scholarly journals Use of Novaluron-Based Autocidal Gravid Ovitraps to Control Aedes Dengue Vector Mosquitoes in the District of Gampaha, Sri Lanka

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Gayan P. Withanage ◽  
Sameera D. Viswakula ◽  
Yasanthi Silva Gunawardene ◽  
Menaka D. Hapugoda
Keyword(s):  
Sri Lanka ◽  
Vector Control ◽  
Repeated Measures ◽  
Field Experiments ◽  
Medical Officer ◽  
Residual Effect ◽  
World Health ◽  
Local Health ◽  
Dengue Vector ◽  
Indoor And Outdoor

Dengue is the most important mosquito-borne viral infection in Sri Lanka causing an enormous social and economic burden in the country. In the absence of therapeutic drugs and the developed vaccines are under investigation, vector control is the best strategy to reduce the disease transmission. Therefore, the development of novel tools to control dengue vector mosquitoes has become the need of the hour. Novaluron is a recently developed Insect Growth Regulator (IGR) which inhibits chitin synthesis in immature stages of insects. The aim of the study was to identify the efficacy of a simple and cost-effective Autocidal Gravid Ovitrap (AGO) developed using Novaluron to control dengue outbreaks in the District of Gampaha, Sri Lanka. Laboratory and semifield experiments were performed to identify the activity range, optimum field dosage, and residual effects of Novaluron following the World Health Organization guidelines, and field experiments were performed in the Ragama Medical Officer of Health (MOH) area. Two study areas 800 m apart were selected and assigned as treated and control areas randomly. In each study area, 30 households were selected randomly. Each household was given two ovitraps, one placed indoors and the other placed outdoors. Mortality and survival counts were recorded separately for one-year time period and data were analyzed using a two-way repeated measures analysis of variance model. During the laboratory experiments, the adult emerging inhibition was 100% in all tested concentrations. The optimum field dosage was 2 ppm and the residual effect was 28 days. In the field experiments, significantly higher mortality counts were recorded in treated areas both indoor- and outdoor-placed AGOs. Two-factor repeated measures ANOVA followed by Tukey’s test confirmed that the mean mortality count is high for the developed AGOs both indoor and outdoor settings. The developed AGO can be deployed to control both indoor and outdoor dengue vector mosquito populations, and in dengue-risk areas, the ovitrap will be supportive to local health authorities to enhance the efficiency of future vector control programs.

scholarly journals A Challenge for a Unique Dengue Vector Control Programme: Assessment of the Spatial Variation of Insecticide Resistance Status amongst Aedes aegypti and Aedes albopictus Populations in Gampaha District, Sri Lanka

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Rasika Dalpadado ◽  
Nayana Gunathilaka ◽  
Deepika Amarasinghe ◽  
Lahiru Udayanaga
Keyword(s):  
Sri Lanka ◽  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Aedes Albopictus ◽  
Rural Areas ◽  
Medical Officer ◽  
Public Health Problem ◽  
World Health ◽  
Susceptibility Status

Background. To date, dengue is considered an important public health problem in Sri Lanka. Irrational use of insecticides without evidence-based applications has primed the development of resistance in mosquito vectors. Method. The present study investigated the resistance status of Aedes aegypti and Aedes albopictus to commonly used insecticides in three selected Medical Officer of Health (MOH) areas (i.e., Attanagalla, Dompe, and Negombo) in Gampaha District, Western Province of Sri Lanka. Entomological surveys were performed using ovitraps and larval collections. Larval bioassays were carried out to determine the LC50, LC90, and LC95 and susceptibility status for organophosphate temephos, whereas adult bioassays were performed to test the 0.03% deltamethrin and 0.8% malathion susceptibility. Results. The study revealed that the temephos concentrations required to control Ae. aegypti (13.7-17.7 times) and Ae. albopictus (4.6-7.6 times) are higher than the diagnostic concentration (0.012 mg/L) proposed by the World Health Organization. The highest resistance levels were observed for both Ae. aegypti ( 14 ± 1.87 ) and Ae. albopictus ( 36 ± 1.87 ) collected from the Negombo MOH area. Therefore, the WHO recommended diagnostic concentration is no longer effective in controlling Ae. aegypti and Ae. albopictus larvae in these areas. Both the dengue vectors have evolved a high level of insecticide resistance to malathion and deltamethrin in the Gampaha District except Ae. albopictus mosquitoes in rural areas. Further, vectors in rural areas are indicated susceptible (>98%) to pyrethroids and emergence of resistance (<97%) for organophosphate insecticides. Conclusion. The results of this study warrant the vector management authorities on the proper application of insecticides and rational use in vector control. The susceptibility status of vector mosquitoes should be continuously monitored especially in dengue-endemic areas parallel to the routine surveillance programme. Further molecular studies are strongly recommended to determine the Knockdown Resistance (kdr) mutations among Aedes populations.

scholarly journals Population Dynamics and Breeding Preference of Aedes Aegypti and Ae. Albopictus Attributing to Dengue Threat in Kelaniya Medical Officer of Health Area in Sri Lanka

2021 ◽  
Author(s):  
L D Amarasinghe ◽  
P. V J. Nadeeka
Keyword(s):  
Population Dynamics ◽  
Sri Lanka ◽  
Aedes Aegypti ◽  
Medical Officer ◽  
Abundant Species ◽  
Mixed Population ◽  
Weather Factors ◽  
Dengue Transmission ◽  
Risk Areas ◽  
Indoor And Outdoor

Abstract Background Aedes aegypti and Ae. albopictus are the two species of dengue vector mosquitoes in Sri Lanka. Indoor and outdoor distribution of these species, their population dynamics and breeding preference are important factors determining the dengue transmission. Gampaha district in Sri Lanka reported to have frequent dengue epidemics from recent past, hence this study was conducted.Methods Ovitrap surveillance was conducted to determine the vector species distribution in indoor and outdoor in Kelaniya Medical Officer of Health (MOH) area of the Gampaha district. Larvae were reared in the laboratory until adults were emerged to identify species morphologically. Breeding preference of vector mosquitoes were carried out by physically observing the presence of mosquito larvae in water collected receptacles in the area. Results Aedes aegypti and Ae. albopictus were reported to distribute throughout Kelaniya MOH area as a mixed population. Ae. albopictus is the most abundant species both indoor and outdoor in Kelaniya MOH area compared to Ae. aegypti. Weather factors, rain days and wind positively correlated with Aedes population. Conclusions Aedes aegypti and Ae. albopictus are frequently present in Kelaniya MOH area as mixed population. High risk areas of the study area were identified.

scholarly journals Insecticide resistance in dengue vectors from hotspots in Selangor, Malaysia

2021 ◽  
Vol 15 (3) ◽  
pp. e0009205
Author(s):  
Rosilawati Rasli ◽  
Yoon Ling Cheong ◽  
M. Khairuddin Che Ibrahim ◽  
Siti Futri Farahininajua Fikri ◽  
Rusydi Najmuddin Norzali ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Aedes Albopictus ◽  
World Health ◽  
Dengue Vector ◽  
Organophosphate Insecticide ◽  
Potential Threat ◽  
Pyrethroid Insecticides ◽  
Dengue Vector Control

Background In Malaysia, dengue remains a top priority disease and usage of insecticides is the main method for dengue vector control. Limited baseline insecticide resistance data in dengue hotspots has prompted us to conduct this study. The present study reports the use of a map on the insecticide susceptibility status of Aedes aegypti and Aedes albopictus to provide a quick visualization and overview of the distribution of insecticide resistance. Method and results The insecticide resistance status of Aedes populations collected from 24 dengue hotspot areas from the period of December 2018 until June 2019 was proactively monitored using the World Health Organization standard protocol for adult and larval susceptibility testing was conducted, together with elucidation of the mechanisms involved in observed resistance. For resistance monitoring, susceptibility to three adulticides (permethrin, deltamethrin, and malathion) was tested, as well as susceptibility to the larvicide, temephos. Data showed significant resistance to both deltamethrin and permethrin (pyrethroid insecticides), and to malathion (organophosphate insecticide) in all sampled Aedes aegypti populations, while variable resistance patterns were found in the sampled Aedes albopictus populations. Temephos resistance was observed when larvae were tested using the diagnostic dosage of 0.012mg/L but not at the operational dosage of 1mg/L for both species. Conclusion The present study highlights evidence of a potential threat to the effectiveness of insecticides currently used in dengue vector control, and the urgent requirement for insecticide resistance management to be integrated into the National Dengue Control Program.

scholarly journals Residual effect of two Bacillus thuringiensis var. israelensis products assayed against Aedes aegypti (Diptera: Culicidae) in laboratory and outdoors at Rio de Janeiro, Brazil

2005 ◽  
Vol 47 (3) ◽  
pp. 125-130 ◽  
Author(s):  
José Bento Pereira Lima ◽  
Nilson Vieira de Melo ◽  
Denise Valle
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Vector Control ◽  
Rio De Janeiro ◽  
Residual Effect ◽  
Dengue Vector ◽  
Health Ministry ◽  
Third Instar Larvae

Resistance of the dengue vector to temephos stimulated its substitution for Bacillus thuringiensis var. israelensis (Bti) since 2001 in Brazil. The persistence of the two Bti formulations employed at that time by the Health Ministry, Vectobac G and Aquabac G, was assayed under laboratory and outdoor conditions. Both formulations were tested at 0.2 g/10 liters of water, the same concentration applied in the field for vector control. The tests were done against Ae. aegypti third instar larvae (Rockefeller strain). In the laboratory, Vectobac G and Aquabac G caused at least 95% mortality until 101 and 45 days after treatment, respectively. In the outdoor assays, test containers of different materials were treated with either formulation and placed in a shaded area. Larvae were introduced each 3-6 days and mortality was recorded 24 and 48 hours later. In the first set of assays, performed in June 2001, mortality levels of 70% or more were attained for 2-5 weeks for both formulations in all containers. The exception was for the iron one that rusted, resulting in low mortality after seven days. In the second set of assays (August 2001), 70% mortality was attained for just 1-2 weeks for all the containers and both formulations.

scholarly journals Risk and the Republican National Convention: Application of the Novel COVID-19 Operational Risk Assessment

2021 ◽  
pp. 1-6
Author(s):  
David Callaway ◽  
Jeff Runge ◽  
Lucia Mullen ◽  
Lisa Rentz ◽  
Kevin Staley ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Health Care ◽  
Care Delivery ◽  
The United States ◽  
Lessons Learned ◽  
World Health ◽  
Local Health ◽  
Mass Gathering ◽  
Wide Range ◽  
National Convention

Abstract The United States Centers for Disease Control and Prevention and the World Health Organization broadly categorize mass gathering events as high risk for amplification of coronavirus disease 2019 (COVID-19) spread in a community due to the nature of respiratory diseases and the transmission dynamics. However, various measures and modifications can be put in place to limit or reduce the risk of further spread of COVID-19 for the mass gathering. During this pandemic, the Johns Hopkins University Center for Health Security produced a risk assessment and mitigation tool for decision-makers to assess SARS-CoV-2 transmission risks that may arise as organizations and businesses hold mass gatherings or increase business operations: The JHU Operational Toolkit for Businesses Considering Reopening or Expanding Operations in COVID-19 (Toolkit). This article describes the deployment of a data-informed, risk-reduction strategy that protects local communities, preserves local health-care capacity, and supports democratic processes through the safe execution of the Republican National Convention in Charlotte, North Carolina. The successful use of the Toolkit and the lessons learned from this experience are applicable in a wide range of public health settings, including school reopening, expansion of public services, and even resumption of health-care delivery.

scholarly journals Indoor and Outdoor Air Quality for Sustainable Life: A Case Study of Rural and Urban Settlements in Poor Neighbourhoods in Kenya

2021 ◽  
Vol 13 (4) ◽  
pp. 2417
Author(s):  
Anne Wambui Mutahi ◽  
Laura Borgese ◽  
Claudio Marchesi ◽  
Michael J. Gatari ◽  
Laura E. Depero
Keyword(s):  
Air Quality ◽  
Elemental Composition ◽  
Black Carbon ◽  
Informal Settlement ◽  
Heavy Traffic ◽  
World Health ◽  
Rural Settlements ◽  
Outdoor Air ◽  
Outdoor Air Quality ◽  
Indoor And Outdoor

This paper reports on the indoor and outdoor air quality in informal urban and rural settlements in Kenya. The study is motivated by the need to improve consciousness and to understand the harmful health effects of air quality to vulnerable people, especially in poor communities. Ng’ando urban informal settlement and Leshau Pondo rural village in Kenya are selected as representative poor neighborhoods where unclean energy sources are used indoor for cooking, lighting and heating. Filter based sampling for gravimetrical, elemental composition and black carbon (BC) analysis of particulate matter with an aerodynamic diameter less than 2.5 µm (PM2.5) is performed. findings from Ng’ando and Leshau Pondo showed levels exceeding the limit suggested by the world health organization (WHO), with rare exceptions. Significantly higher levels of PM2.5 and black carbon are observed in indoors than outdoor samples, with a differences in the orders of magnitudes and up to 1000 µg/m3 for PM2.5 in rural settlements. The elemental composition reveals the presence of potentially toxic elements, in addition to characterization, emission sources were also identified. Levels of Pb exceeding the WHO limit are found in the majority of samples collected in the urban locations near major roads with heavy traffic. Our results demonstrate that most of the households live in deplorable air quality conditions for more than 12 h a day and women and children are more affected. Air quality condition is much worse in rural settlements where wood and kerosene are the only available fuels for their energy needs.

scholarly journals Lymphatic filariasis, infection status in Culex quinquefasciatus and Anopheles species after six rounds of mass drug administration in Masasi District, Tanzania

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Eliza Lupenza ◽  
Dinah B. Gasarasi ◽  
Omary M. Minzi
Keyword(s):  
Vector Control ◽  
Lymphatic Filariasis ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Wuchereria Bancrofti ◽  
Elimination Phase ◽  
Anopheles Species ◽  
The Status ◽  
Household Environment ◽  
Indoor And Outdoor

Abstract Background Lymphatic filariasis (LF) elimination program in Tanzania started in 2000 in response to the Global program for the elimination of LF by 2020. Evidence shows a persistent LF transmission despite more than a decade of mass drug administration (MDA). It is advocated that, regular monitoring should be conducted in endemic areas to evaluate the progress towards elimination and detect resurgence of the disease timely. This study was therefore designed to assess the status of Wuchereria bancrofti infection in Culex quinqefasciatus and Anopheles species after six rounds of MDA in Masasi District, South Eastern Tanzania. Methods Mosquitoes were collected between June and July 2019 using Center for Diseases Control (CDC) light traps and gravid traps for indoor and outdoor respectively. The collected mosquitoes were morphologically identified into respective species. Dissections and PCR were carried out to detect W. bancrofti infection. Questionnaire survey and checklist were used to assess vector control interventions and household environment respectively. A Poisson regression model was run to determine the effects of household environment on filarial vector density. Results Overall, 12 452 mosquitoes were collected of which 10 545 (84.7%) were filarial vectors. Of these, Anopheles gambiae complex, An. funestus group and Cx. quinquefasciatus accounted for 0.1%, 0.7% and 99.2% respectively. A total of 365 pools of Cx. quinquefasciatus (each with 20 mosquitoes) and 46 individual samples of Anopheles species were analyzed by PCR. For Cx. quinquefasciatus pools, 33 were positive for W. bancrofti, giving an infection rate of 0.5%, while the 46 samples of Anopheles species were all negative. All 1859 dissected mosquitoes analyzed by microscopy were also negative. Households with modern latrines had less mosquitoes than those with pit latrines [odds ratio (OR) = 0.407, P < 0.05]. Houses with unscreened windows had more mosquitoes as compared to those with screened windows (OR = 2.125, P < 0.05). More than 80% of the participants own bednets while 16.5% had no protection. Conclusions LF low transmission is still ongoing in Masasi District after six rounds of MDA and vector control interventions. The findings also suggest that molecular tools may be essential for xenomonitoring LF transmission during elimination phase.

scholarly journals Assessment of Aedes aegypti Pupal Productivity during the Dengue Vector Control Program in a Costal Urban Centre of São Paulo State, Brazil

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Marylene de Brito Arduino
Keyword(s):  
Vector Control ◽  
Large City ◽  
Control Program ◽  
Sao Paulo ◽  
São Paulo ◽  
Dengue Vector ◽  
Urban Centre ◽  
Vector Control Program ◽  
Productivity Indices ◽  
Dengue Vector Control

The control of dengue relies on the elimination of vector breeding sites. This study identified the container categories most productive for A. aegypti within the framework of the São Paulo dengue vector control program (DVCP) in São Sebastião, a large city located on the state’s coast where dengue cases have occurred since 2001. Containers were inspected monthly for the occurrence of mosquito immature stages during two consecutive vector-breeding seasons in 2002–2004. Containers were classified by their material, use, and fixed or removable status. Pupal productivity differed significantly among container types, items made of metal and plastic, and boats being those with the highest relative contribution. Significant correlations between traditional indices of A. aegypti abundance (Container Index, House Index, and Breteau Index) and pupal productivity/demographic indices (Pupae/Container, Pupae/House, Pupae/ha, and Pupae/Person) ranged 0.56–0.65; correlations were not statistically significant for any combination involving the Pupae/Container index. The assessment of pupal productivity indices could be incorporated into the DVCP without any additional operational onus, allowing vector control managers to determine appropriate control actions targeting the most productive containers and sites. Further studies are needed to assess whether pupal productivity indices may be used as epidemiological indicators of risk of dengue transmission.

Sign in / Sign up

Export Citation Format

Share Document