Biology Reference
In-Depth Information
times that vary based on the seasonal climate and location. Its larval habitats
include shaded temporary pools found in the forest such as swamps, stump
ground holes or wheel tracks.
The bionomics of the DVS in Asia-Pacific are as variable as in mainland
Asia. This is due to variation observed both within species complexes and
among separate species. Such variations increase the challenge of develop-
ing a single universal vector control strategy across the region, however, a
combination of methods could prove effective (
Lindsay et al., 2004
).
Asia-Pacific summary
. The vivax malaria problem in Asia-Pacific is
complex and presents a variety of challenges to control. Indonesia and the
Philippines are densely populated over large land masses (
Fig. 1.8
B) and
P. vivax
is predicted to be endemic across most of their national terri-
tories. They have the fourth and fifth largest PAR estimates globally with
129 million at risk in Indonesia and 50 million in the Philippines. Some
of the highest predicted
Pv
PR
1-99
values were also observed in this region
(
Fig. 1.3
B1). As in the Asia regions, it is in these areas, where intense
P. vivax
transmission occurs (e.g. Indonesia and Papua New Guinea), where drug
resistance is emerging and malaria cases of equivalent clinical severity to
P.
falciparum
have been observed (
Baird, 2004
;
Pukrittayakamee et al., 2004
;
Tjitra
et al., 2008
;
Price et al., 2009
). This and the large areas of unstable transmission
make this region a worthy and vital candidate for research, control and even-
tually elimination efforts; four of the seven
Pv
MECs have already declared
their status of working towards elimination: Malaysia, the Philippines, the Sol-
omon Islands and Vanuatu (
The Global Health Group and the Malaria Atlas
Project, 2011
). Uncertainty estimates, shown in
Fig. 1.4
B1 and B2, were high
in areas that also displayed high
Pv
PR
1-99
estimates (
Fig. 1.3
B2), such as Papua
New Guinea. While the population-weighted correction shows that parts of
these regions are, for the most part, sparsely populated (
Fig. 1.8
B), improved
surveillance to facilitate high-resolution mapping will be essential to tackle
the final transmission hotspots of this region as elimination efforts progress.
The vector situation in this region is complex and further research is needed
to differentiate members of species complexes and incriminate those vectors
that are vectors of
P. vivax
so that appropriate control measures may be taken.
4.3. Americas
The Americas have amongst the highest
P. vivax
endemicity values in the
world but these typically occur in areas of very low population density, so the
populations at risk are much lower than those found in Asia (
Fig. 1.3
C1 and
Fig. 1.8
C). The diversity of vector species is also less in this region (
Fig. 1.9
C).