Protozoa- Apicomplexa 1: Eimeria Flashcards
(44 cards)
What is the function of the apical complex of apicomplexa?
Orchestrates entry into host cells.
What is the apicoplast?
Organelle within apicomplexa parasites that have a separate genome which is evidence of a plant endosymbiont origin.
Parasites of the apicomplexa phylum are mostly what kind of parasite?
Intracellular.
What are the apicomplexans of veterinary interest?
- Plasmodium spp.
- Eimeria spp.
- Cryptosporidium spp.
- Toxoplasma gondii
- Neospora spp.
- Babesia spp.
- Sarcocystis, Cystoisospora, Besnoitia.
What is Plasmodium spp. most notorious for?
Human malaria, but also avian malaria.
What is the definitive and paratenic host of Toxoplasma gondii?
Definitive: cats
Paratenic: many hosts.
What are the definitive and intermediate hosts for Neospora spp.?
Definitive for carnivores
Intermediate for some herbivores.
What are the definitive and intermediate hosts of Babesia spp.?
Variety of definitive hosts
Intermediate: ticks.
Describe the general life cycle of Eimeria spp.
- The environmental stage (passed in feces of definitive host) is an oocyst.
- Unsporulated when they emerge from the host and sporulate to infective stage in the environment.
- Highly host specific.
What happens when a host is infected with Eimeria spp.?
Oocyst and sporocyst walls are removed mechanically or chemically in the host digestive tract, and banana-shaped sporozoite infects the host gut epithelial wall.
Each successive round of schizogony within the Eimeria life cycle involves ________ host cells, and therefore ___________ pathology.
More and more.
In the Eimeria life cycle, schizonts rupture out of cells which releases what?
Merozoites for the next round.
What is sporogony?
Sexual reproduction of Eimeria spp. within the gut epithelium of the host that produces male and female gametes that fuse to form the oocyst which are shed in feces to complete the life cycle.
What are examples of pathogenic Eimeria spp. found in the poultry industry?
- E. tenella (ceaca)
- E. necatrix (SI)
- E. acervulina
- E. brunetti
- E. maxima
- E. mitis
- E. praecox.
What is the Eimeria species known to infect turkeys?
E. meleagridis.
What are the clinical signs of coccidiosis in poultry?
- Protein losing enteropathy
- Reduced feed conversion efficacy
- Huddling; ruffled feathers
- Damage to caecal tubes
- Blood in feces
- Mortality in latter part of growth cycle.
Mortalities from coccidiosis is commonly associated with which Eimeria species?
E. tenella and E. necatrix.
What are the environmental controls/prevention methods for coccidiosis?
- All in, all out
- Keep litter dry.
What are coccidiostats?
Chemicals that reduce the reproductive rates of coccidia.
What factors must be kept in mind when using coccidiostats as a method of control/prevention for coccidiosis?
- Withdrawal requirements to avoid food residues
- Resistance
- Anti-microbial resistance.
What are the two types of vaccines used against coccidiosis in avian species?
- Precocious strains
- Sub-unit vaccines.
What are precocious strains?
- A mixture of attenuated spp that miss out on the last generation of schizogony and have short pre-patent periods and are less pathogenic.
- Transmission blocking: reduce oocyst build-up.
When are Eimeria vaccines most commonly used?
Broiler breeders.
What do subunit Eimeria vaccines consist of?
Gametocyte proteins against E. maxima.
