Table 2.

The sociodemographic and epidemiological characteristics of severe cases and nonsevere cases.

Factors	Severe cases		No-severe cases		χ2-value	P-value
	N=30	Constituent ratio (%)	N=128	Constituent ratio (%)
Sex
Male	19	21.35	70	78.65	0.739	0.390
Female	11	15.94	58	84.06
Age (years)
≤15	0	0.00	8	100.00	10.640	0.014
16~	1	3.85	25	96.15
31~	17	21.52	62	78.48
50~	12	26.67	33	73.33
The time interval from onset to diagnosis (days)
≤4	5	8.62	53	91.38	7.278	0.026
5~	18	27.69	47	72.31
11~21	7	20.00	28	80.00
The source of the cases
Imported cases	21	26.25	59	73.75	5.557	0.018
Local cases	9	11.54	69	88.46