scholarly journals Aggressive mosquito fauna and malaria transmission in a forest area targeted for the creation of an agro-industrial complex in the south of Cameroon

2016 ◽  
Vol 48 (3) ◽  
pp. 380
Author(s):  
P. Ntonga Akono ◽  
C. Tonga ◽  
O.E. Ngo Hondt ◽  
M.F. Peka Nsangou ◽  
R. Ngaha ◽  
...  

Baseline entomological information should be collected before the implementation of industrial projects in malaria endemic areas. This allows for subsequent monitoring and evaluation of the project impact on malaria vectors. This study aimed at assessing the vectorial system and malaria transmission in two ecologically different villages of the South-Cameroon forest bloc targeted for the creation of an agro-industrial complex. For four consecutive seasons in 2013, adult mosquitoes were captured using Human Landing Catch in NDELLE village (located along a main road in a degraded forest with many fish ponds) and KOMBO village (located 5km far from the main road in a darker forest and crossed by the Mvobo River). Morpho-taxonomic techniques were used alongside molecular techniques for the identification of mosquito species. ELISA test was used for the detection of circumsporozoite protein antigen of <em>Plasmodium falciparum</em>. Mosquito biting rate was higher in NDELLE than in KOMBO (28.18 <em>versus</em> 17.34 bites per person per night). Mosquitoes had a strong tendency to endophagy both in NDELLE (73.57%) and KOMBO (70.21%). Three anophelines species were identified; <em>An. gambiae</em>, <em>An. funestus</em> s.s and <em>An. moucheti</em> s.s.. <em>An. gambiae</em> and <em>An. funestus</em> s.s. represented the bulk of aggressive mosquitoes in NDELLE (n=10,891; 96.62%). <em>An. gambiae</em> was responsible for 62.6% and 77.72% of malaria transmission in KOMBO and NDELLE respectively. Mean entomological inoculation rate recorded in KOMBO and NDELLE were 4.82 and 2.02 infective bites per person per night respectively. Vector control was mainly based on the use of long-lasting insecticidal nets and indoor residual spraying. The degraded forest environment added to the presence of fishponds resulted in the increase of aggressive mosquito density but not of malaria transmission. The managers should use these data for monitoring and evaluation of the impact of their project; malaria control strategies should be included in their project in order to mitigate the risk of increased malaria transmission as a result of the implementation of their projects.

2019 ◽  
Vol 188 (12) ◽  
pp. 2120-2130 ◽  
Author(s):  
Marisa A Hast ◽  
Mike Chaponda ◽  
Mbanga Muleba ◽  
Jean-Bertin Kabuya ◽  
James Lupiya ◽  
...  

Abstract Malaria transmission in northern Zambia has increased in the past decade, despite malaria control activities. Evidence-based intervention strategies are needed to effectively reduce malaria transmission. Zambia’s National Malaria Control Centre conducted targeted indoor residual spraying (IRS) in Nchelenge District, Luapula Province, from 2014 to 2016 using the organophosphate insecticide pirimiphos-methyl. An evaluation of the IRS campaign was conducted by the Southern Africa International Centers of Excellence for Malaria Research using actively detected malaria cases in bimonthly household surveys carried out from April 2012 to July 2017. Changes in malaria parasite prevalence after IRS were assessed by season using Poisson regression models with robust standard errors, controlling for clustering of participants in households and demographic, geographical, and climatological covariates. In targeted areas, parasite prevalence declined approximately 25% during the rainy season following IRS with pirimiphos-methyl but did not decline during the dry season or in the overall study area. Within targeted areas, parasite prevalence declined in unsprayed households, suggesting both direct and indirect effects of IRS. The moderate decrease in parasite prevalence within sprayed areas indicates that IRS with pirimiphos-methyl is an effective malaria control measure, but a more comprehensive package of interventions is needed to effectively reduce the malaria burden in this setting.


2015 ◽  
Vol 5 (4) ◽  
pp. 314-318
Author(s):  
Renitha Rampersad

The South African corporate sector invests millions to support community development and social programs. One of the more fundamental issues about sustainability in a business context is the fact that directors have a fiduciary duty to take into account interests of those stakeholders other than investors/shareholders. This therefore places major importance on sustainability reporting through reports on governance, economic, social and environmental performance and is increasingly being regarded as a key form of stakeholder engagement, and the most accepted formal way of communicating measured outcomes to all stakeholders. A number of methodologies may exist for the development of Corporate Social Responsibility (CSR) strategies or “how-to guides” for community engagement and investment, however, it lacks development in the field of CSR Programme Evaluation. Integrated approaches to the measurement thereof are still in expanding stages of development and statistical data and/or empirical evidence is lacking at this point. Trust and relationships take time to build but are valuable assets, therefore a company must show it has listened and acted in response to stakeholder concerns, this means that ongoing communication and reporting back to stakeholders is a very important component in any engagement strategy. It is therefore important for the corporate sector to not only evaluate the effectiveness of their CSR Programmes, but also to measure the impact on both their beneficiary communities and their business and subsequently on the Return on Investment (ROI). This paper will highlight a case of the South African corporate sectors attempts to evaluate its effectiveness and impact on beneficiary communities and how they quantify the impact of the investment through successful CSR interventions


2019 ◽  
Author(s):  
Demba Kodindo Israël ◽  
Diomba Dobar Abel ◽  
Adoum Mahamat Oumar ◽  
Moundai Tchonfinet ◽  
Amen Nakebang Fadel ◽  
...  

Abstract BackgroudMalaria is a major public health and development problem in Africa. In Chad in 2016, with 720 765 confirmed cases and 1 686 deaths, malaria is the main cause of consultations, hospitalizations and deaths in health facilities. A longitudinal entomological study was carried out from 07 to 24 December 2016 in the Moïssala health district. The objective of the study was to assess the impact of malaria transmission one year after two cycles of indoor residual spraying of 80% bendiocarb wettable powder (Ficam WP 80 W).MethodsTwo areas were defined for the study: the town of Dembo, located in the sprayed area, was chosen as the test town and Moïssala, located in the untreated area, was chosen as the control town. Two sampling methods were used: collection of resting endophilic fauna and direct capture of aggressive mosquitoes from human subjects. ResultsA total of 16 sessions of catches on human subjects totalling 32 man-nights were conducted and 160 rooms were sprayed per site. For 160 sprayed chambers per site, two anopheles were captured in Dembo compared to 547 in Moïssala. Three anophelian species have been morphologically identified. In Moïssala, An gambiae sl (An colluzzii : 96%, An gambiae : 4%), An funestus and An rufipes were captured at rest in the rooms and on human bait. In Dembo, the two anopheles, An colluzzii and An funestus were captured at rest in the rooms. On human bait as in endophilic fauna, An gambiae sp was the most common species in Moïssala. The aggressive anophelian density was zero in Dembo while it is 9 bites per man per night in Mosesala. Only Anopheles gambiae sp was found infected in aggressive wildlife. The sporozoite index of the aggressive fauna of An gambiae sp was 7.45%. Malaria transmission was estimated at 0.67 infected bites per man per night, or 244.55 infected bites per man per year. In endophilic fauna, An gambiae sp and An rufipes were the two species found infected in Moïssala with sporozoite indices of 6.70% (23/343) and 20% (2/10) respectively. However, in Dembo, neither of the two captured individuals was found infected.ConclusionsThe indoor residual spraying campaign in the eastern zone of the Moïssala health district has led to the collapse of the density and aggressiveness of malaria vectors. However, its evaluation over a short period of time is not sufficient to assess the impact of malaria transmission in this stable and highly endemic malaria zone.


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Joseph Wagman ◽  
Idrissa Cissé ◽  
Diakalkia Kone ◽  
Seydou Fomba ◽  
Erin Eckert ◽  
...  

Abstract Background The National Malaria Control Programme (NMCP) of Mali has had recent success decreasing malaria transmission using 3rd generation indoor residual spraying (IRS) products in areas with pyrethroid resistance, primarily in Ségou and Koulikoro Regions. In 2015, national survey data showed that Mopti Region had the highest under 5-year-old (u5) malaria prevalence at 54%—nearly twice the national average—despite having high access to long-lasting insecticidal nets (LLINs) and seasonal malaria chemoprevention (SMC). Accordingly, in 2016 the NMCP and other stakeholders shifted IRS activities from Ségou to Mopti. Here, the results of a series of observational analyses utilizing routine malaria indicators to evaluate the impact of this switch are presented. Methods A set of retrospective, eco-observational time-series analyses were performed using monthly incidence rates of rapid diagnostic test (RDT)-confirmed malaria cases reported in the District Health Information System 2 (DHIS2) from January 2016 until February 2018. Comparisons of case incidence rates were made between health facility catchments from the same region that differed in IRS status (IRS vs. no-IRS) to describe the general impact of the 2016 and 2017 IRS campaigns, and a difference-in-differences approach comparing changes in incidence from year-to-year was used to describe the effect of suspending IRS operations in Ségou and introducing IRS operations in Mopti in 2017. Results Compared to communities with no IRS, cumulative case incidence rates in IRS communities were reduced 16% in Ségou Region during the 6 months following the 2016 campaign and 31% in Mopti Region during the 6 months following the 2017 campaign, likely averting a total of more than 22,000 cases of malaria that otherwise would have been expected during peak transmission months. Across all comparator health facilities (HFs) where there was no IRS in either year, peak malaria case incidence rates fell by an average of 22% (CI95 18–30%) from 2016 to 2017. At HFs in communities of Mopti where IRS was introduced in 2017, peak incidence fell by an average of 42% (CI95 31–63%) between these years, a significantly greater decrease (p = 0.040) almost double what was seen in the comparator HFCAs. The opposite effect was observed in Ségou Region, where peak incidence at those HFs where IRS was withdrawn after the 2016 campaign increased by an average of 106% (CI95 63–150%) from year to year, also a significant difference-in-differences compared to the comparator no-IRS HFs (p < 0.0001). Conclusion Annual IRS campaigns continue to make dramatic contributions to the seasonal reduction of malaria transmission in communities across central Mali, where IRS campaigns were timed in advance of peak seasonal transmission and utilized a micro-encapsulated product with an active ingredient that was of a different class than the one found on the LLINs used throughout the region and to which local malaria vectors were shown to be susceptible. Strategies to help mitigate the resurgence of malaria cases that can be expected should be prioritized whenever the suspension of IRS activities in a particular region is considered.


2021 ◽  
Author(s):  
Peter Onyango Sangoro ◽  
Ulrike Fillinger ◽  
Kochelani Saili ◽  
Theresia Estomih Nkya ◽  
Rose Marubu ◽  
...  

Abstract Background: Concerted effort to control malaria has had a substantial impact on transmission of the disease in the past two decades. In areas where reduced malaria transmission is being sustained through insecticide-based vector control interventions, primarily long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), non-insecticidal complementary tools will likely be needed to push towards malaria elimination. Once interruption in local disease transmission is achieved, insecticide-based measures can be scaled down gradually and eventually phased out, saving on costs of sustaining control programmes and mitigating any unintended negative health and environmental impacts posed by insecticides. These non-insecticidal methods could eventually replace insecticidal methods of vector control. House screening, a non-insecticidal method, has a long history in malaria control, but is still not widely adopted in sub-Saharan Africa. This study aims to add to the evidence-base for this intervention in low transmission settings by assessing the efficacy, impact and feasibility of house screening in areas where LLINs are conventionally used for malaria control. Methods: A two-armed, household randomized clinical trial will be conducted in Mozambique, Zambia and Zimbabwe to evaluate whether combined use of house screens and LLINs affords better protection against clinical malaria in children between 6 months and 13 years compared to the sole use of LLINs. Eight hundred households will be enrolled in each study area, where 400 households will be randomly assigned the intervention, house screening and LLINs while the control households will be provided with LLINs only. Clinical malaria incidence will be estimated by actively following up one child from each household for 6 months over the malaria transmission season. Cross-sectional parasite prevalence will be estimated by testing all participating children for malaria parasites at the beginning and end of each transmission season using rapid diagnostic tests.CDC light traps and pyrethrum spray catches (PSC) will be used to sample adult mosquitoes and evaluate the impact of house screening on indoor mosquito density, species distribution and sporozoite rates.Discussion: This study will contribute epidemiological data on the impact of house screening on malaria transmission and assess the feasibility of its implementation on a programmatic scale. Trial registration: This trial was retrospectively registered on 11th August 2020. Registration number PACTR202008524310568.


2022 ◽  
Vol 21 (1) ◽  
Author(s):  
Adama Gansané ◽  
Baltazar Candrinho ◽  
Aimable Mbituyumuremyi ◽  
Perpetua Uhomoibhi ◽  
Sagnon NFalé ◽  
...  

Abstract Background Vector control tools have contributed significantly to a reduction in malaria burden since 2000, primarily through insecticidal-treated bed nets (ITNs) and indoor residual spraying. In the face of increasing insecticide resistance in key malaria vector species, global progress in malaria control has stalled. Innovative tools, such as dual active ingredient (dual-AI) ITNs that are effective at killing insecticide-resistant mosquitoes have recently been introduced. However, large-scale uptake has been slow for several reasons, including higher costs and limited evidence on their incremental effectiveness and cost-effectiveness. The present report describes the design of several observational studies aimed to determine the effectiveness and cost-effectiveness of dual-AI ITNs, compared to standard pyrethroid-only ITNs, at reducing malaria transmission across a variety of transmission settings. Methods Observational pilot studies are ongoing in Burkina Faso, Mozambique, Nigeria, and Rwanda, leveraging dual-AI ITN rollouts nested within the 2019 and 2020 mass distribution campaigns in each country. Enhanced surveillance occurring in select study districts include annual cross-sectional surveys during peak transmission seasons, monthly entomological surveillance, passive case detection using routine health facility surveillance systems, and studies on human behaviour and ITN use patterns. Data will compare changes in malaria transmission and disease burden in districts receiving dual-AI ITNs to similar districts receiving standard pyrethroid-only ITNs over three years. The costs of net distribution will be calculated using the provider perspective including financial and economic costs, and a cost-effectiveness analysis will assess incremental cost-effectiveness ratios for Interceptor® G2, Royal Guard®, and piperonyl butoxide ITNs in comparison to standard pyrethroid-only ITNs, based on incidence rate ratios calculated from routine data. Conclusions Evidence of the effectiveness and cost-effectiveness of the dual-AI ITNs from these pilot studies will complement evidence from two contemporary cluster randomized control trials, one in Benin and one in Tanzania, to provide key information to malaria control programmes, policymakers, and donors to help guide decision-making and planning for local malaria control and elimination strategies. Understanding the breadth of contexts where these dual-AI ITNs are most effective and collecting robust information on factors influencing comparative effectiveness could improve uptake and availability and help maximize their impact.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Manuela Runge ◽  
Salum Mapua ◽  
Ismail Nambunga ◽  
Thomas A. Smith ◽  
Nakul Chitnis ◽  
...  

Abstract Background Larviciding against malaria vectors in Africa has been limited to indoor residual spraying and insecticide-treated nets, but is increasingly being considered by some countries as a complementary strategy. However, despite progress towards improved larvicides and new tools for mapping or treating mosquito-breeding sites, little is known about the optimal deployment strategies for larviciding in different transmission and seasonality settings. Methods A malaria transmission model, OpenMalaria, was used to simulate varying larviciding strategies and their impact on host-seeking mosquito densities, entomological inoculation rate (EIR) and malaria prevalence. Variations in coverage, duration, frequency, and timing of larviciding were simulated for three transmission intensities and four transmission seasonality profiles. Malaria transmission was assumed to follow rainfall with a lag of one month. Theoretical sub-Saharan African settings with Anopheles gambiae as the dominant vector were chosen to explore impact. Relative reduction compared to no larviciding was predicted for each indicator during the simulated larviciding period. Results Larviciding immediately reduced the predicted host-seeking mosquito densities and EIRs to a maximum that approached or exceeded the simulated coverage. Reduction in prevalence was delayed by approximately one month. The relative reduction in prevalence was up to four times higher at low than high transmission. Reducing larviciding frequency (i.e., from every 5 to 10 days) resulted in substantial loss in effectiveness (54, 45 and 53% loss of impact for host-seeking mosquito densities, EIR and prevalence, respectively). In seasonal settings the most effective timing of larviciding was during or at the beginning of the rainy season and least impactful during the dry season, assuming larviciding deployment for four months. Conclusion The results highlight the critical role of deployment strategies on the impact of larviciding. Overall, larviciding would be more effective in settings with low and seasonal transmission, and at the beginning and during the peak densities of the target species populations. For maximum impact, implementers should consider the practical ranges of coverage, duration, frequency, and timing of larviciding in their respective contexts. More operational data and improved calibration would enable models to become a practical tool to support malaria control programmes in developing larviciding strategies that account for the diversity of contexts.


2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
M. Mamun Huda ◽  
Dinesh Mondal ◽  
Vijay Kumar ◽  
Pradeep Das ◽  
S. N. Sharma ◽  
...  

Background. We field tested and validated a newly developed monitoring and evaluation (M&E) toolkit for indoor residual spraying to be used by the supervisors at different levels of the national kala-azar elimination programs in Bangladesh, India and Nepal.Methods. Methods included document analysis, in-depth interviews, direct observation of spraying squads, and entomological-chemical assessments (bioassay, susceptibility test, chemical analysis of insecticide residues on sprayed surfaces, vector density measurements at baseline, and three follow-up surveys).Results. We found that the documentation at district offices was fairly complete; important shortcomings included insufficient training of spraying squads and supervisors, deficient spray equipment, poor spraying performance, lack of protective clothing, limited coverage of houses resulting in low bioavailability of the insecticide on sprayed surfaces, and reduced vector susceptibility to DDT in India, which limited the impact on vector densities.Conclusion. The M&E toolkit is a useful instrument for detecting constraints in IRS operations and to trigger timely response.


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