Table 3.

Incidence rate by ecological zone

Zone	Person-month	New cases	Incidence rate/1000	95% Conf. interval		RR
				Lower limit	Upper limit
Highland	1928	0	0	–	–
Lowland	2084	1	0.5	0.0000676	0.0034065
Midland	1060	0	0	–		40.2
Riverine	3310	47	14.2	0.0106686	0.0188986
Total	8382	48	57	0.0043155	0.007599

Rate ratio 40.2 (95% CI 7–1623)