Biology Reference
In-Depth Information
vivax
compared to
P. falciparum
. Classification of anopheline species as vec-
tors of malaria has typically meant vectors of
P. falciparum
malaria. This is
most evident in the Africa+ region, but conclusive information is also miss-
ing from the Asian and American regions, where
P. vivax
is the dominant
parasite. In many countries, the status of vector species is determined by
absence of evidence rather than decisive evidence of absence of the para-
site. The research into transmission of
P. vivax
is lagging behind that of
P.
falciparum
. Improved vector surveillance would benefit all regions, but not
without incrimination studies that focus specifically on
P. vivax
.
Currently, the cartographic foundations for estimating the public health
burden of
P. vivax
do not exist and this is perhaps the highest priority for
moving forward. The link between
P. vivax
prevalence and clinical burden
must be established for regions where the disease is monoendemic as well
as where it is sympatric with
P. falciparum
. National estimates of
P. vivax
rely
on routine case reporting sources that vary in their fidelity and are often
crudely distinguished from
P. falciparum
(
WHO, 2011
). Cartographic esti-
mates of
P. vivax
burden would provide valuable information regarding the
impact of the disease independent of inherent biases that may accompany
health system data (
Gupta et al., 2009
;
Rowe et al., 2009
;
Hay et al., 2010a
,
2010b
;
Malaria Eradication Research Agenda, 2011b
;
Mueller et al., 2011
).
There is also a need to define the burden of
P. vivax
in clinically vulnerable
groups such as pregnant women (
Nosten et al., 1999
;
Mueller et al., 2009a
)
and, most notably, children. To estimate the burden of
P. vivax
, it will first be
necessary to gain a better understanding of the impact of relapsing infections
on prevalence. The degree to which relapses contribute to clinical disease
is known to vary geographically, but the cause and pattern of the variation
is still poorly understood (
Battle et al., 2011
;
Betuela et al., 2011
;
White,
2011
) and calls for further investigation. The extent to which
P. falciparum
affects the burden of
P. vivax
remains unknown, and now emerges as an
important question in elimination strategy (
Maitland et al., 1996
,
1997
;
Snounou and White, 2004
;
Genton et al., 2008
).
This chapter described the global public health significance of
P. vivax
in
light of new cartographic technology and evidence, along with the funda-
mentally important emerging understanding of the infection as threatens to
life. The parasite occurs across a broader geographic range, in more diverse
habitats, in more anopheline vector species, and threatens more people
than
P. falciparum
.Vivax malaria is an overwhelmingly Asian and Asia-Pacific
problem, home to 91% of the 2.49 billion PAR, dozens of mosquito vector
species, and endemic habitats as distinct as the temperate Korean peninsula
