Effet de la densite sur les parametres dendrometriques D'Acacia auriculaeformis en association avec le cocotier (Cocos nucifera L.) sur sables quaternaires en C&#244te d'Ivoire

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Health & Demographic Surveillance System Profile: The Taabo Health and Demographic Surveillance System, Côte d'Ivoire

The Taabo Health and Demographic Surveillance System (HDSS) is located in south-central Côte d'Ivoire, approximately 150 km north-west of Abidjan. The Taabo HDSS started surveillance activities in early 2009 and the man-made Lake Taabo is a key eco-epidemiological feature. Since inception, there has been a strong interest in research and integrated control of water-associated diseases such as schistosomiasis and malaria. The Taabo HDSS has generated setting-specific evidence on the impact of targeted interventions against malaria, schistosomiasis and other neglected tropical diseases. The Taabo HDSS consists of a small town, 13 villages and over 100 hamlets. At the end of 2013, a total population of 42 480 inhabitants drawn from 6707 households was under surveillance. Verbal autopsies have been conducted to determine causes of death. Repeated cross-sectional epidemiological surveys on approximately 5-7% of the population and specific, layered-on haematological, parasitological and questionnaire surveys have been conducted. The Taabo HDSS provides a database for surveys, facilitates interdisciplinary research, as well as surveillance, and provides a platform for the evaluation of health interventions. Requests to collaborate and to access data are welcome and should be addressed to the secretariat of the Centre Suisse de Recherches Scientifiques en Côte d'Ivoire: [[email protected]

The importance of considering community-level effects when selecting insecticidal malaria vector products

BACKGROUND\ud \ud Insecticide treatment of nets, curtains or walls and ceilings of houses represent the primary means for malaria prevention worldwide. Direct personal protection of individuals and households arises from deterrent and insecticidal activities which divert or kill mosquitoes before they can feed. However, at high coverage, community-level reductions of mosquito density and survival prevent more transmission exposure than the personal protection acquired by using a net or living in a sprayed house.\ud \ud METHODS\ud \ud A process-explicit simulation of malaria transmission was applied to results of 4 recent Phase II experimental hut trials comparing a new mosaic long-lasting insecticidal net (LLIN) which combines deltamethrin and piperonyl butoxide with another LLIN product by the same manufacturer relying on deltamethrin alone.\ud \ud RESULTS\ud \ud Direct estimates of mean personal protection against insecticide-resistant vectors in Vietnam, Cameroon, Burkina Faso and Benin revealed no clear advantage for combination LLINs over deltamethrin-only LLINs (P = 0.973) unless both types of nets were extensively washed (Relative mean entomologic inoculation rate (EIR) ± standard error of the mean (SEM) for users of combination nets compared to users of deltamethrin only nets = 0.853 ± 0.056, P = 0.008). However, simulations of impact at high coverage (80% use) predicted consistently better impact for the combination net across all four sites (Relative mean EIR ± SEM in communities with combination nets, compared with those using deltamethrin only nets = 0.613 ± 0.076, P < 0.001), regardless of whether the nets were washed or not (P = 0.467). Nevertheless, the degree of advantage obtained with the combination varied substantially between sites and their associated resistant vector populations.\ud \ud CONCLUSION\ud \ud Process-explicit simulations of community-level protection, parameterized using locally-relevant experimental hut studies, should be explicitly considered when choosing vector control products for large-scale epidemiological trials or public health programme procurement, particularly as growing insecticide resistance necessitates the use of multiple active ingredients

Can HIV self-testing reach first-time testers? A telephone survey among self-test end users in Côte d'Ivoire, Mali, and Senegal

BACKGROUND: Coverage of HIV testing remains sub-optimal in West Africa. Between 2019 and 2022, the ATLAS program distributed ~400 000 oral HIV self-tests (HIVST) in Côte d'Ivoire, Mali, and Senegal, prioritising female sex workers (FSW) and men having sex with men (MSM), and relying on secondary redistribution of HIVST to partners, peers and clients to reach individuals not tested through conventional testing. This study assesses the proportion of first-time testers among HIVST users and the associated factors. METHODS: A phone-based survey was implemented among HIVST users recruited using dedicated leaflets inviting them to anonymously call a free phone number. We collected socio-demographics, sexual behaviours, HIV testing history, HIVST use, and satisfaction with HIVST. We reported the proportion of first-time testers and computed associated factors using logistic regression. RESULTS: Between March and June 2021, 2 615 participants were recruited for 50 940 distributed HIVST (participation rate: 5.1%). Among participants, 30% received their HIVST kit through secondary distribution (from a friend, sexual partner, family member, or colleague). The proportion who had never tested for HIV before HIVST (first-time testers) was 41%. The main factors associated with being a first-time tester were sex, age group, education level, condom use, and secondary distribution. A higher proportion was observed among those aged 24 years or less (55% vs 32% for 25-34, aOR: 0.37 [95%CI: 0.30-0.44], and 26% for 35 years or more, aOR: 0.28 [0.21-0.37]); those less educated (48% for none/primary education vs 45% for secondary education, aOR: 0.60 [0.47-0.77], and 29% for higher education, aOR: 0.33 [0.25-0.44]). A lower proportion was observed among women (37% vs 43%, aOR: 0.49 [0.40-0.60]); those reporting always using a condom over the last year (36% vs 51% for those reporting never using them, aOR: 2.02 [1.59-2.56]); and those who received their HISVST kit through primary distribution (39% vs 46% for secondary distribution, aOR: 1.32 [1.08-1.60]). CONCLUSION: ATLAS HIVST strategy, including secondary distribution, successfully reached a significant proportion of first-time testers. HIVST has the potential to reach underserved populations and contribute to the expansion of HIV testing services in West Africa

Effects of short-term treatment with atorvastatin in smokers with asthma - a randomized controlled trial

&lt;b&gt;Background&lt;/b&gt; The immune modulating properties of statins may benefit smokers with asthma. We tested the hypothesis that short-term treatment with atorvastatin improves lung function or indices of asthma control in smokers with asthma.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt; Seventy one smokers with mild to moderate asthma were recruited to a randomized double-blind parallel group trial comparing treatment with atorvastatin (40 mg per day) versus placebo for 4 weeks. After 4 weeks treatment inhaled beclometasone (400 ug per day) was added to both treatment arms for a further 4 weeks. The primary outcome was morning peak expiratory flow after 4 weeks treatment. Secondary outcome measures included indices of asthma control and airway inflammation.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt; At 4 weeks, there was no improvement in the atorvastatin group compared to the placebo group in morning peak expiratory flow [-10.67 L/min, 95% CI -38.70 to 17.37, p=0.449], but there was an improvement with atorvastatin in asthma quality of life score [0.52, 95% CI 0.17 to 0.87 p=0.005]. There was no significant improvement with atorvastatin and inhaled beclometasone compared to inhaled beclometasone alone in outcome measures at 8 weeks.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt; Short-term treatment with atorvastatin does not alter lung function but may improve asthma quality of life in smokers with mild to moderate asthma. Clinicaltrials.gov identifier: NCT0046382

Intestinal parasitic infections in schoolchildren in different settings of Côte d'Ivoire : effect of diagnostic approach and implications for control

BACKGROUND: Social-ecological systems govern parasitic infections in humans. Within the frame of assessing the accuracy of a rapid diagnostic test for Schistosoma mansoni in Cote d'Ivoire, three different endemicity settings had to be identified and schoolchildren's intestinal parasitic infection profiles were characterized. METHODS: In September 2010, a rapid screening was conducted in 11 schools in the Azaguie district, south Cote d'Ivoire. In each school, 25 children were examined for S. mansoni and S. haematobium. Based on predefined schistosome endemicity levels, three settings were selected, where schoolchildren aged 8-12 years were asked to provide three stool and three urine samples for an in-depth appraisal of parasitic infections. Triplicate Kato-Katz thick smears were prepared from each stool sample for S. mansoni and soil-transmitted helminth diagnosis, whereas urine samples were subjected to a filtration method for S. haematobium diagnosis. Additionally, a formol-ether concentration method was employed on one stool sample for the diagnosis of helminths and intestinal protozoa. Multivariable logistic regression models were employed to analyse associations between schoolchildren's parasitic infections, age, sex and study setting. RESULTS: The prevalences of S. mansoni and S. haematobium infections in the initial screening ranged from nil to 88% and from nil to 56%, respectively. The rapid screening in the three selected areas revealed prevalences of S. mansoni of 16%, 33% and 78%. Based on a more rigorous diagnostic approach, the respective prevalences increased to 92%, 53% and 33%. S. haematobium prevalences were 0.8%, 4% and 65%. Prevalence and intensity of Schistosoma spp., soil-transmitted helminths and intestinal protozoan infections showed setting-specific patterns. Infections with two or more species concurrently were most common in the rural setting (84%), followed by the peri-urban (28.3%) and urban setting (18.2%). CONCLUSIONS: More sensitive diagnostic tools or rigorous sampling approaches are needed to select endemicity settings with high fidelity. The observed small-scale heterogeneity of helminths and intestinal protozoan infections has important implications for contro

Chlorfenapyr: a new insecticide with novel mode of action can control pyrethroid resistant malaria vectors

<p>Abstract</p> <p>Background</p> <p>Malaria vectors have acquired widespread resistance to many of the currently used insecticides, including synthetic pyrethroids. Hence, there is an urgent need to develop alternative insecticides for effective management of insecticide resistance in malaria vectors. In the present study, chlorfenapyr was evaluated against <it>Anopheles culicifacies </it>and <it>Anopheles stephensi </it>for its possible use in vector control.</p> <p>Methods</p> <p>Efficacy of chlorfenapyr against <it>An. culicifacies </it>and <it>An. stephensi </it>was assessed using adult bioassay tests. In the laboratory, determination of diagnostic dose, assessment of residual activity on different substrates, cross-resistance pattern with different insecticides and potentiation studies using piperonyl butoxide were undertaken by following standard procedures. Potential cross-resistance patterns were assessed on field populations of <it>An. culicifacies</it>.</p> <p>Results</p> <p>A dose of 5.0% chlorfenapyr was determined as the diagnostic concentration for assessing susceptibility applying the WHO tube test method in anopheline mosquitoes with 2 h exposure and 48 h holding period. The DDT-resistant/malathion-deltamethrin-susceptible strain of <it>An. culicifacies </it>species C showed higher LD50 and LD99 (0.67 and 2.39% respectively) values than the DDT-malathion-deltamethrin susceptible <it>An. culicifacies </it>species A (0.41 and 2.0% respectively) and <it>An. stephensi </it>strains (0.43 and 2.13% respectively) and there was no statistically significant difference in mortalities among the three mosquito species tested (p > 0.05). Residual activity of chlorfenapyr a.i. of 400 mg/m²on five fabricated substrates, namely wood, mud, mud+lime, cement and cement + distemper was found to be effective up to 24 weeks against <it>An. culicifacies </it>and up to 34 weeks against <it>An. stephensi</it>. No cross-resistance to DDT, malathion, bendiocarb and deltamethrin was observed with chlorfenapyr in laboratory-reared strains of <it>An. stephensi </it>and field-caught <it>An. culicifacies. </it>Potentiation studies demonstrated the antagonistic effect of PBO.</p> <p>Conclusion</p> <p>Laboratory studies with susceptible and resistant strains of <it>An. culicifacies </it>and <it>An. stephensi</it>, coupled with limited field studies with multiple insecticide-resistant <it>An. culicifacies </it>have shown that chlorfenapyr can be a suitable insecticide for malaria vector control, in multiple-insecticide-resistant mosquitoes especially in areas with pyrethroid resistant mosquitoes.</p

Insecticide resistance and the future of malaria control in Zambia.

BACKGROUND: In line with the Global trend to improve malaria control efforts a major campaign of insecticide treated net distribution was initiated in 1999 and indoor residual spraying with DDT or pyrethroids was reintroduced in 2000 in Zambia. In 2006, these efforts were strengthened by the President's Malaria Initiative. This manuscript reports on the monitoring and evaluation of these activities and the potential impact of emerging insecticide resistance on disease transmission. METHODS: Mosquitoes were captured daily through a series of 108 window exit traps located at 18 sentinel sites. Specimens were identified to species and analyzed for sporozoites. Adult Anopheles mosquitoes were collected resting indoors and larva collected in breeding sites were reared to F1 and F0 generations in the lab and tested for insecticide resistance following the standard WHO susceptibility assay protocol. Annual cross sectional household parasite surveys were carried out to monitor the impact of the control programme on prevalence of Plasmodium falciparum in children aged 1 to 14 years. RESULTS: A total of 619 Anopheles gambiae s.l. and 228 Anopheles funestus s.l. were captured from window exit traps throughout the period, of which 203 were An. gambiae malaria vectors and 14 An. funestus s.s.. In 2010 resistance to DDT and the pyrethroids deltamethrin, lambda-cyhalothrin and permethrin was detected in both An. gambiae s.s. and An. funestus s.s.. No sporozoites were detected in either species. Prevalence of P. falciparum in the sentinel sites remained below 10% throughout the study period. CONCLUSION: Both An. gambiae s.s. and An. funestus s.s. were controlled effectively with the ITN and IRS programme in Zambia, maintaining a reduced disease transmission and burden. However, the discovery of DDT and pyrethroid resistance in the country threatens the sustainability of the vector control programme

Synergy between Repellents and Organophosphates on Bed Nets: Efficacy and Behavioural Response of Natural Free-Flying An. gambiae Mosquitoes

Background: Chemicals are used on bed nets in order to prevent infected bites and to kill aggressive malaria vectors. Because pyrethroid resistance has become widespread in the main malaria vectors, research for alternative active ingredients becomes urgent. Mixing a repellent and a non-pyrethroid insecticide seemed to be a promising tool as mixtures in the laboratory showed the same features as pyrethroids. Methodology/Principal Findings: We present here the results of two trials run against free-flying Anopheles gambiae populations comparing the effects of two insect repellents (either DEET or KBR 3023, also known as icaridin) and an organophosphate insecticide at low-doses (pirimiphos-methyl, PM) used alone and in combination on bed nets. We showed that mixtures of PM and the repellents induced higher exophily, blood feeding inhibition and mortality among wild susceptible and resistant malaria vectors than compounds used alone. Nevertheless the synergistic interactions are only involved in the high mortality induced by the two mixtures. Conclusion: These field trials argue in favour of the strategy of mixing repellent and organophosphate on bed nets to better control resistant malaria vectors