Table 2. Prevalence and incidence of geohelminths in the studied population, before and after the city-wide sanitation intervention.

Geohelminths	Prevalence					Incidence
	1997 (n = 729)		2003 (n = 890)		p*	1997–1998			2003–2004			p*
	pos	%	pos	%		n**	pos#	%	n**	pos#	%
Ascaris lumbricoides	241	33.1	227	25.5	0.001	488	100	20.5	663	101	15.2	0.02
Trichuris trichiura	313	42.9	256	28.8	0.001	416	46	11.1	634	56	8.8	0.23
Hookworms	72	9.9	15	1.7	0.001	657	15	2.3	875	12	1.4	0.18
Any geohelminth	390	53.5	356	40.0	0.001	400	144	36.0	584	150	25.7	0.001

* Difference between periods = test χ².

** n = negative in first exam.

# pos = positive in the second exam.