E. bovis

Location

• They are usually found in small and large intestine of cattle.

Identification/ Morphology

• Oocyst are ovoid or subspherical, colorless measuring average of 27.7 x 20.3 µm.
• Oocyst have smooth wall with inconspicuous micropyle, no polar granule or oocyst residuum.
• Sporocyst are elongate, ovoid, 13-18 x 5-8 µm and have inconspicuous stieda body and sporocyst residuum.
• Sporozoites are elongate and lie length wise head to tail in the sporocyst and usually have clear globule at each end.

Lifecycle

• Two asexual generation , first generation occurs in endothelial cells of the lacteals of villi in posterior half of SI and mature at 14-18 days of infection.
• Second generation occurs in epithelial cells of cecum and cecum or colon but may extend into meter of SI in heavy infection.
• Sexual stages generally occur in caecum and colon.
• Prepatent period: 16-21 days
• Patent period: 5-15 days
• Sporulation time: 2-3 days.

Ingestion of sporulated oocyst by host —- > Release of sporozoites in endothelial cells of villi. First generation schizogony —- > First generation schizont invades another cells, epithelial cells of villi — > Release of merozoites — > Merozoites undergoes gametogony —- > Formation of zygote from fertilization of male and female gamete — > Oocyst forms and released in feces — > Sporulation in environment in optimum condition —- >  Repeat

Clinical signs and pathogenesis

• Severe diarrhea usually bloody diarrhea (foul-smelling). Diarrhea may also contain masses of mucus and clots of blood.
• Enteritis
• Tenesmus in case of heavy infection.
• Animal may be pyrexic, weak and dehydrate if untreated, they may die.
• Rough coat, dropping ears, listlessness, soiled hindquarters, anorexia, inability to rise ad partial paralysis of anal sphincter in case of mixed infection with zuernii.

PM findings

• Mucosa of ileum appears congested, edematous and thickened with petechiae or diffuse hemorrhage.
• Gut lumen may contain large amount of blood.
• Sloughing of mucosa in chronic case.

Diagnosis

• Diagnosis is usually made through its characteristics symptoms, foul-smelling diarrhea, tenesmus, loss of appetite.
• Demonstration of oocyst in faeces.
• PM findings: characteristic intestinal lesions.

Treatment

• Treatment is usually through sulphonamide, such as sulphodimidine or sulphamethoxypyriazne given orally or parenterally. This is repeated at half the initial dose level on each of next 2 days.
• Though clinical signs are seen only when disease is advanced, these drugs are not effective as much.

Control

• Prevention and control is based on good hygiene or management.
• Feed trough and water containers should be cleaned regularly.
• Bedding should be kept dry.
• Frequent fecal examination should be carried out.
• Calves should be kept isolated within 24 hours after birth. Growing calves should not be kept with adult animals.