Sleeping Sickness Epidemic Spreading in Uganda

Current methods to curb the epidemic of sleeping sickness in eastern Uganda are failing, concludes a Research Letter in this weeks issue of The Lancet.

Sleeping sickness is caused by the Trypanosomaparasite, which is carried by the tsetse fly. The epidemic of Trypanosoma brucei rhodesiensesleeping sickness in eastern Uganda began in 1998 as a result of the movement of the livestock reservoir of the parasite and has continued to spread. Interventions to control the disease were put in place between January 2000 and December 2003 and consisted of mass treatment of livestock with long-acting drugs to kill the parasite.

In this study, Eric Fevre, of the University of Edinburgh in Scotland, and colleagues looked at the prevalence of human infective T b rhodesiensein the cattle population of three villages in the Soroti district of Uganda, which had the intervention, and three where there had been no intervention. They found that there was no significant difference in the prevalence of the parasite in the villages with the intervention and those without it.

The investigators also report that since the first cases of sleeping sickness in 1998, 428 new cases were diagnosed in the Sorotic district over a five-year period, and an additional 300 may have gone undiagnosed.

Fevre states, To be effective, mass treatment interventions need to cover enough of the livestock population to prevent the transmission of parasites to tsetse. Similarly, effective tsetse control must reduce vector challenge sufficiently to effect transmission to human beings . . . As livestock movements results in the spread of T b rhodesiense, controlling such movements or treating livestock before movement is a matter of urgency . . . Outbreaks of Tbrhodesiense in new areas are conceptually straightforward to prevent with effective veterinary interventions but, once established, very difficult to control.

Source: The Lancet