Biology Reference
In-Depth Information
the horn of Africa, Madagascar, the Middle East, Central Asia, Afghanistan,
Pakistan and Northern India, Central parts of China, Korea, North and
Central America (
Fig. 2.6
). Long-incubation-period
P. vivax
(
hibernans
) was
prevalent in Northern Europe and more Northern parts of Russia. Fre-
quent relapse 'strains' were reported in parts of South America, India, South
East Asia and Oceania. It is highly likely that where malaria persists, this
geographical distribution of
P. vivax
phenotypes pertains today, although
there is very little contemporary information apart from reports from South
East Asia and the island of New Guinea (which has higher levels of malaria
transmission than the majority of the other
P. vivax
endemic areas of the
world). Both frequent relapse and long-latency phenotypes overlap in geo-
graphic distributions (
Fig. 2.6
). Where both are present together, it would
be very easy for the long-latency infections to go unrecognised. The recent
discovery of long-latency
P. vivax
in Kolkata is a case in point (
Kim et al.,
2012
) (
Fig. 2.7
). The presence of a spring vivax malaria peak as was the case
Figure 2.6
Approximate geographic distribution of
P. vivax
-latency phenotypes based
upon historical data (
White, 2011
). Areas where tropical 'frequent-relapse phenotypes'
are or were prevalent are shown in pink. Areas where both frequent-relapse and long-
latency phenotypes have been reported are shown in purple, and areas where long-
latency phenotypes were prevalent are shown in grey. Although both South America
and India are generally considered to harbour frequent-relapse phenotypes predomi-
nantly, there is evidence that long-latency phenotypes are present in both areas (par-
ticularly across the North of India). Without genotyping, it may be difficult or impossible
to distinguish the two phenotypes within an endemic area. For interpretation of the
references to colour in this figure legend, the reader is referred to the online version of
this topic.
