Figure 1.
A: Diagrammatic representation of LF cases admitted at Jos Hospital, Nigeria (total duration of the outbreak days), showing period of illness and interrelation among patients [2]. The horizontal bars represent each patient. The x-axis is the time expressed in days from the start of the outbreak, when TS developed the illness (thus time
in the calculation corresponds to
December 1969). The grey portion of the bars are the period between the onset of the symptoms and admission to hospital; the black portion of the bars are the period between admission to hospital and discharge/death of the patients; the red thin lines are the period of exposure to the index case TS. The green bar represent the time when the patient was at the ward for unrelated illness. Note, the same diagram in [2] present an extra case, JT, which is not included here. This case refers to Dr. Jeanette M. Troup one of the first scientists working on Lassa Fever Virus, who contracted the disease from an autopsy accident incurred during examination of one of the fatal cases. B: Diagrammatic representation of LF cases admitted at Zorzor Hospital (total duration of the outbreak
days), Liberia, showing period of illness and interrelation among patients [3]. C: As in Fig. 1.A, but the periods of illness (symptoms plus time at hospital) are randomly permuted. The contact network is kept the same. D: An example of how the time
was calculated. In this particular case
if
and
otherwise, where
is the time when case
is no longer exposed to case
.
Figure 2.
Daily number of referred/visiting patients at KGH (confirmed cases only) from the of April
to the
of January
, [1].
Figure 3.
Individual effective reproduction number and generation time.
Box-plot for the individual for the nosocomial outbreak described in [2] based on the
permutations of the duration of illness. It shows the first and third percentiles, the minimum and maximum values, the median, and outliers (red dots). The dashed line represents the case when the effective reproduction number is equal to
. A: nosocomial outbreak in Jos [2]. B: nosocomial outbreak in Zorzor [3]. C: Distribution of generation time for the two nosocomial outbreaks. The statistics are based on the
permutations of the duration of illness. D: Distribution of generation time for extra-nosocomial cases. The statistics are based on the
permutations of the duration of illness.
Figure 4.
Contribution of human-to-human transmission.
Mean value of the total effective reproduction number, and its daily mean,
, for the KGH epidemic curve vs the proportion
of cases due to human-to-human transmission (blue line). The shaded grey area covers the range between the
and
percentiles in
and/or
; the dashed red line represents the mean, nosocomial, effective reproduction number. A and B:
and
based on the full networks (in Jos and in Zorzor) of nosocomial cases;
days. C and D:
and
based on the extra-nosocomial cases in Jos;
days.
Figure 5.
A: Distribution of all individual for both nosocomial outbreaks, based on the
permutations of the duration of illness. Mean value of the joint data:
, median:
, maximum:
, proportion of cases when
:
, proportion of cases when
:
. B: Distribution of the effective reproduction number for cases of hospitalized patients in KGH for different values of the contribution of human-to-human transmission,
, the corresponding data for the extra-nosocomial (
permutation based on
,
,
,
,
cases in Jos) and all nosocomial outbreaks (based on all Jos and Zorzor cases) are also shown. C: Distribution of the total effective reproduction number, i.e. the average number of cases during the entire duration of the epidemic for different values the contribution of human-to-human transmission,
.
Figure 6.
A: proportion of cases when the individual effective reproduction number is greater than one. (i.e. the ratio of the cardinalities of
and
, where
is set of all simulated
and
the subset of cases when
is greater than one). B: the expected, relative number of cases generated by this proportion. (i.e. the fraction of the areas of
)