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

2021 ◽  
Vol 50 (8) ◽  
pp. 2379-2393
Author(s):  
Ahmad Mohiddin Mohd Ngesom ◽  
Nazni Wasi Ahmad ◽  
Han Lim Lee ◽  
Asmalia Md Lasim ◽  
David Greenhalgh ◽  
...  

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.

2021 ◽  
Vol 05 (02) ◽  
pp. 52-61
Author(s):  
Thi Thanh Huong Le ◽  
◽  
Quynh Nguyen ◽  
Saenthavisouk Vanhnasack ◽  
Sinh Nam Vu

Objectives: The elimination of key breeding sites of dengue vector is applied worldwide to control the vector density under the critical epidemic threshold. This study aimed to identify key breeding sites of Aedes mosquitos and associated factors in Huaylau village, Pakse city, Champasack province in Laos in 2019. Methods: This was a cross-sectional study, combining of immature stage survey of Aedes mosquitoes in all water and discarded containers and the community’s knowledge and practices on the prevention of dengue fever in all 240 households in Huaylau village. Multivariate logistic regression was applied to identify factors associated with the absence of Aedes larvae and pupae in the village. Statistical significance was set at a p-value less than 0.05. Results: Among the 720 water and discarded containers surveyed, the study found 654 Aedes larvae and pupae; of which 94.6% were immature Aedes aegypti. Key breeding sites of Aedes aegypti included water jars (34.2%), plastic drums (30.7%), tanks < 500 litter (14.7%), and discarded containers (12.6%), while that of all Aedes albopictus was discarded containers. The community’s better practices on the prevention of dengue fever contributed to the increased odds of the absence of Aedes larvae ad pupae by 1.612 (95%CI: 1.218-2.134, p<0.01), and the cleanliness of the house were associated with the increased odds of 4.072 of the absent Aedes larvae and pupae in the participated households (95%CI: 1.589-10.434, p<0.01). Conclusions: Aedes aegypti mosquitoes in the Huaylau village laid their eggs in various breeding sites, including water containers and discarded containers while discarded containers were the only key breeding site of Aedes albopictus. Better practices on dengue prevention and better hygiene conditions of the houses contributed to the absence of Aedes larvae and pupae. Special attention should be paid to the clearance of all discarded containers and education of the community people to cover water containers in the village. Keywords: key breeding sites, Aedes, mosquito, pupae, larvae, Champasack province, Lao PDR


2005 ◽  
Vol 42 (3) ◽  
pp. 419-428 ◽  
Author(s):  
A. Paulo G. Almeida ◽  
Susana S. S. G. Baptista ◽  
Carla A. G. C. C. Sousa ◽  
M. Teresa L. M. Novo ◽  
Helena C. Ramos ◽  
...  

ENTOMON ◽  
2019 ◽  
Vol 44 (3) ◽  
pp. 213-218
Author(s):  
Suresh Chand Kaushik ◽  
Sukhvir Singh ◽  
Purnima Srivastava ◽  
R. Rajendran

Detection of viruses in human sera particularly in endemic areas is cumbersome and laborious. Therefore, an alternative approach, Immuno-fluorescence assay (IFA) was performed to determine dengue virus (DENV) positivity in mosquitoes. A total of 1055 adult Aedes aegypti female mosquitoes were tested for IFA test against DENV. Minimum infection rate (MIR) for DENV was found higher during August to November 2016 ranging from 10.75 to 20.83. The average yearly MIR was about 6.64. Higher MIR for Ae. aegypti was found in Sarfabad, Noida (12.71) and Khoda Colony, Ghaziabad (11.90). Minimum MIR (4.67) was observed in Sanjay colony (Faridabad). The main contribution of this study resides in the development of a more suitable monitoring system for early detection of viral circulation and to prioritize early intervention in the non-transmission season.


2020 ◽  
Vol 10 (1) ◽  
pp. 67-77
Author(s):  
Amos Watentena ◽  
Ikem Chris Okoye ◽  
Ikechukwu Eugene Onah ◽  
Onwude Cosmas Ogbonnaya ◽  
Emmanuel Ogudu

Mosquitoes of Aedes species are vectors of several arboviral diseases which continue to be a major public health problem in Nigeria. This study among other things, morphologically identified Aedes mosquitoes collected from Nsukka LGA and used an allele specific PCR amplification for discrimination of dengue vectors. Larval sampling, BG-sentinel traps and modified human landing catches were used for mosquito sampling in two selected autonomous communities of Nsukka LGA (Nsukka and Obimo). A total of 124 Aedes mosquitoes consisting of five (5) different species were collected from April to June, 2019 in a cross-sectional study that covered 126 households, under 76 distinct geographical coordinates. Larvae was mainly collected from plastic containers 73% (n=224), metallic containers 14% (n=43), earthen pots 9% (n=29) and used car tyres 3% (n=9), reared to adult stage 69.35% (n=86), and all mosquitoes were identified using standard morphological keys. Five (5) Aedes mosquito species were captured; Aedes aegypti 83(66.94%), Aedes albopictus 33(26.61%), Aedes simpsoni (4.48%), Aedes luteocephalus (≤1%) and Aedes vittatus (≤1%). Nsukka autonomous community had higher species diversity than Obimo. Allele specific amplification confirmed dengue vectors, Aedes aegypti and Aedes albopictus species on a 2% agarose gel. Since the most recent re-emergence of arboviral diseases is closely associated with Aedes species, findings of this study, therefore, give further evidence about the presence of potential arboviral vectors in Nigeria and describe the role of a simple PCR in discriminating some. Further entomological studies should integrate PCR assays in mosquito vector surveillance.


IDCases ◽  
2021 ◽  
pp. e01220
Author(s):  
Anjali Yadav ◽  
Neha Rastogi ◽  
K. Upasana ◽  
Sunisha Arora ◽  
Dhwanee Thakkar ◽  
...  

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 343
Author(s):  
Manjin Li ◽  
Dan Xing ◽  
Duo Su ◽  
Di Wang ◽  
Heting Gao ◽  
...  

Dengue virus (DENV), a member of the Flavivirus genus of the Flaviviridae family, can cause dengue fever (DF) and more serious diseases and thus imposes a heavy burden worldwide. As the main vector of DENV, mosquitoes are a serious hazard. After infection, they induce a complex host–pathogen interaction mechanism. Our goal is to further study the interaction mechanism of viruses in homologous, sensitive, and repeatable C6/36 cell vectors. Transcriptome sequencing (RNA-Seq) technology was applied to the host transcript profiles of C6/36 cells infected with DENV2. Then, bioinformatics analysis was used to identify significant differentially expressed genes and the associated biological processes. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to verify the sequencing data. A total of 1239 DEGs were found by transcriptional analysis of Aedes albopictus C6/36 cells that were infected and uninfected with dengue virus, among which 1133 were upregulated and 106 were downregulated. Further bioinformatics analysis showed that the upregulated DEGs were significantly enriched in signaling pathways such as the MAPK, Hippo, FoxO, Wnt, mTOR, and Notch; metabolic pathways and cellular physiological processes such as autophagy, endocytosis, and apoptosis. Downregulated DEGs were mainly enriched in DNA replication, pyrimidine metabolism, and repair pathways, including BER, NER, and MMR. The qRT-PCR results showed that the concordance between the RNA-Seq and RT-qPCR data was very high (92.3%). The results of this study provide more information about DENV2 infection of C6/36 cells at the transcriptome level, laying a foundation for further research on mosquito vector–virus interactions. These data provide candidate antiviral genes that can be used for further functional verification in the future.


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