Besnoitia

Besnoitia is a genus of protozoan parasites belonging to the phylum Apicomplexa. These parasites are known to infect a variety of animal hosts, including mammals and reptiles. The genus is named after the French parasitologist Émile Besnoit, who first described the organism.

Morphology and Life Cycle

Besnoitia species are characterized by their formation of tissue cysts in the host. These cysts are typically found in the skin, subcutaneous tissues, and other organs. The life cycle of Besnoitia involves both asexual and sexual reproduction, with definitive hosts (usually carnivores) and intermediate hosts (often herbivores or omnivores).

The asexual stage occurs in the intermediate host, where the parasite forms cysts in tissues. The definitive host becomes infected by ingesting these cysts, where sexual reproduction occurs in the intestinal epithelium, leading to the production of oocysts that are shed in the feces.

Species

Several species of Besnoitia are recognized, including:

• Besnoitia besnoiti - primarily affects cattle, causing besnoitiosis.
• Besnoitia bennetti - affects equids, such as horses and donkeys.
• Besnoitia tarandi - found in reindeer and caribou.

Pathogenesis and Clinical Signs

Infected animals may exhibit a range of clinical signs depending on the species of Besnoitia and the host. Common symptoms include:

• Thickening of the skin
• Hair loss
• Fever
• Swelling of the limbs
• Reduced fertility

In severe cases, the infection can lead to significant economic losses in livestock due to decreased productivity and increased veterinary costs.

Diagnosis

Diagnosis of Besnoitia infection is typically based on clinical signs, serological tests, and histopathological examination of tissue samples. The presence of characteristic cysts in tissues is a key diagnostic feature.

Treatment and Control

There is currently no specific treatment for Besnoitia infections, and management primarily focuses on controlling the spread of the parasite. Measures include:

• Preventing contact between definitive and intermediate hosts
• Implementing biosecurity measures on farms
• Monitoring and culling severely affected animals

Also see

• Apicomplexa
• Coccidia
• Toxoplasma
• Sarcocystis

References

• Dubey, J.P., & Lindsay, D.S. (2003). "The life cycle of Besnoitia species (Protozoa: Apicomplexa) with a special reference to Besnoitia besnoiti and Besnoitia tarandi."
• Elsheikha, H.M., & Khan, N.A. (2011). "Protozoa and Human Disease."