Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Studies of the prevalence and incidence of malaria were conducted in children < 10 years old living in 10 rural villages on the island of Espiritu Santo, Vanuatu, south-west Pacific. Malaria prevalence remained stable at 30% throughout the year but the relative contributions of the 2 major species were highly dependent on season. Plasmodium falciparum predominated in the long wet season (November-May) and P. vivax in the dry season (June-October). Case definitions for malaria, derived using a multiple logistic regression method, showed that parasite densities associated with clinical disease were low; case definitions for P. falciparum (> 1000 parasites/microL in children > 1 year old and > 500 microL in infants) and P. vivax (> 500 parasites/microL at all ages) were both associated with a specificity and sensitivity of > 90%. Like prevalence data, malaria morbidity was highly seasonal; 80% of clinical P. falciparum infections occurred in the wet season and 66% of clinical P. vivax in the dry season. Mixed infections were rare. Malaria was important cause of morbidity with children < 5 years old experiencing 1.3-3.0 episodes of clinical malaria per year and 23% of fevers being attributable to malaria in this age group. Children aged 5-9 years continued to suffer one episode of clinical malaria per year. The peak incidence of P. vivax malaria occurred earlier in life than the peak incidence of P. falciparum malaria. The possible interactions between these 2 parasite species are discussed.

Original publication




Journal article


Trans R Soc Trop Med Hyg

Publication Date





614 - 620


Animals, Anopheles, Child, Child, Preschool, Cohort Studies, Cross-Sectional Studies, Female, Fever, Hemoglobins, Humans, Incidence, Infant, Infant, Newborn, Logistic Models, Longitudinal Studies, Malaria, Falciparum, Malaria, Vivax, Male, Morbidity, Parasitemia, Prevalence, Seasons, Splenomegaly, Vanuatu