Reassessment of asymptomatic carriers of Plasmodium spp. in an endemic area with a very low incidence of malaria in extra-Amazonian Brazil

Malaria Journal

Research

Helder Ricas Rezende¹  Crispim Cerutti²  Angelica Espinosa Miranda²  Filomena E. C. de Alencar²  Julyana Cerqueira Buery²  Blima Fux²  Lícia Natal Fernandes³  Rosely dos Santos Malafronte³ 

[1] Entomology and Malacology Unit, Espírito Santo State Department of Health (SESA), Vitória, Brazil;Graduate Programme in Infectious Diseases, Federal University of Espírito Santo, Vitória, Brazil;Protozoology Laboratory, Institute of Tropical Medicine, University of São Paulo, São Paulo, Brazil;

关键词: Malaria;    Plasmodium vivax;    Plasmodium malariae;    Carrier state;    Polymerase chain reaction;   

DOI  :  10.1186/s12936-017-2103-6

 received in 2017-04-10, accepted in 2017-11-02,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundRegions with residual transmission are potential obstacles to the elimination of malaria. It is, therefore, essential to understand the factors associated with the maintenance of endemic malaria in these areas. The objective was to investigate whether the status of asymptomatic carriers of Plasmodium spp. DNA is maintained in the long term in an extra-Amazonian region of Brazil with low incidence, residual malaria transmission.MethodsAsymptomatic carriers of Plasmodium DNA detected in a survey carried out between 2001 and 2004 were reassessed between 2010 and 2011 using questionnaires, PCR and thick and thin blood smear tests three times at 3-month intervals.ResultsOf the 48 carriers detected between 2001 and 2004, 37 were located. Of these, only two had positive PCR results and, as in the first survey, Plasmodium malariae DNA was detected.ConclusionThe findings suggest that untreated dwellers from this extra-Amazonian region, who initially harbour malaria parasites, may become negative without ever developing apparent symptoms of the disease. Although the possibility of re-infection cannot be ruled out, the finding of two individuals harbouring P. malariae, both in the first and in the second survey, may be compatible with a long-term carrier state for this parasite. Since most clinical cases of malaria in the region are a consequence of infection by Plasmodium vivax, the epidemiological impact of such long-term carriage would be limited.

【 授权许可】

CC BY   
© The Author(s) 2017