**9.3 Pathogenesis**

Following infection in cattle or in goats, the tachyzoites proliferate in macrophages, fibroblasts, and endothelial cells and causing vasculitis. Subsequently they develop to form bradyzoite cysts in fibroblasts in the dermis, subcutaneous tissues, fascia, nasal and laryngeal mucosa (Taylor et al., 2007; Radostits et al., 2008). After developing cysts in the skin, painful subcutaneous swelling, thickening of the skin, alopecia, and necrosis can be occur (Taylor et al., 2007).

### **9.4 Clinical findings**

#### **9.4.1 Bovine besnoitiosis**

Clinical signs occur in two stages: acute and chronic. In acute stage clinical signs include fever, increase in pulse and respiratory rates, painful swelling on the ventral aspects of the body, edema of the skin, sometimes diarrhea, lacrimation and nasal discharge. In chronic stage, there is a severe dermatitis over most of the body (Radostits et al., 2008).

#### **9.4.2 Caprin besnoitiosis**

Thickening of the skin over the lower limbs, around the eyes, nose, face and scrotum, alopecia in all of these areas, and white granular cysts in the sclero-conjunctiva can be seen (Oryan and Azizi, 2008).

#### **9.5 Diagnosis**

Besnoitiosis can be diagnosed by demonstration of B. bradyzoites in skin biopsy smears or scleral conjunctival scrapings (Radostits et al., 2008).

#### **9.6 Treatment and control**

There is no known treatment for this disease (Taylor et al., 2007).

Control is effected by the elimination of infected animals and carriers, and early diagnosis ( Antonio Castillo et al., 2009 ).
