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Potential for large outbreaks of Ebola virus disease.

Camacho A, Kucharski AJ, Funk S, Breman J, Piot P, Edmunds WJ - Epidemics (2014)

Bottom Line: The largest outbreak of Ebola to date is currently underway in West Africa, with 3944 cases reported as of 5th September 2014.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.

View Article: PubMed Central - PubMed

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: anton.camacho@lshtm.ac.uk.

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Related in: MedlinePlus

Drop in the reproduction number (R(t)) owing to change of behaviour in community contacts and visit of outpatients to the hospital. The overall R (lower panel) can be split into an hospital (upper panel) and person-to-person (middle panel) component. The dashed line indicates the epidemic threshold (R = 1) and the dotted line corresponds to the hospital closure (30th September). Solid, dashed and shaded red lines/area as in Fig. 3. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
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fig0020: Drop in the reproduction number (R(t)) owing to change of behaviour in community contacts and visit of outpatients to the hospital. The overall R (lower panel) can be split into an hospital (upper panel) and person-to-person (middle panel) component. The dashed line indicates the epidemic threshold (R = 1) and the dotted line corresponds to the hospital closure (30th September). Solid, dashed and shaded red lines/area as in Fig. 3. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

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).


Potential for large outbreaks of Ebola virus disease.

Camacho A, Kucharski AJ, Funk S, Breman J, Piot P, Edmunds WJ - Epidemics (2014)

Drop in the reproduction number (R(t)) owing to change of behaviour in community contacts and visit of outpatients to the hospital. The overall R (lower panel) can be split into an hospital (upper panel) and person-to-person (middle panel) component. The dashed line indicates the epidemic threshold (R = 1) and the dotted line corresponds to the hospital closure (30th September). Solid, dashed and shaded red lines/area as in Fig. 3. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4255970&req=5

fig0020: Drop in the reproduction number (R(t)) owing to change of behaviour in community contacts and visit of outpatients to the hospital. The overall R (lower panel) can be split into an hospital (upper panel) and person-to-person (middle panel) component. The dashed line indicates the epidemic threshold (R = 1) and the dotted line corresponds to the hospital closure (30th September). Solid, dashed and shaded red lines/area as in Fig. 3. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
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).

Bottom Line: The largest outbreak of Ebola to date is currently underway in West Africa, with 3944 cases reported as of 5th September 2014.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.

View Article: PubMed Central - PubMed

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: anton.camacho@lshtm.ac.uk.

Show MeSH
Related in: MedlinePlus