Recent trends in global insecticide use for disease vector control and potential implications for resistance management.

Insecticides have played a major role in the prevention, control, and elimination of vector-borne diseases, but insecticide resistance threatens the efficacy of available vector control tools. A global survey was conducted to investigate vector control insecticide use from 2010 to 2019. Out of 140 countries selected as sample for the study, 87 countries responded. Also, data on ex-factory deliveries of insecticide-treated nets (ITNs) were analyzed. Insecticide operational use was highest for control of malaria, followed by dengue, leishmaniasis and Chagas disease. Vector control relied on few insecticide classes with pyrethroids the most used overall. Results indicated that IRS programs have been slow to react to detection of pyrethroid resistance, while proactive resistance management using insecticides with unrelated modes of action was generally weak. The intensive use of recently introduced insecticide products raised concern about product stewardship regarding the preservation of insecticide susceptibility in vector populations. Resistance management was weakest for control of dengue, leishmaniasis or Chagas disease. Therefore, it will be vital that vector control programs coordinate on insecticide procurement, planning, implementation, resistance monitoring, and capacity building. Moreover, increased consideration should be given to alternative vector control tools that prevent the development of insecticide resistance.

A retail audit of mosquito control products in Busia County, western Kenya.

BACKGROUND: Approximately 70% of Kenya's population is at risk for malaria. The core vector control methods in Kenya are insecticide-treated mosquito nets (ITNs) and indoor residual spraying, with supplementary larval source management. In 2015, 21% of ITNs were accessed through the private retail sector. Despite the private sector role in supplying mosquito control products (MCPs), there is little evidence on the availability, sales trends, and consumer preferences for MCPs other than ITNs. This study, a component of a larger research programme focused on evaluating a spatial repellent intervention class for mosquito-borne disease control, addressed this evidence gap on the role of the private sector in supplying MCPs. METHODS: A cross-sectional survey was deployed in a range of retail outlets in Busia County to characterize MCP availability, sales trends, and distribution channels. The questionnaire included 32 closed-ended and four open-ended questions with short answer responses. Descriptive analysis of frequency counts and percentages was carried out to glean insights about commercially available MCPs and the weighted average rank was used to determine consumer preferences for MCPs. Open-ended data was analysed thematically. RESULTS: Retail outlets that stocked MCPs commonly stocked mosquito coils (73.0%), topical repellents (38.1%), aerosol insecticide sprays (23.8%) and ITNs (14.3%). Overall, retailers reported the profits from selling MCPs were adequate and they overwhelmingly planned to continue stocking the products. Of respondents who stocked MCPs, 96.8% responded that sales increased during long rains and 36.5% that sales also surged during short rains. ITNs and baby-size nets were often delivered by the wholesaler. Retailers of aerosol sprays, mosquito coils, and topical repellents either collected stock from the wholesaler or products were delivered to them. Other commercially available MCPs included insecticide incense sticks, electric mosquito strikers, insecticide soaps, electrically heated insecticide mats, and electric insecticide emanators, indicating a well-established market. CONCLUSIONS: The wide range of MCPs in local retail outlets within the study area suggests the need and demand for mosquito control tools, in addition to ITNs, that are affordable, easy to use and effective. The presence of a wide range of MCPs, is a promising sign for the introduction of a spatial repellent intervention class of products that meets consumer needs and preferences.

Meeting Increased Demand for Mosquito Adulticides Containing the Active Ingredient Naled Following Hurricanes and Tropical Storms.

The occurrence of tropical storms and hurricanes is a certainty in the Atlantic Basin each year. Many of these never make landfall. Those that do can range in intensity from a weak tropical depression to a very destructive Category 5 hurricane. These storms often produce large amounts of rainfall and flooding, resulting in increases in the mosquito populations in the affected areas. In order to deal with this problem, aerial applications of insecticides over wide areas can provide relief to the impacted area, assisting in the recovery efforts. Meeting the demand for these sudden and large increases in the volume of the insecticide most commonly used in aerial applications requires great coordination, communication, and commitment. We describe the diverse entities involved in the manufacture, distribution, and use of the product and how this increase in need is recognized, managed, and satisfied in a compressed period of time.

Extensive usage of insecticide and changing crop rotation patterns: A South Dakota case study.

Driven by factors such as an increased reliance on genetically modified crops, government policies, and market forces, the crop mix in South Dakota and elsewhere in the United States has become less diverse and moved toward the production of corn and soybeans as the most predominant cash crops over the past two decades. Coinciding with a reduced complexity of crop rotation practices, the prevalence of mono-cropping has increased and crop chemical usage has changed as well. Overall, the reduced reliance on traditional crop rotation practices for mitigating pests corresponds with an increase in crop acres treated with insecticides, expressed as a proportion of total cropland acres, and referred to in the literature as the extensive usage of insecticides. In this paper, we identify how changing cropping patterns in South Dakota have affected the extensive usage of insecticides, an aspect often overlooked by producers and policy makers. Results indicate that increased corn production has contributed to an increase in the share of cropland acres treated with insecticides at the county level in eastern South Dakota.

Acetylcholinesterase inhibitor insecticides related acute poisoning, availability and sales: trends during the post-insecticide-ban period of Anuradhapura, Sri Lanka.

BACKGROUND: Acetylcholinesterase inhibitor insecticides (AChEIIs) were used extensively in the agrarian region of Anuradhapura for the past few decades. As a result, the region faced a heightened risk of toxicity. Carbaryl, carbofuran, chlorpyrifos, dimethoate, and fenthion were the five hazardous AChEIIs banned from Anuradhapura in 2014. Assessment of post-ban trends in acute poisoning will reveal the impact of the ban. Data on availability and sales of remaining AChEIIs will guide towards preventive measures against related toxicities. METHODS: Cross-sectional surveys were conducted at Anuradhapura district of Sri Lanka. Details related to acute AChEII poisoning were sorted from the Teaching Hospital Anuradhapura. Main insecticide vendors in Anuradhapura were surveyed to find information on availability and sales of AChEIIs. Chi-square for goodness of fit was performed for trends in acute poisoning and sales. RESULTS: Hospital admissions related to acute AChEII poisoning have declined from 554 in 2013 to 272 in 2017. Deaths related to acute AChEII poisoning have declined from 27 in 2013 to 13 in 2017. Sales of all five banned AChEIIs had reduced by 100%. Sales of the remaining AChEIIs were declining, except for acephate, phenthoate, and profenofos. However, one of the top selling, most frequently abused carbosulfan, had the highest risk of toxicity. Chi-square for goodness of fit showed a significance (P < 0.001) between the trends of hospital admissions for acute AChEII poisoning and the sales related to AChEIIs. CONCLUSIONS: Hospital admissions related to acute poisoning was declining along with the overall sales of remaining AChEIIs, during the post-AChEII ban period. Nevertheless, future vigilance is needed on the remaining AChEIIs to predict and prevent related toxicities.

Global trends in the production and use of DDT for control of malaria and other vector-borne diseases.

BACKGROUND: DDT was among the initial persistent organic pollutants listed under the Stockholm Convention and continues to be used for control of malaria and other vector-borne diseases in accordance with its provisions on acceptable purposes. Trends in the production and use of DDT were evaluated over the period 2001-2014. RESULTS: Available data on global production of DDT showed a 32% decline over the reporting period, from 5144 to 3491 metric tons of active ingredient p.a. Similarly, global use of DDT, for control of malaria and leishmaniasis, showed a 30% decline over the period 2001-2014, from 5388 metric tons p.a. to 3772 metric tons p.a. India has been by far the largest producer and user of DDT. In some countries, DDT is used in response to the development of resistance in malaria vectors against pyrethroid and carbamate insecticides. Some other countries have stopped using DDT, in compliance to the Convention, or in response to DDT resistance in malaria vectors. Progress has been made in establishing or amending national legal measures on DDT, with the majority of countries reportedly having measures in place that prohibit, or restrict, the production, import, export and use of DDT. Limitations in achieving the objectives of the Stockholm Convention with regard to DDT include major shortcomings in periodic reporting by Parties to the Stockholm Convention, and deficiencies in reporting to the DDT Register. CONCLUSION: Global production and global use of DDT have shown a modest decline since the adoption of the Stockholm Convention.

A Voucher System To Speed Review Could Promote A New Generation Of Insecticides To Fight Vector-Borne Diseases.

Many in the scientific community are concerned about the potential increase in prevalence of insect-borne diseases such as Chagas disease, Chikungunya, dengue fever, malaria, and Zika in the United States and around the world. Beyond vaccines and drugs to prevent and treat these diseases, a comprehensive approach to fighting these diseases should include control of disease-carrying vectors, such as mosquitoes. Vector-control methods, such as using insecticides to treat bed nets and spray the walls of homes, have prevented millions of deaths from malaria. However, mosquitoes are becoming resistant to insecticides, and no new class of insecticides for vector control has been introduced in decades. We recommend the creation of a new type of incentive for the development and commercialization of safe new insecticides: a Vector Expedited Review Voucher, to be awarded to a sponsor that introduces a novel insecticide for public health use. The voucher could be redeemed to expedite registration of a second, more profitable, product by the US Environmental Protection Agency.

[Treatment of scabies and Ascabiol(®) supply disruption: what about the pediatric population?]. / Traitement de la gale et rupture d'Ascabiol(®) : quid de la population pédiatrique ? Gale chez l'enfant et rupture d'Ascabiol(®)

Scabies is a disease in steady increase in Île-de-France region. Standard treatment, Ascabiol(®) (benzyl benzoate/sulfiram), is back-order for several months and its return remains uncertain. Facing this drug shortage, French Drug Agency (ANSM) has imported a drug from Germany, Antiscabiosum 10 % (benzyl benzoate), to treat patients having contraindications for other scabicides available in France (ivermectin, esdepallethrine). However, infants less than 1 year (<15 kg) and asthmatics infants have no alternative treatment. A multidisciplinary workgroup explored the various existing therapeutic alternatives in France and worldwide. From ANSM's recommendations and group's experience, a decision algorithm was proposed for treating patients. However, pediatric context implied the use of off-label drugs. Proposed treatments widely known by practitioners, prescriptions-types, dose, modalities of use and dispensation, and flyers to patients were realized to optimize treatment efficacy.

Ivermectin to reduce malaria transmission: a research agenda for a promising new tool for elimination.

BACKGROUND: The heterogeneity of malaria transmission makes widespread elimination a difficult goal to achieve. Most of the current vector control measures insufficiently target outdoor transmission. Also, insecticide resistance threatens to diminish the efficacy of the most prevalent measures, indoor residual spray and insecticide treated nets. Innovative approaches are needed. The use of endectocides, such as ivermectin, could be an important new addition to the toolbox of anti-malarial measures. Ivermectin effectively targets outdoor transmission, has a novel mechanism of action that could circumvent resistance and might be distributed over the channels already in place for the control of onchocerciasis and lymphatic filariasis. METHODS: The previous works involving ivermectin and Anopheles vectors are reviewed and summarized. A review of ivermectin's safety profile is also provided. Finally three definitive clinical trials are described in detail and proposed as the evidence needed for implementation. Several smaller and specific supportive studies are also proposed. CONCLUSIONS: The use of ivermectin solves many challenges identified for future vector control strategies. It is an effective and safe endectocide that was approved for human use more than 25 years ago. Recent studies suggest it might become an effective and complementary strategy in malaria elimination and eradication efforts; however, intensive research will be needed to make this a reality.

Different delivery mechanisms for insecticide-treated nets in rural Burkina Faso: a provider's perspective.

BACKGROUND: Insecticide-treated nets (ITNs) have been confirmed to be a very effective tool in malaria control. Two different delivery strategies for roll-out of ITN programmes have been the focus of debate in the last years: free distribution and distribution through commercial marketing systems. They are now seen as complementary rather than opponent. Acceptance of these programmes by the community and involved providers is an important aspect influencing their sustainability. This paper looks at how providers perceived, understood and accepted two interventions involving two different delivery strategies (subsidized sales supported by social marketing and free distribution to pregnant women attending antenatal care services). METHODS: The interventions took place in one province of north-western Burkina Faso in 2006 in the frame of a large randomized controlled ITN intervention study. For this descriptive qualitative study data were collected through focus group discussions and individual interviews. A total of four focus group discussions and eleven individual interviews have been conducted with the providers of the study interventions. RESULTS: The free distribution intervention was well accepted and perceived as running well. The health care staff had a positive and beneficial view of the intervention and did not feel overwhelmed by the additional workload. The social marketing intervention was also seen as positive by the rural shopkeepers. However, working in market economy, shopkeepers feared the risk of unsold ITNs, due to the low demand and capacity to pay for the product in the community. CONCLUSION: The combination of ITN free distribution and social marketing was in general well accepted by the different providers. However, low purchasing power of clients and the resulting financial insecurities of shopkeepers remain a challenge to ITN social marketing in rural SSA.

How many mosquito nets are needed to achieve universal coverage? Recommendations for the quantification and allocation of long-lasting insecticidal nets for mass campaigns.

BACKGROUND: Long-lasting insecticidal nets are an effective tool for malaria prevention, and "universal coverage" with such nets is increasingly the goal of national malaria control programmes. However, national level campaigns in several countries have run out of nets in the course of distribution, indicating a problem in the method used to estimate the quantity needed. PRESENTATION OF HYPOTHESIS: A major reason for the shortfall in estimation is the mismatch between the quantification factor used to plan procurement and the allocation algorithm used at community level, in particular the effect of needing to add an additional net to households with an odd number of inhabitants. To solve this problem a revised quantification factor is suggested. TESTING HYPOTHESIS: Based on data from a broad range of household surveys across Africa, the effect of odd-numbered households on numbers of nets distributed is estimated via two frequently used allocation methods. The impact of these algorithms on the proportion of households reaching a person to net ratio of 2:1, a frequently used marker of universal coverage is then calculated. IMPLICATIONS: In order to avoid stock-outs of nets during national coverage campaigns, it is recommended to use a quantification factor of 1.78 people per net, with an additional allocation factor suggested to account for other common problems at the community level resulting in a final recommended ratio of 1.60 people per net. It is also recommend that community level allocation procedures be aligned with procurement estimates to reduce shortages of nets during campaign distributions. These analyses should enable programme managers to make evidence-based decisions and support a more efficient and effective use of LLIN distribution campaign resources.

[The PAHO Strategic Fund: a mechanism to facilitate access to medicines]. / Fundo Estratégico da Organização Pan-Americana da Saúde: mecanismo facilitador para melhorar o acesso aos medicamentos.

OBJECTIVE: To describe the medicine procurement activities of the PAHO Strategic Fund. METHOD: This is a retrospective study covering the period from 2004 to 2007, based on a bibliographic and document survey of Pan American Health Organization (PAHO) archives in the United States, El Salvador, Guatemala, Honduras, and Brazil. The volume of resources and the types of drugs procured by the fund were determined for the years 2004, 2005, and 2006 and for the period of January to September 2007. RESULTS: The survey revealed a well-structured fund handling increasing resources, from US$ 3,475,043.00 in 2004 to US$ 19,646,634.00 in 2007 (January to September). The participation of antiretroviral drugs in this expenditure has grown from less than 8% of the total in 2004 to 57.89% in 2007. Still, in 2007, 66.63% of the financial resources managed by the Strategic Fund were allocated to the purchase of antiretroviral drugs for nine countries (Brazil, Guatemala, El Salvador, Ecuador, Honduras, Haiti, Belize, Nicaragua, and Bolivia) out of a total of 17 participating countries. Brazil was the country using the most resources through the Strategic Fund, accounting for 63% of the expenditure for the purchase of strategic supplies between January and September 2007. CONCLUSION: The proposal to unify the purchase of medications for all participating countries to improve pricing and purchasing management will result in large-scale savings. The Strategic Fund can contribute to increasing access to medicines and improving the management of the public health care system in Latin America.

Fundo Estratégico da Organização Pan-Americana da Saúde: mecanismo facilitador para melhorar o acesso aos medicamentos / The PAHO Strategic Fund: a mechanism to facilitate access to medicines

OBJETIVO: Descrever o funcionamento do Fundo Estratégico para medicamentos da Organização Pan-Americana da Saúde (OPAS). MÉTODO: Estudo retrospectivo, com recorte temporal de 2004 a 2007, fundamentado em levantamento bibliográfico e documental em arquivos dos escritórios da OPAS nos Estados Unidos, El Salvador, Guatemala, Honduras e Brasil. Foram levantados o volume total de recursos e os tipos de medicamentos movimentados por meio do Fundo Estratégico nos anos de 2004, 2005, 2006 e nos meses de janeiro a setembro de 2007. RESULTADOS: O levantamento revelou um fundo bem estruturado que movimentou recursos crescentes, de US$ 3 475 043,00 em 2004 a US$ 19 646 634,00 em 2007 (de janeiro a setembro). Houve um crescimento na participação dos antirretrovirais nesse dispêndio, de pouco menos de 8 por cento do total em 2004 a 57,89 por cento em 2007. Ainda em 2007, 66,63 por cento da movimentação financeira do Fundo Estratégico foram destinados à compra de antirretrovirais para nove países (Brasil, Guatemala, El Salvador, Equador, Honduras, Haiti, Belize, Nicarágua e Bolívia) de um total de 17 países participantes. O país que mais movimentou recursos financeiros por meio do Fundo Estratégico foi o Brasil, com 63 por cento dos gastos para compra de insumos estratégicos no período de janeiro a setembro de 2007. CONCLUSÃO: A proposta de unificar as compras de medicamentos de todos os países participantes para melhor negociação de preços e administração das compras permitirá economias de escala. O Fundo Estratégico pode contribuir para ampliar o acesso aos medicamentos e melhorar a gestão do sistema público de saúde da América Latina.

OBJECTIVE: To describe the medicine procurement activities of the PAHO Strategic Fund. METHOD: This is a retrospective study covering the period from 2004 to 2007, based on a bibliographic and document survey of Pan American Health Organization (PAHO) archives in the United States, El Salvador, Guatemala, Honduras, and Brazil. The volume of resources and the types of drugs procured by the fund were determined for the years 2004, 2005, and 2006 and for the period of January to September 2007. RESULTS: The survey revealed a well-structured fund handling increasing resources, from US$ 3 475 043.00 in 2004 to US$ 19 646 634.00 in 2007 (January to September). The participation of antiretroviral drugs in this expenditure has grown from less than 8 percent of the total in 2004 to 57.89 percent in 2007. Still, in 2007, 66.63 percent of the financial resources managed by the Strategic Fund were allocated to the purchase of antiretroviral drugs for nine countries (Brazil, Guatemala, El Salvador, Ecuador, Honduras, Haiti, Belize, Nicaragua, and Bolivia) out of a total of 17 participating countries. Brazil was the country using the most resources through the Strategic Fund, accounting for 63 percent of the expenditure for the purchase of strategic supplies between January and September 2007. CONCLUSION: The proposal to unify the purchase of medications for all participating countries to improve pricing and purchasing management will result in large-scale savings. The Strategic Fund can contribute to increasing access to medicines and improving the management of the public health care system in Latin America.

Assessment of distribution, knowledge and utilization of insecticide treated nets in selected malaria prone areas of Ethiopia

Background: Insecticide Treated Nets (ITNs) reduce malaria related mortality and morbidity significantly. Taking this into account; the Ethiopian Federal Ministry of Health has been distributing ITNs to malaria prone areas of the country through the support of the Global Fund. Objective: To study distributional coverage and assess the knowledge and utilization of insecticide treated nets in Ethiopia. Methods: A cross-sectional study was conducted in 17 malarious districts targeted for the first phase free distribution of long lasting insecticide treats nets (LLITNs) by the Ministry of Health in 9 administrative regions from October 2005 to September 2006. Region specific list of malarious districts where MOH distributed ITNs was used as the sampling frame for stratified random sampling of districts. One kebele (sub district) was selected from each of the selected districts using simple random sampling; and 15of the total households in the selected kebeles were selected using systematic random sampling. Upon obtaining informed consent from the household head or the oldest person in the household the questionnaire was administered and information was recorded. Data were double entered using EpiData version 3 and analyzed using SPSS version 12. Results: A total of 3131 households were visited; and 51.6of the respondents were males. The overall ITN distribution and utilization were 97.6and 81.6; respectively. The majority of households (53.2) owned a single net per family; highest in Dire Dawa (93.7) and lowest in Afar (17.6). Thirty eight percent of the respondents owned two nets per household. Most of the respondents (91.1) cited that ITNs are useful to control malaria either through prevention of mosquito bites (60) or prevention of the disease (39). Conclusion: ITN distribution; utilization; knowledge of users and its acceptability were good considering the recent introduction of the products. However; the person net ratio gap should be narrowed and emphasis needs to be given to vulnerable groups

Availability of insecticidal molecules to control Aedes albopictus (Skuse).

Following the implementation of the Directive 98/8/CE a few changes in the availability of insecticidal molecules to control Ae. albopictus have been outlined. Available products for larvicidal treatments will predominantly be based upon two growth regulators (diflubenzuron and pyriproxyfen). For the control of the adult forms there will mostly be active ingredients belonging to the pyrethroid group. Importance of surveillance for the onset of tolerance or resistance phenomena.

Quick wins versus sustainability: options for the upscaling of insecticide-treated nets.

A review of the main elements determining strategic choices for the large-scale distribution of insecticide-treated nets (ITNs) clearly shows the need for multiple strategies. Mass distributions of free nets provide a unique opportunity to achieve quickly high coverage rates. However, there is also a need for additional approaches to 1) provide continuous provision of ITNs for newly pregnant women and their babies and 2) provide protection for the rest of the population. Targeted subsidies will continue to be an important tool to achieve the first objective, either through direct distribution of ITNs or through vouchers. To achieve objective 2, a strong and competitive commercial sector for ITNs seems to be a good option. It is clear that "one size doesn't fit all," and more experience needs to be gathered and shared. With planning and good promotion campaigns, these strategies can co-exist and re-enforce each other.