Table 1 Dynamics of infections detected by microscopy/RDT and PCR during longitudinal studies

From: The temporal dynamics and infectiousness of subpatent Plasmodium falciparum infections in relation to parasite density

Country, year

Follow-up frequency

Follow-up duration

% sub- microscopic out of infected samples (N)

% of ever infected individuals only having sub- microscopic samples, n/Nb

Odds ratio of any future slide-positive samples in sub- microscopic infected people versus PCR-negatives (95% CI)

Number of consecutive sub- microscopic samples per sub- microscopic episodeb

Infection status before and after sub- microscopic periods % (n) *b

Senegal, 200562

1 week

9 weeks

29.7 (277)

13.0%

22/169

2.03 (0.83, 6.48)

1: 96% (64)

2: 3% (2)

3: 1% (1)

M, SM, M: 5% (2)

M, SM, Neg: 25% (10)

Neg, SM, M: 5% (2)

Neg, SM, Neg: 65% (26)

Senegal, 200462

1 week

9 weeks

3.4 (269)

0.8%

3/369

N/A

1: 100% (10)

M, SM, M: 0%

M, SM, Neg: 0%

Neg, SM, M: 0%

Neg, SM, Neg: 100% (4)

Papua New Guinea, 200665

8 weeks, some time points with two surveys 24 h apart

16 months

36.1 (1128)

6.3%

15/239

1.72 (0.53, 5.57)

(variable follow-up)

M, SM, M: 30% (105)

M, SM, Neg: 25% (87)

Neg, SM, M: 16% (58)

Neg, SM, Neg: 30% (105)

Ghana, 1994–199564

4 weeks

12 months

25.6 (776)

17.5%

21/120

3.13 (1.52, 7.61)

1: 83% (143)

2: 16% (28)

3: 0.6% (1)

M, SM, M: 22% (22)

M, SM, Neg: 8% (8)

Neg, SM, M: 19% (19)

Neg, SM, Neg:50% (49)

Senegal, 200363 a

8 times in 3 days

3 days

0.0 (168)

0%

0/21

N/A

0

M, SM, M: 0%

M, SM, Neg: 0%

Neg, SM, M: 0%

Neg, SM, Neg: 0%

Ghana, 200032

2 months

12 months

27.4 (1436)

9.1%

30/328

1.0 (0.36, 2.77)

1: 81% (116)

2: 22% (25)

3: 1% (2)

M, SM, M: 62% (89)

M, SM, Neg: 17% (25)

Neg, SM, M: 7% (10)

Neg, SM, Neg: 13% (19)

Tanzania 199666

1 month

6 months

20.7 (338)

8%

5/60

3.09 (0.92, 10.36)

1: 76% (52)

2: 18% (12)

3: 4% (3)

4: 0% (0)

5: 1% (1)

M, SM, M: 40% (27)

M, SM, Neg: 24% (16)

Neg, SM, M: 6% (4)

Neg, SM, Neg: 30% (20)

  1. Details of these studies are given in Supplementary Table 2. Note: the relative densities of different parasite genotypes were not measured, and individuals may have contracted superinfections during the study
  2. *Only includes submicroscopic periods with non-missing samples before and afterwards.
  3. †M, SM, M = microscopy-positive sample, followed by submicroscopic sample(s), followed by microscopy-positive sample
  4. M, SM, Neg = microscopy-positive sample, followed by submicroscopic sample(s), followed by sample negative by PCR and microscopy
  5. Neg, SM, M = sample negative by PCR and microscopy, followed by submicroscopic sample(s), followed by microscopy-positive sample
  6. Neg, SM, Neg = sample negative by PCR and microscopy, followed by submicroscopic sample(s), followed by sample negative by PCR and microscopy
  7. aIndividuals were selected based on being slide-positive at the initial time point
  8. bResults from different studies are not fully equivalent since they depend on sampling frequency, the sensitivity of the different methods, and treatment
Back to article page