Sub-microscopic malaria cases and mixed malaria infection in a remote area of high malaria endemicity in Rattanakiri province, Cambodia: implication for malaria elimination

Malaria Journal

Research

Isabelle Jeanne¹  Christophe Rogier²  Sean Hewitt³  François-Xavier Babin⁴  Linda Duval⁵  Lucy Okell⁶  Duong Socheat⁷  William O Rogers⁸  Monidarin Chou⁹  Sandra Incardona^1,10  Frédéric Ariey^1,10  Nicolas Steenkeste^1,10  Sophy Chy^1,10 

[1] Centre de recherche médicale et sanitaire (CERMES), Niamey, Niger;Equipe « Moustiques et Maladies Emergentes » - UMR 6236 - URMITE, Unité de Recherche en Biologie et Epidémiologie Parasitaires, Institut de Recherche Biomédicale des Armées, Marseille, France;European Commission National Malaria Control Program, Phnom Penh, Cambodia;Fondation Mérieux, Phnom Penh, Cambodia;Laboratoire de Génétique de la réponse aux infections chez l'homme, Institut Pasteur, Paris, France;London School of Hygiene & Tropical Medicine (LSHTM), London, UK;National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia;Naval Medical Research Center Unit 2, 10560, Jakarta, Indonesia;Rodolphe Mérieux Laboratory of Cambodia, University of Health Science, Phnom Penh, Cambodia;Unité d'Epidémiologie Moléculaire, Institut Pasteur du Cambodge, Phnom Penh, Cambodia;

关键词: Malaria;    Plasmodium;    Mixed Infection;    Rapid Diagnostic Test;    Cerebral Malaria;   

DOI  :  10.1186/1475-2875-9-108

 received in 2009-09-19, accepted in 2010-04-22,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundMalaria microscopy and rapid diagnostic tests are insensitive for very low-density parasitaemia. This insensitivity may lead to missed asymptomatic sub-microscopic parasitaemia, a potential reservoir for infection. Similarly, mixed infections and interactions between Plasmodium species may be missed. The objectives were first to develop a rapid and sensitive PCR-based diagnostic method to detect low parasitaemia and mixed infections, and then to investigate the epidemiological importance of sub-microscopic and mixed infections in Rattanakiri Province, Cambodia.MethodsA new malaria diagnostic method, using restriction fragment length polymorphism analysis of the cytochrome b genes of the four human Plasmodium species and denaturing high performance liquid chromatography, has been developed. The results of this RFLP-dHPLC method have been compared to 1) traditional nested PCR amplification of the 18S rRNA gene, 2) sequencing of the amplified fragments of the cytochrome b gene and 3) microscopy.Blood spots on filter paper and Giemsa-stained blood thick smears collected in 2001 from 1,356 inhabitants of eight villages of Rattanakiri Province have been analysed by the RFLP-dHPLC method and microscopy to assess the prevalence of sub-microscopic and mixed infections.ResultsThe sensitivity and specificity of the new RFLP-dHPLC was similar to that of the other molecular methods. The RFLP-dHPLC method was more sensitive and specific than microscopy, particularly for detecting low-level parasitaemia and mixed infections. In Rattanakiri Province, the prevalences of Plasmodium falciparum and Plasmodium vivax were approximately two-fold and three-fold higher, respectively, by RFLP-dHPLC (59% and 15%, respectively) than by microscopy (28% and 5%, respectively). In addition, Plasmodium ovale and Plasmodium malariae were never detected by microscopy, while they were detected by RFLP-dHPLC, in 11.2% and 1.3% of the blood samples, respectively. Moreover, the proportion of mixed infections detected by RFLP-dHPLC was higher (23%) than with microscopy (8%).ConclusionsThe rapid and sensitive molecular diagnosis method developed here could be considered for mass screening and ACT treatment of inhabitants of low-endemicity areas of Southeast Asia.

【 授权许可】

CC BY   
© Steenkeste et al; licensee BioMed Central Ltd. 2010