Background Little is known about Plasmodium malariae, a relatively rare cause of malaria in returned travelers. Recently, polymerase chain reaction (PCR) use for malaria diagnosis has enhanced specificity of P. malariae detection. The study objective was to describe the unique aspects of P. malariae diagnosis and clinical course in travelers. Methods Malaria is a reportable disease in Israel. All PCR-proven P. malariae monoinfections in Israeli travelers between January 2008 and January 2017 were retrieved from the Ministry of Health Reference Parasitology Laboratory. Data regarding method and timing of diagnosis, clinical characteristics, and laboratory testing were collected from patient charts. Results Eighteen patients with P. malariae were included. All cases were acquired in Africa. During the study period, the relative proportion of P. malariae increased (2%-10% of all malaria cases). Malaria was identified by blood smear in 10 of 18 patients (56%) on admission, and by rapid antigen test in 5 of 18 (29%) patients only, while P. malariae speciation was correctly identified by smear in 2 of 18 (11%) patients. Though all patients reported fever, only 4 of 18 (22%) described a quartan fever course. In 7 of 18 (39%) patients, malaria was contracted despite prophylactic treatment. Five patients had prolonged prepatent periods (median, 55 days), all of whom received prior prophylaxis. Conclusions The relative proportion of P. malariae is on the rise. Diagnosis in routine clinical settings is inadequate due to the low sensitivity and specificity of blood smears. PCR should be considered when clinical suspicion is high. Prophylaxis failure, which caused delayed clinical presentation, was documented.

Original languageEnglish
Pages (from-to)1516-1522
Number of pages7
JournalClinical Infectious Diseases
Issue number9
StatePublished - 1 Nov 2017


FundersFunder number
Department of Medicine
Public Health Services
Tel-Aviv University
Hebrew University of Jerusalem
Technion-Israel Institute of Technology
Ministry of Health, State of Israel


    • Plasmodium malariae
    • diagnosis
    • malaria
    • prophylaxis
    • travelers


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