scholarly journals Wolbachia-mediated sterility suppresses Aedes aegypti populations in the urban tropics

2021 ◽  
Author(s):  
◽  
Lee Ching Ng
Keyword(s):  
Aedes Aegypti ◽  
Vertical Distribution ◽  
High Rise ◽  
Promising Tool ◽  
Incompatible Insect Technique ◽  
Tropical Cities ◽  
Dengue Control ◽  
Housing Estates

Incompatible insect technique (IIT) via releases of male Wolbachia-infected mosquitoes is a promising tool for dengue control. In a three-year trial in Singaporean high-rise housing estates, we demonstrated that Wolbachia-based IIT dramatically reduces both wildtype Aedes aegypti populations [reductions of 92.7% (95% CI: 84.7%-95.8%) and 98.3% (97.7%-99.8%)] and dengue incidence [reductions of 71% (43%-87%) to 88% (57%-99%)] in the targeted areas. The study highlights the need to ensure adequate vertical distribution of released males in high-rise buildings, address immigration of wildtype females from neighboring areas, and prevent and mitigate stable establishment of Wolbachia in field mosquito populations. Our results demonstrate the potential of Wolbachia-based IIT (supplemented with irradiation, in Singapore's context) for strengthening dengue control in tropical cities, where dengue burden is the greatest.

scholarly journals Wolbachia strain wAu efficiently blocks arbovirus transmission in Aedes albopictus

2019 ◽  
Author(s):  
Maria Vittoria Mancini ◽  
Christie S. Herd ◽  
Thomas H. Ant ◽  
Shivan M. Murdochy ◽  
Steven P. Sinkins
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Mosquito Species ◽  
Field Trials ◽  
Asian Tiger Mosquito ◽  
Native Strain ◽  
Promising Tool ◽  
Novel Approach ◽  
Asian Tiger ◽  
Tiger Mosquito

AbstractThe global incidence of arboviral diseases transmitted by Aedes mosquitoes, including dengue, chikungunya, yellow fever, and Zika, has increased dramatically in recent decades. The release of Aedes aegypti carrying the maternally inherited symbiont Wolbachia as an intervention to control arboviruses is being trialled in several countries. However, these efforts are compromised in many endemic regions due to the co-localization of the secondary vector Aedes albopictus, the Asian tiger mosquito. Ae. albopictus has an expanding global distribution following incursions into a number of new territories. To date, only the wMel and wPip strains of Wolbachia have been reported to be transferred into and characterized in this vector. A Wolbachia strain naturally infecting Drosophila simulans, wAu, was selected for transfer into a Malaysian Ae. albopictus line to create a novel triple-strain infection. The newly generated line showed self-compatibility, moderate fitness cost and complete resistance to Zika and dengue infections.Author summaryAedes albopictus, the invasive Asian tiger mosquito, is responsible for numerous outbreaks of important viruses such as dengue and Zika in various regions of the world. The need for alterative control interventions propelled the development of a novel approach that exploits a natural insect symbiont, Wolbachia; when transferred into non-native hosts, these maternally-inherited bacteria are able to interfere with the transmission of mosquito-borne viruses, and also provide reproductive advantages to the host, offering a promising tool for self-sustaining field applications. Currently, several field trials are ongoing for the primary vector of dengue and several other arboviruses, Aedes aegypti, providing encouraging results. In this study, Ae. albopictus has been targeted for a similar approach: this mosquito species naturally carries two strains of Wolbachia. The artificial introduction of a third, non-native strain made this line less able to transmit dengue and Zika viruses and had an impact on its fitness.

scholarly journals Establishment of Wolbachia Strain wAlbB in Malaysian Populations of Aedes aegypti for Dengue Control

2019 ◽  
Vol 29 (24) ◽  
pp. 4241-4248.e5 ◽  
Author(s):  
Wasi A. Nazni ◽  
Ary A. Hoffmann ◽  
Ahmad NoorAfizah ◽  
Yoon Ling Cheong ◽  
Maria V. Mancini ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Wolbachia Strain ◽  
Dengue Control

scholarly journals Aedes aegypti lines for combined sterile insect technique and incompatible insect technique applications: the importance of host genomic background

2020 ◽  
Vol 168 (6-7) ◽  
pp. 560-572 ◽  
Author(s):  
Danilo O. Carvalho ◽  
Jorge A. Torres‐Monzon ◽  
Panagiota Koskinioti ◽  
N.D. Asha Dilrukshi Wijegunawardana ◽  
Xiao Liang ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Sterile Insect Technique ◽  
Incompatible Insect Technique

The Relocation of Villagers into Public Housing: Some Suggestive Findings from a Singaporean Stud*1

1977 ◽  
Vol 5 (1) ◽  
pp. 42-54
Author(s):  
Shimon E. Spiro
Keyword(s):  
Public Housing ◽  
Living Arrangements ◽  
Urban Fringe ◽  
Urban Life ◽  
Rural Migrants ◽  
Nuclear Families ◽  
Urban Living ◽  
High Rise ◽  
Gradual Process ◽  
Housing Estates

AbstractThe relocation of villagers into modern high-rise housing estates is, in most countries, the exception rather than the rule. The urbanization of rural populations is, more typically, a gradual process. Rural migrants first settle in inner-city slums and squatter areas of the urban fringe, where they are often able to maintain some of the living arrangements and patterns of social organization which are characteristically rural Only after additional movements within these areas of first settlement, and after sufficient time had elapsed to allow for some assimilation into urban life, will some of the migrants, or their descendants, move into high rise public housing estates. This form of housing is, in many respects, the ultimate in urban living. It is characterized by nuclear families, occupying rigidly defined space, living among strangers, and subject to bureaucratic rules and controls. However, the fact that families typically move to housing estates after having experienced some form of urban living may ease the transition. Also, the fact that slum dwellings are often of physically inferior quality compared to estate housing3 may increase the willingness of new residents to accept some of the constraints of estate living.

scholarly journals Resistensi Aedes aegypti terhadap Insektisida Kelompok Organopospat dan Sintetik Piretroid di Provinsi Sumatera Utara dan Provinsi Jambi

2018 ◽  
pp. 95-106
Author(s):  
Sunaryo Sunaryo ◽  
Dyah Widiastuti
Keyword(s):  
Aedes Aegypti ◽  
Control Program ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Local Public Health ◽  
Health Officer ◽  
Lambda Cyhalothrin ◽  
Dengue Control ◽  
North Sumatra ◽  
F1 Generation

Vector control using insecticide is a major effort to control Dengue Haemorrhagic Fever. The excessive use of insecticides leads to insecticide resistance in Aedes aegypti. This study aimed to determine the resistance status of Aedes aegypti in North Sumatra and Jambi Province to malathion, deltametrin, cypermethrin, lambda cyhalothrin and alpha cypermethrin. A cross sectional study was conducted during 2015, the research location covers North Sumatera area (Tebing Tinggi, Deli Serdang, and Pematang Siantar) and Jambi (Muaro Jambi, Jambi, and Batang Hari). Susceptibility test using WHO kits was applied on F1 generation and interview with Local Public Health Officer was carried out to obtain information about the usage of insecticide in both provinces. Resistance to malathion, cypermethrin, and lambda cyhaltorhin was observed in Ae. aegypti populations from all study area. Tolerant status to deltamethrin only found in Aedes aegypti from Deli Serdang, whilst the other strains were resistant. Ae. aegypti population from all study area were tolerant to alpha cypermethrin. Malathion and cypermethrin were the only insecticide ever used in both provinces. We conclude that alpha cypermethrin was effective to combat Ae. aegypti and can be used as an alternative insecticide for dengue control program in Northern Sumatera and Jambi Province. 

scholarly journals Persistence of malathion used in dengue control on household surfaces

2019 ◽  
Vol 86 ◽  
Author(s):  
Regina Cristina Batista Ferreira ◽  
Solange Papini ◽  
Luiz Carlos Luchini ◽  
Eliane Vieira
Keyword(s):  
Gas Chromatography ◽  
Aedes Aegypti ◽  
Viral Infection ◽  
Vegetable Oil ◽  
Liquid Scintillation ◽  
Soil Samples ◽  
Porous Surfaces ◽  
Dengue Control

ABSTRACT: Dengue is a viral infection transmitted by the mosquito Aedes aegypti. In Brazil, one of the insecticides used to control the mosquito is malathion, which can be diluted in vegetable oil (1:2 v/v). The purpose of this study was to understand the persistence of malathion on different surfaces and soil. Surfaces were contaminated by malathion and then washed with water and soap. The water used to clean the surfaces was extracted and analyzed by gas chromatography with an FID detector. Soil samples received malathion 14C-TG diluted in vegetable oil (1:2 v/v) and were analyzed zero, 3, 7, 18, 32, 60, 120, 240, and 360 days after the application in a liquid scintillation analyzer. Results showed a high persistence of malathion on porous surfaces. Moreover, it did not degrade in the soil for the first 120 days.

scholarly journals Releasing incompatible males drives strong suppression across populations of wild and Wolbachia-carrying Aedes aegypti in Australia

2021 ◽  
Vol 118 (41) ◽  
pp. e2106828118
Author(s):  
Nigel W. Beebe ◽  
Dan Pagendam ◽  
Brendan J. Trewin ◽  
Andrew Boomer ◽  
Matt Bradford ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Mosquito Control ◽  
Local Strain ◽  
Mosquito Vector ◽  
Population Declines ◽  
Wild Type ◽  
Strong Suppression ◽  
Incompatible Insect Technique ◽  
Community Consent ◽  
Proven Method

Releasing sterile or incompatible male insects is a proven method of population management in agricultural systems with the potential to revolutionize mosquito control. Through a collaborative venture with the “Debug” Verily Life Sciences team, we assessed the incompatible insect technique (IIT) with the mosquito vector Aedes aegypti in northern Australia in a replicated treatment control field trial. Backcrossing a US strain of Ae. aegypti carrying Wolbachia wAlbB from Aedes albopictus with a local strain, we generated a wAlbB2-F4 strain incompatible with both the wild-type (no Wolbachia) and wMel-Wolbachia Ae. aegypti now extant in North Queensland. The wAlbB2-F4 strain was manually mass reared with males separated from females using Verily sex-sorting technologies to obtain no detectable female contamination in the field. With community consent, we delivered a total of three million IIT males into three isolated landscapes of over 200 houses each, releasing ∼50 males per house three times a week over 20 wk. Detecting initial overflooding ratios of between 5:1 and 10:1, strong population declines well beyond 80% were detected across all treatment landscapes when compared to controls. Monitoring through the following season to observe the ongoing effect saw one treatment landscape devoid of adult Ae. aegypti early in the season. A second landscape showed reduced adults, and the third recovered fully. These encouraging results in suppressing both wild-type and wMel-Ae. aegypti confirms the utility of bidirectional incompatibility in the field setting, show the IIT to be robust, and indicate that the removal of this arbovirus vector from human-occupied landscapes may be achievable.

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