Nagana

Definition

A chronic or acute disease of domestic and wild ungulates caused by African trypanosomes, primarily Trypanosoma congolense, T. vivax, and T. brucei brucei, transmitted by tsetse flies (genus Glossina). Nagana produces fever, progressive anemia, emaciation, and often death; it represents one of the most significant constraints to livestock production and wildlife management across the tsetse belt of sub-Saharan Africa. The term distinguishes the veterinary syndrome from human African trypanosomiasis (sleeping sickness), though both share common parasite species and vector ecology.

Etymology

From Zulu or Tswana naka na, meaning "to be depressed or low in spirits," referring to the lethargy characteristic of infected animals.

Example

Cattle herds in Kenya's Lambwe Valley suffer severe nagana outbreaks during the rainy season when Glossina fuscipes fuscipes populations expand along riverine vegetation, forcing pastoralists to move stock to higher, tsetse-free ground or rely on trypanocidal drug treatments.

Synonyms

• animal trypanosomiasis
• nagana pest

Related Terms

• tsetse fly
• Glossina
• Trypanosoma
• Trypanosomiasis
• vector-borne disease
• Zoonosis
• sleeping sickness

Usage Notes

In strict usage, "nagana" refers specifically to animal disease caused by T. congolense, T. vivax, and T. brucei brucei, whereas T. b. rhodesiense and T. b. gambiense cause human sleeping sickness. Some authorities restrict "nagana" to T. congolense infections in cattle. The term is sometimes applied loosely to any animal trypanosomiasis in Africa, but specialists distinguish surra (caused by T. evansi, transmitted mechanically) and dourine (T. equiperdum, venereal transmission in equids).