PLoS Neglected Tropical Diseases (May 2022)

Malaria transmission structure in the Peruvian Amazon through antibody signatures to Plasmodium vivax.

  • Jason Rosado,
  • Gabriel Carrasco-Escobar,
  • Oscar Nolasco,
  • Katherine Garro,
  • Hugo Rodriguez-Ferruci,
  • Mitchel Guzman-Guzman,
  • Alejandro Llanos-Cuentas,
  • Joseph M Vinetz,
  • Narimane Nekkab,
  • Michael T White,
  • Ivo Mueller,
  • Dionicia Gamboa

DOI
https://doi.org/10.1371/journal.pntd.0010415
Journal volume & issue
Vol. 16, no. 5
p. e0010415

Abstract

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BackgroundThe landscape of malaria transmission in the Peruvian Amazon is temporally and spatially heterogeneous, presenting different micro-geographies with particular epidemiologies. Most cases are asymptomatic and escape routine malaria surveillance based on light microscopy (LM). Following the implementation of control programs in this region, new approaches to stratify transmission and direct efforts at an individual and community level are needed. Antibody responses to serological exposure markers (SEM) to Plasmodium vivax have proven diagnostic performance to identify people exposed in the previous 9 months.MethodologyWe measured antibody responses against 8 SEM to identify recently exposed people and determine the transmission dynamics of P. vivax in peri-urban (Iquitos) and riverine (Mazán) communities of Loreto, communities that have seen significant recent reductions in malaria transmission. Socio-demographic, geo-reference, LM and qPCR diagnosis data were collected from two cross-sectional surveys. Spatial and multilevel analyses were implemented to describe the distribution of seropositive cases and the risk factors associated with exposure to P. vivax.Principal findingsLow local transmission was detected by qPCR in both Iquitos (5.3%) and Mazán (2.7%); however, seroprevalence indicated a higher level of (past) exposure to P. vivax in Mazán (56.5%) than Iquitos (38.2%). Age and being male were factors associated with high odds of being seropositive in both sites. Higher antibody levels were found in individuals >15 years old. The persistence of long-lived antibodies in these individuals could overestimate the detection of recent exposure. Antibody levels in younger populations (ConclusionsThe large number of current and past infections detected by SEMs allows for detailed local epidemiological analyses, in contrast to data from qPCR prevalence surveys which did not produce statistically significant associations. Serological surveillance will be increasingly important in the Peruvian Amazon as malaria transmission is reduced by continued control and elimination efforts.