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Table 6 The effect of the proportion of systematic non-compliance with annual ivermectin treatment on the microfilarial prevalence and intensity of onchocerciasis infection and its associated morbidity and mortality according to baseline endemicity

From: Modelling the impact of ivermectin on River Blindness and its burden of morbidity and mortality in African Savannah: EpiOncho projections

Pre-control endemicity‡

Mesoendemic

Hyperendemic

Highly hyperendemic

Systematic non-compliance

5%

0.1%

%†change

5%

0.1%

%†change

5%

0.1%

%†change

Skin microfilarial prevalence§ (%)

2.6

1.84

29%

6.68

4.74

29%

20.08

16.69

17%

Microfilarial intensity§ (mf/mg)

0.8

0.49

39%

2.2

1.31

40%

8.18

5.47

33%

Blindness prevalence§ (%)

0.299

0.297

1%

0.95

0.91

4%

4.26

4.13

3%

Visual impairment prevalence§ (%)

0.41

0.4

2%

1.27

1.22

4%

5.7

5.54

3%

Troublesome itch prevalence§ (%)

2.22

1.80

19%

7.66

3.73

16%

14.95

14.09

6%

Excess mortality annual incidence§ (per 1000)

0.09

0.08

11%

0.3

0.26

13%

1.29

1.13

12%

  1. §Values correspond to model outputs 12 months after the 15th annual ivermectin treatment assuming perennial transmission, an overall treatment coverage of 80% (high coverage), and a 7% cumulative, per ivermectin dose, reduction in the rate of microfilarial production by adult female worms. Microfilarial infection intensity is quantified as arithmetic mean microfilarial load per mg of skin in those aged ≥ 20 years.
  2. †Proportional (percent) reduction in parasitological, morbidity and mortality indicators relative to the higher (5%) proportion of systematic non-compliance (lower treatment adherence).
  3. ‡ Pre-control microfilarial prevalence as in Table 1.