Cattle & Sheep Protozoa Flashcards
Which groups are in phylum Sarcomastigophora?
Sarcodina & Mastigophora
Which groups are in phylum Apicomplexa?
Coccidia, Piroplasmidia, & Haemosporidia
What are important characteristics of Sarcodina?
- amoeboid movement (pseudopodia)
- direct lifecycles
What are important characteristics of Mastigophora?
Who belongs to this group?
- one or more flagella
- direct or indirect lifecycles
- Giardia & Tritrichomonas
What are important characteristics of Phylum Ciliophora?
locomotion by cilia
What are important characteristics of Coccidia?
Who belongs to this group?
- obligate intracellular
- sexual & asexual reproduction
- environmental resistant oocysts/sporocysts
- direct/indirect lifecycles
- Eimeria, Cryptosporidium, Toxoplasma, Neospora, Sarcocystis
What are important characteristics of Piroplasmidia?
- parasites of blood cells
- sexual reproduction occurs in vectors (TICKS)
- indirect lifecycles
What are important characteristics of Haemosporidia?
- parasites of blood cells
- sexual reproduction occurs in vectors (BLOOD SUCKING DIPTERANS)
- indirect lifecycles
Which coccidian’s are intestinal?
Eimeria & Cryptosporidium
Which coccidian’s form tissue cysts?
Toxoplasma, Neospora, Sarcocystis
What are the hosts of Giardia duodenalis (A)?
HUMANS, other primates, dogs, cats, LIVESTOCK, rodents, wild mammals
What are the hosts of Giardia duodenalis (E) and what is it alternately known as?
- CATTLE & other hooved livestock
- aka G. bovis
Where do Tritrichomonas foetus live?
in genital mucosa
How are Tritrichomonas foetus transmitted?
sexually
- naturally, but also survives AI
Tritrichomonas foetus in Bulls?
- asymptomatic carriers (primary source in herd)
- infected for life - crypts of the prepuce (deeper in older bulls)
Tritrichomonas foetus in infected cows?
- return to estrus after early embryonic death
- pyometra, decrease in pregnancy rates
- most clear infection & cycle again, a few remain carriers
- re-infection is possible
How to control Tritrichomonas foetus in cattle?
- no effective treatment or vaccine
- test & cull bulls
- suspected or confirmed cases: notify the Office of the Chief Provincial Veterinarian (OCPV) w/in 24hr - AB & BC
- Cows: do not breed for at least 3 months (or cull carriers?)
- use only young bulls (<4yo) on pastures, or AI from clean bulls
- annually notifiable by lab to CFIA
- quarantine new animals to herd
Describe Eimeria’s overarching lifecycle?
Describe Eimeria’s Lifecycle within the host
- Oocyst is released into gut lumen
- Sporozoites released from oocyst in intestine (penetrate epithelial cells, contained w/in PARASITOPHOROUS VACUOLE, in the cytoplasm)
- Sporozoites divide: unique form of multiple fission - Merogony
- Host cell ruptures releasing merozoites which infect new host cells (process repeats 2-5x - sp specific)
- Gamete-like stages form
What is the prepatent period of Eimeria spp?
2-3 weeks
What does Acute Bovine Coccidiosis in dairy calves look like?
- obvious
- young animals (2-6 months), anytime (summer more common for younger)
- infected from dams, triggered by stress
- high morbidity, low mortality
- ABDOMINAL PAIN, D+, DYSTENTERY (blood, mucus, fibrin), TENESMUS, DEHYDRATION, WEAKNESS, INAPPETENCE
-“Winter coccidiosis”
What does Chronic Bovine Coccidiosis in dairy calves look like?
- diagnostic challenge
- chronic D+, sub-clinical production impacts (reduced growth rates, delayed puberty/fertility)
What does Bovine Nervous Coccidiosis in dairy calves look like?
- muscle tremors, hyperesthesia, convulsions w/ ventroflexion of head & neck, nystagmus, high mortality (80-90%). not replicated experimentally, serum from affected calves was neurotoxic in mice.
- increasing in Northern USA & Canada
How do we diagnose Eimeria spp?
- clinical signs
- oocysts in feces (sp ID based on features of sporulated oocysts; flotation technique)
Who are the hosts of Cryptosporidium parvum?
calves < 3 months, livestock, people
Who are the hosts of Cryptosporidium andersoni (abomasum)?
adult cattle
Who are the hosts of Cryptosporidium ubiquitum?
Ruminants
What is the IH & DH of S. bovicanis (S. cruzi)?
cattle & dog
What is the IH & DH of S. ovicanis (S. tenella)?
sheep & dog
What is the IH & DH of S. miescheriana?
pig & dog
What is the IH & DH of S. bovifelis (S. hirsute)?
cattle & cat
What is the IH & DH of S. ovifelis?
sheep & cat
What is the IH & DH of S. porcifelis?
pig & cat
What is the IH & DH of S. hominis?
cattle & human
What is the IH & DH of S. suihominis?
pig & human
How to diagnose Sarcocystis?
- post-mortem (incidental finding)
- abortus: histology & immunohistochemistry, PCR
How to control Sarcocystis?
- prevent dog from eating abortuses, dead stock, or raw meat
- keep feed away from wild & domestic canids & felids
- no treatment
- no need to cull aborting cows
Outcome of Neospora infection in cattle in early pregnancy?
fetal death & resorption
Outcome of Neospora infection in cattle mid pregnancy?
- abortion (typical)
- infected, neurological calf (underweight, unable to stand, flexed or hyper-extended limbs, lack of coordination, & decreased reflexes & sensory perception)
Outcome of Neospora infection in cattle in late pregnancy?
- infected, but clinically normal - may infect their own offspring
- uninfected calf (rare)
What other outcomes are there of Neospora infections in infected cows?
MAY HAVE PROBLEMS WITH SUBSEQUENT PREGNANCIES
- Endemic abortion (endogenous): recrudescence of chronic infection
- Epidemic abortion (exogenous): acute infection following ingestion of sporulated oocyts - ABORTION STORMS
How do we diagnose Neospora in cattle?
- clinical & epidemiological (endemic or epidemic abortions)
- serology: ELISA titres in aborting vs non-aborting cows
- abortus: CNS/muscle histology & immunohistochemistry, PCR
How do we control Neospora in cattle?
- prevent dogs from eating abortuses, dead cattle, raw meat
- keep cattle feed & water away from wild canids & dogs
- do not breed seropositive cattle (cull)
What are the subclasses of G. duodenalis, Assemblage A?
A-I: humans & animals
A-II: humans
A-III & A-IV: exclusively in animals
Not all giardia spp are zoonotic!!
Who is Tritrichomonas foetus?
- Flagellates
- no free living or cyst stage (direct transmission)
- cattle & cat strains differ genetically
What is the most common cause of human cryptosporidiosis?
ingestion of contaminated food & water
What is the lifecycle of sarcocystis?
- Sexual reproduction (gametogony) in small intestine of DH, w/ sporogony (forming sporocysts w/ sporozoites)
- asexual reproduction (merogony) in vascular endothelium in IH, enter striated muscle/nervous tissue
How do you interrupt the lifecycle of Sarcocystis?
What is Acute Sarcocystis?
Dalmeny disease, S. cruzi = bovicanis
- caused by merogony in vascular endothelium
- fever, emaciation, anemia, ABORTION, rarely CNS signs (sheep too)
- high morbidity & mortality
What is chronic Sarcocystis?
Eosinophilic myositis
- post-mortem diagnosis, incidental finding
- greenish focal stripes in skeletal muscle
- breakdown of sarcocysts inducing immune response
What is Neospora caninum?
MOST IMPORTANT CAUSE OF BOVINE ABORTION IN CANADIAN CATTLE
Neospora caninum indirect life cycle?
Lifecycle of Toxoplasma gondii (direct or indirect)?
How do we control Toxoplasma gondii?
- regional variation in seroprevalence in sheep (20-100%)
- prevent access of cats to sheep feed
- vaccines have been developed but not in widespread commercial use (live attenuated strain passaged repeatedly in mice that does not cause tissue cysts administered to sheep to prevent abortion)
- to prevent zoonotic transmission: thoroughly wash hands after handling aborted or stillborn fetuses; cook lamb & mutton to 70 degrees C or freeze at -20 degrees C for at least 3 days
How do we diagnosis Giardia?
- Daily fecal samples for 3 days
- zinc sulphate floatation, direct saline smear (trophozoites are fragile)
- coproantigen/PCR
How do we diagnose Tritrichomonas foetus in cattle?
- decreased pregnancy rates
- increased open cows in newly infected herds
- cows: parasite or DNA on cervical mucous, uterine fluids from aborting cows
- abortus: stomach fluid
- bulls (most reliable, herd level): preputial scrapings (or washes), repeated sampling (3 tests @ weekly intervals)
- direct observation, culture, or PCR (higher sensitivity than culture alone, higher specificity: differentiates from other trichomonads, rumen contaminants, & free-living organisms)
How do we diagnose Cryptosporidium?
- detection of oocysts in feces
- multiple fecal samples over 2-3 day intervals (centrifugal floatation: Sheather’s Sugar solution, fecal smears: acid-fast stain, immunofluorescent staining - cyst antigen - test of choice from diagnostic lab, oocysts are small: 4-8 um, species identification requires molecular analysis)
How do we diagnose Toxoplasma?
- indirect methods: serology, IgG (chronic), & IgM (acute)
- direct: gross pathology: macroscopic necrosis in cotyledons, histology: multifocal necrosis on placentomes & fetal organs, microscopy: tachyzoites in brain & placenta, isolation from blood or body fluids, histology/immunohistochemistry, PCR
What is the animal and public health significance of Giardia?
- prevalence in cattle is high, mostly in dairy
- worldwide distribution, mainly young
- impact: clinical disease is uncommon, can cause acute, intermittent, or chronic diarrhea; reduced gain, feed efficiency, carcass weight can happen; may be influenced by concomitant infections (coccidia, nematodes)
What is the animal and public health significance of Cryptosporidium?
- usually affects young animals (C. parvum - calves as early as 2 days of age; C. angersoni - post-weaned calves, adults)
- acquired through ingestion of contaminated feed, water, & by grooming
- auto infection is possible, can be serious in immunocompromised individuals
- important cause of neonatal diarrhea (almost 100% prevalence, millions of oocysts/ gram of feces)
- low infectious dose (1 oocyst)
Clinical Presentation of Toxoplasma gondii?
- relevant in sheep & goats
- abortion storms in naive animals
