Protozoa - Coccidia - Eimeria Flashcards
What is schizogony?
multiple progeny from 1 cell
formation of merozoites
What is sporogony?
Formation of sporozoites
Apical complex features
Cytoskeletal and secretory functions
-> penetration and invasion
What is a parasitophorus vacuole?
A bag that the parasite sites in to mask it from the hosts immune system. Also replicated and feeds in here.
Apicomplexa replication
- Schizogony
- Gametogony
- Sporogony
- asexual -> merozoites (pathogenic stage)
- sexual - macro and micro gametes -> zygote -> unsporulated oocyst
- Asexual - sporulation of the oocyst in external environment or within the host (infective stage)
Apicomplexa direct lifecycle
Which species and what is the configuration?
Isospora
1 oocyst: 2 sporocyst: 4 sporozoite
= 8
Which species and what configuration?
Eimeria
1 oocyst: 4 Sporocyst: 2 Sporozoite
Which species and what is the configuration?
Sarcocystis
0: 2 sporocyst: 4 sporozoite
Configuration of Cryptosporidium?
1 Oocyst: 0 sporocyst : 4 free sporozoite
Non cysts forming coccidia
- lifecycle direct or indirect?
- Direct lifecycle
- Eimeria
- Cystoisospora
- Cryptosporidium
Hosts of Eimeria
Birds, ruminants, lagomorphs (hare and rabbit)
highly host specific
Eimeria adult site
- endogenous development in the intestinal mucosa
Lifecycle of Eimeria
Oocysts in the faeces -> sporulation (sporogony) -> sporocyst and sporozoite -> infect a new host -> sporozoites released in gut -> invade host cells -> schizogony -> lyse host cell to release merozoites -> gametogony -> zygote -> oocyst
Significance of coccidiosis due to Eimeria
Economic losses - poultry
Enteritis (watery/bloody diarrheo)
Immunity to Eimeria
Immunity develops with exposure
-usually subclinical/asymptomatic infections
Susceptibility to coccidiosis due to Eimeria
- naive animals (weaners)
- low immunity
- high dose
- overcrowding, stress, poor hygiene, poor nutrition
Diagnosis of Eimeria
Post mortem (fresh)
- gross observation, predilection site, pathology
- mucosal smears/scrapings + fixed gut sections for histo
Ante mortem
- faecal floatation for unsporulated oocysts
Control of Eimeria in poultry
Vaccinate
Hygiene
- ammonia based disinfectants
- desiccation
- treat and introduce
- biosecutiry
Sporulation time of Eimeria
1-3 days
best at 21-30 degrees in humid conditions
Anti coccidial agents
Ionophore antibiotic
Toltrazuril
Sulphonamides
Cause of hepatic coccidiosis in rabbits
Eimeria stiedae
Pathogenesis of E. stiedae in rabbits
-Merogony in the bile duct//gall bladder epithelium -> jaundice, diarrgoea, sudden death
Important Eimeria of cattle
E. zuernii
E. bovis
Consuquenced of Eimeria in cattle
- calf diarrhoea/bloody scours
- Production losses
How to deal with Eimeria in cattle
Reduce overcrowding
Coccidiostats in milk replacer, feed or drench with toltazuril
Causes of coccidiosis in lambs and how old are they?
E. crandallis
E. ovinoidalis
1-5 months old
Prevention of coccidiosis in lambs
coccidiostats in feed
- late gestation ewe and prior to weaning lambs
Most important Eimeria in birds?
E. tenella
E. necatrix
Important Eimeria to remember
Bird Eimeria
