Coccidia Flashcards
What constitutes a member of the Apicomplexica phylum?
All are parasitic, no locomotory organelles, all have apical complex
What are the five components of an apical complex?
Polar ring, conoid, micronemes, rhoptries, subpellicle microtubules. Involved in infiltration of the cell
What are the stages of the apicomplexa?
the -zoites, the -onts, and gametocytes
What stage is the -zoite?
The motile, active form
What stage is the -ont?
Usually non-motile
What stage is the gametocytes?
The structures with products of gamete formation
How many hosts do coccidia have?
one
How many life stages does coccidia have?
Three- schizogony, gametogony (both inside host), and sporogony (outside host)
How do coccidia reproduce?
Asexually by multiple fission inside the host, and sexually by gametogony inside the host
What is sporogony?
The production of an oocyst, sporulates outside host to become infective
How many sporocysts and sporozoites does Eimeria have?
4 sporocysts, 2 sporozoites
How many sporocysts and sporozoites does Isospora have?
2 sporocysts, 4 sporozoites
How does host specificity compare between Eimeria and Isospora?
Eimeria is very host specific, usually present in herbivores, while Isospora have less specificity and usually are present in carnivores (swine are exceptions)
What is the typical life cycle of a coccidia?
Ingestion of an infective (sporulated) oocyst; sporocyte released, enters an epithelial cell, becomes a schizont, merozoites develop inside the schizont, schizont bursts and merozoites are released, which enter another epithelial cell. Usually 2-3 generations of schizonts/merozoites. The 2nd or 3rd generation merozoite enters another epithelial cell, becomes a micro- or macrogametocyte, which is fertilized and forms a zygote that forms into an oocyst. Oocyst ruptures and passes out feces, sporogony occurs outside host making the oocyst infective.
What are micro- and macrogametocytes?
Male and female gamonts (respectively), microgametes fertilize the macrogametocyte
What does coccidiasis mean?
The presence of coccidian parasites in a host
What does coccidiosis mean?
The presence of coccidian parasites and the resulting clinical signs
What are the intestinal signs of coccidiosis?
Diarrhea, dehydration, statorrhea, tenesmus, sloughing pieces of mucosa, fever, anorexia
What are the methods for managing the epidemiology coccidiosis?
Decreasing moisture, grouping animals by age, decreasing stress caused by weather, nutrition, shipping, dehorning, castration. Reduce dispersion by humans, wind, birds, etc.
What are methods for controlling coccidiosis in a herd?
Sanitation, chemoprophylaxis (prevention via drugs), chemotherapy (treatment with drugs), immunity
What is the life cycle of Eimeria tenella?
Oocytes are passed in feces, perform sporogony, ingested by host, then proceeds like normal coccidia
How long can Eimeria oocysts stay infective in the environment?
2-3 months
How long is the prepatent period of Eimeria tenella?
about 7 days (period between ingestion and first appearance of oocysts in the feces
What age is most commonly infected by Eimeria tenella?
About four weeks of age, referred to as “cecal coccidiosis”
What contributes to the varying pathogenesis of Eimeria tenella?
Depends on size of infecting dose, breed, age, nutritional status and stress factors
What are the clinical signs of Eimeria tenella?
Diarrhea and massive cecal hemorrhage, blood appearing 4 days post-infection, greatest hemorrhage between 5-6 days after infection. On the 7th day cecum changes from red to mottled reddish-white. Recovery is slow, might be affected by anemia, older birds develop immunity.
What is the life cycle of Eimeria necatrix?
1st and 2nd generation schizonts are in the small intestine, 3rd generation schizonts and gametogony occur in the ceca
What is the pathogenesis of Eimeria necratrix?
Pathology in the middle third of the small intestine, causes extensive scarring, lesions are small and white and death occurs in 5-7 days PI
What are the treatments for avian coccidia?
Sulfonamides, amprolium
What are ways to prevent avian coccidia?
Decoquinate, lasalocid, monesin
What are the vaccines available for avian coccidia?
Livavox, paracox, coccivac, not as effective as continuous prophylaxis
How does one diagnose avian coccidia?
With a post mortem exam or a fecal
What is Eimeria adenoides?
“Turkey coccidia” PPP 4-6 days, Patent period 7-20 days, most of life cycle takes place in the lower 1/3 of the SI, ceca and rectum
What is the pathogenesis of Eimeria adenoides?
Anorexia, droopy wings, ruffled feathers. Terminal intestine becomes swollen and edematous on day four, petechial hemorrhages filled with mucous
What is the pathogen that causes goose coccidia?
Eimeria truncata
