Biology Reference
In-Depth Information
of point records per country were from Kenya (
n
= 757), followed by Tan-
zania and Cameroon (
n
= 383 for both nations). For the most part, the
other countries on the continent had less than 100 point records, with
the exception of Burkina Faso (
n
= 310), Equatorial Guinea (
n
= 113),
Ghana (
n
= 106), Madagascar (
n
= 198), Mali (
n
= 166), Nigeria (
n
= 190),
Senegal (
n
= 209), Sudan (
n
= 125), the Gambia (
n
= 192) and Uganda
(
n
= 135). African countries classified as
P. vivax
endemic that had very
few (≤5) vector occurrence point records were Central African Republic
(
n
= 3), Congo (
n
= 2), Liberia (
n
= 4), Namibia (
n
= 5) and Togo (
n
= 1).
The compiled species distribution maps (
Fig. 1.9
E) illustrate a relatively
straightforward picture of the distribution of the region's DVS:
Anopheles
arabiensis
,
An. funestus s.l.
, and
An. gambiae s.l.
which all have broad distribu-
tions in the region and are confirmed vectors of
P. vivax
. These three DVS
dominate in heterogeneous ranges of different pairs and combinations (of
one another) in such a way that the species are present on their own in only
focused locations. The co-dominant range of the
An. funestus
complex and
An. gambiae
in Central Africa is surrounded by an 'envelope' that houses
all three primary DVS, that is further surrounded by
An. arabiensis
and the
Funestus Complex, and then only
An. arabiensis
on the periphery.
Anoph-
eles arabiensis
tolerates drier environments and is therefore absent from the
forested areas of western Central Africa. The
An. funestus
complex distribu-
tion indicates a presence throughout all of sub-Saharan Africa, including
Madagascar, but excluding much of southern Africa.
Anopheles gambiae
has a
more complex distribution across a band from East (including Madagascar)
to West Africa.
The bionomics of all the African DVS of malaria are summarised in full
elsewhere (
Sinka et al., 2010a
). Here, we briefly describe the behaviours of
those three DVS identified as potential
P. vivax
vectors in the region.
Anoph-
eles arabiensis
,
An. funestus s.l.
, and
An. gambiae s.l.
are known to be primary
vectors of
P. falciparum
, but have also been incriminated as vectors of
P. vivax
through the detection
P. vivax
circumsporozoite proteins in wild-caught
specimens (
Table 1.2
).
Anopheles arabiensis
is often described as zoophilic,
exophagic and exophilic, yet its behaviour appears to be quite variable,
depending on location. For example,
An. arabiensis
found in West Africa
are generally more anthropophilic and endophagic than those in the East.
Such behavioural variability may enhance this species' ability to transmit
P.
vivax
(or any human malaria) allowing it to adapt to avoid control methods
such as IRS. Moreover, with peak biting times ranging from evening (1900)
to early morning (0300),
An. arabiensis
may also avoid control via ITNs.
