Table 2.
Plasmodium falciparum qPCR results, estimated parasite density and polygenomic infections, four sites in Mali
| Rharous | Bamako | Doneguebougou | Bougoula | P value | |
|---|---|---|---|---|---|
| Total | |||||
| Positive qPCR for P. falciparum (%) | 44/149 (30) | 23/249 (9) | 44/100 (44) | 45/149 (30) | <0.0001 |
| Polygenomic infectionsd (%) | 11/30 (37) | 9/22 (41) | 21/30 (70) | 25/30 (83) | <0.0001 |
| Mean MOIc | 1.4e | 1.5f | 1.9 | 2.06 | <0.001 |
| Mean estimated parasitaemia ± SDb (parasites/µL blood) | 4397 ± 8127 | 5348 ± 5209 | 2942 ± 5863 | 8755 ± 24,395 | 0.061 |
| Individuals with fevera | |||||
| Positive qPCR for P. falciparum (%) | 22/44 (50) | 13/38 (34) | 6/8 (75) | 12/18 (66) | 0.051 |
| Polygenomic infectionsd (%) | 9/16 (56) | 5/13 (38) | 3/5 (60) | 6/8 (75) | <0.0001 |
| Mean MOIc | 1.62 | 1.46 | 1.6 | 1.75 | 0.72 |
| Mean estimated parasitaemia ± SDb (parasites/µL blood) | 7335 ± 10639 | 6916 ± 5934 | 9063 ± 12,318 | 5731 ± 9192 | 0.86 |
| Apyretic individualsa | |||||
| Positive qPCR for P. falciparum (%) | 20/93 (21) | 10/211 (5) | 38/91 (42) | 32/131 (24) | <0.0001 |
| Polygenomic infectionsd (%) | 2/14 (14) | 4/9 (44) | 18/25 (72) | 19/22 (86) | <0.0001 |
| Mean MOIc | 1.14 | 1.55 | 1.96 | 2.18 | <0.0001 |
| Mean estimated parasitaemia ± SDb (parasites/µL blood) | 1368 ± 2066 | 3311 ± 3348 | 1976 ± 3523 | 10148 ± 28,407 | <0.01 |
Differences in the denominator are due to missing data (n = 14 missing axillary temperature data)
Statistically significant results are indicated in italic
aFever: axillary temperature ≥37.5 °C and apyretic: axillary temperature <37.5 °C
bEstimation of parasite densities: [(copy number of the gene in 1 µL of DNA) × (100/125)]. Assuming that each genome of P. falciparum has five copies of the 18S rRNA gene [28], that blood volume spotted onto filter papers was 25 µL (half filter paper) and that extracted DNA was eluted into 100 µL
cMOI was calculated based on complete genotypes
MOI calculated in each site = ∑(maximum number alleles for a given sample) ÷ ∑(genotyped samples)
dPolygenomic infections are defined as individuals infected by ≥2 distinct parasite genotypes
eStatistically significant compared with Doneguebougou and Bougoula
fStatistically significant compared with Bougoula