Persistent Plasmodium falciparum infections enhance transmission‑reducing immunity development
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
Scientific Reports
Abstract
Subclinical infections that serve as reservoir populations to drive transmission remain a hurdle
to malaria control. Data on infection dynamics in a geographical area is required to strategically
design and implement malaria interventions. In a longitudinal cohort, we monitored Plasmodium
falciparum infection prevalence and persistence, and anti-parasite immunity to gametocyte and
asexual antigens for 10 weeks. Of the 100 participants, only 11 were never infected, whilst 16 had
persistent infections detected by reverse transcriptase-quantitative polymerase chain reaction
(RT-qPCR), and one participant had microscopic parasites at all visits. Over 70% of the participants
were infected three or more times, and submicroscopic gametocyte prevalence was high, ≥ 48% of
the parasite carriers. Naturally induced responses against recombinant Pfs48/45.6C, Pfs230proC, and
EBA175RIII–V antigens were not associated with either infection status or gametocyte carriage, but
the antigen-specific IgG titers inversely correlated with parasite and gametocyte densities consistent
with partial immunity. Longitudinal analysis of gametocyte diversity indicated at least four distinct
clones circulated throughout the study period. The high prevalence of children infected with distinct
gametocyte clones coupled with marked variation in infection status at the individual level suggests
ongoing transmission and should be targeted in malaria control programs
Description
Research Article
Keywords
immunity, Subclinical infections, malaria control, falciparum infection