Weakness and lethargy

This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.

What it is

Weakness and lethargy are symptoms of the disease surra. They are caused by protozoan trypanosomes infecting the blood of the vertebrate host. These symptoms lead to weight loss and anemia. The disease is caused specifically by Trypanosoma evansi. In some animals the disease is fatal unless treated.

Key facts

Weakness and lethargy are listed among the symptoms caused by the infection. They are part of a progression that leads to weight loss and anemia. Infected animals show loss of appetite and weight loss. The symptoms occur alongside other signs like fever, edema, salivations, and lacrimation.

When to seek professional help

The source indicates professional treatment is associated with the acute form of the disease, which is generally fatal unless treated. This form occurs in animals such as horses, donkeys, mules, cattle, buffalo, deer, camels, llamas, dogs, and cats. A situation requiring professional care is when the disease is diagnosed, as the main method of controlling surra has been drug chemotherapy and chemoprophylaxis. The source notes that before infection becomes severe, it is difficult to catch, implying professional diagnosis is needed. Professional help is also implied in the context of using diagnostic techniques like serological tests or PCR to detect the disease.

Source: Surra (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-09-20.