History of Trypanosomosis in the One-Humped Camel and Development of its Treatment and Cure, with Special Reference to Sudan

Abstract

Sudan has one of the largest populations of domestic animals in Africa. One-humped camel (Camelus dromedarius) numbers were estimated at 4.5 million in 2009. Once used extensively for military transport they are still used in the transport role by spatially mobile pastoralist households and are a major source of milk and meat for these people. Trypanosomosis, due to Trypanosoma evansi, generally known as ‘surra’ but as ‘gufar’ in Sudan was first identified in camels in the country in 1902 and is the main cause of disease although T. vivax infections have recently been discovered in parts of Sudan. This protozoan disease is the most important health problem in camels, causing high morbidity and huge production losses. The causal organism, unlike most other trypanosomes, is not transmitted cyclically with tsetse (genus Glossina) flies as the vector but mechanically by biting flies mainly family Tabanidae but also by others of the Muscidae. Identification of the parasite in camel blood was initially by simple microscopic techniques but biotechnology and molecular methods now enable infection to be diagnosed at an earlier stage and with more accuracy. Prophylactic and curative treatments of trypanosomosis are notoriously complicated and uncertain with the situation in camels being exacerbated because of its peculiar physiology. Many trypanocides have been developed over time but the parasite often develops resistance to these drugs. Some drugs are successful, for some time, as both prophylactics and cures but are often accompanied by undesirable side effects. Other drugs used on conventional domestic stock are ineffective in camels or have lower efficacy. Research on diagnosis and treatment of trypanosomosis is continuing but the disease continues to cause production losses to the detriment of national and household incomes and food security.