Modelling Neglected Tropical Diseases diagnostics: the sensitivity of skin snips for Onchocerca volvulus in near elimination and surveillance settings

Table 1 Demographic and parasitological characteristics of the datasets used to parameterise the model

Country	No. of villages	n ^a	Median (Interquartile range) age (years)	% Female	Location of skin snips	Mean microfilarial load (mf/mg skin)	Mean weight of skin snips (mg)	References
Guatemala	3	1,067	19 (10, 36)	44.2	1 shoulder & 1 hip	shoulder = 26.3 hip = 25.4	shoulder = 1.35 hip = 1.80	[24]
Venezuela	14	613	22 (12, 35)	39.8	1 shoulder & 1 hip	shoulder = 14.2 hip = 31.9^c	shoulder = 1.32 hip = 1.73	[30–32]
Ghana	18	172^b	17–60^b	18.2–31.1	2 hip & 2 calf	hip = 27.4 calf = 16.6^c	hip = 2.15 calf = 2.14	[33]
Cameroon	5	2,528	17 (10, 35)	49.1	2 hip & 2 calf or 2 calf	hip = 8.0 calf = 9.5	Not weighed^d	[34]

^a n, number of individuals whose skin snip data were used in the model
^bParticipants were allocated to four treatment groups. The mean age in the four groups ranged from 32.1 to 38.3 years. The table indicates the minimum and maximum age across all treatment groups
^c P-value for comparison of microfilarial load between the two body sites: P < 0.001 Venezuela; P < 0.001 Ghana
^dSkin snips were not weighed in Cameroon, so it was assumed that a skin snip taken from the hip weighed 2.2 mg, and that one taken from the calf weighed 2.1 mg based on the data from Ghana

ISSN: 1756-3305