Types Of Water Containers Research Articles

Epidemic risk of arboviral diseases: Determining the habitats, spatial-temporal distribution, and abundance of immature Aedes aegypti in the Urban and Rural areas of Zanzibar, Tanzania.

In Zanzibar, little is known about the arboviral disease vector Aedes aegypti in terms of abundance, spatio-temporal distribution of its larval habitats or factors associated with its proliferation. Effective control of the vector requires knowledge on ecology and habitat characteristics and is currently the only available option for reducing the risk of arboviral epidemics in the island nation of Zanzibar. We conducted entomological surveys in households and surrounding compounds from February to May 2018 in the urban (Mwembemakumbi and Chumbuni) and rural (Chuini and Kama) Shehias (lowest government administrative unit) situated in the Urban-West region of Unguja island, Zanzibar. Larvae and pupae were collected, transported to the insectary, reared to adult, and identified to species level. Characteristics and types of water containers were also recorded on site. Generalized linear mixed models with binomial and negative binomial distributions were applied to determine factors associated with presence of Ae. aegypti immatures (i.e. both larvae and pupae) or pupae, alone and significant predictors of the abundance of immature Ae. aegypti or pupae, respectively. The survey provided evidence of widespread presence and abundance of Ae. aegypti mosquitoes in both urban and rural settings of Unguja Island. Interestingly, rural setting had higher numbers of infested containers, all immatures, and pupae than urban setting. Likewise, higher House and Breteau indices were recorded in rural compared to the urban setting. There was no statistically significant difference in Stegomyia indices between seasons across settings. Plastics, metal containers and car tires were identified as the most productive habitats which collectively produced over 90% of all Ae. aegypti pupae. Water storage, sun exposure, vegetation, and organic matter were significant predictors of the abundance of immature Ae. aegypti. Widespread presence and abundance of Ae. aegypti were found in rural and urban areas of Unguja, the main island of Zanzibar. Information on productive habitats and predictors of colonization of water containers are important for the development of a routine Aedes surveillance system and targeted control interventions in Zanzibar and similar settings.

Impacts of biotic and abiotic parameters on immature populations of Aedes aegypti

In recent centuries, the mosquito Aedes aegypti has spread into most urban areas throughout the tropics. This species is considered the main vector of the chikungunya, dengue, yellow fever and Zika viruses and causes major public health issues. The aim of this study is to investigate the relative influence of biotic and abiotic parameters on immature populations of Ae. aegypti. During a one-year-long field experiment, we monitored 108 macroinvertebrate aquatic communities inhabiting four types of water containers across three different urbanized sites in a Neotropical city. A multimodel inference approach revealed that, in addition to abiotic parameters, biotic interactions with aquatic organisms had an important influence on the abundance of Ae. aegypti and that the urbanized site considered influences the outcomes of the interactions. Controphic species other than mosquitoes aided Ae. aegypti development, suggesting a mechanism of facilitation through a chain of processes. However, the abundance of Ae. aegypti was lowered by competition with native mosquito species in the slightly urbanized area and by predation in more urbanized areas. Competitive displacement and reduction, as well as predation by native aquatic organisms, can be considered a form of ecosystem service. The conservation and/or augmentation of natural enemies should improve the short- and long-term success of incompatible and/or sterile insect techniques, thus opening up perspectives for the future of mosquito management.

Seasons and water container types affecting Culex spp. in southern Thailand

Seasons and water container types affecting Culex spp. in southern Thailand

Effect of temperature on the embryronic development of Aedes albopictus (Diptera: Culicidae)

Aedes albopictus (Skuse) is known to be an invasive species and it becomes the main concern on the changes of climate that will cause the expansion and spreading of the mosquito populations. Therefore, this study was designed to determine the development cycles of Ae. albopictus larval at different water temperatures and water holding containers in a controlled environment by using temperature regulated water bath to cover a range of temperature from 25ºC to 35ºC. The experiment was completely randomized in factorial 3 x 5 design (15 treatments), three populations (Selangor-strain, Malacca-strain and Sabah-strain) and three replications. The analysis was based on the observation of the immature stages development (days) in response to different water temperature regimes and types of water containers. The development between three different strains showed no significant difference (p-value: 0.594), however the effect of water temperature on local strains showed that the temperature might shorten the development period of Ae. albopictus. This study concluded that the information on the larval development could act as a preliminary warning in recognizing the pattern of outcome due to seasonal changes throughout the year in Malaysia.

Association of Knowledge, Attitude and Practice of Cleaning Service with the Amount of Mosquito Larvae in Water Container At Bhayangkara Hospital, Palembang, Indonesia

Bacgkround: Efforts in the eradication of mosquito breeding have been done, but have not shown maximum results due to lack of community participation caused by several factors, such as lack of knowledge, attitude and practice that are considered to play important role in reducing the incidence of vector-borne diseases transmitted by mosquitoes. This study aimed was to determine the relationship of knowledge, attitude and practice of cleaning services with the amount of mosquito larvae at water container around Bhayangkara Hospital Palembang. Populations in this study were 25 cleaning services in Bhayangkara Hospital Palembang.
 Methods: Samples in this study were all populations taken by using total sampling technique. Data included the number and types of water containers, the number and species of mosquito larvae found in the water containers, and data of knowledge, attitude and practice of cleaning services. The results were analysed using Kruskal-Wallis statistic test.
 Results: There were 75 water containers, 63 water containers were indoors, one of them contains larvae, and 12 water containers were outdoors, the type of two outdoors water containers that contained larvae were plastic buckets. Total larvae that found were 16 larvae of Aedes aegypti. Based on Kruskal-Wallis statistic test, there was no average difference between the number of mosquito larvae based on knowledge with p>alpha± (0.072>0.05), and there was an average difference between the number of mosquito larvae based on attitudewith p<alpha± (0.006>0.05) and practice with p<alpha± (0.019<0.05).
 Conclusion: There was a negative association between attitude and practice against the number of mosquito larvae, but not with knowledge.

Modeling the complexities of water, hygiene, and health in Limpopo Province, South Africa.

Researchers have long studied the causes and prevention strategies of poor household water quality and early childhood diarrhea using intervention-control trials. Although the results of such trails can lead to useful information, they do not capture the complexity of this natural/engineered/social system. We report on the development of an agent-based model (ABM) to study such a system in Limpopo, South Africa. The study is based on four years of field data collection to accurately capture essential elements of the communities and their water contamination chain. An extensive analysis of those elements explored behaviors including water collection and treatment frequency as well as biofilm buildup in water storage containers, source water quality, and water container types. Results indicate that interventions must be optimally implemented in order to see significant reductions in early childhood diarrhea (ECD). Household boiling frequency, source water quality, water container type, and the biofilm layer contribution were deemed to have significant impacts on ECD. Furthermore, concurrently implemented highly effective interventions were shown to reduce diarrhea rates to very low levels even when other, less important practices were suboptimal. This technique can be used by a variety of stakeholders when designing interventions to reduce ECD incidences in similar settings.

Estimating dengue vector abundance in the wet and dry season: implications for targeted vector control in urban and peri-urban Asia

Background: Research has shown that the classical Stegomyia indices (or “larval indices”) of the dengue vector Aedes aegypti reflect the absence or presence of the vector but do not provide accurate measures of adult mosquito density. In contrast, pupal indices as collected in pupal productivity surveys are a much better proxy indicator for adult vector abundance. However, it is unknown when it is most optimal to conduct pupal productivity surveys, in the wet or in the dry season or in both, to inform control services about the most productive water container types and if this pattern varies among different ecological settings.Methods: A multi-country study in randomly selected twelve to twenty urban and peri-urban neighborhoods (“clusters”) of six Asian countries, in which all water holding containers were examined for larvae and pupae of Aedes aegypti during the dry season and the wet season and their productivity was characterized by water container types. In addition, meteorological data and information on reported dengue cases were collected.Findings: The study reconfirmed the association between rainfall and dengue cases (“dengue season”) and underlined the importance of determining through pupal productivity surveys the “most productive containers types”, responsible for the majority (>70%) of adult dengue vectors. The variety of productive container types was greater during the wet than during the dry season, but included practically all container types productive in the dry season. Container types producing pupae were usually different from those infested by larvae indicating that containers with larval infestations do not necessarily foster pupal development and thus the production of adult Aedes mosquitoes.Conclusion: Pupal productivity surveys conducted during the wet season will identify almost all of the most productive container types for both the dry and wet seasons and will therefore facilitate cost-effective targeted interventions.

Community mobilization and household level waste management for dengue vector control in Gampaha district of Sri Lanka; an intervention study

Introduction: Waste management through community mobilization to reduce breeding places at household level could be an effective and sustainable dengue vector control strategy in areas where vector breeding takes place in small discarded water containers. The objective of this study was to assess the validity of this assumption.Methods: An intervention study was conducted from February 2009 to February 2010 in the populous Gampaha District of Sri Lanka. Eight neighborhoods (clusters) with roughly 200 houses each were selected randomly from high and low dengue endemic areas; 4 of them were allocated to the intervention arm (2 in the high and 2 in the low endemicity areas) and in the same way 4 clusters to the control arm. A baseline household survey was conducted and entomological and sociological surveys were carried out simultaneously at baseline, at 3 months, at 9 months and at 15 months after the start of the intervention. The intervention programme in the treatment clusters consisted of building partnerships of local stakeholders, waste management at household level, the promotion of composting biodegradable household waste, raising awareness on the importance of solid waste management in dengue control and improving garbage collection with the assistance of local government authorities.Results: The intervention and control clusters were very similar and there were no significant differences in pupal and larval indices of Aedes mosquitoes. The establishment of partnerships among local authorities was well accepted and sustainable; the involvement of communities and households was successful. Waste management with the elimination of the most productive water container types (bowls, tins, bottles) led to a significant reduction of pupal indices as a proxy for adult vector densities.Conclusion: The coordination of local authorities along with increased household responsibility for targeted vector interventions (in our case solid waste management due to the type of preferred vector breeding places) is vital for effective and sustained dengue control.

Eco-bio-social determinants of dengue vector breeding: a multicountry study in urban and periurban Asia

To study dengue vector breeding patterns under a variety of conditions in public and private spaces; to explore the ecological, biological and social (eco-bio-social) factors involved in vector breeding and viral transmission, and to define the main implications for vector control. In each of six Asian cities or periurban areas, a team randomly selected urban clusters for conducting standardized household surveys, neighbourhood background surveys and entomological surveys. They collected information on vector breeding sites, people's knowledge, attitudes and practices surrounding dengue, and the characteristics of the study areas. All premises were inspected; larval indices were used to quantify vector breeding sites, and pupal counts were used to identify productive water container types and as a proxy measure for adult vector abundance. The most productive vector breeding sites were outdoor water containers, particularly if uncovered, beneath shrubbery and unused for at least one week. Peridomestic and intradomestic areas were much more important for pupal production than commercial and public spaces other than schools and religious facilities. A complex but non-significant association was found between water supply and pupal counts, and lack of waste disposal services was associated with higher vector abundance in only one site. Greater knowledge about dengue and its transmission was associated with lower mosquito breeding and production. Vector control measures (mainly larviciding in one site) substantially reduced larval and pupal counts and "pushed" mosquito breeding to alternative containers. Vector breeding and the production of adult Aedes aegypti are influenced by a complex interplay of factors. Thus, to achieve effective vector management, a public health response beyond routine larviciding or focal spraying is essential.

Reducing costs and operational constraints of dengue vector control by targeting productive breeding places: a multi‐country non‐inferiority cluster randomized trial

To test the non-inferiority hypothesis that a vector control approach targeting only the most productive water container types gives the same or greater reduction of the vector population as a non-targeted approach in different ecological settings and to analyse whether the targeted intervention is less costly. Cluster randomized trial in eight study sites (Venezuela, Mexico, Peru, Kenya, Thailand, Myanmar, Vietnam, Philippines), with each study area divided into 18-20 clusters (sectors or neighbourhoods) of approximately 50-100 households each. Using a baseline pupal-demographic survey, the most productive container types were identified which produced >or=55% of all Ae. aegypti pupae. Clusters were then paired based on similar pupae per person indices. One cluster from each pair was randomly allocated to receive the targeted vector control intervention; the other received the 'blanket' (non-targeted) intervention attempting to reach all water holding containers. The pupal-demographic baseline survey showed a large variation of productive container types across all study sites. In four sites the vector control interventions in both study arms were insecticidal and in the other four sites, non-insecticidal (environmental management and/or biological control methods). Both approaches were associated with a reduction of outcome indicators in the targeted and non-targeted intervention arm of the six study sites where the follow up study was conducted (PPI, Pupae per Person Index and BI, Breteau Index). Targeted interventions were as effective as non-targeted ones in terms of PPI. The direct costs per house reached were lower in targeted intervention clusters than in non-targeted intervention clusters with only one exception, where the targeted intervention was delivered through staff-intensive social mobilization. Targeting only the most productive water container types (roughly half of all water holding container types) was as effective in lowering entomological indices as targeting all water holding containers at lower implementation costs. Further research is required to establish the most efficacious method or combination of methods for targeted dengue vector interventions.

Studies on the Comparative Oviposition Behavior of Aedes (Stegomyia) Albopictus and Aedes (Stegomyia) Polynesiensis Marks1

Comparative studies on the oviposition behavior of Aedes (Stegomyia) albopictus and A.(S.) polynesiensis were initiated to determine whether these 2 species would select the same breeding sites and, therefore, whether co-habitation of the larval habitats would occur. The oviposition behavior was found to be nearly identical in that both species selected the same types of water containers, and preferred alkaline waters with low illumination and dark color. High concentrations of ammonia and protein solutions were repellent, whereas infusions were most attractive at high concentrations. However, A. polynesiensis females preferred grass over leaf infusion, whereas the reverse was true for A. albopictus. The presence of larvae and pupae in the breeding waters had no effect on the ovipositing females. However, it appeared that some oviposition attractant was liberated into the breeding waters by female A. albopictus; even A. polynesimsis females preferred waters contaminated by the previous presence of eggs of A. albopictus rather than of A. polynesiensis. While gravid females of both species apparently utilize sight, smell and contact chemoreception in choosing breeding waters, A. albopictus responded positively to water colored to mimic a leaf or grass infusion to a greater extent than A. polynesiensis did.