Plasmodium falciparum Infection Status among Children with Schistosoma in Sub-Saharan Africa: A Systematic Review and Meta-analysis

Abstract

BackgroundIt has been suggested that Schistosoma infection may be associated with Plasmodium falciparum infection or related reduction in haemoglobin level, but the nature of this interaction remains unclear. This systematic review synthesized evidence on the relationship of S. haematobium or S. mansoni infection with the occurrence of P. falciparum malaria, Plasmodium density and related reduction in haemoglobin level among children in sub-Saharan Africa (SSA).Methodology/Principal findingsA systematic review in according with PRISMA guidelines was conducted. All published articles available in PubMed, Embase, Cochrane library and CINAHL databases before May 20, 2015 were searched without any limits. Two reviewers independently screened, reviewed and assessed all the studies. Cochrane Q and Moran’s I2 were used to assess heterogeneity and the Egger test was used to examine publication bias. The summary odds ratio (OR), summary regression co-efficient (β) and 95% confidence intervals (CI) were estimated using a random-effects model. Out of 2,920 citations screened, 12 articles (five cross-sectional, seven prospective cohort) were eligible to be included in the systematic review and 11 in the meta-analysis. The 12 studies involved 9,337 children in eight SSA countries. Eight studies compared the odds of asymptomatic/uncomplicated P. falciparum infection, two studies compared the incidence of uncomplicated P. falciparum infection, six studies compared P. falciparum density and four studies compared mean haemoglobin level between children infected and uninfected with S. haematobium or S. mansoni. Summary estimates of the eight studies based on 6,018 children showed a higher odds of asymptomatic/uncomplicated P. falciparum infection in children infected with S. mansoni or S. haematobium compared to those uninfected with Schistosoma (summary OR: 1.82; 95%CI: 1.41, 2.35; I2: 52.3%). The increase in odds of asymptomatic/uncomplicated P. falciparum infection among children infected with Schistosoma remained significant when subgroup analysis was conducted for S. haematobium (summary OR: 1.68; 95%CI: 1.18, 2.41; I2: 53.2%) and S. mansoni (summary OR: 2.15; 95%CI: 1.89, 2.46: I2: 0.0%) infection. However, the density of P. falciparum infection was lower in children co-infected with S. haematobium compared to those uninfected with Schistosoma (summary-β: -0.14; 95% CI: -0.24, -0.01; I2: 39.7%). The mean haemoglobin level was higher among children co-infected with S. haematobium and P. falciparum than those infected with only P. falciparum (summary-mean haemoglobin difference: 0.49; 95% CI: 0.04, 0.95; I2: 66.4%)Conclusions/SignificanceThe current review suggests S. mansoni or S. haematobium co-infection may be associated with increased prevalence of asymptomatic/uncomplicated P. falciparum infection in children, but may protect against high density P. falciparum infection and related reduction in haemoglobin level.

Schistosoma haematobium infection modulates Plasmodium falciparum parasite density and antimalarial antibody responses

“…In our study, a modulation of antimalarial immunity and Pf PD showed that the density of Pf infection was lower in children coinfected with Sh compared to those uninfected with Sh. 38 We found that children infected 20 However, two other studies found discordant results. 18,19 In a Senegalese cohort, Courtin and coll.…”

“…Such misclassification may increase the mean of Pf parasitemia in the Shpositive group making the identification of associations between Sh status and Pf mean parasite density more difficult. We have performed a complementary analysis on the last 3 months of follow-up to cover the prepatent period of Sh (10-12 weeks), and the association was confirmed (P = .016; lower mean parasite density in the Sh-infected group).Sh has been reported to modulate malaria PD in Senegalese children, in which those with light intensity Sh infections had lower Pf PD than Sh uninfected children 3,5,38. In our study, the effect of Sh infection on Pf PD seemed to be independent of the intensity of Sh infection because no difference in Pf PD was observed when Sh infection was dichotomized into low, moderate or heavy Sh intensity.Another study conducted in Mali indicated that Sh infection was associated with lower Pf PD and a reduced risk of progression to symptomatic disease in long-term Pf asymptomatic carriers 7.…”

“…A systematic review and meta‐analysis performed by Degarege and coll. showed that the density of Pf infection was lower in children coinfected with Sh compared to those uninfected with Sh …”

The consequences of mixed-species malaria parasite co-infections in mice and mosquitoes for disease severity, parasite fitness, and transmission success

“…They are studied regarding diagnosis [15][16][17], treatment [18], immune response [19], virulence [12,20], transmission [21][22][23], and in discussions of public health policy [6]. The virulence of malaria infection is also of interest in the context of co-infection with other pathogens, such as HIV and Schistosoma [24][25][26].The consequences of mixed-species infections on malaria disease and parasite fitness are incompletely understood. There is conflicting evidence from laboratory and field studies regarding the capacity of mixed-species infections to exacerbate [27] or ameliorate [14] disease.…”

Co-infecção Plasmodium falciparum e Schistosoma haematobium: papel dos genes HLA não-clássicos de classe I (HLA-G, -E e -F) na suscetibilidade à malária

“…(Briand et al 2005;Lyke et al 2005). This protection was also observed in the group of children with light S. haematobium infection (1-9 eggs/10 mL of urine) compared to moderate (10-49 eggs/10 mL of urine) and heavy (≥ 50 10-49 eggs/10 mL of urine) infection (Briand et al 2005;Lemaitre et al 2014;Doumbo et al 2014;Degarege et al 2016). In addition, any S. haematobium co-infected children were prevented from developing anemia (Doumbo et al 2014;Degarege et al 2016).…”