Nagana
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Nagana, also called nagana pest or Animal African Trypanosomiasis, is a disease of vertebrate animals. The disease is caused by trypanosomes of several species in the genus Trypanosoma. The trypanosomes infect the blood of the vertebrate host, causing fever, weakness, and lethargy which lead to weight loss and anemia; in some animals the disease is fatal unless treated. The trypanosomes are transmitted by tsetse flies.
An interesting feature is remarkable resistance to nagana pathology shown by some breeds of cattle, notably the N'dama - a West African Bos taurus breed. This contrasts with the extreme susceptibility shown by East African Bos indicus cattle such as the zebu.
This disease is the animal counterpart of sleeping sickness, also known as Human African Trypanosomiasis.
Nagana and history
The nagana pest disease has had a massive effect on African history, by keeping horses and camels (and thus cavalry and mounted knights and mounted messengers) out of much of Black Africa.Horses
One main effect was in stopping the southward advance of Islam at the north limit of tsetse fly country.Cattle
Another effect is likely that the southward spread of the Bantu had to wait until their cattle evolved to become resistant to nagana.
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