Table 4. Yearly incidence rates for infection and exposure (as based on the results of Ag-ELISA and EITB, respectively) of individuals who participated in two sampling rounds by period.

Test	Period between samplings	Number of individuals	Yearly incidence rate ([95% Poisson CI]a) per 100,000 person-years
Antigen	P1b (6 months)	0/421	0[0–1790.7]
	P2c (7 months)	1/317	541.6[13.7–3018]
	P3d(13 months)	2/373	496.3 [60.1–1792.7]
Antibody	P1b (6 months)	26/288	18,909.1[12,352–27,706.2]
	P2c (7 months)	17/226	13,399[7,805.4–21,453.1]
	P3d (13 months)	24/264	8,791.2[5,632.7–13,080.6]

^aCI = Poisson exact 95% Confidence Intervals;

^bP1 = June–November period;

^cP2 = November–July period;

^dP3 = June–July period.