Authors

C J Sutherland¹; I N Lubis¹;  ¹ London School of Hygiene & Tropical Medicine

Discussion

As Indonesia works towards the goal of malaria elimination, information is lacking on malaria epidemiology from some western regions. As a basis for studies of antimalarial efficacy, we set out to survey parasite carriage in three communities in North Sumatera Province. Methods. A combination of active and passive detection of infection was carried out among communities in Batubara, Langkat and South Nias regencies. Finger-prick blood samples from consenting individuals of all ages provided blood films for microscopic examination and blood spots on filter paper. Plasmodium species were identified by nested PCR of rRNA genes, and a novel assay which amplifies a conserved sequence specific for the sicavar gene family of P. knowlesi. Results. 614 of 3,731 participants (16.5%) were positive for malaria parasites by microscopy. PCR detected parasite DNA in samples from 1,169 individuals (31.3%). In total, 377 participants (11.8%) harboured P. knowlesi. Also present were P. vivax (14.3%), P. falciparum (10.5%) and P. malariae (3.4%). Conclusions. Amplification of sicavar is a specific and sensitive test for the presence of P. knowlesi DNA in humans. Subpatent and asymptomatic multi-species parasitaemia is relatively common in North Sumatera, and so PCR-based surveillance is required to support control and elimination activities.Our results will be discussed in the general context of persistent complex parasitaemia in asymptomatic primate hosts.