Use of contact isolation to prevent spread: Ebola outbreak in a healthworkers base camp, Port Loko District, Sierra Leone, March 2015

Background: The West African Ebola disease outbreak which started in Guinea in December 2013 has ravaged neighboring countries including Sierra Leone. Health care workers were reported to be the most at risk population. In March 2015, an exposed health worker developed fever and other non-specific symptoms of EVD which prompted investigation to describe its magnitude, identify and ascertain level of risks of contacts and contain the outbreak using contact isolation techniques. Methods & Materials: We conducted a descriptive study. We conducted active case search and reviewed health records The case was investigated with real time PCR and all the contacts were identified, line-listed and followed up. We re-defined a contact as any person with no signs and symptoms but had physical contact with the case or body fluids of the case. We collected information on socio-demographic characteristics and categorized contacts according to risk status. Additional information was obtained orally. Data obtained were analyzed using Microsoft Excel statistical software. Results: The IHP Ebola outbreak generated 2 cases and 51 contacts. Eight (15.7%) of the total contacts were higher risk contacts while 43 (84.3%) were lower risk contacts. Mean age of the contacts was 40.5±5.9 years. One of the two cases was male. Twenty (39.2%) of the 51 contacts were Nurses, 9 (17.6%) clinicians, 2 (3.9%) Anesthesiologists, 3 (5.9) data analysts, 3(5.9%) epidemiologists, 2 (3.9%) Laboratory scientists, 2 (3.9%) Laboratory Technicians, 2 (3.9%) Medical Interns, 2 (3.9%) Morticians, 3 (5.9%) Public Health Officers, 2 (3.9%) Radiologists and 1 (2.0%) Pharmacist. Six (11.8%) contacts took ill while under observation, and 2 (33.33%) tested positive to the virus when blood samples was subjected to real time PCR. The incubation period was estimated to be 2-6 days with a case fatality rate of 0% despite the high infectivity. The secondary attack rate for the outbreak was 3.9%. Conclusion: Ebola outbreaks though a deadly infection; early identification and hospitalization of cases, strengthened surveillance, adequate contact tracing and prompt emergency response has proven to be major factors in curtailing further spread