Protozoa Flashcards
Giardia intestinalis
Common name: Beaver fever
Zoonotic: Yes
Host: Dogs, cats, livestock, humans (grouped in assemblages)
Characteristics: Long-teardrop shape
Site of Infection: small intestine
Life cycle: Asexual reproduction
Infective stage: trophozoite
Diagnostic stage: Trophozoite
Clinical Signs: acute inflammation and diarrhoea
Method of diagnosis: Faecal smear, double centrifugation, ELISA, PCR
Pathogenesis: duodenal ulcerations; malabsorption
Spironucleus (Hexamita) spp.
Common name: n/a
Zoonotic: n/a
Host: Domestic fowl (except chickens)
Characteristics: Two nuclei; three anterior flagella and 2 posterior flagella
Site of Infection: large intestine
Life cycle: same as Giardia
Infective stage: Trophozoite
Diagnostic stage: Trophozoite
Clinical Signs: Listlessness, watery/foamy diarrhoea, grouping of birds and chirpping
Method of diagnosis: History, symptoms, organism found in intestine content
Pathogenesis: Catarrhal enteritis; rapid weight lost; dehydration; muscles are dark and dry; high mortality in young birds
Tritrichomonas foetus
Common name: Cattle and feline version exist
REPORTABLE
Host: Cattle or Feline
Characteristics: Single nucleus; 3 anterior flagella and 1 posterior
Site of Infection: Cattle: genital tracts; feline - large intestine
Life cycle: No cystic stage; asexual reproduction
Infective stage: trophzoite
Diagnostic stage: trophozoite
Clinical Signs: Cattle - asymptomatic
Method of diagnosis: PCR, InPouch TF test
Pathogenesis: preputial discharges, infertility, decreased herd yield
*Trichomonas spp.
Common name: Canker or Frounce
Zoonotic: no
Host: Domestic and wild fowl
Characteristics: Pear shaped; single nucleus; four anterior flagella; axostyle exist; free posterior flagellum
Site of Infection: oral-nasal & upper digestive tract
Life cycle: asexual reproduction
Infective stage: Trophozoite
Diagnostic stage: Trophozoite
Clinical Signs: Smell yellow lesions; inflammation and ulcerations of mucosa; diarrhoea
Method of diagnosis: Finding organism in fluid of mouth or crop; yellowish-white nodules in oral cavity; microscopic examination of lesions
Pathogenesis: principle disease in young birds*
Histomonas spp.
Common name: Blackhead
Zoonotic: no
Host: Fowl; PH: earthworm
Characteristics: Single flagellum while in cecum –> flagellum is lost in liver; pseudopodial movement
Site of Infection: cecum and liver
Life cycle: n/a
Infective stage: trophzoite in egg
Diagnostic stage: trophzoite
Clinical Signs: Weight loss lesions in cecum, death
Method of diagnosis: history, clinical signs, lesions in cecum and liver, identification of trophzoite in liver or cecum
Pathogenesis: haemorrahagic liver (white spots found on liver); infectious enterohepatitis; cecal inflammation and ulceration
Trypanosoma cruzi
Common name: Chagas disease
Zoonotic: yes
Host: Dogs, cats, humans
Reservoir hosts: Armadillos, racoons, opssums, rats, monkeys
Insect vectors: assassin/kissing bug
Characteristics: Nucleus near the middle of its body; posterior end is pointed; single flagellum near posterior end
Site of Infection: muscle and blood
Life cycle: Asexual reproduction - binary fission
Infective stage: Trypomastigote
Diagnostic stage: trophozoite
Clinical Signs: Cardiac disease, pale mucous membrane, lethargy, ascites
Method of diagnosis: Blood smear, xenodiagnosis, serological test
Pathogenesis: pathology in heart muscle, highly pathogenic, hepatomegaly and splenomegaly, tachyarrhythmia, lymphadenopathy
Leishmani spp.
Common name: Kala-azar or Oriental sore
Zoonotic: yes
Host: Dogs, humans
Alternative hosts: many reservoirs; IH: sand flies
Characteristics: large nucleus, rod-shaped kinetoplast
Site of Infection: skin, liver, spleen, bone marrow, and lymph nodes
Life cycle: Asexual reproduction - simple division
Infective stage: n/a
Diagnostic stage: n/a
Clinical Signs: skin ulcerations on lips and eyelids; fever, anaemia, cachexia, generalized lymphadenopathy
Method of diagnosis: Scraps or smears from affected skin; lymph node, spleen or bone marrow biopsy, ab-ELISA, PCR
Pathogenesis: Amastigotes cause pathology in skin, liver, and spleen.
Cystoisospora (Isospora) canis
Common name: Coccidia Zoonotic: no Host: Dogs Paretenic host: Rodents Characteristics: Largest of all coccidian in dogs Site of Infection: Small intestine Life cycle: Typical Eimeridae life cycle Infective stage: Sporulated oocyst Diagnostic stage: Occyst Clinical Signs: Diarrhoea Method of diagnosis: must be distingusihed from Eimeria spp. Pathogenesis: Small intestinal cells are destroyed --> profuse diarrhoea
Isospora suis
Common name: n/a
Zoonotic: n/a
Host: Swine
Site of Infection: Small intestine
Life cycle: Typical Eimeria
Infective stage: Sporulated oocyst
Diagnostic stage: oocyst
Clinical Signs: biphasic diarrhoea - loose faeces to persistent fluid diarrhoea
Method of diagnosis: organism found in faeces under microscope
Pathogenesis: High morbidity, low mortality; destruction of small intestine cells; enteritis
Eimeria spp.
E. Bovis & E. zuernii
Common name: Eimeria of cattle
Zoonotic: no
Host: Cattle
Characteristics: ovoid to spherical oocyst
Site of Infection: small and large intestine
Life cycle: reside in the endothelial or lamina propria cells in the first stage; epithelial cells in the second stage
Infective stage: sporulated oocyst
Diagnostic stage: oocyst
Clinical Signs: Diarrhoea
Method of diagnosis: faecal float to detect oocyst
Pathogenesis: inflammation of mucosa; disruption of large intestine; severity related to parasite density
Eimeria spp. of sheep and goats
E. crandallis & E. ovinoidalis (sheep)
E. Ninakohlyakimovae, E. caprina (goats)
similar to E. bovis
Eimeria leukarti
Common name: Eimeria of equine
Zoonotic: no
Host: all equids
Characteristics: thick dark shell; distinct mycropyle
Site of Infection: small intestine
Life cycle: typical emierian - three phase life cycle 1. sporulation 2. asexual reproduction (infection and schizogony) 3. sexual reproduction
Clinical Signs: intermittent diarrhoea
Method of diagnosis: Sugar floatation; sedimentation
Pathogenesis: inflammation of muscoa; disruption in villous architecture
Eimeria suis
Emieria in swine
Similar to other Eimeria spp.
Eimeria spp. in avian
Common name: Eimeria in avian species
Zoonotic: no
Host: Chickens, turkeys, ducks
Site of Infection: ceca cells
Life cycle: typical eimerian
Infective stage: oocyst
Diagnostic stage: oocyst
Clinical Signs: blood in droppings, high morbidity and mortality
Method of diagnosis: lesions indicative of species
Pathogenesis: Chronic illness due to cecal core (blood clot); E. tenella is the most pathogenic species in young chicks
Toxopasma gondii
Common name: n/a
Zoonotic: yes
Host: Cats
IH: humans, warm blooded animals
Characteristics: oocyst contains 2 sporocysts w/ 4 sporozoites
Site of Infection: intestinal and extraintestinal cells (muscles, liver, lung, brain)
Life cycle: Sporulation in 1 - 5 days
PPP: 3 - 10 days
Clinical Signs: dependent on the organ infected; pneumonia
Method of diagnosis: Oocyst in faeces; serological test; biopsy; PCR; IgM ELISA
Pathogenesis: most animals are asymptomatic; can cause aborptions in humans - parasites form tissue cysts
Sarcosystic spp.
Common name: n/a
Zoonotic: yes
Host: Dogs, Cats, humans,
IH: cattle, herbivores, birds
Characteristics: oocyst contains 2 sporocytes w/ 4 sporozoites; bradyzoites in muscle tissue
Site of Infection: IH - muscle; Final host - GI
Infective stage: Sacrocysts with bardyzoites
Diagnostic stage: sporocyst
Clinical Signs: no signs in final host; IH - fatal: fever, anaemia, anorexia, diarrhoea, abortion
Method of diagnosis: identifying sporocytes in final host; bradyzoites in muscle tissue of IH
Sarcocystis neurona
Common name: Equine protozoal myeloencephalitis (EPM)
Zoonotic: no
Host: Opossum
IH: Cats, skunks, fishers, racoons
Aberrant host: horses
Site of Infection: DH - intestine; IH - muscles; AH - neurons
Life cycle: typical; schizons develop in horses neurons
Clinical Signs: Horses - progessively debilitating disease affecting the CNS (atypical lameness or seizures, difficulty walking or standing)
Method of diagnosis: Histopathological demonstration, western blot test, PCR on CSF
Pathogenesis: Non-pathogenic in definitive host; neurological damage in horses
Neospora spp.
Common name: n/a
Zoonotic: no
Host: Dogs and coyotes
IH: Dogs, cattle, white-tail deer, water buffaloes and sheep
Characteristics: Spherical oocyst (colourless); sporulted oocyst contains 2 sporocytes w/ 4 sporozoites
Site of Infection: Intestine; IH - CNS
Life cycle: Not completely understood
Infective stage: Bradyzoite in cysts
Diagnostic stage: Sporocyst
Clinical Signs: Abortion at 3 months in cattle
Method of diagnosis: Serology of serum and CSF
Pathogenesis: lesions in the CNS, heart, skeletal muscle and liver
Cryptosporidium spp.
Common name: n/a
Zoonotic: yes
Host: ride range of vertebrates serve as host; Humans (C. hominis & C. parvum); Cattle (C. parvum & C. andersoni)
Characteristics: oocysts contains 4 sporozoites
Site of Infection: digestive or respiratory tract
Life cycle: Direct transmission
Infective stage: sporulated oocyst
Diagnostic stage: Oocyst
Clinical Signs: diarrhoea
Method of diagnosis: oocysts in faecal slide (direct smear); sugar floatation; acid fast strains; ELISA; IFA
Pathogenesis: May be asymptomatic; immunocompromised patients are at higher risk
Hepatozoon spp.
Common name: n/a
Zoonotic: no
Host: Dogs
Vector: Tick
Characteristics: Gamonts in blood cell
Site of Infection: schizonts - skeletal and cardiac muscle; Gamonts - white blood cells
Clinical Signs: subclinical infction; severe disease –> joint pain and myositis
Method of diagnosis: peripheral blood examination for parasites; examination of muscle tissue at biopsy
Pathogenesis: neutrophilic leucocytosis; myositis and periosteal bone proliferation; lessions in the proimal long bones of the limbs
Babesia spp.
Common name: n/a
Zoonotic: yes (rare)
Host: Dogs (B. canis & B. gibsoni), occasionally humans
Vectors: Ticks (Rhipicephalus sanuineus)
Characteristics: Trophozoites in RBC; pairs as pyriform merozoites or in tetrades
Site of Infection: Erythorocyte
Life cycle: typical
Infective stage: sporozoite
Diagnostic stage: Trophozoite and merizoite
Clinical Signs: Depression; anorexia; anaemia; splenomegaly
Method of diagnosis: Trophozoites in peripheral blood smears
Pathogenesis: Erythrocyte destruction; cause of canine babesiosis and piroplasmosis
Babesia bigemina
Common name: Texas Cattle Fever Zoonotic: no Host: Cattle Vectors: Ticks (Rhipicephalus spp.) Characteristics: Trophozoite in RBC Site of Infection: Erythrocytes Life cycle: simiarl to B. canis Infective stage: oocyst Diagnostic stage: Trophozoite Clinical Signs: chronic cases - intermittent fever, anaemia, emaciation, oedema, icterus Method of diagnosis: peripheral blood smear for trohozoites; serology (IFA or ELISA) Pathogenesis:
Theileria (cytauxzoon) felis
Common name: n/a Zoonotic: no Host: Cats Characteristics: found in RBC Site of Infection: RBC Life cycle: poorly understood Clinical Signs: Fever, anaemia, icterus Method of diagnosis: Wright's or Giemsa-strained blood smear Pathogenesis: enlargement of infected cell; occlusion of blood vessels (heart, liver, lungs), rapid and fatal disease
Leuocytozoon spp.
Common name: n/a
Zoonotic: no
Host: Domestic and wild fowl
Vectors: Blackflies and biting midges
Characteristics: Spherical to ovoid; found in blood or tissues
Site of Infection: Brain, heart, lung, kidney, gizzard, intestine, lymphoid tissue, blood cells
Life cycle: complicated
Clinical Signs: listless, anaemic, laboured breathing, CNS syndrome, death
Method of diagnosis: Blood smear, biopsy, necropsy
Pathogenesis: morbidity and mortality may be in high in young animals
Balantidium spp.
Common name: n/a
Zoonotic: no
Host: Pigs, rodents, primates, humans
Characteristics: Trohozoites are covered in cilia; kidney shaped nucleus
Site of Infection: large intestine
Life cycle: asexual reproduction - binary fission
Infective stage: cysts
Diagnostic stage: cysts
Clinical Signs: diarrhoea
Method of diagnosis: direct faecal smear; faecal float
Pathogenesis: mild to severe enteritis; dysentery in pigs and humans; ulceration in humans; not a primary pathogen –> can cause secondary disease in the large intestine
