Detection of malarial <scp>DNA</scp> in blood donors – evidence of persistent infection

Kitchen, A. D.; Chiodini, Peter L.; Tossell, Joanne

doi:10.1111/vox.12142

Cited by 24 publications

(19 citation statements)

References 14 publications

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“…While transmission declined, these individuals may have harboured parasites acquired over time and maintained at low levels of parasitaemia. Chronic infections have been shown to persist for up to a decade [29–32]. …”

Section: Discussionmentioning

confidence: 99%

Distinct parasite populations infect individuals identified through passive and active case detection in a region of declining malaria transmission in southern Zambia

Searle

Katowa

Tamaki

et al. 2017

Malar J

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BackgroundSubstantial reductions in the burden of malaria have been documented in parts of sub-Saharan Africa, with elimination strategies and goals being formulated in some regions. Within this context, understanding the epidemiology of low-level malaria transmission is crucial to achieving and sustaining elimination. A 24 single-nucleotide-polymorphism Plasmodium falciparum molecular barcode was used to characterize parasite populations from infected individuals identified through passive and active case detection in an area approaching malaria elimination in southern Zambia.MethodsThe study was conducted in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia, where the parasite prevalence declined over the past decade, from 9.2% in 2008 to less than 1% in 2013. Parasite haplotypes from actively detected, P. falciparum-infected participants enrolled in a serial cross-sectional, community-based cohort study from 2008 to 2013 and from passively detected, P. falciparum-infected individuals enrolled at five rural health centres from 2012 to 2015 were compared. Changes in P. falciparum genetic relatedness, diversity and complexity were analysed as malaria transmission declined.ResultsActively detected cases identified in the community were most commonly rapid diagnostic test negative, asymptomatic and had submicroscopic parasitaemia. Phylogenetic reconstruction using concatenated 24 SNP barcode revealed a separation of parasite haplotypes from passively and actively detected infections, consistent with two genetically distinct parasite populations. For passively detected infections identified at health centres, the proportion of detectable polyclonal infections was consistently low in all seasons, in contrast with actively detected infections in which the proportion of polyclonal infections was high. The mean genetic divergence for passively detected infections was 34.5% for the 2012–2013 transmission season, 37.8% for the 2013–2014 season, and 30.8% for the 2014–2015 season. The mean genetic divergence for actively detected infections was 22.3% in the 2008 season and 29.0% in the 2008–2009 season and 9.9% across the 2012–2014 seasons.ConclusionsDistinct parasite populations were identified among infected individuals identified through active and passive surveillance, suggesting that infected individuals detected through active surveillance may not have contributed substantially to ongoing transmission. As parasite prevalence and diversity within these individuals declined, resource-intensive efforts to identify the chronically infected reservoir may not be necessary to eliminate malaria in this setting.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-017-1810-3) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Distinct parasite populations infect individuals identified through passive and active case detection in a region of declining malaria transmission in southern Zambia

Searle

Katowa

Tamaki

et al. 2017

Malar J

View full text Add to dashboard Cite

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“…In England, 6 donations were positive for Plasmodium antigen in 2012, zero in Australia (antigen supplemental testing not routinely done in France). In England from 2010 to 2013, 14 (0.7%) of 1955 donations with reference serological activity were confirmed malarial DNA positive, all with residency risk and considered to be semi-immune [54]. In a US study of donors deferred for malaria risk, the Lab 21 EIA repeat reactive rate was 1.6%, but none were PCR positive [42].…”

Section: Transfusion-transmitted Infection Casesmentioning

confidence: 99%

The Epidemiology of Imported Malaria and Transfusion Policy in 5 Nonendemic Countries

O’Brien

Delage

Seed

et al. 2015

Transfusion Medicine Reviews

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“…This may be less easily detected with some assays and more likely to fall to undetectable levels over a relatively short time frame. This contrasts with the situation in donors with serological evidence of past infection whose risk is residency; in these donors, malarial antibody titres are generally higher, and antibody usually persists for extended periods (Kitchen et al, 2014). It is unlikely that antibody levels would fall to below detectable until many years after the donor has left an endemic area.…”

Section: Acute Malaria In a Repeat Blood Donormentioning

confidence: 88%