Volume 4 • Issue 4 • 1000157
J Clin Res Bioeth
ISSN: 2155-9627 JCRB, an open access journal
Research Article Open Access
Anogwih et al., J Clin Res Bioeth 2013, 4:4
DOI: 10.4172/2155-9627.1000157
Keywords: Spinosad; Larvicide; Poecilia reticulate; Anopheles
gambiae s.s; Culex quinquefasciatus
Introduction
Current eforts at mosquito control in Nigeria and indeed the
whole of Africa have gradually drifed away from the more traditional
larviciding and environmental management to almost solely on disease
management and domestic adulticiding since the discovery of the
dangers of Dichlorodiphenyltrichloroethane (DDT). Despite ease of
application, disease management and adulticiding alone have failed to
interrupt mosquito vector burden on a nationwide basis evidenced by
the continual establishment of new cases of mosquito related diseases
and subsequently death, particularly amongst children under the age of
fve and pregnant women [1]. While it is true that mosquitoes cannot
be totally eliminated in any ecosystem, good mosquito management
practices that consider environmental issues must be adopted within
the purview of Integrated Vector Management (IVM) to keep mosquito
population below the level of public health concern. Integrated Vector
Management is the targeted use of diferent vector control methods
alone or in combination to achieve the greatest disease control benefts
in the most cost efective manner while minimising negative impacts
on the ecosystem e.g. depletion of biodiversity and adverse side efects
on public health [2].
Te larval stages of mosquito vector are the most vulnerable stages
because they are confned by their nature to various aquatic media
making control practices easier, more efective and highly sustainable.
When mosquito larvae are efectively targeted, the transmission
chain in the mosquito life cycle is broken, thereby resulting in a more
sustainable mosquito control programme. Terefore, to achieve an
efective and long lasting mosquito control programme there is a need
to reprioritize larval control practice and adopt the “double barreled”
approach inherent in a good IVM System. Existing and efcacious
chemical larval control methods can be combined with non-chemical
larval control methods such as the use of guppy fsh that occupy several
open drainages in Lagos, Nigeria. Guppies have been credited for their
high larvivorus potential against mosquito vectors in many parts of the
world [3-10]. As efcient biological control agent, guppies need to be
protected from the deleterious efects of larvicides. Spinosad is an insect
control product derived from the fermentation of a soil bacterium
Saccharopolyspora spinosa [11]. Tis compound was shown to cause
cytogenotoxic damage to guppy species at higher concentration [12].
It was therefore pertinent to conduct an initial investigation on
the genotoxic and ultra structural efects of the biolarvicide at low
concentrations in bid to establish a dosage solution that is compatible
to apply in an aquatic ecosystem particularly for integrated mosquito
larval control practice where the integrity of the fsh as a support
control agent is to be ensured. Micronucleus (MN) is considered as
the most suitable and efective method to use in fsh when evaluating
the genotoxic efects of xenobiotics because of its simplicity and ease
of scoring [13-15]. Te success of integrated mosquito larval control
*Corresponding author: Anogwih JA, Department of Zoology, University of
Lagos, Nigeria, Tel: +2348035506661; E-mail : janogwih@unilag.edu.ng
Received July 14, 2013; Accepted September 27, 2013; Published October 07,
2013
Citation: Anogwih JA, Saliu JK, Linton EW, Makanjuola WA, Chukwu LO (2013)
The Compatibility of Spindor Dust with Poecilia reticulata for Integrated Mosquito
Larviciding. J Clin Res Bioeth 4: 157. doi:10.4172/2155-9627.1000157
Copyright: © 2013 Anogwih JA, et al. This is an open-access article distributed
under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the
original author and source are credited.
The Compatibility of Spindor Dust with Poecilia reticulata for Integrated
Mosquito Larviciding
Anogwih JA
1
*, Saliu JK
1
, Linton EW
2
, Makanjuola WA
1
and Chukwu LO
3
1
Department of Zoology, University of Lagos, Nigeria
2
Biology Department, Central Michigan University, Nigeria
3
Department of Marine Sciences, University of Lagos, Nigeria
Abstract
Background: The compatibility of spindor dust (spinosad), a bio-rational larvicide derived from the fermentation of
a soil bacterium Saccharopolyspora spinosa, was investigated on the mosquito fsh, Poecilia reticulata, and larvae of
both Anopheles gambiae s.s. and Culex quinquefasciatus mosquitoes.
Methods: Three replicates of each to different concentrations of spinosad dust under static bioassay were performed
to determine the acute toxicity of the larvicide on each organism. To investigate the genotoxic and ultrastructural changes
in P. reticulata, the fsh were exposed for 28 days to low concentrations of the test larvicide capable of killing 30% and
70% of Cx. quinquefasciatus larvae. Thereafter, gill and intestinal cells were removed at days 3 and 28 respectively, and
then processed for epifuorescent and transmission electron microscopic studies.
Results: Spinosad showed no lethal toxic effect on P. reticulata but caused an appreciable mortality to Anopheles
and Culex larvae with 24h LC
50
values of 59.34 μgL
-1
and 73.06 μgL
-1
respectively. The larvicide failed to signifcantly
induce micronuclei in the fsh as determined with acridine orange assay (P>0.05). Marked damage characterised
by pycnotic nuclei, loss of cristae in mitochondria, dense and degraded cytoplasm was mostly found in the exposed
intestinal cells of the fsh and the damage severity increased with increasing concentration of spinosad.
Conclusion: Spinosad at 49 μgL
-1
seems to be the threshold above which severe damage occurred in the fsh.
Therefore, spinosad is only compatible with P. reticulata for integrated mosquito larval control at concentration not
greater than 49 μgL
-1
.
Journal of
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ISSN: 2155-9627