A putative clinical association between malaria and invasive bacterial infection (IBI) was first suggested in 1929, and although data accumulated since then does indicate that children with Plasmodium falciparum malaria are at risk of IBI, the exact nature and extent of this relationship remains unclear. James Church and Kathryn Maitland, from Imperial College London, UK, conducted a systematic review, published in BMC Medicine, to try and unravel this association.
Church and Maitland carried out a systematic search of three major scientific databases, PubMed, Embase and Africa Wide Information, to identify articles describing bacterial infection among children with P. falciparum malaria in sub-Saharan Africa and found a total of 25 studies that fulfilled their inclusion criteria. Of these, ten studies reported on children with severe malaria between 1992 and 2010 in 11 countries. In all, these studies involved 7,208 children, including 461 with concomitant IBI, reflecting a mean prevalence of IBI of 6.4 percent.
When they considered studies that included children with all severity malaria (i.e. including children with not just severe malaria, but also asymptomatic and mild cases), they found slightly variant results. The prevalence of IBI in children with malaria was not dissimilar at 5.58 percent (1,166 of 20,889), however, of 27,641 children with non-malarial febrile illness, 2,148 had a concomitant IBI, demonstrating a prevalence of 7.77 percent.
Additionally, the authors investigated the effect of co-infection on mortality in children with severe malaria, and found that there were 81 fatalities in 336 children with malaria and concomitant IBI (24.1 percent) compared with 585 deaths in 5,760 children with malaria alone (10.2 percent).
Although there are limitations to the systematic review, such as the fact that heterogeneity between the included studies was high, the findings suggest that children with severe malaria are at a risk of bacterial infection, and that this results in an increased mortality risk.