Environmental Concentrations of Antibiotics May Diminish Wolbachia infections in Aedes aegypti (Diptera: Culicidae)

2019 ◽  
Vol 56 (4) ◽  
pp. 1078-1086 ◽  
Author(s):  
Nancy M Endersby-Harshman ◽  
Jason K Axford ◽  
Ary A Hoffmann
Keyword(s):  
Aedes Aegypti ◽  
Cytoplasmic Incompatibility ◽  
South East Asia ◽  
Tetracycline Antibiotics ◽  
Tropical Regions ◽  
Breeding Sites ◽  
Septic Tanks ◽  
Dengue Transmission ◽  
Wolbachia Density ◽  
Subterranean Water

Abstract Wolbachia-infected Aedes aegypti (L.) mosquitoes for control of dengue transmission are being released experimentally in tropical regions of Australia, south-east Asia, and South America. To become established, the Wolbachia Hertig (Rickettsiales: Rickettsiaceae) strains used must induce expression of cytoplasmic incompatibility (CI) in matings between infected males and uninfected females so that infected females have a reproductive advantage, which will drive the infection through field populations. Wolbachia is a Rickettsia-like alphaproteobacterium which can be affected by tetracycline antibiotics. We investigated whether exposure of Wolbachia-infected mosquitoes to chlortetracycline at environmentally relevant levels during their aquatic development resulted in loss or reduction of infection in three strains, wAlbB, wMel, and wMelPop. Wolbachia density was reduced for all three strains at the tested chlortetracycline concentrations of 5 and 50 µg/liter. Two of the strains, wMel and wMelPop, showed a breakdown in CI. The wAlbB strain maintained CI and may be useful at breeding sites where tetracycline contamination has occurred. This may include drier regions where Ae. aegypti can utilize subterranean water sources and septic tanks as breeding sites.

scholarly journals A wMel Wolbachia variant in Aedes aegypti from field-collected Drosophila melanogaster with increased phenotypic stability under heat stress

2022 ◽  
Author(s):  
Xinyue Gu ◽  
Perran A Ross ◽  
Julio Rodriguez-Andres ◽  
Katie L. Robinson ◽  
Qiong Yang ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Stress ◽  
Aedes Aegypti ◽  
Cytoplasmic Incompatibility ◽  
Vector Competence ◽  
Temperature Tolerance ◽  
Seasonal Temperature ◽  
Maternal Transmission ◽  
Tropical Regions ◽  
Host Fitness

Mosquito-borne diseases such as dengue, Zika and chikungunya remain a major cause of morbidity and mortality across tropical regions. Population replacement strategies involving the wMel strain of Wolbachia are being used widely to control mosquito-borne diseases transmitted by Aedes aegypti. However, these strategies may be influenced by environmental temperature because wMel is vulnerable to heat stress. wMel infections in their native host Drosophila melanogaster are genetically diverse, but few transinfections of wMel variants have been generated in Ae. aegypti mosquitoes. Here we successfully transferred a wMel variant (termed wMelM) originating from a field-collected D. melanogaster population from Victoria, Australia into Ae. aegypti. The new wMelM variant (clade I) is genetically distinct from the original wMel transinfection (clade III) generated over ten years ago, and there are no genomic differences between wMelM in its original and transinfected host. We compared wMelM with wMel in its effects on host fitness, temperature tolerance, Wolbachia density, vector competence, cytoplasmic incompatibility and maternal transmission under heat stress in a controlled background. wMelM showed a higher heat tolerance than wMel, with stronger cytoplasmic incompatibility and maternal transmission when eggs were exposed to heat stress, likely due to higher overall densities within the mosquito. Both wMel variants had minimal host fitness costs, complete cytoplasmic incompatibility and maternal transmission, and dengue virus blocking under standard laboratory conditions. Our results highlight phenotypic differences between closely related Wolbachia variants. wMelM shows potential as an alternative strain to wMel in dengue control programs in areas with strong seasonal temperature fluctuations.

scholarly journals Increasing Role of Roof Gutters asAedes aegypti(Diptera: Culicidae) Breeding Sites in Guadeloupe (French West Indies) and Consequences on Dengue Transmission and Vector Control

2012 ◽  
Vol 2012 ◽  
pp. 1-3 ◽  
Author(s):  
Joël Gustave ◽  
Florence Fouque ◽  
Sylvie Cassadou ◽  
Lucie Leon ◽  
Gabriel Anicet ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Vector Control ◽  
West Indies ◽  
French West Indies ◽  
Breeding Sites ◽  
The Past ◽  
Dengue Transmission ◽  
Intensive Control ◽  
Dengue Epidemics

During the past ten years, the islands of Guadeloupe (French West Indies) are facing dengue epidemics with increasing numbers of cases and fatal occurrences. The vectorAedes aegyptiis submitted to intensive control, with little effect on mosquito populations. The hypothesis that importantAe. aegyptibreeding sites are not controlled is investigated herein. For that purpose, the roof gutters of 123 houses were systematically investigated, and the percentage of gutters positive forAe. aegyptivaried from 17.2% to 37.5%, from humid to dry locations. In the dryer location, most of houses had no other breeding sites. The results show that roof gutters are becoming the most importantAe. aegyptibreeding sites in some locations in Guadeloupe, with consequences on dengue transmission and vector control.

GAMBARAN INDEKS LARVA AEDES AEGYPTI DI BUFFER WILAYAH KERJA BANDARA SEPINGGAN BALIKPAPAN

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Abdurrakhman abdurrakhman Abdurrakhman
Keyword(s):  
Aedes Aegypti ◽  
Buffer Zone ◽  
Chi Square ◽  
Cross Sectional ◽  
Breeding Sites ◽  
Dengue Disease ◽  
Vector Borne Diseases ◽  
Transportation Equipment ◽  
Chi Square Test ◽  
Larvae Density

ABSTRACT : The House index and Container Index in the buffer area of ​​the working area of ​​Balikpapan Sepinggan Airport is still above 1%, so the potential for the spread of dengue disease. Mobilization of people, goods and transportation equipment will increasingly affect the transmission of disease in ports and airports, especially for vector-borne diseases. This study aims to analyze the risk factors associated with larvae density of Aedes aegypti and describe the larvae index in the buffer zone of the Sepinggan Balikpapan Airport This study was a descriptive study with a cross sectional design. The sample in this study was 121 houses with a proportionate stratified random sampling, the research location was in the buffer zone of Sepinggan Balikpapan Airport in November 2018. The variables studied were houses with positive larvae containers, breeding sites and PSN behavior and larvasidation. The data was analyzed using the chi square test. There was a relationship between houses with larvae positive Aedes aegypti, behavior of Mosquito Nest Eradication (PSN) and larvasidation with larvae density of Aedes aegypti but not for breeding sites (p = 0.00 and 95% CI = 0.64), and   (p = 0.00 and 95% CI = 0.34). The description of several Aedes aegypti larvae index, namely House Index (HI) = 57.02%, Container Index (CI) = 24.36%, Bruteau Index (BI) = 148.76, and Flick Free Numbers (ABJ) = 42.98 %. Houses with larvae of Aedes aegypti larvae and PSN and larvasidation behavior were associated with larvae density of Aedes aegypti. The index of HI, CI and BI larvae is of high value so there is a risk of DBD transmission

Current Status of Pyrethroids Resistance in Aedes aegypti (Culicidae: Diptera) in Lahore District, Pakistan: A Novel Mechanistic Insight

2021 ◽  
Author(s):  
Saira Nawaz ◽  
Hafiz Muhammad Tahir ◽  
Muhammad Asif Mahmood ◽  
Muhammad Summer ◽  
Shaukat Ali ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Enzyme Level ◽  
Laboratory Strain ◽  
Current Status ◽  
Glutathione S Transferase ◽  
Development Of Resistance ◽  
Biochemical Assays ◽  
Dengue Transmission ◽  
Lambda Cyhalothrin ◽  
Glutathione S Transferases

Abstract Aedes aegypti (Linnaeus, 1762) is a major vector responsible for dengue transmission. Insecticides are being used as the most effective tool to control vector populations in Lahore, Pakistan. Control of Ae. aegypti is threatened by the development of resistance against insecticides. The current status of insecticide resistance was evaluated against pyrethroids (deltamethrin, cypermethrin, and lambda-cyhalothrin) in different populations of Lahore (Model Town, Mishri Shah, Sadar Cantt, Walton, and Valencia). The susceptibility of the larval and adult populations was tested following the standard WHO guidelines. Moderate to high levels of resistance were found against pyrethroids in the larval (RR50: 3.6–27.2 and RR90: 5–90) and adult populations (percentage mortality < 98%). Biochemical assays revealed a statistically significant increase in the enzyme level in all field populations compared to the laboratory strain. The value of esterase was one-fold higher, monooxygenase was 3.9- to 4.7-fold higher, and glutathione S-transferases was 1.9- to 2.6-fold higher in field populations compared to the laboratory strain. These results depict the presence of resistance against deltamethrin, cypermethrin, and lambda-cyhalothrin in field populations of Lahore mediated by metabolic enzymes i.e. esterases, monooxygenases, and glutathione S-transferase.

scholarly journals Spatial distribution of potential and positive Aedes aegypti breeding sites

Biomédica ◽  
2017 ◽  
Vol 37 ◽  
pp. 59
Author(s):  
Daniel Elías Cuartas ◽  
Genny Martínez ◽  
Diana María Caicedo ◽  
Jhonny Garcés ◽  
Yoseth Ariza-Araujo ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Aedes Aegypti ◽  
Breeding Sites

Introducción. La distribución espacial de Aedes aegypti es heterogénea, y la interacción entre criaderos positivos y potenciales en el intradomicilio y el extradomicilio es uno de los aspectos más difíciles de caracterizar en los programas de control vectorial.Objetivo. Describir la relación espacial entre los criaderos potenciales y positivos de A. aegypti en el intradomicilio y en el extradomicilio en un sector de Cali, Colombia.Materiales y métodos. Se hizo una encuesta entomológica con el objetivo de recolectar datos de los criaderos en el intradomicilio y el extradomicilio. El análisis exploratorio de los datos espaciales incluyó la localización, la tendencia espacial, la autocorrelación espacial local, la continuidad espacial y la correlación espacial de los criaderos positivos y potenciales según el hábitat.Resultados. Se determinaron las tendencias espaciales. Mediante el análisis de autocorrelación espacial local se ubicaron los conglomerados de criaderos potenciales y positivos del extradomicilio. Se encontró una correlación positiva entre los criaderos potenciales y los positivos y una correlación negativa entre el intradomicilio y el extradomicilio.Conclusiones. La relación espacial entre criaderos positivos y potenciales de A. aegypti en el intradomicilio y el extradomicilio es dinámica y muy sensible a las características de cada territorio, por lo que establecer su distribución en el espacio contribuye a la priorización de recursos y acciones en los programas de control vectorial.

scholarly journals Effects of Alternative Blood Sources on Wolbachia Infected Aedes aegypti Females within and across Generations

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 140 ◽  
Author(s):  
Véronique Paris ◽  
Ellen Cottingham ◽  
Perran Ross ◽  
Jason Axford ◽  
Ary Hoffmann
Keyword(s):  
Aedes Aegypti ◽  
Human Blood ◽  
Mass Rearing ◽  
Egg Hatch ◽  
Mass Release ◽  
Deliberate Release ◽  
Blood Source ◽  
Wolbachia Density ◽  
Infected Line ◽  
Strong Adaptation

Wolbachia bacteria have been identified as a tool for reducing the transmission of arboviruses transmitted by Aedes aegypti. Research groups around the world are now mass rearing Wolbachia-infected Ae. aegypti for deliberate release. We investigated the fitness impact of a crucial element of mass rearing: the blood meal required by female Ae. aegypti to lay eggs. Although Ae. aegypti almost exclusively feed on human blood, it is often difficult to use human blood in disease-endemic settings. When females were fed on sheep or pig blood rather than human blood, egg hatch rates decreased in all three lines tested (uninfected, or infected by wMel, or wAlbB Wolbachia). This finding was particularly pronounced when fed on sheep blood, although fecundity was not affected. Some of these effects persisted after an additional generation on human blood. Attempts to keep populations on sheep and pig blood sources only partly succeeded, suggesting that strong adaptation is required to develop a stably infected line on an alternative blood source. There was a decrease in Wolbachia density when Ae. aegypti were fed on non-human blood sources. Density increased in lines kept for multiple generations on the alternate sources but was still reduced relative to lines kept on human blood. These findings suggest that sheep and pig blood will entail a cost when used for maintaining Wolbachia-infected Ae. aegypti. These costs should be taken into account when planning mass release programs.

scholarly journals Household-Level Risk Factors for Aedes aegypti Pupal Density in Guayaquil, Ecuador

2020 ◽  
Author(s):  
Thien-An Ha ◽  
Tomás M. León ◽  
Karina Lalangui ◽  
Patricio Ponce ◽  
John M. Marshall ◽  
...  
Keyword(s):  
Risk Factors ◽  
Aedes Aegypti ◽  
Vector Control ◽  
Negative Binomial Regression Model ◽  
Control Methods ◽  
Municipal Services ◽  
Breeding Sites ◽  
Household Level ◽  
Level Model ◽  
The Impact

AbstractBackgroundVector-borne diseases are a major cause of disease burden in Guayaquil, Ecuador, especially arboviruses spread by Aedes aegypti mosquitoes. Understanding which household characteristics and risk factors lead to higher Ae. aegypti densities and consequent disease risk can help inform and optimize vector control programs.MethodsCross-sectional entomological surveys were conducted in Guayaquil between 2013 and 2016, covering household demographics, municipal services, potential breeding containers, presence of Ae. aegypti larvae and pupae, and history of using mosquito control methods. A zero-truncated negative binomial regression model was fitted to data for estimating the household pupal index. An additional model assessed the factors of the most productive breeding sites across all of the households.ResultsOf surveyed households, 610 satisfied inclusion criteria. The final household-level model found that collection of large solid items (e.g., furniture and tires) and rainfall the week of and 2 weeks before collection were negatively correlated with average pupae per container, while bed canopy use, unemployment, container water volume, and the interaction between large solid collection and rainfall 2 weeks before the sampling event were positively correlated. Selection of these variables across other top candidate models with ΔAICc < 1 was robust, with the strongest effects from large solid collection and bed canopy use. The final container-level model explaining the characteristics of breeding sites found that contaminated water is positively correlated with Ae. aegypti pupae counts while breeding sites composed of car parts, furniture, sewerage parts, vases, ceramic material, glass material, metal material, and plastic material were all negatively correlated.ConclusionHaving access to municipal services like bulky item pickup was effective at reducing mosquito proliferation in households. Association of bed canopy use with higher mosquito densities is unexpected, and may be a consequence of large local mosquito populations or due to limited use or effectiveness of other vector control methods. The impact of rainfall on mosquito density is multifaceted, as it may both create new habitat and “wash out” existing habitat. Providing services and social/technical interventions focused on monitoring and eliminating productive breeding sites is important for reducing aquatic-stage mosquito densities in households at risk for Ae. aegypti-transmitted diseases.

scholarly journals Proporsi Larva Aedes aegypti dan Aedes albopictus, Hubungannya dengan Kejadian Demam Berdarah Dengue di Daerah Endemik Suburban Kabupaten Sleman, Yogyakarta

2019 ◽  
pp. 163-170
Author(s):  
Bobby Fahmi Muldan Pahlevi ◽  
Tri Wulandari Kesetyaningsih
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Dengue Hemorrhagic Fever ◽  
Urban Areas ◽  
Endemic Area ◽  
Hemorrhagic Fever ◽  
Suburban Area ◽  
Dengue Transmission ◽  
The Relationship

Dengue Hemorrhagic Fever (DHF) is transmitted by Aedes aegypti and Ae. albopictus. Aedes aegypti chooses to live indoors and Ae. albopictus in outdoors. Aedes aegypti has been proven to play a role in dengue transmission in urban areas. It is assumed that suburbs dominated by gardens, so it is possible that Ae. albopictus acts as a vector. The study aimed to analyze the relationship between Ae. albopictus and DHF incidence in suburban area. The study was conducted in Godean, Sleman Regency. 280 ovitrap were placed indoors and outdoors at across seven villages. Each village was represented by one hamlet, so there were 40 ovitrap of each hamlet. The proportion of ovitrap containing Ae. aegypti and Ae. albopictus larvae was calculated. The results showed that Ae. aegypti larvae was more indoors (78.50%) than outdoors (21.45%) in all villages and negatively correlates with DHF (p=0.036; r=-0.776). Aedes albopictus larvae is more commonly found in gardens (80.64%) than in homes (19.36%) and does not correlate with DHF (p = 0.702). It was concluded that in suburban endemic area of ​​Sleman Regency, Ae. aegypti larvae was more indoors and negatively correlated with DHF. Aedes albopictus larva was more in the garden and did not correlate with DHF incidence.

scholarly journals The influence of natural environmental condition towards the existence of vector's larva of dengue hemorrhagic fever: Aedes Aegypti

2017 ◽  
Author(s):  
Susiana Nugraha
Keyword(s):  
Logistic Regression ◽  
Aedes Aegypti ◽  
Dengue Virus ◽  
Dengue Hemorrhagic Fever ◽  
Water Reservoir ◽  
Hemorrhagic Fever ◽  
Morbidity Rate ◽  
Tropical Regions ◽  
Water Replacement ◽  
Dengue Outbreaks

Dengue hemorrhagic fever is a severe and fatal infection that occurs in tropical regions such as Indonesia. In 2014, recorded that dengue morbidity rate was 5.17 per 100,000 inhabitants (approximately 13031 cases) with mortality rate of 0.84% (110 deaths). Demographic and societal changes such as population growth, urbanization, and modern transportation appear to play an important role in the increased incidence and geographical spread of dengue virus. Aedes aegypti, the urban yellow fever mosquito, is also the principal dengue-carrying vector. The Aedes aegypti mosquitoes as a vector of dengue virus normally live and breed in clean water reservoirs that are not directly related to the land such as: bath, bird drinks, water pot, water jars / barrel, cans, old tires, etc. In Indonesia, dengue outbreaks often occur when the seasons change from dry to rain hor vice versa. This study aimed to figure out the influence of natural environment and the existence of the vector’s larva. A logistic regression was performed to ascertain the effects of temperature, humidity, water replacement and the existence of water reservoir on the likelihood of the existence of the vector’s larva . The logistic regression model was statistically significant, p &lt; .005 and the model explained 69% (Nagelkerke R2). This finding shows that the existence of the mosquito’s larva, influenced by temperature, water replacement activity and the existence of water reservoir. Health education about vector control and environmental engineering are necessary to break the chain of mosquito breeding.

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