Potential for large outbreaks of Ebola virus disease.
Bottom Line: By fitting a mathematical model to time series stratified by disease onset, outcome and source of infection, we were able to estimate several epidemiological quantities that have previously proved challenging to measure, including the contribution of hospital and community infection to transmission.Our analysis suggests that the person-to-person reproduction number was 1.34 (95% CI: 0.92-2.11) in the early part of the outbreak.Using stochastic simulations we demonstrate that the same epidemiological conditions that were present in 1976 could have generated a large outbreak purely by chance.
Affiliation: Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom. Electronic address: email@example.com.Show MeSH
Related in: MedlinePlus
Mentions: As the epidemic progressed, we found that the overall reproduction number decreased due to changes in the contact rate within the community and within the hospital. Splitting the overall reproduction number into its person-to-person and hospital components, we found that although hospital transmission was dominant during the early stages of the epidemic, it had dropped significantly by mid September (Fig. 4). Our results suggest the hospital reproduction number Rh was below 1 well before the hospital closed on the 30 of September. Moreover, we found that hospital closure alone could not explain the observed data; when changes in person-to-person and hospital-based transmission were excluded, the model performed significantly worse (Table S3). We estimated that the drop in person-to-person transmission occurred later and less sharply than the reduction in exposure to contaminated syringes. However, the reduction in person-to-person transmission was still enough to drive the overall reproduction number below 1 by the end of September. Overall, these results are consistent with the observations reported by the epidemiological investigation team (Breman et al., 1978).
Affiliation: Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom. Electronic address: firstname.lastname@example.org.