Table 2.

Transmission indices of onchocerciasis at the study sites

Site	Biting rate (bites/person/period)	Parity (%)	Infective females (L3H)/1000 parous flies	Infective larvae (L3H)/1000 parous flies	TP – L3H (L3All) (infective larvae/man/period)
Haijam/V5	1554	83.9	16	41.21	51 (55)
Mbere-Tchad	16,407	75.7	12.75	29.75	367 (702)
Babidan	15,805	66.3	5.15	11.34	146 (506)
Touboro	769	56.4	0	0	0 (0)
Gor	9720	55.9	4.07	5.08	20 (32)
Djeing	2148	39.4	0	0	0 (3)
Koinderi	186	92.9	0	0	0 (0)

L3All = all third-stage larvae retrieved from both thorax and head of the fly; L3H = third-stage larvae retrieved from the head of the fly. Period = the entire period of the study. Mean values do not include months during which no flies were caught. Transmission potential (TP) was calculated by adding the individual monthly transmission potentials of the months covered in this study (Table 3). Biting rate (BR) was calculated as the sum of the individual monthly biting rates of the months covered in this study