Emeria tenella most common species causing bloody enteritis in poultry. Emeria tenella is the best known of poultry coccidia because of the easily recognizable lesions and often spectacular losses it causes in commercial broilers or layer pullets.
Oocyst of Emeria tenella: Oocysts are ovoid, averaging 22 × 19mm. Experimental inoculation of Emeria tenella 102 or more sporulated oocysts can cause morbidity, mortality, and greatly reduced weight, gain, making this one of the most pathogenic species in chickens. Inoculation of Emeria tenella 103 oocysts is sufficient to cause bloody droppings and other signs of infection.
Gross Lesions of Emeria tenella infection:
Even during maturation of the first generation of schizonts, small foci of denuded epithelium may be seen in Emeria tenella infection.
By day 4 PI, the second-generation schizonts are maturing, and hemorrhages are apparent.
The cecal pouch may become greatly enlarged and distended with clotted blood and pieces of cecal mucosa in the lumen in Emeria tenella infection.
On days 6 and 7, the cecal core becomes hardened and drier; eventually it is passed in the feces in Emeria tenella infection. Regeneration of the epithelium is rapid and may be complete by day 10.
Emeria tenella usually can be seen from the serosal surface of the ceca as dark petechiae and foci, which become coalesced in severe infections. The cecal wall is often greatly thickened because of edema and infiltration and later scar tissue.
Histopathology of Emeria tenella infection:
Microscopically, the first-generation schizonts are widely scattered and mature at 2–3 days PI in Emeria tenella infection. Small focal areas of hemorrhage and necrosis may appear near blood vessels of the inner circular muscles of the muscularis layer in Emeria tenella infection.
Heterophil infiltration of the submucosa proceeds rapidly as the large second-generation schizonts develop in the lamina propria in Emeria tenella infection.
These are found in clusters or colonies that generally are progeny of a single first-generation schizont. Maturation of the second-generation schizonts is accompanied by excessive tissue damage, bleeding, disruption of the cecal glands, and destruction of the mucosa and muscularis layer in Emeria tenella infection.
Microgametes and macrogametes are seen in the tissues on days 6 and 7, and mature oocysts are released into the lumen in large numbers in Emeria tenella infection. Regeneration of the epithelium and glands may be complete by day 10 in light infections, but the epithelium may never completely recover in severe infections. Lost muscularis mucosa is not replaced, and the submucosa becomes densely fibrosed in Emeria tenella infection.
Treatment Of Emeria tenella:If properly diagnosed, Emeria tenella infection treated successfully with single antibiotic.
Since there are many anticoccidial drugs but they limitation great limitation of application in the field due to their mode of action. Emeria tenella more exclusive coccidial infection in the field.
Toltrazuril acts on developing 1st schizont & 2nd generation schizont as well gametes of Emeria tenella but others anticoccidials acts on deferents stages. Emeria tenella rapid multiplication trigger by deloiping shizont & gametes stages.
Toltrazuril @7-100mg/kg for 48 hours effective against Emeria tenella infestion at field in acute & percutecase in Emeria tenella infection in chicken.