Table 1.

Population (number examined), number positive for Onchocerca volvulus mf [prevalence], and mean microfilaridermia (arithmetic mean no. of mf/mg and community microfilarial load) at beginning of coffee planting-clearing and harvesting seasons of 1997–1998 and 1998–1999 in localities I (villages of Golondrinas, Rosario Zacatonal, and finca Palestina), and II (village of Nueva América, and fincas of Victoria, Fortuna, and Santa Fé) in Southern Chiapas, Mexico

Localities	Residents			Migrants			Ratio of migrants to residents
	Population (Examined)	Pos [Prev] (95% CI)	AM mf/mg (CMFL)	Population (Examined)	Pos [Prev] (95% CI)	AM mf/mg (CMFL)
Planting season (May-July 1997)
Locality I	437 (318)	36 [11.3%] (8.1–15.3)	0.28 (0.19)	45 (30)	7 [23.3%] (9.9–42.3)	0.78 (0.71)	0.1 : 1
Locality II	374 (235)	34 [14.4%] (10.2–19.6)	1.27 (0.51)	350 (204)	12 [5.9%] (3.1–10.0)	0.12 (0.08)	0.9 : 1
Harvesting season (November 1997–February 1998)
Locality I	385 (250)	32 [12.8%] (8.9–17.6)	0.25 (0.14)	130 (48)	3 [6.3%] (1.3–17.2)	0.54 (0.23)	0.3: 1
Locality II	350 (198)	15 [7.6%] (4.3–12.2)	0.53 (0.22)	850 (258)	7 [2.7%] (1.1–5.5)	0.07 (0.03)	2.4 : 1
Planting season (May-July 1998)
Locality I	370 (236)	30 [12.7%] (8.7–17.6)	0.18 (0.11)	N/A	N/A	N/A	N/A
Locality II	350 (61)	4 [6.6%] (1.8–15.9)	0.06 (0.05)	600 (68)	6 [8.8%] (3.3–18.2)	0.22 (0.09)	1.7 : 1
Harvesting season (November 1998–February 1999)
Locality I	370 (187)	7 [3.7%] (1.5–7.6)	0.11 (0.06)	35 (14)	2 [14.3%] (1.8–42.8)	1.58 (0.39)	0.1 : 1
Locality II	N/A	N/A	N/A	190 (168)	9 [5.4%] (2.5–9.9)	0.26 (0.12)	N/A

N/A: Data not available.