5 may 2020 - 10:03 CET

Histological findings in experimentally infected male calves with chronic besnoitiosis

Carlos Diezma-Díaz, Enrique Tabanera, Ignacio Ferre, Manuel Pizarro-Díaz, Marta González-Huecas, Javier Blanco-Murcia, Luis Miguel Ortega-Mora, Gema Álvarez-García.

Abstract

The histological findings associated to Besnoitia besnoiti infection were exhaustively studied in target tissues from experimentally and chronically infected calves. Calves were inoculated with 10⁶ bradyzoites via intravenous, subcutaneous and intradermal route. Visible pathognomonic sclera cysts were observed in all infected animals. Tissue cysts were more abundant and lesions were more frequent in calves inoculated via intradermal. The most parasitized tissues were skin, including scrotum (40.81% of positive samples), nostril and nasal turbinate. Tissue cysts were already fully developed as the average tissue cyst diameter was 181.20 μm. Microscopic lesions were mainly detected in skin samples, followed by reproductive and upper respiratory tracts. Mild lesions compatible with both acute (thrombus, oedema and inflammation) and chronic besnoitiosis (skin lesions, hyperkeratosis and dilated sweat glands) coexisted. Vascular damage and inflammation were more frequently observed in skin (including scrotum) followed by testicular parenchyma, epididymis and pampiniform plexus. Histological findings evidenced a subclinical chronic besnoitiosis.

Highlights

• Histological findings in Besnoitia experimentally infected calves are described.
• Cysts and lesions were mainly found in calves inoculated via intradermal.
• The most parasitized tissues were skin, nostril and nasal turbinate.
• Mild lesions compatible with both acute and chronic besnoitiosis coexisted.
• Histological findings evidenced a subclinical chronic besnoitiosis.