Journal of Mosquito Research 2015, Vol.5, No.14, 1-8
4
Table 1 Number of
Anopheles
mosquitoes collected per study
site and their species
Table 2 Molecular identification of
Anopheles species
collected
in Mwea and Ahero sentinel sites
2 (a)
Anopheles gambiae s.l
Village
Number of
mosquitoe
s tested by
PCR
An. arabiensis An. gambiae s.s
Indoor Outdoor Indoor Outdoor
Mbuinjeru 200
120
80
0
0
Ndindiruku 200
105
95
0
0
Murinduko 200
130
70
0
0
Kamagaga 52
22
30
0
0
Kobura
180
85
95
0
0
Wagai
18
8
10
0
0
98% threshold for susceptibility in all the assays except
for mosquitoes from Mbuinjeru for the test with DDT
(98%) and those from Murinduko for the test with
Bendiocarb (100%). In Ahero, both permethrin and
bendiocarb had a 96% 24 hr post-exposure effect on
An.
funestus
from Kamagaga village. Bendiocarb and
fenitrothion demonstrated a 96% and a 98% 24 hr
post-exposure effect on
An. funestus
from Kobura
village. Fenitrothion indicated reduced activity on
An.
arabiensis
(96%) and
An. funestus
(98%) from Wagai
village as shown in Table 3.
The Human Blood Index for
An. arabiensis
sampled
from Mwea scheme was at 0.22 (n=405). In Ahero
scheme, the Human Blood Index was at 0.17 (n=169)
for
An. funestus.
It was noted that in both study sites,
bovine was the preferred host with mixed blood
sources. In Mwea,
An. arabiensis
sourced their blood
from humans and animals. In Ahero,
An. funestus
contacted both humans and animals for blood sources
while
An. arabiensis
sourced their blood from only
animals (Table 4).
2 (b)
Anopheles funestus
complex
Village
Number of mosquitoes
tested by PCR
An. funestus s.s
An. rivulorum
An. parensis
An. leesoni
Indoor
Outdoor Indoor Outdoor Indoor
Outdoor Indoor Outdoor
Kamagaga
148
72
68
4
0
2
0
2
0
Kobura
20
15
5
0
0
0
0
0
0
Wagai
182
100
82
0
0
0
0
0
0
In Mwea, the entire 600 field collected female
An.
arabiensis
were tested for
P. falciparum
circumsporozoite
infection. None of the samples from Mbuinjeru and
Ndindiruku villages tested positive for the parasite
infection. In Murinduko, three (3) (n=200) of the
samples collected indoor tested positive for the
parasite (Table 5). In Ahero study site, Kamagaga
village had seven 7 (n=147; 3 indoor, 4 outdoor) of
An.
funestus
positive for the parasite and 4 (n=183; 1
indoor, 3 outdoor) of
An. funestus
positive for the
parasite in Wagai village as shown in Table 5.
Discussion
The present study sought to determine the level of
insecticide resistance; blood feeding patterns and
malaria parasite rates in two areas of Kenya that are
endemic for malaria. Overall, levels of resistance
against insecticides had increased and malaria parasite
rates were lower than previously recorded in both
Mwea and Ahero.
In contrast to earlier studies which reported the
presence of
An. arabiensis
Patton and
An. funestus
Giles in Mwea (Ijumba et al., 2008), the current study
found only
An. arabiensis
. This may be attributed to
massive distribution of insecticides treated mosquito
nets in these rice schemes thus promoting selection
against the population of
An. funestus
which is known
to be anthropophilic and endophagic. In Ahero, the
present study identified
An. funestus
Giles and
An.
arabiensis
Patton as the major
Anopheles
species.
However, this varies from results reported by Chandler
Villages
An. gambiae s.l
An. funestus
Indoor Outdoor
Indoor Outdoor
Mbuinjeru
120
80
0
0
Ndindiruku
105
95
0
0
Murinduko 130
70
0
0
Kamagaga
22
30
80
68
Kobura
85
95
15
5
Wagai
8
10
100
82
