scholarly journals Efficacy of extended release formulations of Natular™ (spinosad) against larvae and adults of Anopheles mosquitoes in western Kenya

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
John E. Gimnig ◽  
Maurice Ombok ◽  
Nabie Bayoh ◽  
Derrick Mathias ◽  
Eric Ochomo ◽  
...  
Keyword(s):  
Field Study ◽  
Extended Release ◽  
Adult Mosquito ◽  
Small Scale ◽  
Larval Source Management ◽  
Intervention Village ◽  
Emulsifiable Concentrate ◽  
Control Village ◽  
Tablet Formulations ◽  
Source Management

Abstract Background Larval source management is recommended as a supplementary vector control measure for the prevention of malaria. Among the concerns related to larviciding is the feasibility of implementation in tropical areas with large numbers of habitats and the need for frequent application. Formulated products of spinosad that are designed to be effective for several weeks may mitigate some of these concerns. Methods In a semi-field study, three formulations of spinosad (emulsifiable concentrate, extended release granules and tablet formulations) were tested in naturalistic habitats in comparison to an untreated control. Cohorts of third instar Anopheles gambiae (Diptera: Culicidae) were introduced into the habitats in screened cages every week up to four weeks after application and monitored for survivorship over three days. A small-scale field trial was then conducted in two villages. Two of the spinosad formulations were applied in one village over the course of 18 months. Immature mosquito populations were monitored with standard dippers in sentinel sites and adult populations were monitored by pyrethrum spray catches. Results In the semi-field study, the efficacy of the emulsifiable concentrate of spinosad waned 1 week after treatment. Mortality in habitats treated with the extended release granular formulation of spinosad was initially high but declined gradually over 4 weeks while mortality in habitats treated with the dispersable tablet formulation was low immediately after treatment but rose to 100% through four weeks. In the field study, immature and adult Anopheles mosquito populations were significantly lower in the intervention village compared to the control village during the larviciding period. Numbers of collected mosquitoes were lower in the intervention village compared to the control village during the post-intervention period but the difference was not statistically significant. Conclusions The extended release granular formulation and the dispersible tablet formulations of spinosad are effective against larval Anopheles mosquitoes for up to four weeks and may be an effective tool as part of larval source management programmes for reducing adult mosquito density and malaria transmission.

scholarly journals The Impact of Improved Lid of Underground Tanks “Tanka” On Breeding of An. Stephensi In Western Rajasthan, India

2021 ◽  
Author(s):  
Himmat Singh ◽  
Sanjeev Kumar Gupta ◽  
Kumar Vikram ◽  
Rekha Saxena ◽  
Amit Sharma
Keyword(s):  
Irrigation System ◽  
Substantial Reduction ◽  
Malaria Vectors ◽  
Adult Mosquito ◽  
Adult Density ◽  
Post Intervention ◽  
Intervention Village ◽  
Ecological Features ◽  
Control Village ◽  
The Impact

Abstract Background: Western Rajasthan of India has a typical desert climate. Until the introduction of canal water irrigation system, malaria was an unstable and seasonal occurrence. Due to scarcity of water, community practiced to have one large underground tank (locally known as Tanka) in their house to store water for long term use. Anopheles stephensi, one of the major malaria vectors, breeds in these "Tankas” if not properly covered and harbor a vector population throughout the year. Methods: Two villages Ajasar (intervention) and Tota (control) with similar ecological features were selected for the study. A pre-assessment was carried out in both villages to assess lids of Tankas, their breeding profile and the adult mosquito density. Awareness of community about malaria and mosquitoes was also assessed during pre-assessment period. In intervention village, lids were replaced with improved polyvinyl lids that were mosquito proof and last longer than conventional lids. Fitness of the lids, was assessed after one year. Entomological assessment was carried out in both intervention and non-intervention villages. The level of awareness of community was assessed both during pre and post intervention.Results : During the pre-assessment, Anopheles breeding was found in 22.1% (58/262) of Tankas of intervention village and 27.1% (19/70) of Tankas of control village. Tankas with iron lids were mainly positive in the intervention village (48.3%) and the control village (42.1%). In intervention village, 200 lids were replaced, and zero positivity was achieved. Before intervention, the species composition of An. stephensi was 46% in intervention and 55% in control village. Per Man Hour Density (PMHD) of An. stephensi was significantly reduced to 0.55 (94.95%) and 0.22 (97.8%) in post-intervention and follow-up, respectively in intervention village. Discussion: The adult density of An. stephensi was reduced significantly (97.8%) in intervention village. Breeding in underground tankas was completely checked in intervention village as compared to the control, where no such substantial reduction was observed. The awareness level of the community was also improved due to their involvement in the study.Conclusion: The study demonstrated that the small changes and interventions to reduce mosquitogenic conditions can be cost effective and long-lasting which may be helpful in control of malaria.

scholarly journals Addressing key gaps in implementation of mosquito larviciding to accelerate malaria vector control in southern Tanzania: results of a stakeholder engagement process in local district councils

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Salum A. Mapua ◽  
Marceline F. Finda ◽  
Ismail H. Nambunga ◽  
Betwel J. Msugupakulya ◽  
Kusirye Ukio ◽  
...  
Keyword(s):  
Malaria Control ◽  
Public Engagement ◽  
Indoor Residual Spraying ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Production Plant ◽  
Community Members ◽  
Key Informants ◽  
Larval Source Management ◽  
Source Management

Abstract Background Larval source management was historically one of the most effective malaria control methods but is now widely deprioritized in Africa, where insecticide-treated nets (ITNs) and indoor residual spraying (IRS) are preferred. However, in Tanzania, following initial successes in urban Dar-es-Salaam starting early-2000s, the government now encourages larviciding in both rural and urban councils nationwide to complement other efforts; and a biolarvicide production-plant has been established outside the commercial capital. This study investigated key obstacles and opportunities relevant to effective rollout of larviciding for malaria control, with a focus on the meso-endemic region of Morogoro, southern Tanzania. Methods Key-informants were interviewed to assess awareness and perceptions regarding larviciding among designated health officials (malaria focal persons, vector surveillance officers and ward health officers) in nine administrative councils (n = 27). Interviewer-administered questionnaires were used to assess awareness and perceptions of community members in selected areas regarding larviciding (n = 490). Thematic content analysis was done and descriptive statistics used to summarize the findings. Results A majority of malaria control officials had participated in larviciding at least once over the previous three years. A majority of community members had neutral perceptions towards positive aspects of larviciding, but overall support for larviciding was high, although several challenges were expressed, notably: (i) insufficient knowledge for identifying relevant aquatic habitats of malaria vectors and applying larvicides, (ii) inadequate monitoring of programme effectiveness, (iii) limited financing, and (iv) lack of personal protective equipment. Although the key-informants reported sensitizing local communities, most community members were still unaware of larviciding and its potential. Conclusions The larviciding programme was widely supported by both communities and malaria control officials, but there were gaps in technical knowledge, implementation and public engagement. To improve overall impact, it is important to: (i) intensify training efforts, particularly for identifying habitats of important vectors, (ii) adopt standard technical principles for applying larvicides or larval source management, (iii) improve financing for local implementation and (iv) improve public engagement to boost community awareness and participation. These lessons could also be valuable for other malaria endemic areas wishing to deploy larviciding for malaria control or elimination.

scholarly journals A Community-based Lifestyle Education Program Addressing Non-communicable Diseases in Low-literacy Areas of the South Pacific: A Pilot Control Cohort Study

2020 ◽  
Vol 7 (3) ◽  
pp. 5-10
Author(s):  
Lillian Kent ◽  
Pia Reierson ◽  
Darren Morton ◽  
Kesa Vasutoga ◽  
Paul Rankin
Keyword(s):  
Risk Factors ◽  
Blood Pressure ◽  
Chronic Disease ◽  
Group Process ◽  
Disease Risk ◽  
Density Lipoprotein ◽  
Control Group ◽  
Low Literacy ◽  
Intervention Village ◽  
Control Village

Lifestyle interventions can effectively reduce chronic disease risk factors. This study examined the effectiveness of an established lifestyle intervention contextualized for low-literacy communities in Fiji. Ninety-six adults from four villages, with waist circumference (WC) indicative of risk of chronic disease, were randomly selected to an intervention or control group. Process evaluation indicated one intervention and one control village fulfilled the study protocol. There were no differences between intervention and control for body mass index BMI (P = 0.696), WC (P = 0.662), total cholesterol (TC) (P = 0.386), and TC:high-density lipoprotein (HDL) ratio (P = 0.485). The intervention village achieved greater reductions than the control village at 30 and 90 days for systolic blood pressure (30 days: −11.1% vs. −2.5%, P = 0.006; 90 days: −14.5% vs. −6.7%, P = 0.019); pulse rate (30 days: −7.0% vs. −1.1%, P = 0.866; 90 days: −7.1% vs. 4.3%, P = 0.027), and HDL (30 days: −13.9% vs. 1.7%, P = 0.206; 90 days: −18.9% vs. 2.2%, P = 0.001); at 90 days only for diastolic blood pressure (−14.4% vs. −0.2%, P = 0.010); at 30 days only for low-density lipoprotein (−11.6% vs. 8.0%, P = 0.009); and fasting plasma glucose (−10.2% vs. 4.3%, P = 0.032). However, for triglycerides, the control achieved greater reductions than the intervention village at 30 days (35.4% vs. −12.3%, P = 0.008; marginal at 90 days 16.4% vs. −23.5%, P = 0.054). This study provides preliminary evidence of the feasibility and potential effectiveness of the intervention to lower several risk factors for chronic disease over 30 days in rural settings in Fiji and supports consideration of larger studies.

scholarly journals A Comparative Analysis of Determinants of Household Knowledge of Split and Grouped Mosquito Larval Source Management for Malaria Prevention and Control in Rural Malawi

2021 ◽  
Author(s):  
Dumisani Mfipa ◽  
Mphatso Kamndaya ◽  
Kingsley Lungu
Keyword(s):  
Malaria Prevention ◽  
Cross Sectional Study ◽  
Stagnant Water ◽  
Chi Square ◽  
Cross Sectional ◽  
Larval Source Management ◽  
Clean Environment ◽  
Chi Square Test ◽  
High Level ◽  
Source Management

Abstract BackgroundLimited studies have compared determinants of household knowledge of split and grouped mosquito larval source management (LSM) methods. Thus, we compared determinants of household knowledge of split and grouped mosquito LSM methods for malaria control in Malawi. MethodsA cross-sectional study was conducted among 479 households in Nthache, Mwanza district, Malawi. Household knowledge of mosquito LSM methods; draining stagnant water, larviciding, clean environment and clearing grass/bushes were assessed by using a validated structured household questionnaire administered to an adult household member. Chi-square test was used to compare the distribution of household knowledge of each of the split and grouped mosquito LSM methods. Multivariable logistic regression was used to examine factors associated with household knowledge of each of the split and grouped mosquito LSM methods. ResultsHousehold knowledge of draining stagnant water was lower than high-level knowledge of grouped mosquito LSM methods (32.9% versus 83.5%, p=0.000). Household knowledge of clearing grass/bushes was lower than high-level knowledge of grouped mosquito LSM methods (8.2% versus 77.7%, p=0.000). Household knowledge of clean environment was lower than high-level knowledge of grouped mosquito LSM methods (21.8% versus 63.8%, p=0.000). No significant differences were observed between knowledge of larviciding and high-level knowledge of grouped mosquito LSM methods (4.1% versus 5.8%, p=0.421). Respondents without education had 57% less the odds of having knowledge of draining stagnant water than those with primary education (AOR=0.43, 95% CI 0.26-0.69). Those from iron-roofed households and the widowed had three and more than four times the odds of having knowledge of larviciding than those from grass-thatched households and the married (AOR=3.03, 95% CI 1.26-7.29 and AOR=4.73, 95% CI 1.34-16.73), respectively. ConclusionsExcept for larviciding, household knowledge of grouped mosquito LSM methods was significantly higher than split methods. Policy for integrated vector management should address determinants of split mosquito LSM methods to improve household knowledge.

scholarly journals Influence of Splitting on Dissolution Properties of Metoprolol Tablets

2009 ◽  
Vol 9 (3) ◽  
pp. 245-249 ◽  
Author(s):  
Edina Vranić ◽  
Alija Uzunović
Keyword(s):  
Controlled Release ◽  
Extended Release ◽  
Release Formulation ◽  
Extended Release Formulation ◽  
Dissolution Properties ◽  
Tablet Formulations ◽  
Score Line ◽  
Adequate Design ◽  
Release Tablet

The objective of this work was to compare several profiles of dissolution data for metoprolol controlled release tablet formulations in order to identify possible changes in dissolution profiles of whole and scored tablets. Adequate design of score lines (on one or both sides) as well as the technology of preparation of tablet mixtures ensure forming a score line of adequate thickness, shape, size, curvature. According to the obtained results, this type of extended release formulation is eligible for splitting and use in therapy either as a whole or scored tablets.

scholarly journals Defining the larval habitat: abiotic and biotic parameters associated with Anopheles farauti productivity

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Kimberley McLaughlin ◽  
Thomas R. Burkot ◽  
Jance Oscar ◽  
Nigel W. Beebe ◽  
Tanya L. Russell
Keyword(s):  
Vector Control ◽  
Control Strategy ◽  
World Health ◽  
Effective Control ◽  
Biological Parameters ◽  
Insecticide Treated Nets ◽  
Larval Habitats ◽  
Anopheles Farauti ◽  
Larval Source Management ◽  
Source Management

Abstract Background In the Solomon Island, the dominant malaria vector, Anopheles farauti, is highly anthropophagic and increasingly exophilic and early biting. While long-lasting insecticide-treated nets remain effective against An. farauti, supplemental vector control strategies will be needed to achieve malaria elimination. Presently, the only World Health Organization recommended supplemental vector control strategy is larval source management (LSM). Effective targeted larval source management requires understanding the associations between abiotic, chemical and biological parameters of larval habitats with the presence or density of vector larvae. Methods Potential and actual An. farauti larval habitats were characterized for presence and density of larvae and associated abiotic, chemical and biological parameters. Results A third of all sampled potential habitats harboured An. farauti larvae with 80% of An. farauti positive habitats being in three habitat classifications (swamps/lagoons, transient pools and man-made holes). Large swamps were the most abundant positive habitats surveyed (43% of all An. farauti positive habitats). Habitats with An. farauti larvae were significantly associated with abiotic (pH, nitrate, ammonia and phosphate concentrations and elevated temperature) and biotic (predators) parameters. Conclusion Large swamps and lagoons are the largest and most abundant An. farauti habitats in the Solomon Islands. Positive habitats were more frequently associated with the presence of predators (vertebrates and invertebrates) and higher water temperatures. Cohabitation with predators is indicative of a complex habitat ecosystem and raises questions about the potential of biological control as an effective control strategy. Increased presence of An. farauti with higher water temperature suggests a potential explanation for the coastal distribution of this species which is not found inland at elevated altitudes where temperatures would be cooler.

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