Pre-elimination stage of malaria in Sri Lanka: assessing the level of hidden parasites in the population

Malaria Journal

Research

Michael Alifrangis¹  Flemming Konradsen²  Rupika S Rajakaruna³  Priyanie H Amerasinghe⁴ 

[1] Centre for Medical Parasitology at the Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark;Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Denmark;Copenhagen School of Global Health, Department of International Health, Immunology and Microbiology, University of Copenhagen, Denmark;Department of Zoology, University of Peradeniya, Peradeniya, Sri Lanka;International Water Management Institute, C/o International Crops Research Institute for the Semi-Arid Tropics, Patancheru - 502 324, Hyderabad, Andhra Pradesh, India;

关键词: Malaria;    Malaria Case;    Vivax Infection;    High Malaria Transmission;    Active Case Detection;   

DOI  :  10.1186/1475-2875-9-25

 received in 2009-08-20, accepted in 2010-01-20,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundWith the dramatic drop in the transmission of malaria in Sri Lanka in recent years, the country entered the malaria pre-elimination stage in 2008. Assessing the community prevalence of hidden malaria parasites following several years of extremely low transmission is central to the process of complete elimination. The existence of a parasite reservoir in a population free from clinical manifestations, would influence the strategy for surveillance and control towards complete elimination.MethodsThe prevalence of hidden parasite reservoirs in two historically malaria endemic districts, Anuradhapura and Kurunegala, previously considered as high malaria transmission areas in Sri Lanka, where peaks of transmission follow the rainy seasons was assessed. Blood samples of non-febrile individuals aged five to 55 years were collected from randomly selected areas in the two districts at community level and a questionnaire was used to collect demographic information and movement of the participants. A simple, highly sensitive nested PCR was carried out to detect both Plasmodium falciparum and Plasmodium vivax, simultaneously.ResultsIn total, 3,023 individuals from 101 villages participated from both districts comprising mostly adults between the ages 19-55 years. Out of these, only about 1.4% of them (n = 19) could recall having had malaria during the past five years. Analysis of a subset of samples (n = 1322) from the two districts using PCR showed that none of the participants had hidden parasites.DiscussionA reservoir of hidden parasites is unlikely to be a major concern or a barrier to the ongoing malaria elimination efforts in Sri Lanka. However, as very low numbers of indigenous cases are still recorded, an island-wide assessment and in particular, continued alertness and follow up action are still needed. The findings of this study indicate that any future assessments should be based on an adaptive sampling approach, involving prompt sampling of all subjects within a specified radius, whenever a malaria case is identified in a given focus.

【 授权许可】

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