Table 6.

Age Pattern of Worms^a

Treatment Group	Time, mo	No. of Patients/Nodulesb	No. of Living Female Worms					No. of Living Male Worms
			All	Age				Allc	Age
				Newly Acquired	Young	Middle	Old		Newly Acquired	Young	Middle	Old
Doxycycline (6 wk)	20	56/157	125	8	12	48	57	41	0	2	27	10
Placebo	20	63/205	191	7	30	73	81	55	1	2	34	17

^a Characteristics for the age of a worm included loss of body wall integrity, loss of nuclei of all organs, and absence of aspartic protease (APR) staining. Very degenerated worms, still APR positive, were classified as moribund and grouped in the category “dead.” Older worms were larger and presented degenerated tissues. Gomori iron stain showed that the worms accumulated more iron with increasing age, first in the gut and later in other organs. Using an antibody against O. volvulus lysosomal aspartic protease, the gut of young worms was stained only weakly, whereas it was stronger in older worms, accompanied by additional staining of hypodermis and epithelia. These criteria as well as morphological findings (diameter, position within the nodule) were used to discriminate newly acquired worms [4, 15].

^b Only evaluable patients/nodules are included. In contrast to Tables 4–6, newly acquired worms are included.

^c In 3 male worms, it was not possible to distinguish the age pattern of the worm in the respective histological sections. Therefore, “All” is not always a summary of the 4 categories.