Table 2. Ratio of West Nile neuroinvasive disease to infection by age-group.

Age (years)	WNND cases in study area (surveillance data)	Population in study area     (census data) [24,25]	Ratio of WNND to infection (95% CI)
<18	2	40,064	NA
18–39	5	61,258	1:331 (1:870–1:123)
40–59	10	48,671	1:277 (1:492–1:151)
60–69	12	25,447	1:225 (1:380–1:129)
70–79	33	14,279	1:38 (1:66–1:21)
80+	18	4,295	1:21 (1:37–1:12)
All ages	80	194,014	1:141 (1:209–1:92)

WNND: West Nile neuroinvasive disease95% CI: 95% confidence intervalNA: non applicable