Characterization of Anopheles gambiae s.l. and insecticide resistance profile relative to physicochemical properties of breeding habitats within Accra Metropolis, Ghana

Malaria is endemic in Ghana as in most countries of sub-Saharan Africa. This study was conducted to characterize Anopheles gambiae s.l. and determine pyrethroid resistance profiles relative to physicochemical properties of breeding habitats in Accra, Ghana. Eight aquatic habitats containing Anopheles larvae were identified and from each habitat, larvae and water were sampled. Adult An. gambiae reared from larvae were morphologically identified and tested for permethrin (0.75%) and deltamethrin (0.05%) resistance using WHO bioassay method. An. gambiae s.s. found were identified to their molecular levels and kdr mutation detected using PCR-based methods. Twenty-nine physicochemical parameters of each water sample were measured and their levels connected with pyrethroid resistance and proportions of An. gambiae s.s. molecular forms in habitats. A total of 2,257 mosquitoes were morphologically identified as An. gambiae s.l. and all 224 processed for PCR were identified as An. gambiae s.s., of which 56.46% and 43.54% were M and S-forms, respectively. Both forms occurred in sympatry in all larval habitats and no S/M hybrids were detected. However, M-form larvae were in high proportion in polluted habitats than the S-form. An. gambiae s.s. was highly resistant to both deltamethrin and permethrin with mortality rates of 42.98-70.0% and 6.5-20.0% respectively. The frequency of kdr mutation was 60.5 % (n=195). This mutation occurred in both S and M-forms, but was mainly associated with the S-form (X2=10.92, df =1, P=0.001). Carbonate and pH were both selected in discriminant function analysis as best predictors of high proportion of M-form in the habitats. The adaptation of An. gambiae s.s. in polluted aquatic habitats coupled with occurrence of insecticide resistance is quite alarming particularly for urban malaria control and needs further exploration in a wider context

Characterization of Anopheles gambiae s.l. and insecticide resistance profile relative to physicochemical properties of breeding habitats within Accra Metropolis, Ghana

Malaria is endemic in Ghana as in most countries of sub-Saharan Africa. This study was conducted to characterize Anopheles gambiae s.l. and determine pyrethroid resistance profiles relative to physicochemical properties of breeding habitats in Accra, Ghana. Eight aquatic habitats containing Anopheles larvae were identified and from each habitat, larvae and water were sampled. Adult An. gambiae reared from larvae were morphologically identified and tested for permethrin (0.75%) and deltamethrin (0.05%) resistance using WHO bioassay method. An. gambiae s.s. found were identified to their molecular levels and kdr mutation detected using PCR-based methods. Twenty-nine physicochemical parameters of each water sample were measured and their levels connected with pyrethroid resistance and proportions of An. gambiae s.s. molecular forms in habitats. A total of 2,257 mosquitoes were morphologically identified as An. gambiae s.l. and all 224 processed for PCR were identified as An. gambiae s.s., of which 56.46% and 43.54% were M and S-forms, respectively. Both forms occurred in sympatry in all larval habitats and no S/M hybrids were detected. However, M-form larvae were in high proportion in polluted habitats than the S-form. An. gambiae s.s. was highly resistant to both deltamethrin and permethrin with mortality rates of 42.98-70.0% and 6.5-20.0% respectively. The frequency of kdr mutation was 60.5 % (n=195). This mutation occurred in both S and M-forms, but was mainly associated with the S-form (X2=10.92, df =1, P=0.001). Carbonate and pH were both selected in discriminant function analysis as best predictors of high proportion of M-form in the habitats. The adaptation of An. gambiae s.s. in polluted aquatic habitats coupled with occurrence of insecticide resistance is quite alarming particularly for urban malaria control and needs further exploration in a wider context

Formation of Covalently Bonded Polycyclic Hydrocarbon Ions by Intracluster Polymerization of Ionized Ethynylbenzene Clusters

Here we report a detailed study aimed at elucidating the mechanism of intracluster ionic polymerization following the electron impact ionization of van der Waals clusters of ethynylbenzene (C₈H₆)_<i>n</i> generated by a supersonic beam expansion. The structures of the C₁₆H₁₂, C₂₄H₁₈, C₃₂H₂₄, C₄₀H₃₀, and C₄₈H₃₆ radical cations resulting from the intracluster ion–molecule addition reactions have been investigated using a combination of mass-selected ion dissociation and ion mobility measurements coupled with theoretical calculations. Noncovalent structures can be totally excluded primarily because the measured fragmentations cannot result from noncovalent structures, and partially because of the large difference between the measured collision cross sections and the calculated values corresponding to noncovalent ion–neutral complexes. All the mass-selected cluster ions show characteristic fragmentations of covalently bonded molecular ions by the loss of stable neutral fragments such as CH₃, C₂H, C₆H₅, and C₇H₇. The population of the C₁₆H₁₂ dimer ions is dominated by structural isomers of the type (C₆H₅)CCCH^<b>•+</b>CH(C₆H₅), which can grow by the sequential addition of ethynylbenzene molecules, in addition to some contributions from cyclic isomers such as the 1,3- or 1,4-diphenyl cyclobutadiene ions. Similarly, two major covalent isomers have been identified for the C₂₄H₁₈ trimer ions: one that has a blocked cyclic structure assigned to 1,2,4- or 1,3,5-triphenylbenzene cation, and a second isomer of the type (C₆H₅)CCC­(C₆H₅)CHCH^<b>•+</b>CH(C₆H₅) where the covalent addition of further ethynylbenzene molecules can occur. For the larger ions such as C₃₂H₂₄, C₄₀H₃₀, and C₄₈H₃₆, the major isomers present involve the growing oligomer sequence (C₆H₅)CC[C­(C₆H₅)CH]_<i>n</i>CH^<b>•+</b>CH(C₆H₅) with different locations and orientations of the phenyl groups along the chain. In addition, the larger ions contain another family of structures consisting of neutral ethynylbenzene molecules associated with the blocked cyclic isomer ions such as the diphenylcyclobutadiene and triphenylbenzene cations. Low-energy dissociation channels corresponding to evaporation of ethynylbenzene molecules weakly associated with the covalent ions are observed in the large clusters in addition to the high-energy channels corresponding to fragmentation of the covalently bonded ions. However, in small clusters only high-energy dissociation channels are observed corresponding to the characteristic fragmentation of the molecular ions, thus providing structural signatures to identify the product ions and establish the mechanism of intracluster ionic polymerization

Reproductive Rights Advocacy: Concentration of effort, dilution of intention

Pascale Allotey and Daniel D. Reidpath discuss the issue of female genital cutting and obstetric fistulae within the context of reproductive rights advocacy. They use these examples to discuss the potential effects on the broader reproductive rights agenda of interventions that focus narrowly on what is often a symptom of unaddressed structural violence. They argue for a broader rights approach rather than simply focusing on ameliorating the specific harm, in order to focus on the more fundamental goal, that is, the promotion of the positive freedoms. Development (2005) 48, 69–74. doi:10.1057/palgrave.development.1100181