TABLE 2.

Effect of oxytetracycline, rifampin, and a combination regimen on adult worms of Onchocerca ochengi in naturally infected cattle

Groupa	Time (wpt)	No. of cattle	No. of nodules		No. of worms per nodule site (no. of viable worms onlyb) in:		Median motility score inc:
			Intact	Degeneratedd	Males	Females	Males	Females
CON-1	0	6	6	0	1.7	1.3	2	2
	4	6	6	0	3.3	1.3	1	2
	12	5	5	0	0.8	1.2	1.5	2
	24	5	5	0	1.4	1.0 (0.8)	2	1
	36	5	5	0	2.2 (2.0)	1.0 (0.8)	1	1
	55	5	5	0	0.8	1.0 (0.8)	2	2
PIR	0	6	6	0	4	1.2	2	2
	4	6	6	0	1.5	1.0	1	1.5
	12	5	5	0	0.8	1.0	2	1
	24	5	4	1	0.2 (1.0)	1.2	2	1
	36	5	5	0	0.4 (0.0)	1.0 (0.2)	0	0
	55e	5	2	3	0	0.4 (0.2)	—f	1
OXY3-1	0	6	6	0	1.5	1.0	2	2
	4	6	6	0	1.5	1.0	1	2
	12	6	6	0	0.8	1.0	2	1.5
	24	6	5	1	1.3	0.8 (0.7)	1	1
	36	6	6	0	1.0 (0.3)	1.0 (0.2)	0	0
	55	6	2	4	0.2	0.3	2	1
OXY6	0	6	6	0	1.5	1.2	2	2
	4	6	6	0	1.7	1.0 (0.8)	2	1.5
	12	4	4	0	2.0	1.0	2	2
	24	4	4	0	3.0 (2.0)	1.3 (1.0)	1	1
	36	4	4	0	0.3	1.0 (0.5)	1	0.5
	55e	4	2	2	0	0.5 (0.3)	—f	0.5
CON-2	0	6	6	0	0.8	1.0	2	2
	4	6	6	0	1.2	1.0	2	2
	12	6	6	0	1.5	1.0	2	2
	24	6	6	0	1.5	1.0 (0.3)	2	0
	36	6	5	1	1.5	0.8	2	2
	52	5	5	0	1.8	1.0	2	2
OXY3-2	0	6	6	0	1.7	1.0	2	2
	4	6	6	0	0.3	1.2 (1.0)	1.5	1
	12	6	6	0	0.3	1.0	1.5	1
	24	6	6	0	0.5	1.0 (0.7)	2	1
	36	6	6	0	0.7	1.0 (0.8)	2	1
	52e	6	6	0	0.3	1.0 (0.5)	1	0.5
RIF3	0	6	6	0	1.2	1.0 (0.8)	2	2
	4	6	6	0	2.0	1.0	1	1
	12	6	6	0	1.3	1.0	2	2
	24	6	6	0	0.5	1.0 (0.8)	2	1
	36	6	6	0	0.3	1.0 (0.5)	2	0.5
	52	6	6	0	0.8 (0.5)	1.0 (0.8)	1	1
COM	0	6	6	0	0.8	1.0	2	1.5
	4	6	6	0	1.3	1.0	2	2
	12	6	6	0	0.5	1.0	2	2
	24	6	6	0	1.3	1.0 (0.8)	2	1
	36	6	5	1	1.0	0.8	1.5	2
	52	6	6	0	0.3	1.0 (0.7)	1.5	2

^aCON-1, no treatment; PIR, oxytetracycline once monthly for 6 months; OXY3-1 and OXY3-2, oxytetracycline twice weekly for 3 weeks; OXY6, oxytetracycline twice weekly for 6 weeks; CON-2, DMSO solvent only; RIF3, rifampin twice weekly for 3 weeks; COM; rifampin and oxytetracycline twice weekly for 3 weeks.

^bWorms were considered viable where the motility score was ≥1. Note that O. ochengi nodules normally contain a single female worm and a variable number of males (0 to >10).

^cMotility was scored on a 3-point scale after incubation of worms for 30 min at 37°C, as follows: 0, no movement; 1, sluggish movement; and 2, highly active.

^d“Degenerated” refers to worm remnants only or fragmented nodules from skin biopsy specimens (in which fragmentation was too advanced to allow sexing and motility scoring).

^eThe total number of viable worms recovered at the end of the experiment was significantly reduced compared with the number in control animals (P < 0.05).

^fData were missing due to the absence of male worms in all nodules.