Absence of malaria-specific mortality in children in an area of hyperendemic malaria.

We conducted a prospective community-based malaria surveillance study on a cohort of children < 10 years old living in an area of hyperendemic malaria (spleen rates > 50% in children aged 2-9 years) in Vanuatu, Melanesia, supported by a concurrent prospective descriptive study of malaria admissions to the local hospital. The incidence of clinical malaria in children < 10 years old was 1.9 episodes/year. The annual incidence of severe malaria (severe malarial anaemia and cerebral malaria) was only 2/1000 in children aged < 5 years. The only manifestation of severe malaria seen in indigenous children was anaemia. No death could be attributed to malaria. While the incidence of uncomplicated clinical malaria in this population was comparable to that in many parts of Africa, the incidence of severe forms of the disease was significantly lower. This could not be attributed to differing rates of malaria transmission, chloroquine resistance, or to host protective or behavioural factors. These findings suggest that studies which compare disease patterns in geographically disparate populations may be instrumental in developing a better understanding of the determinants of clinical outcome in Plasmodium falciparum malaria and that such regional differences must be considered when planning or interpreting the effects of malaria interventions.