A pre-intervention study of malaria vector abundance in Rio Muni, Equatorial Guinea: Their role in malaria transmission and the incidence of insecticide resistance alleles

BACKGROUND: Following the success of the malaria control intervention on the island of Bioko, malaria control by the use of indoor residual spraying (IRS) and long-lasting insecticide-treated nets (LLITN) was extended to Rio Muni, on the mainland part of Equatorial Guinea. This manuscript reports on the malaria vectors present and the incidence of insecticide resistant alleles prior to the onset of the programme. METHODS: Anopheles mosquitoes were captured daily using window traps at 30 sentinel sites in Rio Muni, from December 2006 to July 2007. The mosquitoes were identified to species and their sporozoite rates, knockdown resistance (kdr) and acetylcholinesterase (AChE) sensitivity measured, to define the role of vector species in malaria transmission and their potential susceptibility to insecticides. RESULTS: A total of 6,162 Anopheles mosquitoes were collected of which 4,808 were morphologically identified as Anopheles gambiae s.l., 120 Anopheles funestus, 1,069 Anopheles moucheti, and 165 Anopheles nili s.l.. Both M and S molecular forms of Anopheles gambiae s.s. and Anopheles melas were identified. Anopheles ovengensis and Anopheles carnevalei were the only two members of the An. nili group to be identified. Using the species-specific sporozoite rates and the average number of mosquitoes per night, the number of infective mosquitoes per trap per 100 nights for each species complex was calculated as a measure of transmission risk. Both kdr-w and kdr-e alleles were present in the S-form of An. gambiae s.s. (59% and 19% respectively) and at much lower frequencies in the M-form (9.7% and 1.8% respectively). The kdr-w and kdr-e alleles co-occurred in 103 S-form and 1 M-form specimens. No insensitive AChE was detected. CONCLUSION: Anopheles gambiae s.s, a member of the Anopheles gambiae complex was shown to be the major vector in Rio Muni with the other three groups playing a relatively minor role in transmission. The demonstration of a high frequency of kdr alleles in mosquito populations before the onset of a malaria control programme shows that continuous entomological surveillance including resistance monitoring will be of critical importance to ensure the chosen insecticide remains effective

Why are anopheline mosquitoes not present in the Seychelles?

<p>Abstract</p> <p>Background</p> <p>Species of anopheline mosquitoes are largely distributed over emerged lands around the world and, within the tropics, few areas are without these insects, which are vectors of malaria parasites. Among the exceptions is the Seychelles archipelago in the western Indian Ocean. However, in the Aldabra island group, located in the extreme western portion of the archipelago, <it>Anopheles gambiae s.l. </it>was introduced, leading to massive proliferation and then elimination, with the most recent autochthonous malaria cases recorded in 1931.</p> <p>Methods</p> <p>In order to re-examine the absence of anopheline mosquitoes in the Seychelles, an entomological field survey was conducted in December 2008 at 17 sites on four granitic islands, including Mahé and Praslin, and ten sites on coralline atolls in the extreme west, including Aldabra.</p> <p>Results</p> <p>No evidence of larval or adult anophelines was found at the surveyed sites, which supports their absence in the Seychelles.</p> <p>Conclusions</p> <p>In the granitic islands of the Seychelles, the climate is favourable for anophelines. However, these islands are protected by their remoteness and prevailing seasonal winds. In addition, stagnant freshwater, required in anopheline larval development, is relatively uncommon on the granitic islands because of the steep slopes. In the southwestern atolls (Aldabra and Providence-Farquhar groups), the presence of a long dry season of up to nine months and the total absence of permanent natural freshwater prevents the breeding of anophelines and their successful colonization. The Seychelles does not have any native land mammals and like in other parts of the world (Antarctica, Iceland, New Caledonia, Central Pacific islands) their absence is associated with the lack of anophelines. This suggests an obligatory relationship for anophelines to feed on terrestrial mammals, without alternative for blood-feeding sources, such as bats, birds and reptiles.</p

Scale-up of an intensified bioprocess for the expansion of bovine adipose-derived stem cells (bASCs) in stirred tank bioreactors

Cultivated meat is an emerging field, aiming to establish the production of animal tissue for human consumption in an in vitro environment, eliminating the need to raise and slaughter animals for their meat. To realise this, the expansion of primary cells in a bioreactor is needed to achieve the high cell numbers required. The aim of this study was to develop a scalable, microcarrier based, intensified bioprocess for the expansion of bovine adipose-derived stem cells as precursors of fat and muscle tissue. The intensified bioprocess development was carried out initially in spinner flasks of different sizes and then translated to fully controlled litre scale benchtop bioreactors. Bioprocess intensification was achieved by utilising the previously demonstrated bead-to-bead transfer phenomenon and through the combined addition of microcarrier and medium to double the existing surface area and working volume in the bioreactor. Choosing the optimal time point for the additions was critical in enhancing the cell expansion. A significant fold increase of 114.19 ± 1.07 was obtained at the litre scale in the intensified bioprocess compared to the baseline (**p < .005). The quality of the cells was evaluated pre- and post-expansion and the cells were found to maintain their phenotype and differentiation capacity

Un nouvel instrument destiné à mesurer la qualité de vie des personnes âgées : le WHOQOL-OLD version française

International audiencePurposeWe present the validation data of the French version of a new quality of life questionnaire, specifically developed for use with older adults (> 60 years old): the WHOQOL-OLD module. This questionnaire, which contains 24 items in six domains, is a complementary module of the WHOQOL-BREF quality of life questionnaire. It was internationally developed by a World Health Organization (WHO) group.MethodsThe first development and pilot studies led to a first questionnaire applied in field studies in 20 centers all over the world. They were done in 5566 subjects and allowed the validation of the final form of the WHOQOL-OLD questionnaire. For its French version, 281 subjects, with a mean age of 74 years, were recruited in three centers (Paris, Nancy and Geneva).ResultsThe results of the psychometric properties of the questionnaire, particularly the multitrait analysis, are compatible with the assumptions underlying the construction of scores. Otherwise, scores present a sufficient accuracy to use this instrument in group comparisons.ConclusionThe WHOQOL-OLD questionnaire can be used in older people in health services, clinical research and epidemiologic studies.ProposCet article présente le développement et les premières données de validation de la version française d’un nouveau questionnaire de mesure de la santé perçue ou de la qualité de vie des personnes âgées (> 60 ans) : le module WHOQOL-OLD. Ce questionnaire, mis au point dans le cadre d’un projet international sous l’égide de l’OMS avec le soutien de l’Union européenne, est destiné à compléter le questionnaire de qualité de vie générique WHOQOL-BREF. Il comporte 24 questions regroupées en six dimensions.MéthodesLe développement initial du questionnaire et les études pilotes réalisées ont conduit à un premier questionnaire qui a fait l’objet d’études de terrain dans 20 centres répartis dans le monde entier. Elles ont concerné 5566 personnes et permis la validation du WHOQOL-OLD dans sa version finale. En ce qui concerne la version française, 281 sujets, d’âge moyen 74 ans, ont été recrutés par trois centres (Paris, Nancy et Genève).RésultatsLes résultats de l’analyse des propriétés psychométriques du questionnaire, notamment l’analyse multitrait, sont compatibles avec les hypothèses sous-jacentes à la construction des scores. Par ailleurs, les scores présentent une précision suffisante pour utiliser cet instrument dans les comparaisons de groupes.ConclusionAu total, le questionnaire WHOQOL-OLD peut être utilisé auprès des personnes âgées dans les études de service de santé, la recherche clinique et les études épidémiologiques