Repeated outbreaks of Viral hemorrhagic fevers in Uganda

A Mbonye, J Wamala, W Kaboyo, V Tugumizemo, J Aceng, I Makumbi

Abstract

Background: Since the year 2000, Uganda has experienced repeated outbreaks of viral hemorrhagic fevers (VHF). Ebola VHF outbreak occurred in the districts of Gulu in 2000, Bundibugyo, 2007, Luwero, 2011, Kibaale in July 2012, Luwero in November 2012. Marburg VHF was earlier reported in Ibanda in 2007. More recently in 2012, two outbreaks of Marburg VHF have occurred in Ibanda and Kabale districts.

Objective: To present the epidemiological picture of the Marburg VHF recently reported in Ibanda and Kabale districts and propose research questions to generate evidence to mitigate future epidemics.

Methods: A case definition for a VHF was developed. A frequency distribution of symptoms of confirmed and probable cases was done. Descriptive analyses of reported cases using simple percentages, percent distributions and computation of means was performed.

Results: The Marburg epidemic was reported in early September and by November 2012, a cumulative of 14 cases (9 confirmed and 5 probable) including 7 deaths had been registered, giving a case fatality rate (CFR) of 50%. A total of 202 contacts had been listed; out of which 193 had completed the 21-day follow-up period. The index case was a 33-year old male, a teacher at Nyakatukura Secondary School in Ibanda district. He travelled to Ibanda from Kabale, his home district on 31st August 2012, reportedly healthy. He fell sick on 3rd September 2012 with complaints of fever, headache, loss of appetite and general body weakness. Overall, the dominant symptoms for all cases were fever, vomiting, loss of appetite, headache, abdominal pain, fatigue, diarrhea, and the least in occurrence was bleeding which accounted for 35.5% of all the cases.

Conclusion: The source of infection for all the five Ebola Hemorrhagic fever outbreaks in Uganda and the recent Marburg VHF outbreak in Ibanda and Kabale is not known. Currently there is suspicion that there could be an animal reservoir of the Ebola and Marburg viruses from where occasional spillage into the human population occurs resulting in disease outbreaks. This and other hypotheses require further investigation.

Key words: viral hemorrhagic fevers, epidemics, Marburg, Ebola, Uganda