Three ebola outbreaks in Uganda 2000-2011

Three separate outbreaks of Ebola associated with high fatality occurred in Uganda between 2000 and 2011. A country wide national response contained each epidemic with various degrees of success .The experiences challenges and successes are described in Gulu, Bundibugyo and Luwero outbreaks.Objectives: The study linked the following objectives: to describe the three Ebola outbreaks and the national response in Uganda from 2000-2011; to establish the risk factors associated with the Bundibugyo ebolavirus outbreak, 2007; to estimate the case fatality rate related to the Bundibugyo ebolavirus outbreak, 2007. Methods: A descriptive design study documented the three different outbreaks. The occurrence and epidemiological characteristics of each epidemic were defined and described basedd on the adapted case definition for Ebola haemorrhagic fever. Data and information was systematically collected from cases and contacts routinely using questionnaires covering personal, demographic and social parameters. Active case search, isolation, as well as community mobilisation for public education including the media were the major strategies used. Risk factors were studied using a case control design (Paper III) which compared cases and non-cases in a sub set of presumed cases identified at community level. A quantitative study of a subset of cases with only laboratory confirmed acute phase blood samples estimated the corresponding case fatality rate (Paper IV). Results: Two large outbreaks of the Sudan ebolavirus and the Bundibugyo ebolavirus occurred in Uganda in 2000 (425 cases) and 2007 (116 cases) respectively, followed in 2011by a single case outbreak in Luwero. Clinical characteristics were similar in all the three outbreaks: acute onset of high grade fever, severe headache and chest pain, abdominal pain, associated with some bleeding tendencies. Clustering of cases was common. The case definition helped in screening suspected cases but the major weakness of this approach was that it had a low specificity, and less than 50% of suspected cases identified by the community were confirmed as true Ebola patients. In Gulu, attack rates were higher among women than men (RR=1.6; 95% C.I. = 1.3; 1.9). Children between 5-14 years had the lowest attack rate. The risk increased with age and was highest at 60-64 years age group (RR =16.4; 95% CI = 9.4; 28.8). Case fatality was highest in the SEBOV subtype (53%; 955 CI = 47.8-57.5) and lowest in the BEBOV (33.6%; 95% CI 25.0-42.2; p=0.005). There was two fold increase in mortality (RR=1.8, p value