Diagnostic schemes for reducing epidemic size of african viral hemorrhagic fever outbreaks

Abstract

Introduction: Viral hemorrhagic fever (VHF) outbreaks, with high mortality rates, have often been amplified in African health institutions due to person-to-person transmission via infected body fluids. By collating and analyzing epidemiological data from documented outbreaks, we observed that diagnostic delay contributes to epidemic size for Ebola and Marburg hemorrhagic fever outbreaks. Methodology: We used a susceptible-exposed-infectious-removed (SEIR) model and data from the 1995 outbreak in Kikwit, Democratic Republic of Congo, to simulate Ebola hemorrhagic fever epidemics. Our model allows us to describe the dynamics for hospital staff separately from that for the general population, and to implement health worker-specific interventions. Results: The model illustrates that implementing World Health Organization/US Centers for Disease Control and Prevention guidelines of isolating patients who do not respond to antimalarial and antibacterial chemotherapy reduces total outbreak size, from a median of 236, by 90% or more. Routinely employing diagnostic testing in post-mortems of patients that died of refractory fevers reduces the median outbreak size by a further 60%. Even greater reductions in outbreak size were seen when all febrile patients were tested for endemic infections or when febrile health-care workers were tested. The effect of testing strategies was not impaired by the 1-3 day delay that would occur if testing were performed by a reference laboratory. Conclusion: In addition to improving the quality of care for common causes of febrile infections, increased and strategic use of laboratory diagnostics for fever could reduce the chance of hospital amplification of VHFs in resource-limited African health systems.

Ebola from emergence to epidemic: the virus and the disease, global preparedness and perspectives

“…The diagnosis of EVD is done on the basis of clinical symptoms, detection of antigen/virus and the antibodies [15,47]. Antigen/virus detection can be adopted for infection at early stages while antibody detection can be done at the late stage of infection.…”

“…A multiplex realtime fluorescence quantitative PCR has also been developed to detect the Ebola and Marburg viruses [54]. Though RT-PCR is more effective in detecting EBOV, the disadvantage of this technique is the need for sophisticated instruments that cannot be afforded by most parts of Africa where the disease is reported the most [47]. For the rapid and simple detection of Ebola virus, an efficient reverse-transcription loopmediated isothermal amplification (LAMP) method with high specificity and rapidity has been reported to have been developed, targeting the trailer region of the viral genome [55].…”

Knowledge, attitudes, and practices of health care workers on Ebola virus disease in Conakry, Guinea: A cross-sectional study

“…These findings could explain the high incidence of confirmed EVD in HCWs in the current (MacIntyre et al, 2014). The vast majority of documented EVD outbreaks involving hospitals have explained no socomial transmissions by inadequate isolation of facilities, lack of use of gloves and protective clothing by HCWs (Okeke et al, 2014). In 1995 during the Ebola outbreak that occurred in Kikwit, the investigators reported that the high transmission of EVD in health care workers was due to the lack of use of aseptic-nursing techniques during surgical and obstetrical care and patient care in general, especially during the of EVD cases (Kerstiëns and Matthys 1999).…”

The current Ebola outbreak: old and new contexts

“…Responding to cases involves a correct coordination between isolation and treatment, contact tracing and follow-up of each contact for 21 days after exposure, and the strategic use of laboratories that could reduce the chances of hospital amplification of EVD in resource-limited health systems such as in the three West African countries currently ravaged by Ebola [4].…”