dc.contributor.author |
Ross, Amanda |
dc.contributor.author |
Koepfli, Cristian |
dc.contributor.author |
Schoepflin, Sonja |
dc.contributor.author |
Timinao, Lincoln |
dc.contributor.author |
Siba, Peter |
dc.contributor.author |
Smith, Thomas |
dc.contributor.author |
Mueller, Ivo |
dc.contributor.author |
Felger, Ingrid |
dc.contributor.author |
Tanner, Marcel |
dc.date |
2016-06-06T09:59:27Z |
dc.date |
2016-06-06T09:59:27Z |
dc.date |
2016-05-04 |
dc.date |
2016-05-31T11:04:06Z |
dc.identifier.citation |
1935-2727 |
dc.identifier.uri |
http://hdl.handle.net/2445/99261 |
dc.format |
18 p. |
dc.format |
application/pdf |
dc.language.iso |
eng |
dc.publisher |
Public Library of Science (PLoS) |
dc.relation |
Reproducció del document publicat a:
http://dx.doi.org/10.1371/journal.pntd.0004582 |
dc.relation |
PLoS Neglected Tropical Diseases, 2016, vol. 10, num. 5, p.
e0004582 |
dc.relation |
http://dx.doi.org/10.1371/journal.pntd.0004582 |
dc.rights |
cc by (c) Ross et al., 2016 |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.rights |
http://creativecommons.org/licenses/by/3.0/es/ |
dc.subject |
Plasmodium vivax |
dc.subject |
Papua Nova Guinea |
dc.subject |
Plasmodium vivax |
dc.subject |
Papua New Guinea |
dc.title |
The Incidence and Differential Seasonal Patterns of Plasmodium
vivax Primary Infections and Relapses in a Cohort of Children in
Papua New Guinea |
dc.type |
info:eu-repo/semantics/article |
dc.type |
info:eu-repo/semantics/publishedVersion |
dc.description.abstract |
Plasmodium vivax has the ability to relapse from dormant
parasites in the liver weeks or months after inoculation,
causing further blood-stage infection and potential onward
transmission. Estimates of the force of blood-stage infections
arising from primary infections and relapses are important for
designing intervention strategies. However, in endemic settings
their relative contributions are unclear. Infections are
frequently asymptomatic, many individuals harbor multiple
infections, and while high-resolution genotyping of blood
samples enables individual infections to be distinguished,
primary infections and relapses cannot be identified. We develop
a model and fit it to longitudinal genotyping data from children
in Papua New Guinea to estimate the incidence and seasonality of
P vivax primary infection and relapse. The children, aged one to
three years at enrolment, were followed up over 16 months with
routine surveys every two months. Blood samples were taken at
the routine visits and at other times if the child was ill.
Samples positive by microscopy or a molecular method for species
detection were genotyped using high-resolution capillary
electrophoresis for P vivax MS16 and msp1F3, and P falciparum
msp2. The data were summarized as longitudinal patterns of
success or failure to detect a genotype at each routine
time-point (eg 001000001). We assume that the seasonality of P
vivax primary infection is similar to that of P falciparum since
they are transmitted by the same vectors and, because P
falciparum does not have the ability to relapse, the seasonality
can be estimated. Relapses occurring during the study period can
be a consequence of infections occurring prior to the study: we
assume that the seasonal pattern of primary infections repeats
over time. We incorporate information from parasitological and
entomology studies to gain leverage for estimating the
parameters, and take imperfect detection into account. We
estimate the force of P vivax primary infections to be 11.5
(10.5, 12.3) for a three-year old child per year and the mean
number of relapses per infection to be 4.3 (4.0, 4.6) over 16
months. The peak incidence of relapses occurred in the two month
interval following the peak interval for primary infections: the
contribution to the force of blood-stage infection from relapses
is between 71% and 90% depending on the season. Our estimates
contribute to knowledge of the P vivax epidemiology and have
implications for the timing of intervention strategies targeting
different stages of the life cycle. |