
Apicomplexa
- apical complex
- locomotion by gliding
- life cycle largely intracellular
- sexual and asexual phases occur
A
Eucoccidiorida
- Eimeria
- isospora
- cystoisospora
- hepatoozoon
- sarcocystis
Piroplasmorida
- babesia
- Cytauxzoon (Theileria)
Haemosporida
- leucocytozoon
- plasmodium
13
Q
Eucoccidiorida
- Eimeria
- Isospora
- Cystoisospora
- Hepatozoon
- Sarcocystis
A
- parasites of epithelial cells
- sexual and asexual reproduction occurs in epithelial cells
14
Q
Piroplasmorida
- Babesia
- Cyauxzoon (Theileria)
A
- parasites of blood cells
- ticks as vectors
- sexual reproduction takes place in ticks
15
Q
Haemosporida
- Leucocytozoon
- Plasmodium
A
- Parasites of blood cells
- biting insects as vectors
- sexual reproduction takes place in insects
16
Q
GIARDIA INTESTINALIS
A
DOGS, CAT, CATTLE, HUMANS
- 8 assemblages with host specificity ( A and B are zoonotic concern)
- infection: SMALL INTESTINE
Life Cycle:
- cysts are ingested by the host and may or may not cause clinical signs
- when the host has diarrhea, will find both trophozoites and cysts (feces must be fresh)
- no diarrhea, then will most likely only find cysts
- fecal flotation with zinc sulphate
- no tx approved in USA for dogs and cats, use of fenbendazole and metronidazole
- tx in cattle: benzimidazole
17
Q
SPIRONUCLEUS (HEXAMITA) SPP
S. meleagridis = turkeys
S. columbae = pigeons
A
Domestic and wild fowl - CHICKENS ARE NOT AFFECTED
- two nuclei, flagellated
- cyst is the infective stage
- infection: LARGE INTESTINE
- INFECTIOUS CATARRHAL ENTERITIS
- young birds affected
- droppings from carrier birds
- contamination of shoes or equipment carries fecal material form one location to another
- results in listlessness, water or foamy diarrhea, rapid weight loss, severe losses in young birds of 3-5 weeks
18
Q
TRITRICHOMONAS FOETUS
A
CATTLE
- 3 anterior flagella and an undulating membrane
- urogenital tracts: transmitted by coitus (venereal disease)
- causes abortions in cows less than 4 mo pregnant
- bulls over 4 years of age should be culled, younger than 3 years old typically recover but can become easily reinfected
- diagnosis: culture using IN Pouch test
REPORTABLE DISEASE
19
Q
FELINE TRICHOMONOSIS
A
- primary route of infection is by fecal-oral route
- purebred breeds more susceptible and older than 1 year old
- leads to diarrhea
- diagnosis with In Pouch
- Ronidazole tx drug
20
Q
TRICHOMONAS SPP.
A
CANKER (pigeons) FROUNCE (hawks) - domestic and wild fowl
- rophozoites in oral-nasal vacity and upper digestive tract
- 3 modes of infection: pigeons milk (mother to baby), contaminated drinking water, raptor feeding on infected prey bird
- infects the mouth, crop, esophagus and pharynx
- leads to small yellowish lesions (cankers) in the mouth
21
Q
HISTOMONAS SPP.
A
BLACKHEAD DISEASE of fowl, primarily turkeys
- heterakis is the vector
- infects cecum and liver
- cecum = flagellum / liver = no flagellum but filopodium present
- causes INFECTIOUS ENTEROHEPATITIS
- affects young turkeys and can be fatal
- hemorrhagic liver with cahrasteric lesions: yellow to yellow-green circular depressions
- marked cecal inflammation and ulceration
22
Q
TRYPANOSOMA CRUZI
A
DOGS, CATS AND HUMANS
- kissing bugs act as vectors
- ID: elongated trypomastigote in blood smear
- trypomastigote in blood smear
- xenodiagnosis or serological test confirming infected animal
23
Q
LEISHMANIA SPP.
A
KALA-AZAR (visceral) ORIENTAL SORE (cutaneous) of dogs and humans
- ID: amastigotes round or oval in host macrophages
- infect skin, liver, spleen, bone marrow and lymph node
- DX: tissue biopsy - amastigotes in macrophages, IFA, ELISA, PCR
- metacyclic promastigote is the infective stage
24
Q
ISOSPORA CANIS
A
DOGS and rodents serve as an intermediate host
- strict host specificity
- usually seen in younger host due to immunity developing in older hosts
- for the animal suffering clinical signs, most of the time antiprotozoal medications are not successful due to the damage already being done
- TWO SPOROCYSTS each containing 4 sporozoites
- both asexual and sexual reproduction take place in the host
- sporulation can take place outside the host
- SMALL INTESTINE
- tx: management is critical
25
ISOSPORA SUIS
PIGS and does NOT involve a paratenic host
- sporulation takes place outside the host and then the pig ingests the sporulated oocysts
- undergo asexual reproduction in the small intestine and release protozoa (merogony)
- cycle can repeat merogony three times
- will cause clinical signs in piglets at about two weeks old, exhibit diarrhea
* * high morbidity, low mortality
- some of the protozoa from the second stage can undergo sexual reproduction and release unsporulated oocysts in the host feces
26
EIMERIA SPP
- requiring one host (often restricted to a certain host species)
- merogony and gametogony within hosts, sporogony typically outside the host
life cycle:
1. sporulation
2. asexual reproduction: infection and schizogony
3. sexual reproduction: gametogony and oocyst formation
SPORULATED OOCYST CONTAIN FOUR SPOROCYSTS
- coccidiasis is inevitable - immunity
- coccidiosis is preventable
27
PIG - EIMERIA
FOUR SPOROCYSTS
- small intestine
- small intestinal cells are destroyed: enteritis, diarrhea
- diagnosis: oocysts
- treatment and prevention: avoid overcrowding and poor sanitation, immunity develops, antiprotozoal remedies
28
CATTLE - EMERIA
- ID: unsporulated oocysts in feces
| - small intestine
29
SHEEP & GOATS - EMERIA
- SMALL and LARGE INTESTINE
- pathogenesis- inflammatory changed, disruption of the mucosa (asexual reproduction can destroy or damage the epithelial cells and cause clinical signs)
clinical signs
- diarrhea: putty-like to watery to bloody (E. ovinoidalis)
- leads to dehydration and weakness
- severity related to species, parasite density and number of cells affected
outbreaks associated with:
- lambs 1-3 months old
- lot fed animals
- irrigated pastures
- corralling
- stress
30
EIMERIA LEUKARTI - EQUINE
- oval oocyst 80x69, thick dark shell and distinct micropyle, shell can come off
- PPP is 15 days with three phases: 1. sproulation outside the host, 2. asexual reproduction: infection and schizogony occurs outside the host, 3. sexual reproduction: gametogony and oocyst formation
- SMALL INTESTINE
- inflammatory changes in mucosa and disruption of villous architecture
- clinical signs: intermittent diarrhea, foals most susceptible
- sugar flotation or specific sedimentation techniques used
31
AVIAN - EMERIA
E. TENELLA
E. NECATRIX
E. BURNETTE
- CHICKENS, TURKEYS, DUCKS
- best diagnosed during necropsy
- SMALL and LARGE INTESTINE
- E. TENELLA MOST PATHOGENIC SPECIES IN YOUNG CHICKS
- prevention: prophylaxes using coccidiostats in food or water, vaccines effective with species specificity
diagnosis
- E. tenella = ceca
- E. necatrix = small intestine
- E. brunette = ileum, cecum and rectum
32
EIMERIA TENELLA
- CHICKENS
- living in the epithelium of intestinal ceca
- leading a high mortality rate in young birds
- pathogenesis: bloody diarrhea, sloughing of epithelium, plugged cecum due to clotted blood and cell debris causing necrosis, high morbidity and high mortality
33
TOXOPLASMA GONDII
CAT - zoonosis
- intermediate host: humans and warm blooded animals
- both INTESTINAL and EXTRAINTESTINAL CELLS (muscle, liver, lung, brain, ect)
Felid Infection
- cats eating infected animals (rodents) [direct transmission of oocysts]
- takes about 4-5 days
- typically asymptomatic
- cats develop immunity after initial infection and shed only once in a lifetime for 1-2 weeks
- an infected cat can cause harm to individuals with a weakened immune system and a pregnant woman's unborn child
Sheep and Goats
- distinct white foci on aborted fetuses and aborted placenta
- heavy infections, areas of necrosis in vital organs such as myocardium, lungs, liver and brain
Human infection
- food-borne, animal to humans, mother to child
34
SARCOCYSTIS SPP.
Dogs, cats, humans, carnivores and birds
- intermediate hosts: callt, herbivores, omnivores, birds (several species are zoonotic)
- sarcocysts with bradyzoites are the infective stage for the final host (MUSCLES IN IH)
- sporocyst - infective stage for the intermediate host (GASTROINTESTINAL TRACT IN FH)
- avoid raw meat and prevent fecal contamination
35
SARCOCYSTIS NEURONA
EQUINE PROTOZOAL MYELOENCEPHALITIS (EPM)
- most common infectious neuronal disease diagnosed in horses
- opossums are definitive host
- horses are aberrant host
- normal life cycle: gametogony in final host, schizogony in intermediate host --> bradyzoites in muscle tissue
- accidental life cycle - schzonts develop in horse's neurons instead of the muscles
pathogenesis
- final host: non pathogenic
- intermediate host: pathogenic effect due to 2nd stage schizogony in vascular endothelium
- accidental host: pathogenic due to 3rd stage schizogony in nervous tissue rather than muscle
clinical signs in HORSES
- a progressively debilitating disease affecting the CNS, brain, brainstem and spinal cord
- unusual or atypical lameness or seizures
- difficulty with standing, walking or swallowing
- may progress rapidly
- focal muscle atrophy
36
NEOSPORA SPP.
DOGS
- IH include dogs, cattle, sheep, goats and horses
- oocysts 12 microM and colorless
life cycle
- gametogony in dog
- sporulated oocysts ingested by intermediate host, excyst and enter cells extra intestinally
- most infections in cattle and dogs occur TRANSPLACENTALLY (tachyzoites) which can lead to abortions
- bradyzoites in cysts (in neural cells) which are the infective stage for the final host
- sporulated oocyst is infective stage for the intermediate host
sites of infection
- FH - INTESTINE
- IH- many types of cells, predilection site CNS
37
CRYPTOSPORIDIUM SPP.
C. HOMINIS
C. PARVUM
C. ANDERSONI
- cross infection among host species
- C. hominis infects humans
- C. parvum infects calves
38
HEPATOZOON SPP
H. canis
H. americanum
DOGS
- gamonts circulating in the white blood cells
- schizonts in various tissues
- H. canis - subclinical infection
- H. americanum - severe disease, joint pain, myositis
- spread by amblyomma maculatum tick
39
BABESIA CANIS
DOGS
- trophozoites or merozoites in red blood cells (pear shaped located inside RBC)
- infects ERYTHROCYTES
- clinical signs: depression, anorexia, anemia, splenomegaly
- spread by RHIPICEPHALUS SANGUINEUS TICK
40
BABESIA GIBSONI
- smaller than B. canid
| - piroplasms in RBC only 1-2 micrometers vs. 4-5 micrometers
41
BABESIA BIGEMINA
TEXAS CATTLE FEVER
- RHIPICEPHALUS (BOOPHILUS) SPP. TICK
- infects ERYTHROCYTES
- clinical signs arise from the destruction of red blood cells
- OLDER ANIMALS MORE SUSCEPTIBLE
42
CYTAUXZOON FELIS (THEILERIA)
CATS, BOBCATS
- small merozoites in red blood cells
- infect BLOOD
- pathogenesis: fever, anemia, icterus, developing schizonts cause enlargement of the infected cells, occlusion of blood vessels - heart, liver, lungs
- no satisfactory treatment
43
LEUCOCYTOZOON SPP
DOMESTIC AND WILD FOWL
- VECTORS: blackflies and biting midgens
- spherical to oval to spindle shaped masses
- organisms in blood or tissues
- infect brain, heart, lung, kidney, gizzard, intestine, lymphoid tissues, blood cells
- pathogenic for young ducks and geese
- listless, anemic, labored breathing, CNS symptoms, death
44
BALANTIDIUM COLI
ZOONOTIC
PIGS, RODENTS, PRIMATES, HUMANS
- trophozoites and cysts in the LARGE INTESTINE
- mild to severe enteritis and sysentery in pigs and humans
- ulceration in humans
- usually cysts seen
- tetracyclines are effective
