A secure semi-field system for the study of Aedes aegypti.

BACKGROUND: New contained semi-field cages are being developed and used to test novel vector control strategies of dengue and malaria vectors. We herein describe a new Quarantine Insectary Level-2 (QIC-2) laboratory and field cages (James Cook University Mosquito Research Facility Semi-Field System;...

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Main Authors: Scott A Ritchie, Petrina H Johnson, Anthony J Freeman, Robin G Odell, Neal Graham, Paul A Dejong, Graeme W Standfield, Richard W Sale, Scott L O'Neill
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2011-01-01
Series:PLoS Neglected Tropical Diseases
Online Access:http://europepmc.org/articles/PMC3062535?pdf=render
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author Scott A Ritchie
Petrina H Johnson
Anthony J Freeman
Robin G Odell
Neal Graham
Paul A Dejong
Graeme W Standfield
Richard W Sale
Scott L O'Neill
author_facet Scott A Ritchie
Petrina H Johnson
Anthony J Freeman
Robin G Odell
Neal Graham
Paul A Dejong
Graeme W Standfield
Richard W Sale
Scott L O'Neill
author_sort Scott A Ritchie
collection DOAJ
description BACKGROUND: New contained semi-field cages are being developed and used to test novel vector control strategies of dengue and malaria vectors. We herein describe a new Quarantine Insectary Level-2 (QIC-2) laboratory and field cages (James Cook University Mosquito Research Facility Semi-Field System; MRF SFS) that are being used to measure the impact of the endosymbiont Wolbachia pipientis on populations of Aedes aegypti in Cairns Australia. METHODOLOGY/PRINCIPAL FINDINGS: The MRF consists of a single QIC-2 laboratory/insectary that connects through a central corridor to two identical QIC-2 semi-field cages. The semi-field cages are constructed of two layers of 0.25 mm stainless steel wire mesh to prevent escape of mosquitoes and ingress of other insects. The cages are covered by an aluminum security mesh to prevent penetration of the cages by branches and other missiles in the advent of a tropical cyclone. Parts of the cage are protected from UV light and rainfall by 90% shade cloth and a vinyl cover. A wooden structure simulating the understory of a Queenslander-style house is also situated at one end of each cage. The remainder of the internal aspect of the cage is covered with mulch and potted plants to emulate a typical yard. An air conditioning system comprised of two external ACs that feed cooled, moistened air into the cage units. The air is released from the central ceiling beam from a long cloth tube that disperses the airflow and also prevents mosquitoes from escaping the cage via the AC system. Sensors located inside and outside the cage monitor ambient temperature and relative humidity, with AC controlled to match ambient conditions. Data loggers set in the cages and outside found a <2 °C temperature difference. Additional security features include air curtains over exit doors, sticky traps to monitor for escaping mosquitoes between layers of the mesh, a lockable vestibule leading from the connecting corridor to the cage and from inside to outside of the insectary, and screened (0.25 mm mesh) drains within the insectary and the cage. A set of standard operating procedures (SOP) has been developed to ensure that security is maintained and for enhanced surveillance for escaping mosquitoes on the JCU campus where the MRF is located. A cohort of male and female Aedes aegypti mosquitoes were released in the cage and sampled every 3-4 days to determine daily survival within the cage; log linear regression from BG-sentinel trapping collections produced an estimated daily survival of 0.93 and 0.78 for females and males, respectively. CONCLUSIONS/SIGNIFICANCE: The MRF SFS allows us to test novel control strategies within a secure, contained environment. The air-conditioning system maintains conditions within the MRF cages comparable to outside ambient conditions. This cage provides a realistic transitional platform between the laboratory and the field in which to test novel control measures on quarantine level insects.
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spelling doaj.art-a7912cc4235748f3bf51f7bd7367f3d02022-12-21T19:48:57ZengPublic Library of Science (PLoS)PLoS Neglected Tropical Diseases1935-27271935-27352011-01-0153e98810.1371/journal.pntd.0000988A secure semi-field system for the study of Aedes aegypti.Scott A RitchiePetrina H JohnsonAnthony J FreemanRobin G OdellNeal GrahamPaul A DejongGraeme W StandfieldRichard W SaleScott L O'NeillBACKGROUND: New contained semi-field cages are being developed and used to test novel vector control strategies of dengue and malaria vectors. We herein describe a new Quarantine Insectary Level-2 (QIC-2) laboratory and field cages (James Cook University Mosquito Research Facility Semi-Field System; MRF SFS) that are being used to measure the impact of the endosymbiont Wolbachia pipientis on populations of Aedes aegypti in Cairns Australia. METHODOLOGY/PRINCIPAL FINDINGS: The MRF consists of a single QIC-2 laboratory/insectary that connects through a central corridor to two identical QIC-2 semi-field cages. The semi-field cages are constructed of two layers of 0.25 mm stainless steel wire mesh to prevent escape of mosquitoes and ingress of other insects. The cages are covered by an aluminum security mesh to prevent penetration of the cages by branches and other missiles in the advent of a tropical cyclone. Parts of the cage are protected from UV light and rainfall by 90% shade cloth and a vinyl cover. A wooden structure simulating the understory of a Queenslander-style house is also situated at one end of each cage. The remainder of the internal aspect of the cage is covered with mulch and potted plants to emulate a typical yard. An air conditioning system comprised of two external ACs that feed cooled, moistened air into the cage units. The air is released from the central ceiling beam from a long cloth tube that disperses the airflow and also prevents mosquitoes from escaping the cage via the AC system. Sensors located inside and outside the cage monitor ambient temperature and relative humidity, with AC controlled to match ambient conditions. Data loggers set in the cages and outside found a <2 °C temperature difference. Additional security features include air curtains over exit doors, sticky traps to monitor for escaping mosquitoes between layers of the mesh, a lockable vestibule leading from the connecting corridor to the cage and from inside to outside of the insectary, and screened (0.25 mm mesh) drains within the insectary and the cage. A set of standard operating procedures (SOP) has been developed to ensure that security is maintained and for enhanced surveillance for escaping mosquitoes on the JCU campus where the MRF is located. A cohort of male and female Aedes aegypti mosquitoes were released in the cage and sampled every 3-4 days to determine daily survival within the cage; log linear regression from BG-sentinel trapping collections produced an estimated daily survival of 0.93 and 0.78 for females and males, respectively. CONCLUSIONS/SIGNIFICANCE: The MRF SFS allows us to test novel control strategies within a secure, contained environment. The air-conditioning system maintains conditions within the MRF cages comparable to outside ambient conditions. This cage provides a realistic transitional platform between the laboratory and the field in which to test novel control measures on quarantine level insects.http://europepmc.org/articles/PMC3062535?pdf=render
spellingShingle Scott A Ritchie
Petrina H Johnson
Anthony J Freeman
Robin G Odell
Neal Graham
Paul A Dejong
Graeme W Standfield
Richard W Sale
Scott L O'Neill
A secure semi-field system for the study of Aedes aegypti.
PLoS Neglected Tropical Diseases
title A secure semi-field system for the study of Aedes aegypti.
title_full A secure semi-field system for the study of Aedes aegypti.
title_fullStr A secure semi-field system for the study of Aedes aegypti.
title_full_unstemmed A secure semi-field system for the study of Aedes aegypti.
title_short A secure semi-field system for the study of Aedes aegypti.
title_sort secure semi field system for the study of aedes aegypti
url http://europepmc.org/articles/PMC3062535?pdf=render
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