No serological evidence for Zika virus infection and low specificity for anti-Zika virus ELISA in malaria positive individuals among pregnant women from Madagascar in 2010.

Norbert Georg Schwarz,Oumou Maiga-Ascofaré,Denise Dekker,Doris Winter,Jonas Schmidt-Chanasit,Njary Randriamampionona,Dennis Tappe,Jürgen May,Raphael Rakotozandrindrainy,Stephanie Jansen,Eva Mertens

doi:10.1371/journal.pone.0176708

Abstract

It was previously reported that a malaria infection may interfere with the specificity of a commercial ELISA test against Zika virus (ZIKV). We analyzed 1,216 plasma samples from healthy, pregnant women collected in two sites in Madagascar in 2010 for ZIKV antibodies using a commercial ELISA and for Plasmodium infection by PCR. This screen revealed six putative ZIKV-positive samples by ELISA. These results could not be confirmed by indirect immunofluorescence assays or virus neutralization tests. Four of these six samples were also positive for P. falciparum. We noted that the frequency of malaria positivity was higher in ZIKV-ELISA positive samples (50% and 100% in the two study sites) than ZIKV-negative samples (17% and 10%, respectively), suggesting that malaria may have led to false ZIKV-ELISA positives.

Highlights

Zika virus (ZIKV) is a mosquito-borne flavivirus, transmitted by Aedes mosquitoes
False positive results were described with serum samples from malaria patients [17]. In this seroprevalence study we investigated the presence of ZIKV antibodies in archived plasma samples that were collected in Madagascar from pregnant women in 2010, and for which serology for chikungunya virus (CHIKV), dengue virus (DENV) and PCR for malaria had been performed previously in order to assess if ZIKV was circulating on the island at that time
Malaria parasites may interfere with anti-ZIKV Enzyme Linked Immunosorbent Assays (ELISA) tests and may lead to false positive test results

Summary

Introduction

Zika virus (ZIKV) is a mosquito-borne flavivirus (family Flaviviridae), transmitted by Aedes mosquitoes. It was first identified in a monkey in the Zika forest of Uganda in 1947 [1]. In the following 60 years, ZIKV was repeatedly shown to circulate in mosquitoes in Africa and Asia, and was isolated from humans with asymptomatic to mild infection [2, 3]. ZIKV gained global attention after its introduction into Brazil in 2013 [4, 5] and subsequent rapid spread in the Americas starting in May 2015. As of November 2016, autochthonous transmission of ZIKV was reported from 47 countries and territories in South and Latin America [6]; and an association between ZIKV infection and neurological complications.

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