<s>
An	O
epidemic	B-Application
curve	I-Application
,	O
also	O
known	O
as	O
an	O
epi	B-Application
curve	I-Application
or	O
epidemiological	B-Application
curve	I-Application
,	O
is	O
a	O
statistical	O
chart	O
used	O
in	O
epidemiology	O
to	O
visualise	O
the	O
onset	O
of	O
a	O
disease	O
outbreak	O
.	O
</s>
<s>
Epidemic	B-Application
curves	I-Application
generally	O
show	O
the	O
frequency	O
of	O
new	O
cases	O
compared	O
to	O
the	O
date	O
of	O
disease	O
onset	O
.	O
</s>
<s>
This	O
epidemic	B-Application
curve	I-Application
shows	O
a	O
presumed	O
first	O
case	O
,	O
known	O
as	O
the	O
index	O
case	O
on	O
November	O
6	O
,	O
1978	O
.	O
</s>
<s>
Sometimes	O
,	O
cases	O
could	O
have	O
been	O
exposed	O
days	O
or	O
weeks	O
prior	O
,	O
and	O
diseases	O
with	O
longer	O
incubation	O
periods	O
would	O
flatten	O
these	O
epidemic	B-Application
curves	I-Application
and	O
lower	O
the	O
peaks	O
.	O
</s>
<s>
The	O
first	O
description	O
of	O
epidemiological	B-Application
curves	I-Application
from	O
the	O
COVID-19	O
pandemic	O
showed	O
the	O
pattern	O
of	O
a	O
"	O
mixed	O
outbreak	O
"	O
.	O
</s>
