Wash resistance and bio-efficacy of Olyset~? Plus, a long-lasting insecticide-treated mosquito net with synergist against malaria vector, Anopheles stephensi

Objective: To determine the wash resistance of Olyset~? Plus using World Health Organization Pesticide Evaluation Scheme standard washing procedure and to assess the value of knock down and mortality rates of Anopheles stephensi at different regimens of long lasting insecticide treated nets washings.Methods: The study was conducted at the Bioassay Laboratory of Culicidae Insectary,School of Public Health, Tehran University of Medical Sciences, Iran. The net was made of polyester impregnated with permethrin and piperonyl butoxide at a ratio of 2:1. The washing resistance was assessed using Le Chat?soap and a shaker incubator set at a speed of 155 r/min, 30℃ for 10 min. The cone bioassay test was carried out according to World Health Organization recommended guideline with tolerant field strain of female Anopheles stephensi to pyrethroids.Results: The knockdown and mortality rates of female mosquitoes exposed to Olyset~? Plus from un-washed nets to 2 washings were 79.7% and 88.8% respectively. Mortality was dropped to zero while active ingredient estimated 0.532 mg/100 cm^2 to 0.481 mg/100 cm^2 after 15 washings. A positive correlation was seen between residues of permethrin on nets, knockdown rate and mortality rate of female Anopheles stephensi exposed to different regimes of washed Olyset~? Plus(r = 0.954, P = 0.001).Conclusions: It is recommended that a preliminary survey conducted on resistance level of Anopheles vectors before the distribution of Olyset~? Plus in malaria endemic communities.

Field evaluation of KO-Tab 1-2-3^®long lasting insecticidal net performance in Milenge, Zambia

Insecticide treated nets (ITNs) play a pivotal role in the prevention and control of malaria. Conversely, inadequate levels of ownership, utilization and durability invariably compromise their efficacy. Operational performance of the KO-Tab 1-2-3 Long Lasting Insecticidal Nets (LLINs) was assessed using the World Health Organization (WHO) standard entomological and epidemiological procedures, and a pretested structured questionnaire. The median knock down time for Anopheles funestus s.l. was 30 minutes (95% CI 26.3 - 34.0). Post exposure mean mortality rates were 34% at one hour and 80.0% at 24 hours (OR = 0.13, P = 0.00002). Children between the ages of 1 - 4 years old exhibited higher false positives as compared to the 5 - 15 years age groups (OR = 0.10, P = 0.0006). Parasite prevalence varied between rapid diagnostic tests (RDTs) (40.4%) and microscopy (31.3%) (OR = 0.67, P = 0.2825) with 9.2% discordant RDT false positives. All malaria positive children were Plasmodium falciparum mono-infections. Hospital admissions reduced by 28% between 2005 and 2008, with case fatality rates reducing by 19% between 2006 and2007 inchildren under five years. No marked heterogeneity between LLINs ownership (66%) and utilization (48.3%) was observed (OR = 0.49, P = 0.0978). There was complete (100%) community level knowledge of KO-Tab 1-2-3 LLINs. The study provides evidence of potential of KO-Tab 1-2-3 LLINs for operational scale distribution, and substantiates the need for further longitudinal studies to monitor their insecticidal and physical durability.

Situational Analysis of Malaria Control Following the 2021 Distribution of Long Lasting Insecticide-Treated Bed Nets in the Tiko Health District, South West Region, Cameroon

Malaria is still a major public health concern in Cameroon as more than 20 million people are at risk of the disease. Despite the government’s effort to scale up the distribution of long lasting insecticide-treated bed nets (LLINs), full ownership and optimal use is still limited. In 2021, over a million LLINs were made available for distribution in the South West Region. However, the current situation of malaria has not yet been ascertained following the 2021 mass distribution campaign (MDC). Therefore, the aim of this study was to determine LLIN ownership, coverage, usage and the prevalence of malaria following the 2021 MDC in the Tiko Health District (THD), South West Region of Cameroon. A cross-sectional study was carried from May 1 to 27, 2022 in which a multi-stage sampling technique was used to enroll eligible participants. Data were collected from household heads using questionnaires and capillary blood samples collected from consented household members were used to test for malaria. Data were analyzed using SPSS version 25 at 0.05 significance level. From the 150 households surveyed, 96 (64.0%) owned a mosquito net before the recent MDC. There was an overall significant increase (p p = 0.644) in LLINs ownership between areas where door-to-door (79.5%) and fixed “Hit and Run” (75.8%) strategies were used in the distribution of LLINs in THD. The prevalence of malaria was 10.2%. The regular use of LLINs was significantly associated (p = 0.007) with low malaria prevalence. The 2021 MDC had an impact on malaria prevalence in those who properly used them.

Assessment of the Willingness to Buy and the Use of Insecticide Treated Nets (ITN) among Caregivers of Under-Five Children Attending Immunization Clinics in a Private Tertiary Hospital in Plateau State, Nigeria

Introduction: Malaria control becomes effective if countries adopt the World Health Organization & Global Malaria Programme (WHO/GMP) recommendation with includes diagnosis of malaria cases and treatment with effective medicines, distribution of insecticide-treated nets (ITNs) and indoor residual spraying (IRS). Ownership and utilization of mosquito nets for malaria prevention is still sub-optimal with only 62% ownership of at least one mosquito net and only 37% of children using the nets. This seeks to investigate the willingness to buy and the use ITN use among caregivers of under five children attending immunization clinic in Bingham University Teaching Hospital. Methodology: A descriptive cross sectional study design carried out among 242 caregivers of all ages and sex of under-five children attending immunization clinic at Bingham University Teaching Hospital (BHUTH) in Jos North Local Government Area of Plateau State, Nigeria. A Simple Random Sampling technique was used to select respondents. Findings: Two hundred and sixteen 216 (89.3%) of the children use ITNs, majority of the children 190 (78.5%) slept under ITN the night before the interview, 226 (93.4%) owned ITNs, 156 (64.5%) got the ITNs for free while 60 (24.8%) paid for it and majority 172 (71.1%) of the children use ITN every night. Tertiary education, having much younger children (less than 3 years) and perception as a means of malaria prevention were associated with higher use of ITNs. Majority 220 (90.9%) the caregivers were willing to buy ITN and also recommend ITN to others. Caregivers who were traders and civil servants were willing to buy ITN than farmers, tertiary education, having children 1 - 3 months old, and owning 3 or more ITNs was associated with willingness to buy ITNs. Conclusion: About 90% of the children of caregivers use ITNs and over three quarters slept under ITN the night before the interview and majority use it every night. Majority the caregivers were willing to buy ITN and also recommend ITN to others. The government and health care workers should continue to encourage and enlighten caregivers to keep using ITNs for their children and sustain mass free distribution of ITNs to improve ownership and utilization of ITNs.

Improving the Use of Insecticide-Treated Nets among Children under Five Years Old in Benin, West Africa

Background: In Benin, malaria represents the first cause of consultation and hospitalization (48% for children under 5 years old) in health units. It also accounts for 23.1% of deaths recorded in health facilities (MoH, 2019). Between the two main components of vector control adopted by Benin government, the mass distribution campaigns of Insecticide-Treated Nets (ITNs) remained the only proven cost-effective way to rapidly achieve high and equitable coverage (WHO, 2017). After the fourth mass distribution campaign conducted in 2017, the Demographic and Health Survey (DHS) data indicated that the percentage of children who slept under an ITN has increased from 20% in 2006 to 70% in 2011-2012 and to 76% in 2017-2018 while the incidence of malaria (tested positive) is increasing rapidly among children under 5 years old, growing from 36.5% in 2009 to 28.8% in 2012 and then to 51.4% in 2019. This study aims to understand this contrast by identifying the origin of the increase in ITN use over time among children under five years old and the factors which determine this use. Methods: Data from the Demographic and Health Survey (DHS) conducted in Benin respectively in 2006 and in 20018 were used during the analysis, which covered 13,445 children under five years old from 2006 DHS and 12,255 children from 2017-2018 DHS. Firstly, the data were analyzed using decomposition method to highlight the origin of the increase of ITN use over time among children under five years old. Secondly, the chi-square test analysis estimated the association between ITN use and some characteristics (wealth index, maternal or caregiver education level and child age). Finally, the logistic regression model was used to identify the main factors, which influence the net use over the study period. Results: This study shows that the improvement of basic conditions is the main origin of behavior change in the use of ITNs among children under five years old. This improvement of the basic conditions consists of making ITNs available in households and informing household members about the benefits of ITN use. So, the free ITN distribution campaigns, routine distribution, awareness campaigns about the benefits of ITN use are the strategies, which increase the household capacities and knowledge, allowing household members to make their children sleep under net. The analysis also shows that region of residence, wealth index of household, household size, religion, and child age continue to determine the ITN use among children under age 5 years old and MNCP will integrate the factors in malaria prevention strategies in order to achieve universal use of ITNs. Conclusions: Although, sleeping under ITN behavior has indeed spread among children under 5 years old, policymakers and other stakeholders should design strategies to maintain and improve the current level of ITN use to reach the collective protection threshold (80% according to WHO). Therefore, to address the challenges of universal use of ITN, the study recommends expanding the routine distribution system to private sector health centers;discussing issues related to health service utilization (particularly ITN use) within a consultation framework at the communal level. In addition, collecting qualitative and quantitative data in the Oueme region will allow better understanding of all aspects of the ITN use gap among children under 5 years.

Socio-cultural factors influencing insecticide treated bed net utilization in a malaria endemic city in north-central Nigeria

Objective:To ascertain the socio-cultural factors influencing the rate of utilization of insecticide treated bed nets(ITNs) in a malaria endemic city of Makurdi,north central Nigeria. Methods:The study was cross-sectional in nature using systematic sampling method to identify households.Both quantitative and qualitative data was generated from adult women using structured and semi structured questionnaires,and focused group discussions(FGDs) to obtain information on rate and patterns of utilization of ITNs.Information such as age,educational level, marital status,awareness or otherwise of the existence of malaria,and factors influencing rate of ownership and utilization of ITNs were obtained.FGDs were used to obtain qualitative information on rate of utilization of ITNs not captured in the questionnaires.Data obtained was analysed using Epi Info 6 statistical software.Results:Among the respondents interviewed,97.0% (2 013/2 075) were aware of existence of malaria and 87.0% of these(1 751/2 013) would associate it with mosquitoes.The rate of ownership of any bed net,ITNs and untreated bed nets(UTNs) was 25.1% ,17.0% and 8.3% ,respectively.Utilization of ITNs among children was 30.0% (112/373) and UTNs 12.9% (48/373).Positive contributors to ITNs utilization were literacy,enhanced economy, experience of marriage,and being gainfully employed(P【0.05);while negative contributors were ignorance,poverty and some cultural beliefs and values.Conclusions:A more synchronized advocacy should be carried out on the potential benefits of ITNs utilization and sustained.Also ITNs should be made available to the people of the community at minimal or no cost.

Factors Affecting Utilisation of Insecticide Treated Net among Household with Children Less than Five Years in Hodan District, Mogadishu, Somalia

Malaria is hyper-endemic in Somalia and remains one of the leading causes of morbidity and mortality, especially vulnerable groups such as old people, pregnant women, and children under five years. The prevalence of the disease is the highest along the rivers, settlements in southern Somalia, with artificial water reservoirs, where there is a year-round transmission. About 80% of malaria cases in Somalia occur in the Shebelle and Juba river basins. Outside of the malaria-endemic areas, it is estimated that 87% of Somalia is at risk of being exposed to malaria epidemics. According to a recent KAP (knowledge, attitude, and practices) survey, less than 10% of the households have Insecticide-treated mosquito net. This cross-sectional study was conducted to describe the factors affecting utilization of Insecticide-treated net among households with children under 5 years in Hodan district. The study was all adult households (more than 18 yrs.) with five years. A total of 50 respondents were interviewed during the period of data collection. A structured questionnaire dealing with socio-demographic characteristics, household’s knowledge about the Insecticide-treated net and availability and ownership and uses of Insecticide-treated net were used as data collection instrument. Results were presented in frequency tables and graphics. The majority of respondents indicated that 30 out of 50 (60%) have Insecticide-treated mosquito net while 20 out of 50 (40%) do not have it. The main reason for those who do not have Insecticide-treated mosquito net they did not able to afford it. Knowledge about malaria and Insecticide-treated mosquito net importance, the majority of respondents (92%) believe that there is a great benefit to use Insecticide-treated mosquito net for a reason to protect them mosquito bites. 20 (40%) were primary education and they didn’t know the causes of malaria (38 out of 50, 76%). The households of the Hodan district need special attention to the utilization of Insecticide-treated mosquito net. Free provision of Insecticide-treated net awareness creation on the utilization of Insecticide-treated mosquito nets and participated in an income generates supremely important activities. This study demonstrated a wide gap between knowledge, Insecticide-treated mosquito net ownership, and Utilization among the household with children less than 5 years. Therefore, the suggested recommendations arising from this study are for effective case management and control efforts of malaria. One of the strongest weapons in the fight against malaria is the use of insecticide-treated mosquito net while sleeping.

Knowledge &Utilization of Long Lasting Impregnated Nets among Housewives in Al Moneera City and Al Koozi Villages, Hodieda Governorate, Republic of Yemen 2007

Malaria is considered as one of the main health problem in the Republic of Yemen. In February 2006 National Malaria Control Program started freely distribution of Long Lasting Impregnated Nets (LLINs) for vulnerable groups to malaria infection (pregnant women and children under 5 years). After one year of distribution, there is a need to measure the use rate among vulnerable groups and explore factors affecting their use. The aim of the study was to investigate the use rate of long lasting impregnated nets among children under five years and pregnant women in Al Moneera city and Al Koozi villages of Hodieda governorate. Methodology: Cross section study with multistage sample, Random selection of one urban and one rural locality. 768 housewives were interviewed, proportionally allocated sample according to the number of vulnerable groups in each locality. Systematic random sample to select households. Results: The use rate of LLINs for vulnerable groups was 74.3% CI (71.2 - 77.4). There was no statistically significant association between the use of LLINs and residence, also with ages of housewives, occupation, type of house, but there is strong statistically significant association between use of LLINs and having correct information about how to use and to take care of them P value < 0.001, also with educational status of housewives;P value 0.03 and educational status of fathers;P value 0.01. (84%) have correct information about how to use and take care of LLINs and the main source of information was health workers who distributed them. Only 13.4% realized pregnant women as a vulnerable group to malaria infection while about 77.9% realized children as a vulnerable group to malaria infection. The main reason of LLINs use (84.8%) was protection from nuisance of insects. Conclusion and recommendations: There is shortage in the information about the protective effect of LLINs from malaria infection and the main reason of using them is protection from nuisance of insects. There is a need to increase health awareness about the role of LLINs in malaria prevention.

Bioefcacy and durability of Olyset® Plus, a permethrin and piperonyl butoxide-treated insecticidal net in a 3-year long trial in Kenya

Background:Long-lasting insecticide nets(LLINs)are a core malaria intervention.LLINs should retain efficacy against mosquito vectors for a minimum of three years.Efficacy and durability of Olyset®Plus,a permethrin and piperonyl butoxide(PBO)treated LLIN,was evaluated versus permethrin treated Olyset®Net.In the absence of WHO guidelines of how to evaluate PBO nets,and considering the manufacturer’s product claim,Olyset®Plus was evaluated as a pyrethroid LLIN.Methods:This was a household randomized controlled trial in a malaria endemic rice cultivation zone of Kirinyaga County,Kenya between 2014 and 2017.Cone bioassays and tunnel tests were done against Anopheles gambiae Kisumu.The chemical content,fabric integrity and LLIN survivorship were monitored.Comparisons between nets were tested for signifcance using the Chi-square test.Exact binomial distribution with 95%confdence intervals(95%CI)was used for percentages.The WHO efcacy criteria used were≥95%knockdown and/or≥80%mortality rate in cone bioassays and≥80%mortality and/or≥90%blood-feeding inhibition in tunnel tests.Results:At 36 months,Olyset®Plus lost 52%permethrin and 87%PBO content;Olyset®Net lost 24%permethrin.Over 80%of Olyset®Plus and Olyset®Net passed the WHO efcacy criteria for LLINs up to 18 and 12 months,respec‑tively.At month 36,91.2%Olyset®Plus and 86.4%Olyset®Net survived,while 72%and 63%developed at least one hole.The proportionate Hole Index(pHI)values representing nets in good,serviceable and torn condition were 49.6%,27.1%and 23.2%,respectively for Olyset®Plus,and 44.9%,32.8%and 22.2%,respectively for Olyset®Net but were not signifcantly diferent.Conclusions:Olyset®Plus retained efcacy above or close to the WHO efcacy criteria for about 2 years than Olyset®Net(1–1.5 years).Both nets did not meet the 3-year WHO efcacy criteria,and showed little attrition,comparable physical durability and survivorship,with 50%of Olyset®Plus having good and serviceable condition after 3 years.Better community education on appropriate use and upkeep of LLINs is essential to ensure efectiveness of LLIN based malaria interventions.

湖北省疟疾高发区媒介按蚊对杀虫剂敏感性的监测

[目的 ]了解采取不同灭蚊措施后 ,嗜人按蚊和中华按蚊对溴氰菊酯和 DDT的敏感性。 [方法 ]采用WHO成蚊滤纸接触法 ,观察蚊虫死亡率。 [结果 ]溴氰菊酯浸帐灭蚊 1年、3年和 DDT滞留喷洒灭蚊 3年的地区 ,嗜人按蚊对溴氰菊酯区分剂量死亡率分别为 83.8% ,83.7%和 84.7% ,为初步抗性群体 ,L T5 0 分别为 8.6 9,7.48和9.87min;中华按蚊对溴氰菊酯区分剂量死亡率分别为 76 .5 % ,5 7.0 %和 79.0 % ,为抗性群体 ,L T5 0 分别为 12 .0 ,15 .4和 11.2 m in;DDT喷洒地区嗜人按蚊对 DDT区分剂量死亡率为 95 .8% ,为初步抗性群体 ,L C5 0 为 0 .73% ;中华按蚊对 DDT区分剂量死亡率为 44 % ,为高抗群体 ,L C5 0 >4%。[结论 ]大量地在稻田使用杀虫剂 ,导致中华按蚊对溴氰菊酯和 DDT已产生抗药性 ,尚未发现嗜人按蚊产生明显抗药性。

标准洗涤法对长效蚊帐药效影响观察

目的观察经不同洗涤次数的长效蚊帐对蚊虫毒效的影响。方法长效蚊帐按WHO标准洗涤程序洗涤不同次数后,分别按强迫接触法、通道法进行药效测定。结果蚊帐在洗涤10、20次时,强迫接触法测试结果显示对中华按蚊击倒率下降率分别为37.5%、78.9%,通道法测试结果显示对中华按蚊阻碍吸血率下降率分别为19.7%、35.0%;上述2种方法测试结果显示蚊帐在洗涤10次时,中华按蚊的死亡率分别为62.5%、100%,与洗涤0次的蚊帐无显著差异(P>0.05),而在洗涤20次时,死亡率分别为15.0%、65.5%,死亡率已明显下降(P<0.05)。结论采用长效蚊帐应用于现场防治蚊虫时,在洗涤20次后,应更换蚊帐或重新浸泡药物后使用。

江苏省恶性疟防治研究

为了解江苏省恶性疟的流行特点和媒介传疟作用，制定有效的防治对策以尽快控制和消灭恶性疟，我们通过多年大量的现场流行病学调查和实验研究，证实嗜人按蚊是江苏省传播恶性疟的主要媒介。根据调查和研究结果，在全省恶性疟流行区采取了大范围持续的室内滞留喷洒灭蚊，和药物浸泡蚊帐巩固灭蚊，同时抓好传染源和易感人群的综合防治措施，结果在较短时间内控制了恶性疟的流行，并大幅度降低了间日疟发病率。经多年疟疾监测证实，已连续８年未发生当地感染的恶性疟病例，达到基本消灭恶性疟的标准，取得了显著的防治效果。

河南省淮滨县实施全球基金疟疾项目效果的评价

[目的]评价河南省淮滨县2003～2005年实施全球基金疟疾项目期间的疟疾疫情、防治措施及防治效果。[方法]收集淮滨县2003～2005年疟疾流行、防治措施、防治效果及媒介监测资料,分析流行情况,评价防治措施及效果。[结果]2003～2005年淮滨县共报告疟疾病例1765例,平均年发病率为8.93/万。2004年和2005年疟疾发病分别比上年下降53.58%和72.04%。建立发热病人镜检站18个,血检发热病人39070人,发现650例阳性病人。捕获中华按蚊4744只,未发现嗜人按蚊,疟疾暴发发点氟氯氰菊酯药物浸泡蚊帐340顶。氯、伯喹治疗现症病人1765人,休止期服药7571人,流行季节预防服药2471人。培训专业技术116人次,疟防宣传6259份,督导检查108次。居民和中小学生疟防知识知晓率由2003年的14.36%和9.36%提高到2004年的54.21%和47.36%。2005年144例疟疾病人平均确诊时间(2.82±2.89d)显著低于河南省的平均确诊时间(6.64±10.49d)(单样本t检验,t=-15.844,P=0.000)。[结论]在全球基金疟疾项目的支持下,河南省淮滨县疟防工作成绩显著,以项目管理促进疟防的方式值得推广。

Assessment of household ownership of bed nets in areas with and without artemisinin resistance containment measures in Myanmar

Background:Myanmar lies in the Greater Mekong Subregion where there is artemisinin-resistant Plasmodium falciparum malaria.As the artemisinin compound is the pillar of effective antimalarial therapies,containing the spread of artemisinin resistance is a national and global priority.The use of insecticide-treated bed nets/long-lasting insecticidal nets(ITNs/LLINs)is the key intervention for ensuring the reduction of malaria transmission and the spread of resistant strains,and for eventually eliminating malaria.This study aimed at assessing household ownership of,access to,and utilization of bed nets in areas of Myanmar with and without artemisinin resistance containment measures.Methods:Secondary data from a nationwide community-based malaria survey conducted by the National Malaria Control Program in 2014 were analyzed.Based on evidence of artemisinin resistance,Myanmar was divided into tiers 1,2,and 3:townships in tiers 1 and 2 were aggregated as the Myanmar Artemisinin Resistance Containment(MARC)areas and were compared with tier 3 townships,which were defined as non-MARC areas.The chi-square test was used to compare groups,and the level of significance was set at P≤0.05.Results:Of the 6328 households assessed,97.2%in both MARC and non-MARC areas had at least one bed net(any type),but only 63%of households had ITNs/LLINs.Only 44%of households in MARC areas and 24%in non-MARC areas had adequate numbers of ITNs/LLINs(one ITN/LLIN per two persons,P<0.001).Nearly 44%of household members had access to ITNs/LLINs.Regarding the utilization of ITNs/LLINs,45%of household members used them in MARC areas and 36%used them in non-MARC areas(P<0.001,desired target=100%).Utilization of ITNs/LLINs among children aged below five years and pregnant women(high malaria risk groups)was low,at 44%and 42%,respectively.Conclusions:This study highlights the nationwide shortfalls in the ownership of,access to,and utilization of ITNs/LLINs in Myanmar,which is of particular concern in terms of containing the spread of artemisinin resistance.It highlights the need for priority attention to be paid and mobilization of resources in order to improve bed net coverage and utilization through bed net distribution and/or social marketing,information dissemination,and awareness-raising.

利用全封闭式防虫网阻隔小菜蛾在青菜田发生效果研究

为了验证尼龙防虫网对小菜蛾的阻隔作用,设置全封闭式防虫网大棚、半封闭式防虫网大棚和用药棚3种处理,对2017年上半年和下半年种植的两茬青菜分别进行3次调查。结果表明:防虫网全封闭的大棚,青菜上的小菜蛾幼虫种群数(<0. 08头/株)和小菜蛾对青菜的为害率(<3. 11%)均显著小于半封闭式防虫网大棚(> 0. 13头/株;> 8. 89%)。半封闭式防虫网大棚青菜产量(<8 599. 95 kg/hm^2)显著低于其他2种处理棚的产量(> 16 225. 05 kg/hm^2)。与用药棚相比,全封闭式防虫网大棚不仅青菜产量比用药棚略增加,而且每茬青菜可减少农药制剂使用量> 3 000 g/hm^2。综上,全封闭式防虫网塑料大棚对小菜蛾具有非常好的阻隔效果,该结果可为农药的减量使用提供科学依据。

驱蚊帐药效试验标准研究

目的建立国内驱蚊帐对不同蚊虫药效登记试验标准。方法圆锥型接触筒法。结果氟氯苯.氯菊酯驱蚊帐经20次洗涤后,中华按蚊接触3 min,其击倒率和死亡率分别为96.0%和85.7%;致倦库蚊接触20 min,其击倒率和死亡率分别为90.7%和80.4%;淡色库蚊接触30 min,其击倒率和死亡率分别为90.7%和82.9%。结论以中华按蚊、致倦库蚊和淡色库蚊为试虫进行驱蚊帐药效试验测定,建议接触时间分别为3、20和30 min;评价标准为1h击倒率≥90%、24h死亡率≥80%。

中缅边境两个少数民族居民蚊帐使用情况及其影响因素

目的 了解佤族和拉祜族居民蚊帐使用情况及其影响因素 ,探讨促进蚊帐使用和推广杀虫剂浸泡蚊帐 (ITNs)的方法。方法 问卷调查 ,对资料采用 Epi Info 2 0 0 0进行统计学处理。结果 佤族和拉祜族经常或有时使用蚊帐的分别占 2 .8%和 4 .8% ;而没有蚊帐的分别占 6 7.7%和5 9.7% ;L ogistic多因素回归分析结果证实 ,大部分有蚊帐者不经常使用蚊帐防蚊的原因与当地居民缺乏疟疾预防知识有关。结论 两个少数民族中的蚊帐覆盖率和使用率均很低 ,健康教育、交流沟通和市场营销等是促进蚊帐和 ITNs的使用的适当策略。

Efficacy of PermaNet^(■)3.0 and PermaNet^(■)2.0 nets against laboratory-reared and wild Anopheles gambiae sensu lato populations in northern Tanzania

Background:Mosquitoes have developed resistance against pyrethroids,the only class of insecticides approved for use on long-lasting insecticidal nets(LLINs).The present study sought to evaluate the efficacy of the pyrethroid synergist PermaNet^(■)3.0 LLIN versus the pyrethroid-only PermaNet^(■)2.0 LLIN,in an East African hut design in Lower Moshi,northern Tanzania.In this setting,resistance to pyrethroid insecticides has been identified in Anopheles gambiae mosquitoes.Methods:Standard World Health Organization bioefficacy evaluations were conducted in both laboratory and experimental huts.Experimental hut evaluations were conducted in an area where there was presence of a population of highly pyrethroid-resistant An.arabiensis mosquitoes.All nets used were subjected to cone bioassays and then to experimental hut trials.Mosquito mortality,blood-feeding inhibition and personal protection rate were compared between untreated nets,unwashed LLINs and LLINs that were washed 20 times.Results:Both washed and unwashed PermaNet^(■)2.0 and PermaNet^(■)3.0 LLINs had knockdown and mortality rates of 100%against a susceptible strain of An.gambiae sensu stricto.The adjusted mortality rate of the wild mosquito population after use of the unwashed PermaNet^(■)3.0 and PermaNet^(■)2.0 nets was found to be higher than after use of the washed PermaNet^(■)2.0 and PermaNet^(■)3.0 nets.Conclusions:Given the increasing incidence of pyrethroid resistance in An.gambiae mosquitoes in Tanzania,we recommend that consideration is given to its distribution in areas with pyrethroid-resistant malaria vectors within the framework of a national insecticide-resistance management plan.

卫生杀虫剂有机硅缓释剂型的研究

实验室制成含量〉80％的有机硅缓释载体，以有机硅为载体制成缓释杀虫剂，用于DPA单兵防蚊装备及卫生杀虫纱窗。在现场，DPA单兵防蚊装备100％有效保护时间为132天，清洗5次后仍为132天，在某地山区灌丛生境所做的试验有效保护率达100％；塑料杀虫窗纱对蚊、蝇的KT50分别为4．6和8．7min；金属杀虫窗纱为7．0和6．2min，24h死亡率均达100％，在相当于4年的时间内，对2种昆虫的Kk均在30min以内，24h死亡率亦达95％以上。结果表明合成的有机硅材料有良好的缓释效果，制成的2种驱蚊灭蚊装备，效果良好，值得推广应用。

驱蚊帐药效实验研究

目的检测驱蚊帐驱、灭蚊效果。方法按NY/T 1151.4-2012《农药登记卫生用杀虫剂室内药效试验及评价第4部分驱蚊帐》开展驱蚊帐室内接触筒药效检测和模拟现场药效检测,对经不同洗涤次数的驱蚊帐的药效结果用SPSS11.5进行χ2检验和相关性分析。结果实验室接触筒实验中,样品1在经0、10、20次洗涤后,对致倦库蚊的1 h击倒率为77.7%、28.8%和0,24 h致死率为57.9%、17.2%、0;样品2则为91.8%、90.4%、74.7%和88.1%、80.3%、29.4%,不同洗涤次数间驱蚊帐对致倦库蚊杀灭效果的差异均有统计学意义(P<0.05)。模拟现场实验中,样品1和样品2经洗涤20次后对致倦库蚊的12 h击倒率分别为57.7%和29.9%,24 h死亡率分别为57.7%和29.9%。结论洗涤影响驱蚊帐的驱灭蚊效果,实验方法的统一有利于对驱蚊帐产品开展效果评价。