Exflagellation of Plasmodium vivax in peripheral blood: An uncommon finding and its significance

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Date: April-June 2019
From: Journal of Laboratory Physicians(Vol. 11, Issue 2)
Publisher: Medknow Publications and Media Pvt. Ltd.
Document Type: Article
Length: 1,437 words
Lexile Measure: 1570L

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Byline: Mukund. Sable, Gaurav. Chhabra, Shruti. Mishra

Malaria continues to be a major public health problem. The life cycle of malaria is completed in two hosts Anopheles mosquito - definitive host and humans - the intermediate host. Exflagellation of microgametocyes in the life cycle of Plasmodium vivax occurs in mosquitoes and is rarely seen in human peripheral blood. Less than 15 occurrences of exflagellated microgametocyte of Plasmodium species have been reported to date. The appearance of exflagellated microgametes in human blood may pose a diagnostic dilemma due to its resemblance with other hemoparasites such as Borrelia and Trypanosoma.


Malaria is a major public health issue, particularly in Africa and Southeast Asia. It is caused due to infection with Plasmodium protozoa. The life cycle of Plasmodium species is complex and multistage, with sexual stage occurring in infected female Anopheles mosquito (definitive host) and asexual stage occurring in humans (intermediate host). All the asexual stages of Plasmodium vivax such as ring forms, late trophozoites, schizonts, and gametocytes are observed commonly in human blood whereas, sexual stages such as exflagellation of microgametocyte and microgametes are rarely seen in humans. Less than 15 occurrences of exflagellated microgametocyte of Plasmodium spp. have been reported to date. Herein, we report a case of P. vivax infection with different stages of exflagellation and numerous exflagellated microgametes in addition to the ring forms of P. vivax in peripheral blood of a patient with high-grade fever and its significance in the clinical laboratory diagnosis.

Case Report

A 70-year-old female patient presented in the emergency department with high-grade fever for the last 2 days. The patient's blood sample was sent to the laboratory in ethylenediaminetetraacetic acid (EDTA) vacutainer for complete hemogram analysis. On receipt, in the laboratory, the sample was run on XT4000i (Sysmex, Kobe, Japan) automated hematology analyzer. The hemogram analysis revealed total leukocyte count of 11.43/[micro]l with a system generated flag of abnormal white blood cell scattergram, and no differential count was reported by the analyzer. The scatter plot revealed no clear-cut separation of neutrophil and eosinophil population in WDF channel on SFL (Side Fluorescence) versus SSC (Side Scatter) plot, indicating the presence of hemoparasite [Figure...

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Gale Document Number: GALE|A587540646