A Cluster of Plasmodium ovale Infections in Belgian Military Personnel after Deployment in Kindu, Democratic Republic of Congo: A Retrospective Study.

Diana Isabela Costescu Strachinaru,Peter Vanbrabant,Marjan Van Esbroeck,An Wauters,Patrick Soentjens,Mihai Strachinaru

doi:10.3390/tropicalmed6030125

Abstract

Plasmodium ovale malaria is often neglected due to its less severe course compared to Plasmodium falciparum. In 2011–2012, Belgian Armed Forces identified a cluster of P. ovale cases among military personnel after deployment in the Democratic Republic of Congo (DRC). In this retrospective, monocentric, observational study, clinical and biological features of soldiers diagnosed with P. ovale after deployment in DRC were reviewed. Species diagnosis was based on polymerase chain reaction (PCR) and/or thick blood smear. Medical records of 149 soldiers screened at the Queen Astrid Military Hospital after deployment were reviewed. Eight cases (seven P. ovale infections and one P. ovale—falciparum coinfection) were identified. All had positive thick smears, and seven were confirmed by PCR. Chemoprophylaxis was mefloquine in all subjects. Median time of disease onset was 101 days after return from the endemic region. Median delay between return and diagnosis was 103 days. All P. ovale bouts were uncomplicated. None had relapses after primaquine treatment. This military cohort highlights a hotspot of P. ovale in Eastern DRC. Non-specific symptoms, the less severe presentation, the lack of sensitive parasitological tools in the field and long delays between infection and symptoms probably lead to underestimation of P. ovale cases.

Highlights

Malaria is the most common cause of fever in returning travelers and migrants from endemic regions [1,2]
This study presents a cluster of eight P. ovale infections in a military population deployed in Democratic Republic of Congo (DRC), revealed through active surveillance that allowed the detection of rare events such as non-falciparum malaria
This cluster was of concern for the military medical authorities for several reasons: the risk of incapacitation of infected soldiers in the field, the availability of only insensitive diagnostic tools such as rapid diagnostic tests (RDTs) and the need for an eradication treatment with PQ to avoid subsequent relapses related to hypnozoites

Summary

Introduction

Malaria is the most common cause of fever in returning travelers and migrants from endemic regions [1,2]. Military personnel deployed in these regions are at risk [3,4]. Plasmodium ovale (P. ovale) is endemic to areas in Central and West Africa and in Southeast. In populations with endemic circulation, fever occurs when parasitemia exceeds. P. ovale malaria usually has a less severe clinical course when compared to Plasmodium falciparum (P. falciparum) and deadly cases are rare; it is often neglected. A systematic review of P. ovale malaria published in 2017, which included

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