Trypanosoma evansi

Parasite140104-fig2 Surra (Trypanosoma evansi infection) in a Tunisian dog

Trypanosoma evansi is a protozoan parasite belonging to the genus Trypanosoma. It is the causative agent of a disease known as Surra, which affects a wide range of domestic and wild animals. This parasite is primarily transmitted through the bite of various species of biting flies, particularly those in the genus Tabanus and Stomoxys.

Morphology

Trypanosoma evansi is characterized by its elongated, spindle-shaped body, which measures approximately 15-34 micrometers in length. The organism possesses a single flagellum that originates from a basal body and runs along the length of the body, forming an undulating membrane. The nucleus is centrally located, and the kinetoplast, a unique mitochondrial structure, is situated near the posterior end of the parasite.

Life Cycle

The life cycle of Trypanosoma evansi involves both vertebrate hosts and invertebrate vectors. In the vertebrate host, the parasite multiplies by binary fission in the blood, lymph, and various tissues. When a biting fly feeds on an infected animal, it ingests the parasites, which then multiply in the fly's midgut. The parasites migrate to the salivary glands of the fly, where they become infective and can be transmitted to a new host during subsequent feedings.

Pathogenesis

Trypanosoma evansi causes Surra, a disease that manifests with symptoms such as fever, anemia, edema, and weight loss. The severity of the disease can vary depending on the species of the host and the strain of the parasite. In chronic cases, the disease can lead to severe debilitation and death if left untreated.

Diagnosis

Diagnosis of Trypanosoma evansi infection can be achieved through various methods, including microscopic examination of blood smears, serological tests such as ELISA, and molecular techniques like PCR. Early and accurate diagnosis is crucial for effective management and control of the disease.

Treatment and Control

Treatment of Trypanosoma evansi infection typically involves the use of trypanocidal drugs such as suramin, diminazene aceturate, and melarsomine. Control measures include the use of insect repellents, insecticide-treated nets, and the management of vector populations to reduce the risk of transmission.

Geographical Distribution

Trypanosoma evansi is widely distributed across tropical and subtropical regions, particularly in parts of Africa, Asia, and South America. The spread of the parasite is closely associated with the distribution of its vector species.

Related Pages

• Trypanosoma
• Surra
• Tabanus
• Stomoxys
• ELISA
• PCR