Abstract

Background Ebola Virus Disease (EVD) was first discovered in 1976 in Zaire along Ebola River affecting more than 250 people and had a mortality rate of 53%. Currently, there are five (Zaire ebolavirus, Reston ebolavirus, Sudan ebolavirus, Tai Forest ebolavirus and Bundibugyo ebolavirus) strains of Ebola Virus. The Zaire ebolavirus has the highest (88%) mortality rate; Reston ebolavirus was discovered in Reston, Virginia, USA in 1989 in imported monkeys from Mindanao, Tai Forest ebolavirus was accidently discovered in 1994 in Tai Forest, Cote d'Ivoire. In 2005, the first direct evidence implicating bats as reservoir host for Ebola Virus emerged. EVD has various symptoms including fever, hemorrhage, myalgia, and diarrhea. There were more than 8,000 confirmed EVD cases and more than 4,000 EVD-related deaths were reported in Sierra Leone during the 2013 - 2016 West Africa EVD outbreak. Method We anonymized and later separately analysed the medical records of laboratory-confirmed pediatric, adult EVD patients, and a mixed cohort of EVD cases who received treatment at the 34 Military Hospital and the Police Training School ETCs in Sierra Leone; we also analysed the anonymized medical records of mixed cohort of laboratory-confirmed EVD cases who received treatment at the Kenema Government Hospital ETC (KGHETC). Results Majority of the 139 paediatric EVD cases in our study reported anorexia (99.1%), chest pain (98.6%), muscle pain (97.8%), headache (95.0%), fever (82.7%), diarrhoea (71.3%), fatigue (67.0%), had Stage 2 EVD infection (64.0%) upon admission at the 34 Military Hospital ETC. The associations between the Case Fatality Rate (CFR), sex, age groups and occupational levels for our adult EVD cases admitted at the 34 Military Hospital were all statistically significant. Our predictive EVD patients mortality risk score for our mixed cohort of 1077 EVD patients admitted at the 34 Military Hospital shows that, those EVD patients who had an in-facility risk score of 12 had in 100% of cases a fatal outcome. The CFR for the 205 EVD patients treated at KGHETC was lower for those EVD patients who came from outside Kenema District compared to those who were admitted directly from within Kenema. Conclusion Based on the findings of our studies we recommend an adaptation of current EVD case definitions. We were able to identify a range of characteristics of EVD patients that were associated with adverse treatment outcomes. However, as both setting and virus strains may be different in future situations, the adoption of our model in future outbreak situations has to be taken with caution.