Understanding the role of climatic and environmental variables on the population dynamics of Anopheles gambiae s.s. and the implications for vector control strategies in different settings

Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low- or high-density insect populations. We assessed whether variation in phenotypic traits predict the dynamics of Anopheles gambiae sensu lato mosquitoes, the most important vectors of human malaria. Anopheles gambiae dynamics were monitored over a six-month period of seasonal growth and decline. The population exhibited density-dependent feedback, with the carrying capacity being modified by rainfall (97% w AIC c support). The individual phenotypic expression of the maternal ( p = 0.0001) and current ( p = 0.040) body size positively influenced population growth. Our field-based evidence uniquely demonstrates that individual fitness can have population-level impacts and, furthermore, can mitigate the impact of exogenous drivers (e.g. rainfall) in species whose reproduction depends upon it. Once frontline interventions have suppressed mosquito densities, attempts to eliminate malaria with supplementary vector control tools may be attenuated by increased population growth and individual fitness.

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Insecticide resistance in Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Anopheles gambiae Giles (Diptera: Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa

Acta Tropica ◽

10.1016/j.actatropica.2013.06.004 ◽

2013 ◽

Vol 128 (1) ◽

pp. 7-17 ◽

Cited By ~ 22

Author(s):

Olivier Gnankiné ◽

Imael H.N. Bassolé ◽

Fabrice Chandre ◽

Isabelle Glitho ◽

Martin Akogbeto ◽

...

Keyword(s):

West Africa ◽

Insecticide Resistance ◽

Vector Control ◽

Anopheles Gambiae ◽

Bemisia Tabaci ◽

Malaria Vector ◽

Control Strategies ◽

Malaria Vector Control ◽

Anopheles Gambiae Giles

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Modelling the impact of vector control interventions on Anopheles gambiae population dynamics

Parasites & Vectors ◽

10.1186/1756-3305-4-153 ◽

2011 ◽

Vol 4 (1) ◽

Cited By ~ 112

Author(s):

Michael T White ◽

Jamie T Griffin ◽

Thomas S Churcher ◽

Neil M Ferguson ◽

María-Gloria Basáñez ◽

...

Keyword(s):

Population Dynamics ◽

Vector Control ◽

Anopheles Gambiae ◽

Gambiae Population ◽

The Impact

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Modelling Anopheles gambiae s.s. Population Dynamics with Temperature- and Age-Dependent Survival

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph120605975 ◽

2015 ◽

Vol 12 (6) ◽

pp. 5975-6005 ◽

Cited By ~ 18

Author(s):

Céline Christiansen-Jucht ◽

Kamil Erguler ◽

Chee Shek ◽

María-Gloria Basáñez ◽

Paul Parham

Keyword(s):

Population Dynamics ◽

Anopheles Gambiae ◽

Anopheles Gambiae S.S ◽

Age Dependent

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Efficacy of Interceptor® G2, a new long-lasting insecticidal net against wild pyrethroid-resistant Anopheles gambiae s.s. from Côte d’Ivoire: a semi-field trial

Parasite ◽

10.1051/parasite/2018042 ◽

2018 ◽

Vol 25 ◽

pp. 42 ◽

Cited By ~ 12

Author(s):

Soromane Camara ◽

Ludovic Phamien Ahoua Alou ◽

Alphonsine Amanan Koffi ◽

Yao Cyntia Muriel Clegban ◽

Jean-Paul Kabran ◽

...

Keyword(s):

Insecticide Resistance ◽

Vector Control ◽

Anopheles Gambiae ◽

Cote D'ivoire ◽

Côte D’Ivoire ◽

Blood Feeding ◽

Phase Iii ◽

Anopheles Gambiae S.S ◽

Cote D’Ivoire ◽

Côte D'ivoire

Background: The widespread insecticide resistance in malaria vector populations is a serious threat to the efficacy of vector control tools. As a result, the World Health Organization (WHO) supports the development of alternative tools that combine several insecticides with the aim of improving vector control and the management of insecticide resistance. In the present study, a long-lasting insecticidal net treated with a mixture of chlorfenapyr and alphacypermethrin was evaluated against wild pyrethroid-resistant Anopheles gambiae s.s in M’bé, Côte d’Ivoire. Centers for Disease Control and Prevention (CDC) bottle tests were carried out with resistant An. gambiae s.s. of M’bé and the susceptible strain, to assess the resistance level to chlorfenapyr and alphacypermethrin. Results: CDC bottle bioassays revealed a high level of resistance of An. gambiae s.s. population from M’bé to alphacypermethrin, whereas they revealed low resistance to chlorfenapyr. In experimental huts, Interceptor® G2 that was unwashed or washed 20 times killed 87% and 82% of An. gambiae s.s., respectively, whereas Interceptor® LN that was either unwashed or washed 20 times killed only about 10% of the mosquitoes. The blood-feeding inhibition induced by Interceptor® was not significantly different compared to untreated nets, whereas Interceptor® G2 that was unwashed or washed 20 times induced 42% and 34% inhibition of blood-feeding, respectively. Conclusion: Interceptor® G2 met the WHOPES criteria to undergo a phase III study. Investigation of its efficacy at a community level and the conduct of randomized controlled trials dealing with epidemiological outputs are warranted in order to study the potential of Interceptor® G2 to better protect communities.

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Susceptibility of Anopheles gambiae complex to carbamates and organophosphate insecticides in Uyo, Akwa Ibom State, Nigeria

Nigerian Journal of Parasitology ◽

10.4314/njpar.v41i1.18 ◽

2020 ◽

Vol 41 (1) ◽

pp. 114-118

Author(s):

N.I. Udoidung ◽

K.N. Opara ◽

P.D. Okodi ◽

N.D. Ekpo ◽

I. Atting

Keyword(s):

Vector Control ◽

Anopheles Gambiae ◽

Malaria Vector ◽

Control Strategies ◽

Sub Saharan Africa ◽

World Health ◽

Malaria Vector Control ◽

Insecticide Susceptibility ◽

Post Exposure ◽

Organophosphate Insecticides

Rapid emergence in insecticide resistance among malaria vector populations to commonly used public health insecticides poses a challenge to current malaria vector control strategies and interventions in sub- Saharan Africa. This study was conducted to determine the susceptibility status of female An.gambiae s.l to Propoxur (0.01%) and bendiocarb (0.1%) (carbamate) and pirimiphosmethyl (0.25%) (organophosphate) insecticides in Uyo Metropolis, Akwa Ibom State, Nigeria. The larvae of An. gambiae s.l were collected from natural water bodies and other potential breeding sites from different sites in Uyo Metropolis. Insecticide susceptibility bioassays were performed according to the World Health Organization standard operating procedures on 2-3 days old, sugar-fed but none blood fed female Anopheles mosquitoes. Post exposure mortality after 24 hours and knockdown values for KDT50 and KDT95 were calculated. Knock-down at 1 hour insecticide exposure ranged from 94 % to 100 %. Mortality after 24 hours post exposure was 100% for all insecticides except Propoxur which was 98 %. There was high variability in KDT50 and KDT95 values (in minutes) with propoxur (4.337 and 15.620), Bendiocarb (9.523 and 20.996) and pirimiphosmethyl (39.908 and 61.722) respectively. Adopting the WHO criteria, the mosquitoes were not resistant to any of the insecticides tested. The results therefore showed that vector control campaigns employing the use of any of these insecticides in the study area would not be compromised. However, there is need for continued monitoring to ensure early detection of resistance. Keywords: Anopheles gambiae; insecticide susceptibility; Uyo; Akwa Ibom State; Nigeria.

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The relative role of ecological interactions and environmental variables on the population dynamics of marine benthic polychaetes

Marine Biodiversity ◽

10.1007/s12526-016-0569-z ◽

2016 ◽

Vol 48 (2) ◽

pp. 1203-1212

Author(s):

Fabio A. Labra ◽

Rodrigo A. Moreno ◽

Sergio A. Alvarado ◽

Franklin D. Carrasco ◽

Sergio A. Estay ◽

...

Keyword(s):

Population Dynamics ◽

Environmental Variables ◽

Relative Role ◽

Ecological Interactions

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Distribution of Members of the Anopheles Gamibiae s.l. In Oyo State, South West Nigeria

Pan African Journal of Life Sciences ◽

10.36108/pajols/9102/30(0140) ◽

2019 ◽

Vol 3 (1) ◽

pp. 138-144

Author(s):

Adedapo O. Adeogun ◽

Kehinde O.K. Popoola ◽

Abiodun K. Olakiigbe ◽

Samson T. Awolola

Keyword(s):

Vector Control ◽

Anopheles Gambiae ◽

Anopheles Arabiensis ◽

Habitat Type ◽

The State ◽

Anopheles Coluzzii ◽

Anopheles Gambiae S.S ◽

Breeding Sites ◽

Anopheles Mosquitoes ◽

Anopheles Gambiae S.L

Background: Members of the Anopheles gambiae s.l. remain the most efficient vectors of malaria parasite in Africa. However, for timely and effective vector control activities, the distribution of these important vectors in local communities is crucial. We therefore determine the distribution of the members of Anopheles gambiae s.l. in Oyo State, Nigeria Methods: Larval stages of Anopheles mosquitoes were collected from identified mosquito breeding sites in six localities (Oluyole, Eruwa, Oyo, Ojoo, Bodija, and Ogbomoso) in Oyo State and reared to adults. Three to five days old adult emergence were identified morphologically using standard methods. A total of 100 mosquitoes were selected from each of localities for molecular analysis. DNA were extracted and Polymerase Chain Reaction (PCR-ID) followed by restriction endonucleases digestion was used for molecular identification. Results: A total of 58 larval breeding sites were sampled out of which 12 (20.7%) had Anophelines only, 21 (36.2%) contained Culicines only and the remaining 25 (43.1%) had both Anophelines and Culicines. The mosquitoes were mostly found in footprints, followed by tire tracks, pools, puddle and ponds. The habitat type distribution for Anopheline and Culicines were not different (χ2=5.25, DF=5, P>0.01). A total of 1,725 Anophelines emerged from the collection out of which, 823 were females. All the female samples were morphologically identified as members of the Anopheles gambiae s.l.. A total of 600 (72.9%) of the female Anopheline population was subjected to PCR. PCR-ID showed that the mosquito populations contained higher numbers of Anopheles arabiensis (58%) than Anopheles gambiae s.s. (42%). Enzyme digest indicate that samples from Oluyole, Iwo road and Bodija were man-ly the M form (now called An. coluzzii), while both M (An. colizzii) and S (An. gambiae) form occur in sympatry in Oyo town and Eruwa. Conclusion: This study presents information on the distribution of Anopheles arabiensis, Anopheles coluzzii and Anopheles gambiae in Oyo State. This has implication on the vector control activities in the State as members of these Anopheles mosquitoes exhibit varying feeding behaviours, transmission pattern and resistance profiles. Such information is useful in planning vector control activities for the State

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