Table 2 Malariometric indices by study village (determined by microscopy and PCR)
From: Epidemiology of forest malaria in Central Vietnam: the hidden parasite reservoir
Village 1% (n) | Village 2 | Village 3 | Village 4 | TOTAL % (n/N) [95% CI] | ||
|---|---|---|---|---|---|---|
Total screened (by microscopy) | 350 | 256 | 532 | 312 | 1,450 | |
Parasite prevalence (microscopy) | 4.9 (17) | 3.9 (10) | 9.8 (52) | 10.9 (34) | 7.8 (113/1450) | [6.3; 9.6]° |
Prevalence by age group (years): | ||||||
≤9 | 4.7 (6/127) | 1.2 (1/84) | 9.9 (20/202) | 15.4 (18/117) | 8.5 (45/530) | [6.3; 11.3] °° |
10–19 | 7.6 (5/66) | 7.6 (4/53) | 25.6 (20/78) | 11.4 (8/70) | 13.9 (37/267) | [9.4; 20.0] |
20–39 | 4.2 (4/95 | 5.3 (4/75) | 5.6 (9/160) | 7.9 (6/76) | 5.7 (23/406) | [3.8; 8.3] |
≥40 | 3.2 (2/62) | 2.3 (1/44) | 3.3 (3/92) | 4.1 (2/49) | 3.2 (8/247) | [1.6; 6.4] |
Species distribution (proportion): | ||||||
- P. falciparum | 58.8 (10) | 80.0 (8) | 96.2 (50) | 70.6 (24) | 81.4 (92) | [72.8; 87.8]° |
- P. vivax | 41.2 (7) | 20.0 (2) | 1.9 (1) | 29.4 (10) | 17.7 (20) | [11.6; 26.1] |
- Mixed | 0 | 0 | 1.9 (1) | 0 | 0.9 (1) | [0.1; 6.3] |
Parasite density (geometric mean): | ||||||
- P. falciparum | 1390.9 | 938.5 | 2008.3 | 3007.6 | 2006.9 | [1,523.8; 2,643.1] |
- P. vivax | 340.9 | 423.3 | 726.6 | 794.9 | 559.7 | [301.9; 1,037.7] |
Infections with gametocytes, % (n) | 64.7 (11/17) | 40.0 (4/10) | 15.4 (8/52) | 52.9 (18/34) | 36.3 (41/113) | [28.0; 45.5]°° |
Proportion asymptomatic, % (n) | 76.5 (13/17) | 80.0 (8/10) | 73.1 (38/52) | 58.8 (20/34) | 69.9 (79/113) | [60.1; 78.2] |
Total surveyed (PCR) | N = 75 | N = 55 | N = 133 | N = 64 | N = 327 | |
Parasite prevalence*, % (n) | 16.4 (13/75) | 18.9 (12/55) | 20.2 (25/133) | 42.5 (24/64) | 23.6 (74/327) | [19.0; 28.9] |
Species distribution: | ||||||
P. falciparum (Pf) | 25.8 (4) | 52.6 (6) | 77.5 (17) | 58.6 (14) | 59.2 (41) | [47.2; 70.2]° |
P. vivax (Pv) | 74.2 (9) | 47.4 (6) | 22.5 (8) | 37.9 (9) | 39.6 (32) | [28.7; 51.6] |
Pf + Pv | 0 | 0 | 0 | 3.5 (1) | 1.2 (1) | [0.2; 8.7] |
Prop. sub-patent infections, % (n) | 79.0 (10) | 73.7 (8) | 44.9 (14) | 57.2 (14) | 58.7 (46) | [46.2; 70.2] |
Prop. asymptomatic infections, % (n) | 100.0 (13) | 71.9 (9) | 62.3 (15) | 78.6 (18) | 75.4 (55) | [63.7; 84.2] |
Prevalence ratio LM/PCR | 0.30 | 0.21 | 0.48 | 0.26 | 0.33 | |
Mean haemoglobin, g/dl | 13.1 | 13.4 | 11.9 | 11.9 | 12.4 | [12.2; 12.6]** |
Prevalence anaemia (Hb <10.0 g/dl) | 3.4 (2) | 2.7 (1) | 14.9 (19) | 11.7 (7) | 9.6 (29) | [6.6; 13.7]° |