Parasitology 9: Protozoa 1 Flashcards
Protozoa
cellular?
organisms?
groups?
group differentiation?
Unicelular
eukaryotic
Several groups
-Locomotion: cilia or flagella or no specific organelles for movement
-Reproduction: sexual, asexual, or both
-Location in host: some intra and others extracellular
-Life cycles: direct and indirect lifecycle
Biggest difference between Protozoa and worms
Protozoa are:
Single cell
ASEXUAL and maybe sexual reproduction in vertebrate host
MICROparasites
Individual can transform into new stage in final host and go on to infect new host (ex. Giardia)
Diagnostic stages seen in fecal samples called oocysts or cysts
Can protozoan (especially trypanosomes) undergo many cycles of Ag variation?
True
Phylum Apicomplexa division?
most IMPORTANT and COMPEX of the protozoan parasite groups
COCCIDIA TYPE ORGANSIM = GI TRACT
Hemosporozoa (blood parasites- hemoparasite)
Coccidian parasites
succes and group range?
repro?
location of parasite?
life cycle
host specific?
clinical disease?
most common sign?
identification stage?
- Highly successful and widespread group
- Sexual and asexual reproduction
- Most are parasites of the GI tract
- Both direct and indirect life cycles, depending on species
- Usually host specific for host where sexual reproduction occurs
- Clinical disease primarily related to GI tract: diarrhea most common sign
- Usually diagnosed by identification of stage specialized for transmission
in feces: oocyst
Coccidiosis
meaning?
animals they effect with what factors?
what limits further infection?
GI disease caused by coccidia parasites is called coccidiosis
Usually a disease of young animals in combination with environmental factors
-Heavy exposure to oocysts
-Stress
-Diet change
-Weaning
-Other
Immunity limits further infection and prevents disease
What is the diagnosis of Coccidiosis?
Clinical diagnosis
*diarrhea MUST be present**
Coccidia oocycts
passed in?
shell and cell inside~compare to strongylid eggs?
resistant to what conditions~ time it can survive?
survive well where?
what is sporogony and what does that equate?
how many cells undergo division to form what?
Passed in feces
Thin shell with single cell inside – smaller than strongylid eggs (12-50 µm)
Highly resistant to environmental conditions: may survive “≥” 1 year in protected locations (out of direct sun or desiccation)
Survive very well in animal housing and outside
Undergo sporogony in the environment: sporulated oocyst
Single cell undergoes division in environment to form sporocysts containing sporozoites
Are stongyld eggs bigger or smaller than coccidia oocysts?
BIGGER
Coccidian parasites
Simplest life cycle in what group?
what species do they effect?
are they host specific?
economically what species do they effect?
host have how many species of coccidia?
Starting with the simplest life cycle in this group:
-Eimeria spp. (many species)
-Common intestinal parasite
- Ruminants
- Birds
- Rodents
- Pigs
- Others
Very host specific
Economically important parasites of ruminants and poultry
Host may have more than one species of coccidia
Summary of the EIMERIA life cycle?
It has 3 processes
in environment
Sporogony
in organism
Schizogony or Merogony (asexual)
Gametogony (sexual)
Coccidiosis
how is disease caused?
what effects the pathogenicity?
Disease caused by destruction of cells as coccidia stages emerge to continue their life cycle
Pathogenicity of each coccidia species affected by
- Cell type infected. For example, infection of epithelial cells at tips of villi results in less damage than infection of regenerative cells at base of villi - each species uses specific cells
- Number of generations of multiplication
Ruminant coccidiosis
infected with how many host-specific ____species worldwide?
pathogenic?
cattle?
sheep and goats?
how is the immunity?
Th1 or Th2?
animals exposure & when?
adults carry?
Ruminants infected with multiple host-specific Eimeria species worldwide
Not all species are pathogenic
Cattle: 12 species are considered valid. However, Eimeria bovis and E. zuernii most pathogenic
Sheep and goats also have just a few species (host specific) that cause most disease
Immunity is species specific and partial (gradually develops)
What kind of immune response Th1
All animals routinely exposed from early age and some protection from dam
adult animals carry LOW level of infection
Ruminant coccidiosis
Pathology and clinical outcome influences by several factors?
Eimeria species present
Infection dose
Species replication potential
Inflammatory/immune response
Concurrent infections (other pathogens)
Management practices
Related stress
What is the impact of coccidia infection?
Subclinical
clinical disease mild to severe signs
Subclinical
-Some studies show impacts on weight gain
Clinical disease mild to severe
-Diarrhea, with blood if very severe
-Fecal stained perianal area
-Straining to defecate and subsequent rectal prolapse
-Weight loss and/or stunting
-Death
Ruminant coccidiosis and what is the diagnosis & control?
Diagnosis
-All young animals have oocysts in manure by a few months of age
-Presence of oocysts alone doesn’t provide diagnosis of coccidiosis
-Clinical judgement important
Control
-Fix environmental elements that disrupt balance
-Improve sanitation, feed off the ground
-Fix damp spots, good for oocysts
-Reduce stress
-Use of coccidial drugs
What is important to consider when a patient is infected with coccidia eggs?
It does NOT mean they have coccidiosis (disease)
the amount of eggs isn’t always a good indicator because many coccidia oocyst may be NONINFECTIOUS
look for clinical signs like diarrhea
Poultry coccidiosis
amount of species of _____ species?
important?
problem in what kind of chicken flocks?
pathogenicity?
sites of infection?
Each type of bird host infected with multiple different Eimeria species
One of the most important production diseases of confined poultry: several billion $ spent world wide annually for prevention in broilers
Also can be a problem in backyard chicken flocks
Coccidia species vary in pathogenicity
Different sites of infection can produce different signs
In confinement housing, all birds receive some form of prevention for coccidia to reduce severity of infection
Anticoccidial drugs
Vaccine composed of live oocysts
Backyard birds may have food containing drugs for prevention or be treated if disease develops
Other domestic and wild birds have their own species that can be pathogenic
Coccidia in dogs and cats?
genus?
____ specific?
life cycle summary?
diagnosis
Enteric coccidiosis caused by coccidia in genus Cystoisospora (Former Isospora)
Host specific
Diagnosis
-oocysts in the feces: large and small oocycsts in both cats and dogs from different species
coprophagy in dogs leads to presence of Eimeria oocysts in canine fece: spurious parasites
What are the clinical signs for coccidosis for canine and feline
Diarrhea
What is the genus and species for pigs and rabbits (coccidia)
Cystoisospora suis: pigs
Neonatal diarrhea, stunting, death if compounded by other factors
Hepatic coccidiosis of rabbits
Eimeria stiedae: Parasites in the bile ducts, causes severe damage
Also have intestinal coccidiosis
