Haemolysis and haem oxygenase-1 induction during persistent "asymptomatic" malaria infection in Burkinabé children

Malar J. 2018 Jul 6;17(1):253. doi: 10.1186/s12936-018-2402-6.


Background: The haemolysis associated with clinical episodes of malaria results in the liberation of haem, which activates the enzyme haem oxygenase-1 (HO-1). HO-1 has been shown to reduce neutrophil function and increase susceptibility to invasive bacterial disease. However, the majority of community-associated malaria infections are subclinical, often termed "asymptomatic" and the consequences of low-grade haemolysis during subclinical malaria infection are unknown.

Study design and results: As part of an ongoing study of subclinical malaria in Burkina Faso, 23 children with subclinical Plasmodium falciparum infections (determined by qPCR) were compared with 21 village-matched uninfected control children. Infected children showed evidence of persistent haemolysis over 35 days, with raised plasma haem and HO-1 concentrations. Concentrations of IL-10, which can also directly activate HO-1, were also higher in infected children compared to uninfected children. Regression analysis revealed that HO-1 was associated with haemolysis, but not with parasite density, anaemia or IL-10 concentration.

Conclusions: This study reveals that subclinical P. falciparum malaria infection is associated with sustained haemolysis and the induction of HO-1. Given the association between HO-1, neutrophil dysfunction and increased risk of Salmonella bacteraemia, prolonged HO-1 induction may explain epidemiological associations and geographic overlap between malaria and invasive bacterial disease. Further studies are needed to understand the consequences of persistent subclinical malaria infection, low-grade haemolysis and raised HO-1 on immune cell function and risk of comorbidities.

Keywords: Anaemia; Burkina Faso; HO-1; Haemolysis; IL-10; Subclinical malaria.

MeSH terms

  • Asymptomatic Infections
  • Burkina Faso
  • Child
  • Child, Preschool
  • Female
  • Heme Oxygenase-1 / genetics*
  • Heme Oxygenase-1 / metabolism
  • Hemolysis*
  • Humans
  • Malaria, Falciparum / metabolism*
  • Male
  • Plasmodium falciparum / physiology*


  • Heme Oxygenase-1