scholarly journals Spatio-seasonal distribution of Anopheles gambiae sensu lato and dynamics of the Voltage gate sodium channel knock down resistance mutation (Vgsc1014F) in the city of Lomé, Togo

2019 ◽  
Vol 13 (3) ◽  
pp. 1654
Author(s):  
Koffi Mensah Ahadji-Dabla ◽  
Carine Ngoagouni ◽  
B. Dominic Dery ◽  
Yawo Georges Apétogbo ◽  
Guillaume Koffivi Ketoh ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Anopheles Gambiae ◽  
Resistance Mutation ◽  
Seasonal Distribution ◽  
Knock Down ◽  
The City ◽  
Voltage Gate

scholarly journals Compensatory mechanisms in resistant Anopheles gambiae AcerKis and KdrKis neurons modulate insecticide-based mosquito control

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Stéphane Perrier ◽  
Eléonore Moreau ◽  
Caroline Deshayes ◽  
Marine El-Adouzi ◽  
Delphine Goven ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Anopheles Gambiae ◽  
Calcium Concentration ◽  
Mosquito Control ◽  
Point Mutations ◽  
Resting Membrane Potential ◽  
Compensatory Mechanisms ◽  
Pyrethroid Insecticides

AbstractIn the malaria vector Anopheles gambiae, two point mutations in the acetylcholinesterase (ace-1R) and the sodium channel (kdrR) genes confer resistance to organophosphate/carbamate and pyrethroid insecticides, respectively. The mechanisms of compensation that recover the functional alterations associated with these mutations and their role in the modulation of insecticide efficacy are unknown. Using multidisciplinary approaches adapted to neurons isolated from resistant Anopheles gambiae AcerKis and KdrKis strains together with larval bioassays, we demonstrate that nAChRs, and the intracellular calcium concentration represent the key components of an adaptation strategy ensuring neuronal functions maintenance. In AcerKis neurons, the increased effect of acetylcholine related to the reduced acetylcholinesterase activity is compensated by expressing higher density of nAChRs permeable to calcium. In KdrKis neurons, changes in the biophysical properties of the L1014F mutant sodium channel, leading to enhance overlap between activation and inactivation relationships, diminish the resting membrane potential and reduce the fraction of calcium channels available involved in acetylcholine release. Together with the lower intracellular basal calcium concentration observed, these factors increase nAChRs sensitivity to maintain the effect of low concentration of acetylcholine. These results explain the opposite effects of the insecticide clothianidin observed in AcerKis and KdrKis neurons in vitro and in vivo.

scholarly journals A simplified high-throughput method for pyrethroid knock-down resistance (kdr) detection in Anopheles gambiae

2005 ◽  
Vol 4 (1) ◽  
Author(s):  
Amy Lynd ◽  
Hilary Ranson ◽  
P J McCall ◽  
Nadine P Randle ◽  
William C Black ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
High Throughput ◽  
Knock Down ◽  
High Throughput Method

scholarly journals Pyrethroid and Etofenprox Resistance in Anopheles gambiae and Anopheles coluzzii from Vegetable Farms in Yaoundé, Cameroon: Dynamics, Intensity and Molecular Basis

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5543
Author(s):  
Michael Piameu ◽  
Philippe Nwane ◽  
Wilson Toussile ◽  
Konstantinos Mavridis ◽  
Nadja Christina Wipf ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Mortality Rates ◽  
World Health ◽  
Anopheles Coluzzii ◽  
Cross Sectional ◽  
Metabolic Genes ◽  
Anopheles Gambiae S.L ◽  
Underlying Mechanisms ◽  
Health Organization ◽  
The City

Previous studies have indicated widespread insecticide resistance in malaria vector populations from Cameroon. However, the intensity of this resistance and underlying mechanisms are poorly known. Therefore, we conducted three cross-sectional resistance surveys between April 2018 and October 2019, using the revised World Health Organization protocol, which includes resistance incidences and intensity assessments. Field-collected Anopheles gambiae s.l. populations from Nkolondom, Nkolbisson and Ekié vegetable farms in the city of Yaoundé were tested with deltamethrin, permethrin, alpha-cypermethrin and etofenprox, using 1× insecticide diagnostic concentrations for resistance incidence, then 5× and 10× concentrations for resistance intensity. Subsamples were analyzed for species identification and the detection of resistance-associated molecular markers using TaqMan® qPCR assays. In Nkolbisson, both An. coluzzii (96%) and An. gambiae s.s. (4%) were found together, whereas only An. gambiae s.s. was present in Nkolondom, and only An. coluzzii was present in Ekié. All three populations were resistant to the four insecticides (<75% mortality rates―MR1×), with intensity generally fluctuating over the time between mod-erate (<98%―MR5×; ≥98%―MR10×) and high (76–97%―MR10×). The kdr L995F, L995S, and N1570Y, and the Ace-1 G280S-resistant alleles were found in An. gambiae from Nkolondom, at 73%, 1%, 16% and 13% frequencies, respectively, whereas only the kdr L995F was found in An. gambiae s.s. from Nkolbisson at a 50% frequency. In An. coluzzii from Nkolbisson and Ekié, we detected only the kdr L995F allele at 65% and 60% frequencies, respectively. Furthermore, expression levels of Cyp6m2, Cyp9k1, and Gste2 metabolic genes were highly upregulated (over fivefold) in Nkolondom and Nkolbisson. Pyrethroid and etofenprox-based vector control interventions may be jeopardized in the prospected areas, due to high resistance intensity, with multiple mechanisms in An. gambiae s.s. and An. coluzzii.

scholarly journals Efficacy of the Microbial Larvicide VectoMax<sup>®</sup>G against <i>Anopheles gambiae</i> s.l. and <i>Culex</i> spp. Larvae under Laboratory and Open Field Trial Experiments in the City of Yaoundé, Cameroon

2022 ◽  
Vol 10 (01) ◽  
pp. 34-51
Author(s):  
Kopya Edmond ◽  
Foko Dadji Gisele Aurelie ◽  
Sonhafouo-Chiana Nadège ◽  
Bamou Roland ◽  
Djamouko-Djonkam Landre ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Open Field ◽  
Field Trial ◽  
The City

scholarly journals Functional analysis of a rat sodium channel carrying a mutation for insect knock-down resistance (kdr ) to pyrethroids

FEBS Letters ◽  
1997 ◽  
Vol 413 (2) ◽  
pp. 327-332 ◽  
Author(s):  
H Vais ◽  
M.S Williamson ◽  
C.A Hick ◽  
N Eldursi ◽  
A.L Devonshire ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Sodium Channel ◽  
Knock Down

Hyperkalemic periodic paralysis aggravated by voltage - gate sodium channel blocker antiepileptic drug?

2020 ◽  
Vol 139 ◽  
pp. 109683 ◽  
Author(s):  
S. Zukić ◽  
O. Sinanović ◽  
M. Alečković-Halilović ◽  
R. Hodžić ◽  
L. Kovačević ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Antiepileptic Drug ◽  
Channel Blocker ◽  
Periodic Paralysis ◽  
Sodium Channel Blocker ◽  
Hyperkalemic Periodic Paralysis ◽  
Voltage Gate

scholarly journals Rotavirus associated diarrhoea during infancy in the city of S. Luís (MA), Brazil: a two-year longitudinal study

1991 ◽  
Vol 33 (6) ◽  
pp. 459-464 ◽  
Author(s):  
Klaus Eberhard Stewien ◽  
Luís C.F. da Cunha ◽  
Aymoré de C. Alvim ◽  
Stelito A. dos Reis Filho ◽  
Maria A.B. Alvim ◽  
...  
Keyword(s):  
Rainy Season ◽  
Age Distribution ◽  
Seasonal Distribution ◽  
Control Group ◽  
Severe Dehydration ◽  
The North ◽  
Group A ◽  
Severity Of The Disease ◽  
Two Peaks ◽  
The City

A total of 479 diarrhoeic children and 337 children without diarrhoea (controls) less than 5 years old were investigated in a two-year study in the city of S. Luís (MA), with the purpose to determine the incidence, the age distribution and the seasonality of rotaviruses, as well as to establish the severity of the disease in this region between the North and the Northeast of Brazil. rotavirus incidence was highest in children of the 1st. year of life, showing an average of 25% per year among the diarrhoeic patients attending the two main hospitals and three health units at the periphery of the city. It was shown that rotaviruses are significant enteropathogens in children less than 18 months old. Frequency of rotaviruses droped in diarrhoeic patients 18 to 23 months old to only 4%, the same percentage observed in children of the control group. A typical seasonal distribution of rotaviruses was not seen during the two years of study. There was a peak in the incidence of rotaviruses in 1986, during the rainy season, and two peaks in 1987, one in the rainy season and one in the dry season. It was also shown that severity of diarrhoea in rotavirus positive cases was higher than in the negative cases. Rotavirus diarrhoeic patients had more loose stools per day, and higher frequencies of vomiting and fever, resulting more often (> 2 times) in moderate or severe dehydration. Finally, it is concluded that the introduction of immunoprophylaxis may reduce significantly the high mortality rates in early childhood observed in S. Luís.

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