What is supposed to happen? Has it been happening?

Some questions derived from CDC mosquito control guidelines:

1. Where has the County engaged in source reduction, as recommended?

The only source reduction we know of has been undertaken by West Chester Borough to prevent water from standing in storm drains. Does anyone know of other examples?

2. Where has the County engaged in larval mosquito control, as recommended?

They have told us that they do so, but so far have said they do not have records for 2015-17 and do not have time to tell us where for 2018; our Right to Know request on this with the PA Department of Environmental Protection is pending.

3. Has the County maintained a database of aquatic habitats to identify the sources of vector mosquitoes and a record of larval control measures applied to each (last paragraph below)?

From point 2 above, it would seem doubtful; but the public has a right to know, and we will.

Source material: Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, “West Nile Virus in the United States: Guidelines for Surveillance, Prevention, and Control,” 2016, p. 33. (See the points we have put in boldface below. Download the full publication here).

Integrated Vector Management

Mosquito abatement programs successfully employ integrated pest management (IPM) principles to reduce mosquito abundance, providing important community services to protect quality of life and public health (Rose 2001). Prevention and control of WNV and other zoonotic arboviral diseases is accomplished most effectively through a comprehensive, integrated vector management (IVM) program applying the principles of IPM. IVM is based on an understanding of the underlying biology of the arbovirus transmission system, and utilizes regular monitoring of vector mosquito populations and WNV activity levels to determine if, when, and where interventions are needed to keep mosquito numbers below levels which produce risk of human disease, and to respond appropriately to reduce risk when it exceeds acceptable levels.

Operationally, IVM is anchored by a monitoring program providing data that describe:
• Conditions and habitats that produce vector mosquitoes.
• Abundance of those mosquitoes over the course of a season.
• WNV transmission activity levels expressed as WNV infection rate in mosquito vectors.
• Parameters that influence local mosquito populations and WNV transmission.

These data inform decisions about implementing mosquito control activities appropriate to the situation, such as:
Source reduction through habitat modification.
• Larval mosquito control using the appropriate methods for the habitat.

• Adult mosquito control using pesticides applied from trucks or aircraft when established thresholds have been exceeded.
Community education efforts related to WNV risk levels and intervention activities.

Monitoring also provides quality control for the program, allowing evaluation of:
• Effectiveness of larval control efforts.
• Effectiveness of adult control efforts.
• Causes of control failures (e.g., undetected larval sources, pesticide resistance, equipment failure)….

and p. 34:

Larval Mosquito Surveillance

“Larval surveillance involves identifying and sampling a wide range of aquatic habitats to identify the sources of vector mosquitoes, maintaining a database of these locations, and a record of larval control measures applied to each. This requires trained inspectors to identify larval production sites, collect larval specimens on a regular basis from known larval habitats, and to perform systematic surveillance for new sources. This information is used to determine where and when source reduction or larval control efforts should be implemented….


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