Ovitrap Index Research Articles

Endemicity of Dengue with Density Figure and Maya Index in Bengkulu City, Indonesia

BACKGROUND: One of the factors contributing to dengue’s endemicity is the density of the dengue vector, namely, Aedes aegypti as the primary vector and Aedes albopictus as the secondary vector. Bentiring and Kandang Limun villages are high endemic areas of dengue. AIM: This study aimed to determine the relationship between dengue endemicity and density figure (DF) and Maya index (MI) in Bentiring and Kandang Limun villages, Bengkulu city. METHODS: This study used a cross-sectional design. The sampling technique used proportionate stratified sampling. The sampling refers to the guidelines for dengue entomology surveys according to the WHO 1999 criteria. A total of 400 ovitraps were installed, 200 ovitraps inside the house and 200 ovitraps outside the house. RESULTS: The results showed that Bentiring and Kandang Limun villages had a high risk of dengue transmission based on entomological parameters, namely, ovitrap index (OI) 56% and 55% (DF 6), house index (HI) 45% and 44% (DF 6), container index (CI) 23% and 23% (DF 6), and BI 96% and 120% (DF 7 and 8). The areas have a high risk of dengue transmission based on the MI 71% and 76%, respectively. There is a relationship between dengue endemicity and entomological index in Bentiring and Kandang Limun villages, Bengkulu city, with a significance value (p = 0.000) and a powerful correlation (r = 1.000). CONCLUSION: There is a relationship between dengue endemicity and the MI in Bentiring village and Kandang Limun village, Bengkulu city, with a significance value (p = 0.014 and 0.058) and a powerful correlation (r = 0.920 and r = 1.000), respectively. The entomological index and DF are predictors for dengue prevention and control environment to minimize mosquito breeding sites and reduce disease transmission.

Ovitrap surveillance of dengue vector mosquitoes in Bandung City, West Java Province, Indonesia

Larval surveillance is the central approach for monitoring dengue vector populations in Indonesia. However, traditional larval indices are ineffective for measuring mosquito population dynamics and predicting the dengue transmission risk. We conducted a 14-month ovitrap surveillance. Eggs and immature mosquitoes were collected on a weekly basis from an urban village of Bandung, namely Sekejati. Ovitrap-related indices, namely positive house index (PHI), ovitrap index (OI), and ovitrap density index (ODI), were generated and correlated with environmental variables, housing type (terraced or high-density housing), ovitrap placement location (indoor or outdoor; household or public place), and local dengue cases. Our results demonstrated that Aedes aegypti was significantly predominant compared with Aedes albopictus at each housing type and ovitrap placement location. Ovitrap placement locations and rainfall were the major factors contributing to variations in PHI, OI, and ODI, whereas the influences of housing type and temperature were subtle. Indoor site values were significantly positively correlated to outdoor sites’ values for both OI and ODI. OI and ODI values from households were best predicted with those from public places at 1- and 0-week lags, respectively. Weekly rainfall values at 4- and 3-week lags were the best predictors of OI and ODI for households and public places, respectively. Monthly mean PHI, OI, and ODI were significantly associated with local dengue cases. In conclusion, ovitrap may be an effective tool for monitoring the population dynamics of Aedes mosquitoes, predicting dengue outbreaks, and serving as an early indicator to initiate environmental clean-up. Ovitrap surveillance is easy for surveyors if they are tasked with a certain number of ovitraps at a designated area, unlike the existing larval surveillance methodology, which entails identifying potential breeding sites largely at the surveyors’ discretion. Ovitrap surveillance may reduce the influence of individual effort in larval surveillance that likely causes inconsistency in results.

Evaluating the Potential of Pyriproxyfen Dissemination using Mosquito Home System against Aedes albopictus at a Dengue Hotspot Area

Aedes mosquitoes were found to lay their eggs in the cryptic breeding sites. Eliminating cryptic and open breeding sites is essential in reducing dengue virus transmission. However, it is often challenging for health officers to assess these breeding sites which are usually missed during larval surveillance. The autodissemination approach may produce a better outcome by manipulating female mosquitoes to disperse insecticide to other Aedes spp. mosquito habitats. Thus, the present study aims to evaluate the effectiveness of the pyriproxyfen autodissemination technique using Mosquito Home System against the population of mosquitoes. This study was conducted in Bandar Baru Bangi, Selangor, Malaysia. The Mosquito Home System was deployed to control Aedes spp. populations at treatment sites using before-after-control-impact (BACI) design. The presence of pyriproxyfen distribution was confirmed using the WHO larval bioassay which resulted in 10-35% larvae mortalities. Autodissemination of pyriproxyfen significantly reduced the population size of mosquito eggs (p<0.05), larvae (p<0.05), and ovitrap index (p<0.05) at the treatment areas compared to the control areas. Moreover, rainfall was correlated positively against ovitrap index (r = 0.247), larvae (r = 0.420), and eggs (r = 0.422). The study provides promising results for controlling Aedes spp. populations and also highlights the potentials of this technique as an alternative in vector control programmes. However, further studies on larger scale field trials are warranted.

Dengue disease dynamics are modulated by the combined influences of precipitation and landscape: A machine learning approach

BackgroundDengue is an endemic vector-borne disease influenced by environmental factors such as landscape and climate. Previous studies separately assessed the effects of landscape and climate factors on mosquito occurrence and dengue incidence. However, both factors concurrently coexist in time and space and can interact, affecting mosquito development and dengue disease transmission. For example, eggs laid in a suitable environment can hatch after being submerged in rain water. It has been difficult for conventional statistical modeling approaches to demonstrate these combined influences due to mathematical constraints. ObjectivesTo investigate the combined influences of landscape and climate factors on mosquito occurrence and dengue incidence. MethodsEntomological, epidemiological, and landscape data from the rainy season (July–December) were obtained from respective government agencies in Metropolitan Manila, Philippines, from 2012 to 2014. Temperature, precipitation and vegetation data were obtained through remote sensing. A random forest algorithm was used to select the landscape and climate variables. Afterward, using the identified key variables, a model-based (MOB) recursive partitioning was implemented to test the combined influences of landscape and climate factors on ovitrap index (vector mosquito occurrence) and dengue incidence. ResultsThe MOB recursive partitioning for ovitrap index indicated a high sensitivity of vector mosquito occurrence on environmental conditions generated by a combination of high residential density areas with low precipitation. Moreover, the MOB recursive partitioning indicated high sensitivity of dengue incidence to the effects of precipitation in areas with high proportions of residential density and commercial areas. ConclusionsDengue dynamics are not solely influenced by individual effects of either climate or landscape, but rather by their synergistic or combined effects. The presented findings have the potential to target vector surveillance in areas identified as suitable for mosquito occurrence under specific climatic conditions and may be relevant as part of urban planning strategies to control dengue.

Measuring the effectiveness of integrated vector management with targeted outdoor residual spraying and autodissemination devices on the incidence of dengue in urban Malaysia in the iDEM trial (intervention for Dengue Epidemiology in Malaysia): study protocol for a cluster randomized controlled trial

BackgroundIn common with many South East Asian countries, Malaysia is endemic for dengue. Dengue control in Malaysia is currently based on reactive vector management within 24 h of a dengue case being reported. Preventive rather than reactive vector control approaches, with combined interventions, are expected to improve the cost-effectiveness of dengue control programs. The principal objective of this cluster randomized controlled trial is to quantify the effectiveness of a preventive integrated vector management (IVM) strategy on the incidence of dengue as compared to routine vector control efforts.MethodsThe trial is conducted in randomly allocated clusters of low- and medium-cost housing located in the Federal Territory of Kuala Lumpur and Putrajaya. The IVM approach combines: targeted outdoor residual spraying with K-Othrine Polyzone, deployment of mosquito traps as auto-dissemination devices, and community engagement activities. The trial includes 300 clusters randomly allocated in a 1:1 ratio. The clusters receive either the preventive IVM in addition to the routine vector control activities or the routine vector control activities only. Epidemiological data from monthly confirmed dengue cases during the study period will be obtained from the Vector Borne Disease Sector, Malaysian Ministry of Health e-Dengue surveillance system. Entomological surveillance data will be collected in 12 clusters randomly selected from each arm.To measure the effectiveness of the IVM approach on dengue incidence, a negative binomial regression model will be used to compare the incidence between control and intervention clusters. To quantify the effect of the interventions on the main entomological outcome, ovitrap index, a modified ordinary least squares regression model using a robust standard error estimator will be used.DiscussionConsidering the ongoing expansion of dengue burden in Malaysia, setting up proactive control strategies is critical. Despite some limitations of the trial such as the use of passive surveillance to identify cases, the results will be informative for a better understanding of effectiveness of proactive IVM approach in the control of dengue. Evidence from this trial may help justify investment in preventive IVM approaches as preferred to reactive case management strategies.Trial registrationISRCTN ISRCTN81915073. Retrospectively registered on 17 April 2020.

Sterile Insect Technique: Successful Suppression of an Aedes aegypti Field Population in Cuba.

Simple SummaryThe sterile insect technique (SIT) is a species-specific and environment-friendly method of insect control that relies on the release of large numbers of sterile insects. Mating released sterile males with wild females leads to a decrease in the reproductive potential and to the local suppression of the target population. There is increased interest in applying this approach to manage disease-transmitting mosquito populations. The main focus of this pilot trial was to assess the efficacy of the SIT for the suppression of Aedes aegypti populations. Two areas in Havana city, Cuba, were selected as control and release trial sites. The presence, density and fertility of the target wild population were monitored through a network of ovitraps. Approximately 1,270,000 irradiated Ae. aegypti males were released in the 50 ha target area over a period of 20 weeks. The released mosquitoes showed excellent mating competitiveness and induced high levels of sterility in the wild Ae. aegypti population. The target natural population was suppressed as reflected in the ovitrap index and in the mean number of eggs/trap values which dropped to zero by the last 3 weeks of the trial. We conclude that the released sterile male Ae. aegypti competed successfully and induced significant sterility in the local target Ae. aegypti population, resulting in suppression of the vector.Dengue virus infections are a serious public health problem worldwide. Aedes aegypti is the primary vector of dengue in Cuba. As there is no vaccine or specific treatment, the control efforts are directed to the reduction of mosquito populations. The indiscriminate use of insecticides can lead to adverse effects on ecosystems, including human health. The sterile insect technique is a species-specific and environment-friendly method of insect population control based on the release of large numbers of sterile insects, ideally males only. The success of this technique for the sustainable management of agricultural pests has encouraged its evaluation for the population suppression of mosquito vector species. Here, we describe an open field trial to evaluate the effect of the release of irradiated male Ae. aegypti on a wild population. The pilot trial was carried out in a suburb of Havana and compared the mosquito population density before and after the intervention, in both untreated control and release areas. The wild population was monitored by an ovitrap network, recording frequency and density of eggs as well as their hatch rate. A significant amount of sterility was induced in the field population of the release area, as compared with the untreated control area. The ovitrap index and the mean number of eggs/trap declined dramatically after 12 and 5 weeks of releases, respectively. For the last 3 weeks, no eggs were collected in the treatment area, clearly indicating a significant suppression of the wild target population. We conclude that the sterile males released competed successfully and induced enough sterility to suppress the local Ae. aegypti population.

Aedes larval bionomics and implications for dengue control in the paradigmatic Jaffna peninsula, northern Sri Lanka

BackgroundThe larval bionomics of Aedes across the Jaffna peninsula in northern Sri Lanka was investigated to obtain information needed for developing more effective larval source reduction measures to control endemic arboviral diseases.MethodsThe habitats of preimaginal stages of Aedes mosquitoes were surveyed, and ovitrap collections were carried out in densely populated areas of the Jaffna peninsula. Aedes larval productivities were analysed against habitat characteristics, rainfall and dengue incidence. Adults emerging from collected larvae were tested for dengue virus (DENV).ResultsOnly Aedes aegypti, Ae. albopictus and Ae. vittatus were identified in the field habitat collections and ovitraps. Aedes aegypti was the predominant species in both the field habitat and ovitrap collections, followed by Ae. albopictus and small numbers of Ae. vittatus. Tires and open drains were the preferred field habitats for Ae. aegypti, although larval productivity was higher in discarded plastic containers. The three Aedes species differed in field habitat preferences. Concomitant presence of the three Aedes species was observed in the field habitats and ovitraps. Larval productivities were inversely correlated with the salinity of the field habitat. Rainfall in the preceding month significantly correlated with larval productivity in the field habitats. DENV serotype 2 was detected in Ae. aegypti collected from ovitraps in the city of Jaffna. High Breteau, House and Container indices of 5.1, 5.1 and 7.9%, respectively, were observed in the field habitat surveys and ovitrap indices of up to 92% were found in Jaffna city.ConclusionsAedes larval indices in populated areas of the peninsula showed a high potential for dengue epidemics. Unacceptable littering practices, failure to implement existing dengue control guidelines, vertical transmission of DENV in vector mosquitoes and preimaginal development in brackish water and open surface drains, as well as in domestic wells that provide potable water, are serious constraints to the current Aedes larval source reduction methods used to control dengue in the Jaffna peninsula. Similar shortcomings in arboviral disease control are likely present in other resource-constrained tropical coastal zones worldwide.Graphical

Ovitrap Surveillance of the Dengue Vectors Aedes aegypti and Aedes albopictus in Selected Endemic Areas in Sandakan, Sabah

Ovitrap technique could be considered an efficient tool for monitoring of Aedes populations. This study aimed to monitor the dengue vector population and to provide baseline data of vector density in selected endemic areas. 1600 ovitraps were placed indoor and outdoor randomly in selected houses from January till July 2014 at eight selected localities. 96%–100% of ovitraps were recovered after seven days. In total, 9399 larvae were examined of which 2674 (28.2%) were Ae. Aegypti and 6752 (71.8%) Ae. albopictus. Ae. albopictus were dominant than Ae. aegypti in every locality. Highest collection of Ae. albopictus was recorded in Kampung Air (total larvae = 1357), followed by Kampung Bokara (total larvae = 1165) and Taman Fajar (total larvae = 846). Three main localities that recorded highest collection of Ae. aegypti were Kampung Bokara (total larvae = 504), Kampung Air (total larvae = 457) and Taman Fajar (total larvae = 341). Ae. albopictus was found more abundant compared to Ae. aegypti. The ovitrap index recorded in all localities (ranged 18.0% - 59.0%) was more than the transmission threshold (10%). Mix breeding of Ae. aegypti and Ae. albopictus were also detected for outdoor ovitraps. In conclusion, this study found that selected localities in Sandakan district have a high risk for transmission and outbreaks of dengue. Furthermore, this study also provided a baseline data of Aedes density for further planning of prevention and control activities.

Monitoring Aedes Population using Ovitrap Index and Larval Abundance in an Urban University Residence

Autocidal ovitraps have played a significant role in surveillance and control of dengue vectors, Aedes aegypti and Aedes albopictus. Malaysia has witnessed the deployment of several types of autocidal ovitraps, which includes the Mosquito Larvae Trapping Device (MLTD) introduced by Kuala Lumpur City Hall. This study aimed to assess Aedes larval abundance and local meteorological variables in a university residence, in Cheras, Kuala Lumpur. MLTD (n=30) baited with organic NPK fertiliser (5:5:5) solutions were deployed. Larvae collection and trap servicing were performed weekly for a duration of eight weeks. Rearing and species identification for larvae were conducted in the laboratory. Out of 2,152 Aedes larvae, 85% of them were Ae. albopictus whilst the remaining were Ae. aegypti. Outdoor collection of Ae. albopictus surpassed its indoor collection (mean larvae per trap of 9.28 versus 6.08). Conversely, an indoor collection of Ae. aegypti was greater than its outdoor collection (mean larvae per trap of 1.72 versus 0.86). The highest ovitrap indices were observed in Week 5 and 6 which were 90% and 93%, respectively. Week 1 had the lowest ovitrap index, 30%. Our analyses revealed a positive correlation between Aedes larval abundance and maximum temperature (r=0.830, p=0.011) whereas minimum relative humidity was shown to have a negative correlation (r=-0.778, p=0.023), with the larval abundance. Routine monitoring of dengue vectors at its immature stages can provide information on the density and fluctuation of the local mosquito population. Coupled with concurrent meteorological variables, it can guide vector control operations as part of dengue prevention strategies.

APPLICATION OF LARVITRAP AND OVITRAP TO CONTROL Aedes sp. IN DHF ENDEMIC AREAS

Alternative mosquito vector control at this time that is cheap, practical and relatively safe to the environment is needed by developing countries such as Indonesia.One of the methods of controlling Aedes sp without insecticides is the use of larvae traps (larvitrap). The working principle of larvitrap is that the eggs trapped in the tool The incidence rate (IR) of Dengue Hemorrhagic Fever per 100.000 population in Central Java in the last five years is as follows: 2011 amounted to 15,27 in 2012 amounted to 19,29 in 2013 amounted to 45,52 in 2014 amounted to 32,95 and years 2015 amounted to 34,87. Since 2010 DHF has spread to all districts / cities in Central Java. Larvitrap and ovitrap are tools that can be used as traps for Aedes sp. Both of these tools can be used with additional attractants which can serve to attract the attention of Aedes sp. in order to lay eggs on the tool. Larvae that hatch from eggs in the larvitrap eventually cannot become adults and will die. Mosquito eggs trapped in the ovitrap can be destroyed so that they do not develop into adult mosquitoes. The research objective was to determine the effectiveness of using larvitrap and ovitrap as a control tool for Aedes sp (DHF vector).The research method used is experimental research. The research location is in the Banyumas Regency area. Larvitrap made of plastic jars and pralon was painted black and modified using gauze on the top. Ovitrap from plastic cups was painted black and given an ovistrip. Larvitrap and ovitrap were placed in DHF endemic areas. After the larvitrap and ovitrap are taken, the number of trapped Aedes sp and the larvitrap / ovitrap index is calculated. Furthermore, analyzed the effectiveness of using larvitrap and ovitrap as a means of controlling mosquitoes Aedes sp.The results showed that the larvitrap index in the larvitrap installation in Pandak Village was 60%, while in Mersi Village it was 56,7%. The ovitrap index in the ovitrap installation in Pandak Village was 36,7%, while in Mersi Village it was 33,3%. The number of larvae trapped in the larvitrap installation in Pandak Village were 832 larvae, while in Mersi Village there were 985 larvae. The number of eggs trapped in the ovitrap installation in Pandak Village were 518 eggs, while in Mersi Village there were 811 eggs.The conclusion of this research is that larvitrap is more effective to control Aedes sp than ovitrap. The community is advised to use larvitrap as a tool to control the Aedes sp (DHF vector.

Spatial analysis of dengue incidence and Aedes aegypti ovitrap surveillance in Belo Horizonte, Brazil.

Understanding the intra-urban spatial dynamics of Aedes aegypti and dengue transmission is important to effectively guide vector control. Ovitraps are a sensitive, cost-effective vector surveillance tool, yet few longitudinal studies have evaluated ovitrap indices and dengue occurrence. We aimed to assess the spatial patterns of dengue incidence and Ae.aegypti ovitrap positivity index (OPI) over time and to examine the spatial relationship between these two variables. This study used 12years (2007-2018) of dengue case records and biweekly Ae.aegypti ovitrap data in Belo Horizonte, Brazil. We aggregated data by year and health centre catchment area (n=152) and used both univariate and bivariate global Moran's I statistic and LISA to evaluate spatial clustering. Annual dengue incidence ranged from 18 to 6262/100000 residents and displayed spatial autocorrelation in 10/12years, with shifting areas of high incidence. Annual OPI ranged from 35.7 to 47.6% and was clustered in all study years, but unlike dengue had consistent spatial patterns over time. Bivariate analysis found both positive (6/12years) and negative (1/12years) spatial associations between the two variables. Low detected presence of Ae.aegypti was not a limiting factor in dengue transmission. However, stable spatial distribution of OPI suggests that certain areas may have persistent breeding sites. Future research should identify factors related to persistent Ae.aegypti hotspots to better guide vector management. Vector control efforts should be paired with additional data on population immunity, circulating serotypes and urban factors to better predict and control outbreaks.

Urbanisation is a main driver for Aedes aegypti dynamics and arboviral risk in Côte d’Ivoire

Abstract Background Aedes mosquito-borne arboviruses have (re-)emerged and caused considerable public health concerns in major sub-Saharan African cities subjected to rapid urbanisation. We assessed the effects of urbanisation on Aedes aegypti dynamics and biting pattern, and the risk of transmission of yellow fever (YF) and dengue (DEN) viruses along urban-rural gradient in Côte d'Ivoire. Methods We collected Aedes mosquitoes as eggs, larvae/pupae, and adults seasonally in urban, suburban and rural areas using ovitrap, larval survey and human-baited double net trap methods from January 2015 to December 2016. We sampled household data and characterised Aedes larval breeding sites. Ae. aegypti indices and biting rates were compared by area. Results Ae. aegypti was the most abundant species in all areas. It showed higher abundance in urban areas (n = 26,072; 99.4%). Larval indices were associated with human activities, including waste and water management. Tires and discarded containers were the most productive breeding sites in all areas. Household water receptacles displayed high Aedes-positive rate (23.6%) in urban areas. Positive ovitrap index was higher in urban (53.5%) compared to suburban (43.1%) and rural (29.7%). Stegomyia indices were highest in urban followed by suburban and rural areas, with respective house index of 67.2, 51.4 and 27.8, container index of 57.1, 43.5 and 19.7, and Breteau index of 95.2, 78.9 and 8.8. Biting rate was 4.3 and 2.7-fold higher in urban (83.5 bite/person/day) and suburban (52.1 bite/person/day) compared to rural (19.4 bite/person/day), respectively. Ae. aegypti indices were higher during rainy seasons. Conclusions In Côte d'Ivoire, urbanisation raised Ae. aegypti abundance and biting rate. As a result, YF and DEN risk indices were above WHO-established epidemic thresholds in urban area thus exposing local communities to high risk of getting diseases. Integrated community-based vector control programs should be applied to reduce arboviral risk. Key messages Urbanisation raises Aedes aegypti abundance and arboviral disease risk in Côte d’Ivoire. Integrated community clean-up actions are required to control Aedes vectors.

PENGUKURAN OVITRAP INDEX (OI) SEBAGAI GAMBARAN KEPADATAN NYAMUK DI RW 6 KELURAHAN TENGGILIS MEJOYO KECAMATAN TENGGILIS MEJOYO KOTA SURABAYA

<p><em>Environment that is far from dirty elements and disturbing animals is one of the criteria for a clean and healthy environment. The potential for Dengue Hemorrhagic Fever (DHF) transmission can be illustrated by the density of mosquito populations in an area. Ovitrap index (OI) is one method that can be used to measure mosquito populations. Researchers are interested in conducting research on the measurement of mosquito density with the Ovitrap Index and the tendency to lay eggs at Aedes spp. inside or outside the house. The purpose of this study was to determine the density of mosquitoes with Ovitrap Index (OI) in RW 6, Tenggilis Mejoyo Sub-District, Tenggilis Mejoyo Sub-District, Surabaya City. This research is a descriptive study with cross sectional approach. The research sample is the larvae of the Aedes spp. who was trapped in an ovitrap in RW 6, Tenggilis Mejoyo Sub-District, Tenggilis Mejoyo Sub-District, Surabaya City. Installation of ovitrap in the house found positive ovitrap contained mosquito eggs in almost all RT. Installation of ovitrap outside the home found positive ovitrap contained mosquito eggs only at RT 01 and RT 02 at week IV. The mosquito larvae examined were Aedes Aegypti and Aedes Albopictus species spread in all RT. Suggestions for further research are to increase the number of samples and ovitraps that are added so that the results become more varied.</em></p>

Targeted outdoor residual spraying, autodissemination devices and their combination against Aedes mosquitoes: field implementation in a Malaysian urban setting.

Currently, dengue control relies largely on reactive vector control programmes. Proactive vector-control using a rational, well-balanced integrated vector management approach may prove more successful for dengue control. As part of the development of a cluster randomized controlled epidemiological trial, a study was conducted in Johor Bahru, Malaysia. The study included one control site (three buildings) and three intervention sites which were treated as follows: targeted outdoor residual spraying only (TORS site, two buildings); deployment of autodissemination devices only (ADD site, four buildings); and the previous two treatments combined (TORS + ADD site, three buildings). The primary entomological measurement was per cent of positive ovitraps-ovitrap index (OI). The effect of each intervention on OI was analyzed by a modified ordinary least squares regression model. Relative to the control site, the TORS and ADD sites showed a reduction in the Aedes OI (-6.5%, P = 0.04 and -8.3%, P = 0.10, respectively). Analysis by species showed that, relative to control, the Ae. aegypti OI was lower in ADD (-8.9%, P = 0.03) and in TORS (-10.4%, P = 0.02). No such effect was evident in the TORS + ADD site. The present study provides insights into the methods to be used for the main trial. The combination of multiple insecticides with different modes of action in one package is innovative, although we could not demonstrate the additive effect of TORS + ADD. Further work is required to strengthen our understanding of how these interventions impact dengue vector populations and dengue transmission.

Entomological Status Based on Vector Density Index and Transovarial Infection on Aedes Sp. Mosquito in Meteseh Village, Semarang City

Dengue Hemorrhagic Fever (DHF) is a disease caused by Dengue virus. In 2016, the number of DHF patients in areas of Health services of Rowosari was 247 cases, IR 289.6/100.000 populations and the highest number of the patients was from Meteseh Village. The most usual mechanism happened in the vertical transmission, transovarial infection, from adult mosquito to the egg. The study was conducted to describe of entomological status of House Index (HI), Container Index (CI), Breteau Index (BI), House index (HI), Ovitrap Index (OI) of larvae as well as transovarial infection in Aedes sp. The research method was descriptive method by conducting test to the entomology status of DHF incidence. Based on the survey in Meteseh sub-village (XVI), a result found that average House Index 8.99%, Container Index 2.88%, Breteau Index 16.40%, HI 8,99 Ovitrap Index 35.46% with the egg density at 1.023 eggs. The identified mosquitoes were 30, and from the identification result of Aedes sp., two Aedes species were found, 28 Aedes aegypti,and only 2 Aedes albopictus. The transovarial infection in Aedes sp. using ELISA method was found 6 mosquito samples which were positive of dengue virus, with the detail in neighborhood 01 (1 sample), neighborhood 02 (2 samples), neighborhood 03 (3 samples). DHF in Meteseh Sub village in Semarang City was probably happened because correlated with transovarial infection.

Comparison Between Larval Survey Index and Positive Ovitrap Index in the Evaluation of Populations of Aedes (Stegomyia) aegypti (Linnaeus, 1762) North of Paraná, Brazil.

Aedes (Stegomyia) aegypti (Linnaeus, 1762) is one of the world’s most widely distributed mosquitoes and is the vector of the dengue virus, one of the most important reemerging diseases. Besides dengue, A. aegypti can also transmit urban yellow fever, chikungunya, and Zika virus, making it of great medical importance. Thus, it is of extreme importance to find reliable methods to evaluate the presence of A. aegypti in urban areas. In Brazil, rapid index surveys of Aedes aegypti by means of larval survey (LIRAa) is the official method to estimate the Breteau (BI) and property infestation (PII) indexes, which indicates how many infested containers with larvae of A. aegypti were found by the total number of properties surveyed and the proportion of houses infested, respectively. As the LIRAa requires access to private residences and trained personal to find breeding sites and do not reveal the mosquito’s presence when in low density, it has not demonstrated efficacy in determining the presence of A. aegypti. To evaluate an alternative method, the LIRAa method was compared with an oviposition trap, made with hay infusion and a hardboard pallet, to evaluate the BI and the PII. The 2 methods were carried out simultaneously through 4 surveys, sampling 60 homes per survey. To evaluate the best configuration of ovitraps for surveillance of A. aegypti, the ovitraps were installed in intradomicile and peridomicile areas, with 1 to 5 traps per residence and with 1 to 3 pallets per trap, and these different configurations were compared using the positive ovitrap index (POI) and egg density index (EDI). The ovitraps showed greater sensitivity for detecting the presence of A. aegypti, with a BI of 72.5% and PII of 54.2%, whereas the LIRAa revealed only 2.1% for the BI and 1.3% for the PII. Therefore, the use of sentinel traps can provide information in a more rapid and precise manner. As there were no differences in the ovitraps distributions patterns, the ovitraps can be installed in the peridomicile area, with 2 traps per surveillance point and 1 pallet per trap, making their installation easier and more cost-efficient, facilitating the work of health agents in future surveillances complementing LIRAa’s actions for efficient monitoring.

Detection of Transovarial Transmission on Aedes sp. in Gombong Kebumen Central Java

Abstract. Gombong Subdistrict is one of dengue-endemic area in Kebumen Regency, Central Java. The high number of dengue cases in this area raises the question of whether there has been transovarial transmission occured from the Aedes sp. to their eggs. Transovarial transmission could be dangerous because the next generation of mosquitoes can directly become competent vectors as transmitters of the dengue virus (DENV). The purpose of this study is to detect dengue virus transovarial transmission in Aedes sp. in Gombong Subdistrict. This is a descriptive research in Gombong, Semanding, and Kali Tengah villages, Gombong Sub District. A total of 300 houses, 100 houses from each village were selected in this study. There were 600 Oviposition traps (ovitraps) were installed both inside and outside of houses for 6 days. Ovitraps were calculated by its Ovitrap Index (OI). Detection of transovarial transmission was carried by rearing field mosquitoes to Filial 1 then identified by RT-PCR assay. This study showed that OI in the three villages was higher in outdoor compared to indoor positions. All tested samples were negative DENV, indicated that there were no transovarial transmission occured at the study sites. Transmission in these study areas might still through horizontal mechanism transmission by mosquito bites. Although there is no transovarial transmission, awareness of dengue transmission must be continued by eradicating of mosquito nests such as 3M plus activities on a regular basis

Biology characteristics of Aedes albopictus (Diptera: Culicidae) in Central Zones of Shah Alam, Selangor

Aedes sp. mosquitoes are the known vectors of dengue fever. The factors influencing the continuous occurrence of dengue fever have not yet been studied or fully understood. Therefore, this study was designed to assess the demographic parameter of Aedes albopictus (Diptera: Culicidae) in terms of their development, survival, and reproduction in Central Zone of Shah Alam. The study was conducted through ovitrap surveillance and mosquito rearing method. A total of 570 ovitraps were placed in nineteen (n=19) localities in the Central Zone of Shah Alam. Positive Ovitrap Index (POI) and mean eggs per trap (MET) was used to identify the infestation profile of dengue vectors in a locality. The biology and demographic parameters of dengue vector, such as development rate, survivorship and mortality rate were observed for each locality. Section 18 (POI: 73.3, MET: 35.05) was one of the localities that has high distribution and abundance of dengue vector. It was found that Section 24 was the locality with high development rate, high survivorship, and low mortality rate. These parameters were then used to formulate a life table for Aedes species mosquitoes in Central Zone of Shah Alam. As a conclusion life table analysis can be used to estimate the life cycle of the dengue vector. However, in-depth studies on the life table analysis need to be done in order to gain more understanding and so that authorized parties could plan for proper action to be taken.

PERBEDAAN KEPADATAN TELUR NYAMUK AEDES AEGYPTI BERDASARKAN LANTAI

Dengue fever caused by Aedes aegypti mosquito is the main vector of dengue hemorrhagic fever (DHF) in urban areas. This study aims to determine differences in density of Aedes aegypti mosquitoes based on the floor of the building, because the number of dengue fever in Bukittinggi is quite high. This research was conducted in May-June 2019 in the STIKes Fort De Kock Bukittinggi building. This research is experimental with the independent variable building floor density and the dependent variable is the density of the aedes aegypti mosquito seen from the ovitrap index. The object of the experiment was ovitrap, the number of ovitraps used was 54 ovitraps. The results of this study to determine differences in density of Aedes aegypti mosquitoes based on the floor of the building at various concentrations were tested using ANOVA. The results showed that of 54 ovites there were 86 Aedes aegypti mosquito eggs. Based on the ANOVA test results with an ? value of 5% or 0.05, p value = 0.524 (p??) is obtained, which means that H? is accepted. So there is a minimum floor that does not have a significant difference in the density of Aedes aegypti mosquito eggs. It can be concluded that there is no difference based on the floor with the density of Aedes aegypti mosquito eggs including, with an ? value of 5% or 0.05, a p value = 0.524 (p??), which means that H? is accepted. So there is a minimum floor that does not have a significant difference in the density of Aedes aegypti mosquito eggs. Keywords :Floor,ovitrap,Aedes aegypti mosquito

Effectiveness and public acceptance of a slow release formulation of Bacillus thuringiensis israelensis (Mosquito Dunks®) in controlling the population density of dengue vectors in Sri Lanka

A slow release, solid formulation of Bacillus thuringiensis israelensis (Bti)-Mosquito Dunks® was evaluated for its effectiveness in controlling of dengue vectors in Sri Lanka. A small-scale simulation field study showed a high effectiveness of 98–100% mortality at 15 days post-treatment and the mortality rate started to drop down by 30 days post-treatment. The larval density in the large-scale field study showed a progressive drop during the post-treatment period achieving the highest by 30 days (62.5%) and a subsequent increase by 45 days post-treatment, while in the control area showed a continuous increase. Reduction in the mean number of positive breeding places per house among sampling bouts was highly significant (p = 0.016). In the control area, oviposition activity showed a marked reduction 15 days post-treatment (71.4% Ovi-trap index, 82.3% Egg density index) after an initial increase at 8 days post-treatment. Mean number of eggs per trap showed a highly significant difference among the sampling bouts in the test area. Public acceptance of the product was very high (93.3%). A single selective application of the Bti-Mosquito Dunks® when used at recommended dosage is effective in controlling population densities of vectors of dengue approximately up to 30 days.