Publications des scientifiques de l'IRD

Touré Mahama, Etang J. D., Carnevale Pierre, Chandre Fabrice. (2007). Effectiveness of Permanet in Cote d'Ivoire rural areas and residual activity on a knockdown-resistant strain of Anopheles gambiae. Journal of Medical Entomology, 44 (3), p. 498-502. ISSN 0022-2585.

Titre du document
Effectiveness of Permanet in Cote d'Ivoire rural areas and residual activity on a knockdown-resistant strain of Anopheles gambiae
Année de publication
2007
Type de document
Article référencé dans le Web of Science WOS:000246328500015
Auteurs
Touré Mahama, Etang J. D., Carnevale Pierre, Chandre Fabrice
Source
Journal of Medical Entomology, 2007, 44 (3), p. 498-502 ISSN 0022-2585
The effectiveness of long-lasting preimpregnated nets of Permanet type (deltamethrin, 50 mg/m(2)) erected in households in rural areas of Cote d'Ivoire was tested on two laboratory strains of Anopheles gambiae s.s.: the Kisumu susceptible strain and the Vk per pyrethroids resistant strain with > 70% kdr allelic frequency. Treated nets were distributed in households in three villages of Danane forest area in western part of Cote d'Ivoire. In each village, a net was sampled for bioassays. Three Permanets also were erected in the laboratory, serving as control samples. From May 2001 to July 2002, the effectiveness of these deltamethrin-pretreated nets was monitored using World Health Organization-cone tests on the two strains of An. gambiae. Mortality rates were recorded 24 h postexposure. Knockdown times for 50 and 95% mosquitoes (kdT(50) and kdT(95), respectively) were estimated by means of WIN DL software. One-way analysis of variance was used to compare the knockdown times. Times to failure of nets were analyzed using Cox model. The kdT(50) of the Kisumu susceptible strain with both laboratory samples and nets used in the field varied around 10 min. No significant difference was recorded between the kdT(50) of the Kisumu susceptible strain with laboratory kept nets and samples of nets used in the field. The kdT(95) values were in the same scale with the two types of nets. The kdT(50) of the Vk per resistant strain when exposed to used nets were twofold that of the Kisumu susceptible strain at the beginning of the trial, and they increased to fivefold 15 mo later. These latter kdT(50) significantly differed to those of the Kisumu susceptible strain tested with laboratory and field samples of nets. The kdT(95) significantly differed from those of the Kisumu strain with laboratory kept nets and with field kept nets. Baseline bioassay mortality rates were always 99-100% with the Kisumu susceptible strain, and they did not show any significant difference between laboratory-kept nets and field-used nets during the 15-mo trial. With the Vk per resistant strain, the expected long-lasting activity was not achieved. A high decrease of mortality rates was observed from 69 to 75% in the first 3 mo to 2% at the month 15. This mortality was associated with significant differences between Vk per resistant strain tested with field-used nets compared with Kisumu susceptible strain tested with both laboratory kept-nets and field-used nets. This study emphasized the actual long-lasting effectiveness of Permanet against the An. gainbiae Kisumu susceptible reference strain and a rapid decrease of residual activity against a strain with kdr-based resistance to pyrethroids.
Plan de classement
Entomologie médicale / Parasitologie / Virologie [052]
Description Géographique
COTE D'IVOIRE
Localisation
Fonds IRD [F B010037998]
Identifiant IRD
fdi:010037998
Contact