Number Of Positive Containers Research Articles

Entomological surveillance of dengue vector Aedes aegypti in Delhi during COVID-19 pandemic

Introduction: Dengue has become endemic in Delhi and incidences are alarmingly risen due to key factors similar as occurring globally i.e. large scale migration to Delhi for economic avenues has led to mushrooming of unauthorised areas and lack of 24 X 7 water supply has compelled citizens to store water in improper containers thus increasing breeding sites. In Delhi, staff of vector-borne disease control programme was dedicated to prevention and control of COVID-19 Pandemic thereby compromising the entomological surveillance and control measures for VBDs. Material and Methods: This is a descriptive study based on analysis of entomological data generated during surveillance by the entomological team of City SP Zone under North Delhi Municipal Corporation from January 2020 to Jun 2021. Peridomestic areas were checked for the presence of mosquito breeding. If the container was found positive either source reduction was done or was treated with Temephos Granules.Results: In Delhi, previously approx. 70% of dengue cases were reported from the age group 11 to 40 years. In 2020, due to lockdown, no mobility in the human population might have restricted the Dengue cases. High breeding was reported during unlock period and dengue cases from mid-July 2020 onwards were increased. During post-monsoon, the number of positive containers increased proportionately may be due to reduced surveillance.Conclusion: Vector surveillance and strategies of Integrated Vector Management (IVM) suffered during Lockdown of 2020 and 2021. Any neglected co-infection of dengue along with COVID may lead to diagnostic and case management challenges. Hence surveillance of VBDs can’t be ignored in such situations as COVID-19.

Species composition and risk of transmission of some Aedes-borne arboviruses in some sites in Northern Ghana.

Aedes-borne viral diseases mainly Yellow Fever (YF), Dengue (DEN), Zika (ZIK) and Chikungunya (CHK) have contributed to many deaths’ in the world especially in Africa. There have been major outbreaks of these diseases in West Africa. Although, YF outbreaks have occurred in Ghana over the years, no outbreak of DEN, ZIK and CHK has been recorded. However, the risk of outbreak is high due to its proximity to West African countries where outbreaks have been recently been recorded. This study surveyed the mosquito fauna to assess the risk of transmission of Yellow fever (YFV), Dengue (DENV), Chikungunya (CHKV) and Zika (ZIKV) viruses in Larabanga and Mole Game Reserve areas in Northern Ghana. The immature and adult stages of Aedes mosquitoes were collected from Larabanga and Mole Game Reserve area. There was a significant (P>0.001) number of mosquitoes collected during the rainy season than the dry season. A total of 1,930 Aedes mosquitoes were collected during the rainy season and morphologically identified. Of these, 1,915 (99.22%) were Aedes aegypti and 15 (0.22%) were Aedes vittatus. During the dry season, 27 Ae. aegypti mosquitoes were collected. A total of 415 Ae. aegypti mosquitoes were molecularly identified to subspecies level of which Ae. (Ae) aegypti aegypti was the predominant subspecies. Both Ae. aegypti aegypti and Ae aegypti formosus exist in sympatry in the area. All Aedes pools (75) were negative for DENV, ZIKV and CHKV when examined by RT- PCR. Three Larval indices namely House Index, HI (percentage of houses positive for Aedes larvae or pupae), Container Index, CI (the percentage of containers positive for Aedes larvae or pupae) and Breteau Index, BI (number of positive containers per 100 houses inspected) were assessed as a measure for risk of transmission in the study area. The HI, CI and BI for both sites were as follows; Mole Game Reserve (HI, 42.1%, CI, 23.5% and BI, 100 for rainy season and 0 for all indices for dry season) and Larabanga (39%, 15.5% and 61 for rainy season and 2.3%, 1.3% and 2.3 for dry season). The spatial distribution of Aedes breeding sites in both areas indicated that Aedes larvae were breeding in areas with close proximity to humans. Lorry tires were the main source of Aedes larvae in all the study areas. Information about the species composition and the potential role of Aedes mosquitoes in future outbreaks of the diseases that they transmit is needed to design efficient surveillance and vector control tools.

Density of Aedes Aegypti Larves Based on Knowledge, Attitude and Action of Terminal Management in Daya Regional Terminal Kota Makassar

Purpose: This study aims to determine the density of Aedes aegypti larvae based on the knowledge, attitudes and actions of terminal managers at the Regional Terminal Daya Makassar City.
 Methods: The research design used was descriptive observational. There are two samples in this study, namely the container sample and the terminal manager sample. The sampling technique for containers used total sampling method and for terminal managers, purposive sampling method was used. Data were analyzed by univariate.
 Results: The results of the analysis showed that the number of positive containers for larvae was 69 (CI = 33%) with a value of DF = 8 and was a high density category. A total of 9 respondents (39.1%) had good knowledge and 14 respondents (60.9%) had poor knowledge. A total of 10 respondents (43.5%) had a good attitude and as many as 13 respondents (56.5%) had a bad attitude. In terms of action, (4.3%) of the respondents reflected good, while 22 respondents (95.7%) had actions in the unfavorable category.
 Conclusion: It is concluded that increasing public knowledge is essential to eradicate mosquito nests in the community. By enhancing the knowledge of the individuals, the PSN activities carried out routinely can break the life cycle of the mosquitoes that can cause DHF.The level of education that the terminal manager has, the better the ability to absorb the information provided will affect the knowledge held by the terminal manager.

Influence of strategic points in the dispersion of Aedes aegypti in infested areas.

ABSTRACTOBJECTIVE:To evaluate whether sites with large amount of potential breeding sites for immature forms of Aedes aegypti, called strategic points, influence in the active vector's dispersion into properties in their surroundings.METHODS:We selected four areas in the municipality of Campinas, three of them with strategic points classified as high, moderate, and low risk according to infestation and a control area, without strategic points. Between October 2015 and September 2016, we monthly installed oviposition traps and evaluated the infestation by Ae. aegypti in all properties of each selected area. To verify if there was vector dispersion from each strategic point, based on its location, we investigated the formation of clusters with excess of eggs or larvae or pupae containers, using the G i spatial statistics.RESULTS:The amount of eggs collected in the ovitraps and the number of positive containers for Ae. aegypti did not show clusters of high values concerning its distance from the strategic point. Both presented random distribution not spatially associated with the positioning of strategic points in the area.CONCLUSIONS:Strategic points are not confirmed as responsible for the vector's dispersion for properties in their surroundings. We highlight the importance of reviewing the current strategy of the vector control program in Brazil, seeking a balance from the technical, operational, and economic point of view, without disregarding the role of strategic points as major producers of mosquitoes and their importance in the dissemination of arboviruses in periods of transmission.

Analysis of Health Indicators in Two Rural Communities on the Colombian Caribbean Coast: Poor Water Supply and Education Level Are Associated with Water-Related Diseases.

Water-related diseases are closely linked with drinking water, sanitation, and hygiene (WASH) indicators, socioeconomic status, education level, or dwelling's conditions. Developing countries exhibit a particular vulnerability to these diseases, especially rural areas and urban slums. This study assessed socioeconomic features, WASH indicators, and water-related diseases in two rural areas of the Colombian Caribbean coast. Most of this population did not finish basic education (72.3%, N = 159). Only one of the communities had a water supply (aqueduct), whereas the other received water via an adapted tanker ship. No respondents reported sewage services; 92.7% (N = 204) had garbage service. Reported cases of diarrhea were associated with low education levels (P = 2.37 × 10-9) and an unimproved drinking water supply (P = 0.035). At least one fever episode was reported in 20% (N = 44) of dwellings, but the cases were not related to any indicator. The Aedes/House index (percentage of houses that tested positive for Aedes larvae and/or pupae) was 69%, the container index (percentage of water-holding containers positive for Aedes larvae or pupae) 29.4%, and the Breteau index (number of positive containers per 100 houses in a specific location) was three positive containers per 100 inspected houses. The presence of positive containers was associated with the absence of a drinking water supply (P = 0.04). The community with poorer health indicators showed greater health vulnerability conditions for acquisition of water-related diseases. In summary, water supply and educational level were the main factors associated with the presence of water-related diseases in both communities.

Actualización de los biotopos preimaginales de Aedes aegypti (Linnaeus, 1762) en Camagüey, Cuba

Several illnesses of vectorial origin have a great medical and veterinary relevance, due to the adaptations developed by the species involved in their transmission. To support preventive programs with updated ecological information of Ae. aegypti populations, an entomological survey was carried out in three Health Areas of Camagüey, Cuba, during low and high rain seasons of 2013. For this, we assessed the type and number of positive containers, quantified larvae and pupae in positive containers, according to the container location in or outside the house. Both the container representativeness percentage and the pupal index by specific containers were calculated (PIsC). The total of houses as well as the positive habitual-use and non-disposable containers were compared among weather seasons, using the non parametric Chi2 test. The existent relationship between the total of positive houses and the habitual-use and non-disposable container was explored through the test of proportions hypothesis, with a level of significance of P ≤ 0.05. Ae. aegypti colonized 73 different types of containers, being habitual-use and non-disposable a 23.2 %. This number included 76 % of the positive containers. The greatest larvae collections were obtained in exterior water tanks and barrels, with important pupal production (PIsC = 3.04 and 1.75, respectively), and as well as significant differences towards the rainy season respect to positive houses (PUIA: Chi2 = 32.89; P = 0.00; PUE: Chi2 = 127.44; P = 0.00 and PUJAM: Chi2 = 127.44; P = 0.00), and the habitual-use and non-disposable container (PUIA: Chi2 = 30.37; P = 0.00; PUE: Chi2 = 37.26; P = 0.00 and PUJAM: Chi2 = 81.82; P = 0.00). These data reinforce the priority given to the control and surveillance actions conducted by the community in their respective houses.

Fly emergence from manure of Japanese quail fed thymol- or isoeugenol-supplemented diets

Many problems in poultry production are caused by a combination of interrelated factors such as management, stress, nutrition, and exposure to pathogens. Saprophagous flies that develop in poultry manure are a potential route of pathogen transmission. Besides being a nuisance, defecation and regurgitation of flies soil equipment and structures and can reduce light levels of lighting fixtures. These effects clearly affect management and may contribute to reductions in poultry egg production, health, and welfare. Many essential oils or their main components have bioactive effects such as natural repellents and insecticides, antioxidants, anticholesterolemics, and antimicrobials. This study evaluated if supplementing quail feed with thymol or isoeugenol as functional food could alter the production of flies from manure. Dropping samples deposited by quail fed with a supplementation of 2,000 mg of thymol or isoeugenol per kg of feed or no supplement (control) were collected. Each sample was incubated inside an emergence cage that was inspected daily to collect emerging adult flies. Fewer flies emerged from droppings of quail fed a thymol-supplemented diet (P = 0.01) and there was a tendency to a lower emergence from droppings of isoeugenol-fed quail (P = 0.09). The number of positive containers for Musca domestica was smaller from quail droppings of thymol- (P = 0.02) or isoeugenol- (P = 0.01) supplemented feed than from the control counterparts, suggesting an oviposition repellent effect. Supplementing quail feed with thymol or isoeugenol has an overall moderate effect against flies, reducing M. domestica emergence.

Crouching Tiger, Hidden Trouble: Urban Sources of Aedes albopictus (Diptera: Culicidae) Refractory to Source-Reduction

Our ultimate objective is to design cost-effective control strategies for Aedes albopictus, the Asian tiger mosquito, an important urban nuisance and disease vector that expanded worldwide during the last 40 years. We conducted mosquito larval surveys from May through October 2009 in the City of Trenton, New Jersey, USA, while performing intensive monthly source-reduction campaigns that involved removing, emptying, or treating all accessible containers with larvicides and pupicides. We examined patterns of occurrence of Ae. albopictus and Culex pipiens, another urban mosquito, among different container types by comparing observed and expected number of positive containers of each type. Expected use was based on the relative frequency of each container type in the environment. Aedes albopictus larvae and pupae were found significantly more often than expected in medium volumes of water in buckets and plant saucers but were rarely collected in small volumes of water found in trash items such as discarded cups and cans. They were also absent from large volumes of water such as in abandoned swimming pools and catch basins, although we consistently collected Cx. pipiens from those habitats. The frequency of Ae. albopictus in tires indicated rapid and extensive use of these ubiquitous urban containers. Standard larval-based indices did not correlate with adult catches in BG-Sentinel traps, but when based only on Ae. albopictus key containers (buckets, plant saucers, equipment with pockets of water, and tires) they did. Although we found that only 1.2% of the 20,039 water-holding containers examined contained immature Ae. albopictus (5.3% if only key containers were counted), adult populations were still above nuisance action thresholds six times during the 2009 mosquito season. We conclude that in urban New Jersey, effective source reduction for Ae. albopictus control will require scrupulous and repeated cleaning or treatment of everyday use containers and extensive homeowner collaboration.

Intersectoral coordination, community empowerment and dengue prevention: six years of controlled interventions in Playa Municipality, Havana, Cuba

To document the process, outcome and effectiveness of a community-based intervention for dengue control. The primary intervention, focused on strengthening intersectoral coordination, was initiated by researchers in January 2000 in a pilot area in Playa municipality, Havana. In August 2002 health authorities extended the intervention to neighbouring areas, one of which was selected for evaluation. In August 2003 a complementary strategy, focused on community empowerment, was initiated in half of the pilot area. In our control area, routine dengue activities continued throughout the study period. Longitudinal process assessment was carried out using document analysis, interviews and group discussions. Random population surveys in 1999, 2002 and 2005 assessed levels of participation and behavioural changes. Entomological surveillance data from 1999 to 2005 were used to determine effectiveness. Mean scores for participation in the pilot area were 1.6, 3.4 and 4.4 at baseline, and 2 years after initiating intersectoral coordination and intersectoral coordination plus community empowerment interventions, respectively. While in the control area little behavioural change was observed over time, changes were considerable in the pilot and extension areas, with 80% of households involved in the community empowerment intervention showed adequate behavioural patterns. The pilot and extension areas attained comparable entomological effectiveness with significantly lower Breteau indices (BIs) than the control area. The pilot (sub-) area with the community empowerment intervention reached BIs below 0.1 that continued to be significantly lower than the one in the control area until the end of the study. The study showed a trend in the levels and quality of participation, behavioural change and effectiveness of Aedes control from the routine activities only over an intervention with intersectoral coordination to one that combined intersectoral coordination and community empowerment approach.

The Effect of West Nile Virus Perceptions and Knowledge on Protective Behavior and Mosquito Breeding in Residential Yards in Upstate New York

A knowledge, attitudes, and practices (KAP) questionnaire combined with entomological surveys of residential mosquito-breeding sites were conducted in two Upstate New York neighborhoods. We tested the hypothesis that "correct" West Nile virus (WNV) knowledge and perceptions correspond with the use of practices that prevent mosquitoes from breeding and biting. Our results demonstrate that perceptions of WNV relate to the number of positive containers in yards and the use of mosquito preventive measures. In contrast, WNV knowledge was not related. Culex pipiens and Cx. restuans were common species found breeding in containers. Aedes japonicus was the most abundant species in 77% of positive containers (buckets, flower pots, and birdbaths). This new, invasive mosquito together with the Culex species identified in this study represent significant potential as vectors of WNV and other arboviruses affecting human and animal health. We conclude that more training and education programs should focus on WNV control strategies and recognizing mosquito breeding in residential yards. This is the first study to directly investigate the relationship between KAP and breeding of WNV vectors in residential yards.

Hallazgo de Aedes aegypti (Linnaeus 1762), en el casco urbano del corregimiento de La Pedrera, Amazonas, Colombia

Before 2005, Aedes aegypti had not been recorded in the Colombian province of Amazonas. Because this species has been increasing its range throughout Colombia, an entomological surveillance program has been routinely directed toward detecting it presence in Amazonas by the Amazonas State Health Authority. Surveillance data were used as the basis for recording Aedes aegypti in Amazonas Province. Household surveys of Ae. aegypti larvae were conducted by trained personnel belonging to the Amazonas State Health Authority. The following standard larval indices were estimated: house index (HI)--the percentage of premises with positive containers, the container index (CI)--the percentage of positive containers among the water-holding containers, and the Breteau index (BI)--the number of positive containers per 100 premises. Residents were questioned concerning their perception of mosquito presence in their houses. Subsequently, control activities were undertaken to reduce the mosquito's infestation. Aedes aegypti was found in the urban area of the village of La Pedrera. During the first household survey, the indices were HI=29.6%, CI=9.0% and, BI=40.8%. After control activities, these values decreased; however, elimination of the infestation was not possible in this geographical area. The community recognizes the mosquito immature forms in water containers in houses and associated them as vectors of several diseases. The presence of Ae. aegypti mosquitoes in the village La Pedrera was verified. Aedes albopictus was not found in this area.

Chikungunya-type fever outbreak: some aspects related to this new epidemic in Jaffna district, northern Sri Lanka

Chikungunya, a disease caused by alpha virus and transmitted by Aedes mosquitoes, had seldom been heard by the people of Jaffna until early November 2006, although a chikungunya-type fever epidemic was reported in western Sri Lanka in 1965 [1-3]. While few samples have been confirmed for the presence of CHIK virus, widespread of chikungunya-type fever outbreaks have been reported from many parts of the country since September 2006. Similar outbreaks of CHIK virus have also been reported from many states of India including Tamil Nadu since December 2005 [4-6]. In Sri Lanka, Mannar district, which lies very close (32km) to Rameshwaram island of Tamil Nadu, was the area to first experience the fever outbreak. It has been estimated that the ongoing fever epidemic in Jaffna district has affected thousands of people between November and mid December 2006 (personal communicationDPDHS Office, Jaffna). It is difficult to establish the origin and mode of spread of CHIK fever to Jaffna because this epidemic occurred when the main land route (A-9) between Jaffna and the rest of the country remained closed since August 2006 owing to renewed armed conflict. Only sea and air transport facilities are available to facilitate public movement between Jaffna and the rest of the country. The closure of the main highway has hindered the availability of food and drugs in the market. Even the available items are sold for higher prices, creating an additional burden for ordinary people to meet daily requirements and raising concerns about nutrition and health. Although the disease has affected a large number of people, there are no facilities in Jaffna Teaching Hospital to diagnose CHIK fever. According to the health authorities in Jaffna, a few samples sent by air to the Medical Research Institute were confirmed for CHIK virus. A study was carried out under these circumstances in a highly affected village in Jaffna district to assess the severity of the fever as well as public attitudes and responses toward the epidemic. A structured questionnaire-based study was carried out in mid December 2006. Entire households in Inuvil-West (09°43’N:80°01’E), a residential rural area located 7km away from Jaffna city, were visited during this study. The suspected chikungunya-type fever cases were initially reported from this locality and almost the entire village was affected by the disease. There is a single Government Central Dispensary in addition to a privately owned hospital and a few small medical centers. The questionnaire was composed of multiple choice questions and an interview. There are four major parts: a) demographic information, b) symptoms and manner of treatment for chikungunya fever, c) knowledge about chikungunya, mosquitoes and mosquito-borne diseases, and d) attitude and practice to prevent mosquito bites. Basically the structured questionnaire was formulated to elucidate information on: monthly income, educational background, number of family members affected by fever, symptoms, manner of treatment (from government hospitals or private medical centers), recovery, how much was known about chikungunya, mosquitoes and their role in disease transmission, severity of the mosquito menace, mosquito biting time, and type of personal protective measures taken against mosquito bites. The questionnaires were written in Tamil (native language) and administered to heads of households from 0900 h to 1300 h. If no male head of household was available, a female head of household was interviewed. Larval surveys were also carried out in houses of all the respondents to obtain the following Aedes larval indices a) House Index (HI) the percentage of houses or premises with one or more habitats positive for Aedes larvae, b) Container Index (CI) the percentage of water holding containers positive for Aedes larvae, and c) Breteau Index (BI) the number of positive containers per 100 houses [7]. One hundred sixty two heads of households (67 males and 95 females), consisting 653 individuals, were interTropical Medicine and Health Vol. 35 No. 3, 2007, pp. 249-252 Copyright 2007 by The Japanese Society of Tropical Medicine

Towards active community participation in dengue vector control: results from action research in Santiago de Cuba, Cuba

Community participation is advocated as essential for attaining effective dengue prevention, but knowledge of how to foster this is limited. In Santiago de Cuba, multiple small task forces were created at the neighbourhood level that included all stakeholders in the control of Aedes aegypti. The task forces assessed the perceived needs and elaborated action plans to promote specific behavioural change and to reduce environmental risks through social communication strategies and intersectoral local government activities. We monitored five dimensions of the participation process and assessed behavioural and environmental results and entomological outcomes. Participation was weak to good. At the household level, uncovered water storage containers decreased from 49.3% to 2.6% between 2000 and 2002, and removing larvicide from them dropped from 45.5% to 1%. There was a reduction of 75% in the absolute number of positive containers and a significant decrease from 1.23% to 0.35% in the house index. Local task forces, in which the interests of householders as well as vector control workers are directly represented, can lead to effective government-community partnerships that resolve problems of mutual concern.

Factors that modify the larval indices of Aedes aegypti in Colima, Mexico

In order to investigate the variables that could have the greatest impact on larval indices of Aedes aegypti, the main vector of dengue, a descriptive, longitudinal study was carried out in the city of Colima, which is located in the Mexican Pacific coastal state of the same name. A total of 187 dwellings were inspected to determine the house index (HI) and the number of positive containers per house (C+/H), during the rainy season and the dry season. The following were recorded as independent variables: the air temperature, the season, the use of ultra low volume (ULV) spraying of malathion, the Premise Condition Index (PCI), and the score on a survey of knowledge, attitudes, and practices (KAP). Both the multivariate logistic regression and the multivariate lineal regression showed a reduction of HI and C+/H due to the effect of the dry season. Paradoxically, the temperature seemed to have a negative correlation with the larval indices, and this effect was more pronounced during the dry season. The PCI showed the most significant correlation with HI and C+/H, independently of the other variables. The ULV sprayings showed a small negative effect on the indices, while the KAP score did not indicate any association at all. Some conclusions that can be drawn from this study are as follows: higher temperatures can reduce the larval indices during the dry season, the PCI can be an adequate estimator of the Ae. aegypti infestation rate, ULV spraying reduces the number of larval breeding sites, and the KAP score has little association with the larval indices.

Distribution of Container-Inhabiting Aedes Larvae (Diptera: Culicidae) at a Dengue Focus in Thailand

A Thai village with dengue transmission was surveyed for Aedes aegypti (L.) and Ae. albopictus (Skuse) larvae at the end of the rainy season. All containers (1,819) in 186 households were surveyed, recording the presence of larvae, container type, level of water, kind of cover, and location. The number of positive containers was proportional to the total number of containers in a household. Standard water jars (approximately 200 liters) contributed 57% and small water jars (< 100 liters) contributed 16% of the total infested containers. Each of the other 10 container types contributed < or = 10% of the total infested containers and were not statistically different from each other. Containers inside houses were infested significantly more often than were those outdoors, those under elevated houses or roofs, or those in bathrooms. Unexpectedly, standard water jars located outdoors that were covered with commercial metal lids were infested significantly more often than were uncovered jars.