Background
Materials and methods
Ethical consideration
Study population
Data collection
MDA rounds/intake assessment
Distance to the nearest river
Parasitological and laboratory assessment
Statistical analysis
Results
Baseline characteristics of study participants
Variable | N | a-Microfilaridermic (n = 34) | N | Microfilaridermic (n = 105) | p-value |
---|---|---|---|---|---|
Age (years) | 34 | 41.5 [34.5–45.0] | 105 | 37.0 [30.0–44.0] | 0.070¥ |
Year in an endemic area (years) | 34 | 30.0 [22.0–35.0] | 105 | 25.0 [15.0–30.0] | 0.007¥ |
Gender (male, n.%) | 34 | 22 [64.7] | 105 | 70 [66.7] | 0.834a |
Distance to the nearest river (n.%) | |||||
< 1.00 km | 34 | 12 [35.3] | 105 | 43 [41.0] | 0.046a |
1.00–2.00 km | 20 [58.8] | 40 [38.1] | |||
> 2.00 km | 2 [5.9] | 22 [21.0] | |||
Occupation | 34 | 105 | 0.001b | ||
Farmer | 23 [67.7] | 89 [84.8] | |||
Trader | 8 [23.5] | 3 [2.8] | |||
Others | 3 [8.8] | 13 [12.4] | |||
Has taken IVM before, n (%) | 34 | 34 [100.0] | 105 | 95 [90.5] | 0.062b |
Individual IVM intake | 34 | 4.0 [3.75–5.0] | 105 | 4.0 [3.0–5.0] | 0.056¥ |
total nodule sites | 34 | 1.0 [1.0–2.0] | 105 | 2.0 [1.0–2.0] | 0.089¥ |
total nodule counts | 34 | 1.0 [1.0–2.3] | 105 | 2.0 [1.0–3.0] | 0.169¥ |
Mf skin load (Mf/mg) | 34 | 0.00 [0.00–0.00] | 105 | 0.62 [0.25–2.00] | < 0.001¥ |
MF + participants exhibit disproportionate abnormalities in haematological and biochemical indices
Variable | unit | Classification | a-Microfilaridermics (MF-, n = 34) | Microfilaridermics (MF+, n = 105) | Total n (%) | Reference range |
---|---|---|---|---|---|---|
RBC | x106/L | Normal | 31 (91.2) | 98 (93.3) | 129 (92.8) | 2.50–5.50 |
Abnormal | 3 (8.8) | 7 (6.7) | 10 (7.2) | |||
HGB | g/dL | Normal | 34 (100.0) | 105 (100.0) | 139 (100.0) | 8.0–17.0 |
Abnormal | 0 (0.0) | 0 (0.0) | 0 (0.0) | |||
HCT | % | Normal | 34 (100.0) | 105 (100.0) | 139 (100.0) | 26.0–50.0 |
Abnormal | 0 (0.0) | 0 (0.0) | 0 (0.0) | |||
PLT | x103/L | Normal | 33 (97.1) | 104 (99.0) | 137 (98.6) | 50–400 |
Abnormal | 1 (2.9) | 1 (1.0) | 2 (1.4) | |||
Total WBC | x109/L | Normal | 34 (100.0) | 104 (99.0) | 138 (99.3) | 3.00–15.00 |
Abnormal | 0 (0.0) | 1 (1.0) | 1 (0.7) | |||
Neutrophil Abs | x109/L | Normal | 34 (100.0) | 104 (99.0) | 138 (99.3) | 1.50–7.00 |
Abnormal | 0 (0.0) | 1 (1.0) | 1 (0.7) | |||
Lymphocyte Abs | x109/L | Normal | 33 (97.1) | 98 (93.3) | 131 (94.2) | 1.00–3.70 |
Abnormal | 1 (2.9) | 7 (6.7) | 8 (5.8) | |||
Monocyte Abs | x109/L | Normal | 34 (100.0) | 95 (90.5) | 129 (92.8) | 0.00–0.70 |
Abnormal | 0 (0.0) | 10 (9.5) | 10 (7.2) | |||
Eosinophil Abs | x109/L | Normal | 29 (85.3) | 51 (48.6) | 80 (57.6) | 0.00–0.40 |
Abnormal | 5 (14.7) | 54 (51.4) | 59 (42.4) | |||
Basophil Abs | x109/L | Normal | 34 (100.0) | 105 (100.0) | 139 (100.0) | 0.00–0.10 |
Abnormal | 0 (0.0) | 0 (0.0) | 0 (0.0) | |||
Neutrophil % | % | Normal | 34 (100.0) | 104 (99.0) | 138 (99.3) | 37.0–72.0 |
Abnormal | 0 (0.0) | 1 (1.0) | 1 (0.7) | |||
Lymphocyte % | % | Normal | 25 (73.5) | 86 (81.9) | 111 (79.9) | 20.0–50.0 |
Abnormal | 9 (26.5) | 19 (18.1) | 28 (20.1) | |||
Monocyte % | % | Normal | 33 (97.1) | 99 (94.3) | 132 (95.0) | 0.0–14.0 |
Abnormal | 1 (2.9) | 6 (5.7) | 7 (5.0) | |||
Eosinophil % | % | Normal | 24 (70.6) | 44 (41.9) | 68 (48.9) | 0.0 − 6.0 |
Abnormal | 10 (29.4) | 61 (58.1) | 71 (51.1) | |||
Basophil % | % | Normal | 34 (100.0) | 102 (97.1) | 136 (97.8) | 0.0–1.0 |
Abnormal | 0 (0.0) | 3 (2.9) | 3 (2.2) | |||
ALT | U/L | Normal | 30 (88.2) | 99 (94.3) | 129 (92.8) | 0.0–40.0 |
Abnormal | 4 (11.8) | 6 (5.7) | 10 (7.2) | |||
AST | U/L | Normal | 32 (94.1) | 95 (90.5) | 127 (91.4) | 0.0–40.0 |
Abnormal | 2 (5.9) | 10 (9.5) | 12 (8.6) | |||
GGT | U/L | Normal | 30 (88.2) | 97 (92.4) | 127 (91.4) | 0.0–55.0 |
Abnormal | 4 (11.8) | 8 (7.6) | 12 (8.6) | |||
Creatinine | µmol/L | Normal | 31 (91.2) | 102 (97.1) | 133 (95.7) | 53.0–124.0 |
Abnormal | 3 (8.8) | 3 (2.9) | 6 (4.3) | |||
eGFR | mL/min/1.73m2 | Normal | 17 (50.0) | 66 (62.9) | 83 (59.7) | > 90.00 |
Abnormal | 17 (50.0) | 39 (37.1) | 56 (40.3) |
MF + participants show significant variabilities in haematological and biochemical indices
Variable | unit | N | a-Microfilaridermic (n = 34) | N | Microfilaridermic (n = 105) | p-value |
---|---|---|---|---|---|---|
median (IQR) | median (IQR) | |||||
RBC | x109/L | 34 | 4.73 [4.24–5.24] | 105 | 4.57 [4.20–4.95] | 0.209 |
HGB | g/dL | 34 | 13.5 [12.1–14.6] | 105 | 13.1 [12.1–14.2] | 0.390 |
HCT | % | 34 | 41.2 [38.2–43.6] | 105 | 40.1 [37.1–42.8] | 0.253 |
PLT | x109/L | 34 | 196 [123–246] | 105 | 200 [161–247] | 0.343 |
Total WBC | x109/L | 34 | 4.71 [3.97–5.50] | 105 | 5.39 [4.78–6.60] | 0.001 |
Neutrophil Abs | x109/L | 34 | 1.78 [1.54–2.54] | 105 | 1.99 [1.46–2.69] | 0.602 |
Lymphocyte Abs | x109/L | 34 | 2.07 [1.79–2.44] | 105 | 2.28 [1.85–2.85] | 0.069 |
Monocyte Abs | x109/L | 34 | 0.43 [0.32–0.53] | 105 | 0.47 [0.35–0.59] | 0.110 |
Eosinophil Abs | x109/L | 34 | 0.14 [0.08–0.36] | 105 | 0.42 [0.19–0.84] | < 0.0001 |
Basophil Abs | x109/L | 34 | 0.02 [0.01–0.03] | 105 | 0.03 [0.02–0.04] | 0.001 |
Neutrophil % | % | 34 | 40.4 [35.6–48.4] | 105 | 37 [31.2–44.7] | 0.055 |
Lymphocyte % | % | 34 | 44.9 [38.9–53.6] | 105 | 42.2 [36.3–49.0] | 0.198 |
Monocyte % | % | 34 | 9.0 [7.7–9.8] | 105 | 8.0 [6.5–10.5] | 0.216 |
Eosinophil % | % | 34 | 3.2 [1.9–7.5] | 105 | 8.0 [3.8–14.1] | < 0.0001 |
Basophil % | % | 34 | 0.4 [0.3–0.6] | 105 | 0.5 [0.4–0.7] | 0.057 |
ALT | U/L | 34 | 24.0 [20.1–29.6] | 105 | 22.4 [17.5–30.2] | 0.513 |
AST | U/L | 34 | 22.3 [18.5–29.0] | 105 | 23.0 [17.8–28.5] | 0.745 |
GGT | U/L | 34 | 33.4 [21.9–39.6] | 105 | 25.3 [20.1–32.8] | 0.013 |
Creatinine | µmol/L | 34 | 95.0 [79.0–103.0] | 105 | 91.0 [79.5–101.0] | 0.289 |
eGFR | mL/min/1.73m2 | 34 | 89.7 [82.8–94.8] | 105 | 94.8 [84.4–107.5] | 0.040 |
Increased blood composite ratios are significantly associated with MF + participants
BCRs correlate positively with eosinophil but negatively with neutrophil levels in MF + participants
BCRs show fair predictability in classifying MF + and a-MF participants
Parameter | Cut-off | Sensitivity (95% CI) | Specificity (95% CI) | Accuracy (95% CI) | PPV (95% CI) | NPV (95% CI) | p-Value |
---|---|---|---|---|---|---|---|
Eosinophil [Abs] | > 0.415 | 50.5 [40.6–60.4] | 88.2 [72.6–96.7] | 59.7 [51.1–67.9] | 93.0 [83.8–97.1] | 36.6 [31.5–42.0] | < 0.001 |
Basophil [Abs] | > 0.025 | 63.8 [53.9–73.0] | 67.7 [49.5–82.6] | 64.8 [56.2–72.7] | 85.9 [78.6–91.0] | 37.7 [30.0–46.1] | 0.001 |
ENR x10 | > 2.265 | 50.5 [40.6–60.4] | 91.2 [76.3–98.1] | 60.4 [51.8–68.6] | 94.6 [85.5–98.2] | 37.4 [32.4–42.6] | < 0.001 |
EMR | > 0.395 | 79.1 [70.0–86.4] | 61.8 [43.6–77.8] | 74.8 [66.8–81.8] | 86.5 [80.5–90.8] | 48.8 [37.7–60.1] | < 0.001 |
EBR | > 14.25 | 51.4 [41.5–61.3] | 85.3 [68.9–95.1] | 59.7 [51.1–67.9] | 91.5 [82.5–96.1] | 36.3 [30.9–42.0] | < 0.001 |
ELR x10 | > 1.160 | 63.8 [53.9–73.0] | 70.6 [52.5–84.9] | 65.5 [56.9–73.3] | 87.0 [79.6–92.0] | 38.5 [31.1–46.9] | < 0.001 |
Eosinophil count and BCRs are independently associated with increased odds of microfilaridermia in Onchocerciasis
Variable | Univariate analysis | |
---|---|---|
OR (95 CI %) | p-value | |
Age (years) | 0.97 [0.93–1.01] | 0.121 |
Year in an endemic area (years) | 0.96 [0.92–0.99] | 0.011 |
gender (male) | 1.09 [0.48–2.46] | 0.834 |
Distance to the river (< 1 km) | 0.33 [0.07–1.59] | 0.165 |
Distance to the river (1–2 km) | 0.18 [0.04–0.85] | 0.030 |
Occupation (Farmer) | 2.66 [1.09–6.51] | 0.032 |
Individual IVM intake | 0.79 [0.61–1.02] | 0.080 |
Total nodule sites | 1.54 [0.89–2.66] | 0.124 |
Total nodule counts | 1.11 [0.85–1.45] | 0.425 |
Total WBC | 1.74 [1.20–2.51] | 0.003 |
Basophil | 1.65 [1.16–2.34] | 0.005 |
Eosinophil | 28.18 [3.97–200.13] | 0.001 |
GGT | 0.98 [0.96–1.00] | 0.067 |
eGFR | 1.02 [1.00–1.05] | 0.062 |
ENR x10 | 1.60 [1.18–2.19] | 0.003 |
EMR | 3.68 [1.64–8.26] | 0.002 |
EBR | 1.09 [1.03–1.15] | 0.003 |
ELR x10 | 1.93 [1.29–2.88] | 0.001 |
Variable | Multivariate analysis | |||||
---|---|---|---|---|---|---|
Model 1 + ENR | Model 1 + EMR | Model 1 + EBR | ||||
aOR (95 CI %) | p-value | aOR (95 CI %) | p-value | aOR (95 CI %) | p-value | |
Age (years) | 0.99 [0.93–1.05] | 0.687 | 0.99 [0.93–1.05] | 0.676 | 0.99 [0.93–1.05] | 0.688 |
gender (male) | 0.61 [0.20–1.80] | 0.367 | 0.65 [0.22–1.92] | 0.438 | 0.60 [0.20–1.80] | 0.361 |
Year in an endemic area (years) | 0.97 [0.92–1.01] | 0.162 | 0.97 [0.92–1.02] | 0.174 | 0.96 [0.92–1.01] | 0.105 |
Distance to the river (< 1 km) | 0.29 [0.05–1.68] | 0.167 | 0.26 [0.04–1.50] | 0.130 | 0.31 [0.05–1.76] | 0.185 |
Distance to the river (1–2 km) | 0.18 [0.03–1.02] | 0.052 | 0.15 [0.03–0.84] | 0.031 | 0.17 [0.03–0.97] | 0.046 |
Occupation (Farmer) | 5.67 [1.58–20.33] | 0.008 | 4.97 [1.41–17.56] | 0.013 | 6.01 [1.67–21.59] | 0.006 |
Individual IVM intake | 0.90 [0.65–1.25] | 0.526 | 0.92 [0.51–1.49] | 0.563 | 0.92 [0.66–1.28] | 0.619 |
Total nodule counts | 0.94 [0.58–1.52] | 0.791 | 0.92 [0.57–1.49] | 0.745 | 0.91 [0.56–1.46] | 0.687 |
Total nodule sites | 1.52 [0.57–4.08] | 0.408 | 1.48 [0.55–4.02] | 0.441 | 1.48 [0.55–3.99] | 0.436 |
ENR x10 | 1.42 [1.05–1.93] | 0.025 | ||||
EBR | 2.64 [1.25–5.60] | 0.011 | ||||
EMR x10 | 1.07 [1.01–1.10] | 0.020 | ||||
Multivariate analysis | ||||||
Model 1 + ELR | Model 1 + Eosinophil | |||||
aOR (95 CI %) | p-value | aOR (95 CI %) | p-value | |||
Age (years) | 0.99 [0.93–1.06] | 0.654 | 0.99 [0.93–1.05] | 0.696 | ||
gender (male) | 0.56 [0.19–1.69] | 0.304 | 0.55 [0.18–1.71] | 0.300 | ||
Year in an endemic area (years) | 0.97 [0.92–1.02] | 0.177 | 0.97 [0.92–1.02] | 0.196 | ||
Distance to the river (< 1 km) | 0.28 [0.05–1.66] | 0.163 | 0.25 [0.04–1.50] | 0.126 | ||
Distance to the river (1–2 km) | 0.16 [0.03–0.91] | 0.039 | 0.16 [0.03–0.93] | 0.041 | ||
Occupation (Farmer) | 5.94 [1.65–21.39] | 0.006 | 5.74 [1.55–21.25] | 0.009 | ||
Individual IVM intake | 0.91 [0.65–1.27] | 0.566 | 0.92 [0.66–1.30] | 0.646 | ||
Total nodule counts | 0.93 [0.57–1.49] | 0.751 | 0.91 [0.56–1.49] | 0.709 | ||
Total nodule sites | 1.43 [0.53–3.87] | 0.484 | 1.52 [0.56–4.15] | 0.411 | ||
ELR x10 | 1.69 [1.14–2.51] | 0.009 | ||||
Eosinophil [abs] | 13.86 [2.07–92.90] | 0.007 |
ENR, EMR, EBR and ELR significantly improve the conventional model for predicting microfilaridermia
Parameter | C-statistics | ||
---|---|---|---|
Estimate | 95% CI | p-value | |
Model 1 | 0.778 | 0.692–0.864 | < 0.0001 |
Model 1 + Eosinophil | 0.825 | 0.752–0.899 | < 0.0001 |
Model 1 + ENR | 0.820 | 0.740–0.899 | < 0.0001 |
Model 1 + EMR | 0.821 | 0.745–0.897 | < 0.0001 |
Model 1 + EBR | 0.811 | 0.733–0.889 | < 0.0001 |
Model 1 + ELR | 0.814 | 0.739–0.889 | < 0.0001 |
Model 1 + ENR + EMR + EBR + ELR | 0.818 | 0.742–0.894 | < 0.0001 |
Model 1 + Eosinophil + Combined ratios | 0.829 | 0.756–0.902 | < 0.0001 |