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Background. The population effects of influenza vaccination in children have not been extensively studied, especially in tropical, developing countries. In rural Senegal, we assessed the total (primary objective) and indirect effectiveness of a trivalent inactivated influenza vaccine (IIV3). Methods. In this double-blind, cluster-randomized trial, villages were randomly allocated (1:1) for the high-coverage vaccination of children aged 6 months through 10 years with either the 2008-09 northern hemisphere IIV3 or an inactivated polio vaccine (IPV). Vaccinees were monitored for serious adverse events. All village residents, vaccinated and unvaccinated, were monitored for signs and symptoms of influenza illness using weekly home visits and surveillance in designated clinics. The primary outcome was all laboratory-confirmed symptomatic influenza. Results. Between 23 May and 11 July 2009, 20 villages were randomized, and 66.5% of age-eligible children were enrolled (3918 in IIV3 villages and 3848 in IPV villages). Follow-up continued until 28 May 2010. There were 4 unrelated serious adverse events identified. Among vaccinees, the total effectiveness against illness caused by the seasonal influenza virus (presumed to all be drifted A/H3N2, based on antigenic characterization data) circulating at high rates among children was 43.6% (95% confidence interval [CI] 18.6-60.9%). The indirect effectiveness against seasonal A/H3N2 was 15.4% (95% CI -22.0 to 41.3%). The total effectiveness against illness caused by the pandemic influenza virus (A/H1N1pdm09) was -52.1% (95% CI -177.2 to 16.6%). Conclusions. IIV3 provided statistically significant, moderate protection to children in Senegal against circulating, pre-2010 seasonal influenza strains, but not against A/H1N1pdm09, which was not included in the vaccine. No indirect effects were measured. Further study in low-resource populations is warranted.

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In Senegal, a laboratory study was conducted in 2005 to ascertain the effect that different numbers of the host-specific weevil Neohydronomus affinis Hustache (Coleoptera: Curculionidae) per plant had on selected plant growth parameters of its target weed, water lettuce Pistia stratiotes Linnaeus (Araceae). Compared to the control, the weevil caused a significant reduction in all parameters measured, except for daughter plant production. There were no significant differences in impact on the plant between the three different densities of weevil (one, two and three pairs per plant). Under laboratory conditions one pair per plant is deemed sufficient to effect complete control of water lettuce over a six-week period.Keywords: biological control, complete control, inoculumAfrican Journal of Aquatic Science 2010, 35(3): 267–271

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The South American floating aquatic plant Pistia stratiotes (Araceae) was introduced into Senegal in the early 1990s and by 1994 had covered some 2 034 ha on Lake Guiers. The biological control agent Neohydronomus affinis (Coleoptera: Curculionidae) was released in this area between September 1994 and April 1995. A quantitative post-release evaluation showed that the weed cover decreased by about 25% every two months, completely eliminating the water lettuce mats within eight months. The weevils dispersed some 150 km in 18 months and controlled water lettuce in several water bodies in the Djoudj National Park. A resurgence of the weed in the Senegal River Delta in 2005 prompted further releases of the weevil, once again resulting in effective control. The biological control programme against water lettuce in Senegal has been highly successful and the weed is no longer considered problematic.African Journal of Aquatic Science 2009, 34(1): 35–44

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International audience; We analyzed the nucleotide sequence and tissue distribution of the Enzootic Nasal Tumour Virus (ENTV) circulating in Sahelian breeds of sheep in West Africa. New ENTV specific primers were designed in the variable region spanning from the end of the viral transmembrane (TM) gene to the U3 region of the long terminal repeat (LTR). These primers selectively amplified a fragment of the ENTV genome from the tumour tissues of sheep affected with enzootic nasal adenocarcinoma (ENA). ENTV nucleotides sequences obtained from two separate sheep were 99.5% homolog. The sequence analysis revealed a genome clustering more closely with ENTV-1 (94% homology) than with ENTV-2 (84% homology). An internal primer was designed for enhanced detection after hemi-nested PCR (hn-PCR). Tissues exploration using hn-PCR revealed the presence of provirus in the retropharyngeal lymph node draining the nasal region and in the healthy lung tissue from ENA-sheep. Despite this improved detection assay, the ENTV genome remained undetectable from the peripheral blood leukocytes of ENA sheep. The observed tissue distribution is consistent with the ENTV-1 dissemination pattern. These data are relevant to the preclinical and antemortem diagnosis of sheep ENA.; Nous avons analysé la séquence nucléotidique et la distribution tissulaire du virus de la tumeur nasale enzootique (ENTV) qui sévit chez les souches sahéliennes de mouton d’Afrique de l’Ouest. Des oligonucléotides spécifiques du ENTV ont été conçus dans la région variable qui s’étend de la fin du gène codant la protéine virale trans-membranaire (TM) à la région U3 du LTR. Ces amorces permettent d’amplifier sélectivement un fragment du génome viral à partir du tissu tumoral d’ovin atteint d’Adénocarcinome Nasal Enzootique (ENA). Les séquences virales obtenues de deux animaux sont à 99,5 % homologues. Leur analyse a révélé un génome plus proche du ENTV-1 (homologie 94 %) que du ENTV-2 (homologie 84 %). Un «primer» interne a été conçu pour accroître le pouvoir de détection après PCR nichée (hn-PCR). L’exploration des tissus par cette méthode a révélé la présence de pro-virus dans le ganglion rétropharyngé qui draine la région nasale, ainsi que dans le poumon sain de mouton atteint. Malgré cette capacité accrue de détection, le génome du ENTV est resté indétectable depuis les leucocytes circulants de mouton atteint. La distribution tissulaire observée est en accord avec la dissémination du ENTV-1. Ces résultats ont des implications pour le diagnostic pré-clinique et ante-mortem de la tumeur nasale enzootique du mouton.