Artificial wetlands and mosquito control in Australia

1998 ◽  
pp. 158-164
1987 ◽  
Vol 19 (10) ◽  
pp. 51-59 ◽  
Author(s):  
W. V. Alexander ◽  
A. Wood

South Africa is a relatively water-short country which has many rural communities with water-borne sewage infrastructures requiring low technology treatment facilities. In order to protect the water resources of the country the authorities have set high standards for effluent quality (COD < 75 mg/l, NH3 < 10 mg/l, E. coli < 1000 and in some areas P < 1 mg/l). Traditionally, oxidation ponds have been used in these applications but have not been able to consistently meet the required standards and recently interest has been shown in artificial wetlands as a low technology means of solving the problem. As a result several experimental projects are at present being initiated in South Africa, both as primary and secondary treatment for domestic sewage and also as a tertiary treatment to remove nitrogen, phosphorus and E. coli from conventional sewage plant effluents. The designs of these experimental projects are described in the paper and it is hoped that data will be available for presentation at the seminar.


BMJ ◽  
1941 ◽  
Vol 1 (4176) ◽  
pp. 86-87
Keyword(s):  

1930 ◽  
Vol 64 (690) ◽  
pp. 56-86 ◽  
Author(s):  
Robert Matheson

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Stéphane Perrier ◽  
Eléonore Moreau ◽  
Caroline Deshayes ◽  
Marine El-Adouzi ◽  
Delphine Goven ◽  
...  

AbstractIn the malaria vector Anopheles gambiae, two point mutations in the acetylcholinesterase (ace-1R) and the sodium channel (kdrR) genes confer resistance to organophosphate/carbamate and pyrethroid insecticides, respectively. The mechanisms of compensation that recover the functional alterations associated with these mutations and their role in the modulation of insecticide efficacy are unknown. Using multidisciplinary approaches adapted to neurons isolated from resistant Anopheles gambiae AcerKis and KdrKis strains together with larval bioassays, we demonstrate that nAChRs, and the intracellular calcium concentration represent the key components of an adaptation strategy ensuring neuronal functions maintenance. In AcerKis neurons, the increased effect of acetylcholine related to the reduced acetylcholinesterase activity is compensated by expressing higher density of nAChRs permeable to calcium. In KdrKis neurons, changes in the biophysical properties of the L1014F mutant sodium channel, leading to enhance overlap between activation and inactivation relationships, diminish the resting membrane potential and reduce the fraction of calcium channels available involved in acetylcholine release. Together with the lower intracellular basal calcium concentration observed, these factors increase nAChRs sensitivity to maintain the effect of low concentration of acetylcholine. These results explain the opposite effects of the insecticide clothianidin observed in AcerKis and KdrKis neurons in vitro and in vivo.


Author(s):  
Md. Sahidur Rahman ◽  
Md. Omar Faruk ◽  
Sumiya Tanjila ◽  
Nur Mohammad Sabbir ◽  
Najmul Haider ◽  
...  

Abstract Background Studying the characteristics of Aedes mosquito habitats is essential to control the mosquito population. The objective of this study was to identify the breeding sites of Aedes larvae and their distribution in Chattogram, Bangladesh. We conducted an entomological survey in 12 different sub-districts (Thana) under Chattogram City, during the late monsoon (August to November) 2019. The presence of different wet containers along with their characteristics and immature mosquitoes was recorded in field survey data form. Larvae and/or pupae were collected and brought to the laboratory for identification. Results Different indices like house index, container index, and the Breteau index were estimated. The multiple logistic regression analysis was applied to identify habitats that were more likely to be positive for Aedes larvae/pupae. A total of 704 wet containers of 37 different types from 216 properties were examined, where 52 (7.39%) were positive for Aedes larvae or pupae. Tire, plastic buckets, plastic drums, and coconut shells were the most prevalent container types. The plastic group possessed the highest container productivity (50%) whereas the vehicle and machinery group was found as most efficient (1.83) in terms of immature Aedes production. Among the total positive properties, 8% were infested with Aedes aegypti, 2% with Aedes albopictus, and 1% contained both species Ae. aegypti and A. albopictus. The overall house index was 17.35%, the container index was 7%, and the Breteau index was 24.49. Containers in multistoried houses had significantly lower positivity compared to independent houses. Binary logistic regression represented that containers having shade were 6.7 times more likely to be positive than the containers without shade (p< 0.01). Conclusions These findings might assist the authorities to identify the properties, containers, and geographical areas with different degrees of risk for mosquito control interventions to prevent dengue and other Aedes-borne disease transmissions.


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