Background: Hyperparasitaemia is a feature of childhood severe malaria but there is little information on the risk
factors for hyperparasitaemia in malarious children
Methods: The risk factors associated with Plasmodium falciparum hyperparasitaemia, defined as asexual
parasitaemia > 250,000/μl, at presentation were evaluated in 3338 malarious children enrolled prospectively
between 2008 and 2010 in an endemic area of southwestern Nigeria.
Results: At enrolment, 97 (3%) of 3338 malarious children had hyperparasitaemia. In a multiple regression model, 3
factors were found to be independent risk factors for the presence of hyperparasitaemia at enrolment: an age ≤ 11
years (Adjusted odds ratio [AOR] = 2.85, 95% confidence interval [CI] 1.23-6.61, P = 0.014), fever (AOR = 2.02, 95%
CI 1.23-3.29, P = 0.005), and enrolment after year 2008 (AOR = 0.42, 95% CI 0.24-0.73, P = 0.002). Duration of illness
≤ 3 d was associated with increased risk of hyperparasitaemia. There was no association between season and
hyperparasitaemia. Compared to non-hyperparasitaemia, hyperparasitaemia was associated with an increased risk of
progression to cerebral malaria (P < 0.0001). The risk of progression in hyperparasitaemic children was higher in <
5-year olds (P = 0.02).
Conclusion: Young age and presence of fever are independent risk factors for hyperparasitaemia which is
associated with an increased risk of progression to cerebral malaria. The findings have implications for case and
community management of childhood hyperparasitaemia and for malaria control efforts in sub-Saharan Africa
where severe malaria is relatively common
