Biology Reference
In-Depth Information
and tropical New Guinea. This is the same region where treatments are
failing due to drug resistance or reluctance to use threatening and impracti-
cal treatments like primaquine. Vivax malaria today threatens many people
with very serious illness and is especially difficult to prevent and treat. The
evidence presented in this chapter and others in this thematic issue disclaim
the long-held presumption of inconsequence with infection by
P. vivax
.
6. METHODS
The full methods that would allow the reader to reproduce these maps
are given in
Gething et al. (2012)
and
Sinka et al. (2010b)
. Here, we bring
together the full suite of methodologies and present a set of summaries that
highlight the data used and the assumptions made to allow the value of the
resulting estimates to be assessed.
6.1. Defining the Limits of
P. vivax
Transmission
To adequately assess the global burden of
P. vivax
, the limits of the infection
and the global distribution of risk must first be identified. Knowledge of the
spatial distribution, and the clinical incidence within those limits, provide a
foundation on which control efforts and measures of progress can be based.
MAP began these efforts through defining the spatial limits of infection and
the PAR, informed by ecological variables and the distribution of Duffy
negative individuals, and then applied those limits to mapping the transmis-
sion and varying levels of
P. vivax
endemicity globally.
6.1.1. International Limits of
P. vivax
The global spatial limits of
P. vivax
malaria were first defined for 2009
(
Guerra et al., 2010
) and the methods and results have since been updated
for 2010 (
Gething et al., 2012
). A list of 95
P. vivax
malaria endemic coun-
tries (
Pv
MECs), illustrated in
Fig. 1.10
A1-D1, was identified using previous
methods based on international health and travel guidelines (
Centers for
Disease Control and Prevention, 2009
;
Guerra et al., 2010
;
WHO, 2010b
;
Gething et al., 2011a
). The
Pv
MECs were grouped into three regions: the
Americas; Africa, Saudi Arabia andYemen (Africa+); and Central and South
East Asia (CSE Asia), which was further divided into Asia and Asia-Pacific
in order to resolve PAR estimates (referred to here as Asia and Asia-Pacific)
(Fig. 1.2). The borders of these countries, along with national survey infor-
mation and relevant, published sources and personal communications,
defined the first version of the
P. vivax
spatial limits map (
Guerra et al., 2010
).
