# Introduction
For centuries, people have recognized that rats and mice are not only a nuisance but are a public health problem. Rats and mice damage and contaminate food, damage structures, and carry diseases that threaten health and quality of life, and they can cause injury and death. This manual describes techniques to help us protect ourselves from these disease vectors by gathering information (surveillance) about infestations and about the causative conditions of infestation. Accurate recordkeeping by public health officials provides the information needed to manage rodent and other pest problems.
Urban rodent surveys of exterior areas are the primary means for obtaining information on rodent infestations and on premises with environmental health deficiencies that support commensal rodent populations in housing and on premisess. Survey areas should include residential, commercial, and civic buildings; vacant lots; and public areas. The rodent species primarily targeted in surveys are the Norway rat (Rattus norvegicus), roof rat (Rattus rattus), and house mouse (Mus musculus).
Urban rodent surveys, as well as surveys for other pests, fulfill an essential surveillance requirement for every integrated pest management (IPM) program, which is the need for detailed information about conditions in a defined community. IPM is a long-term, effective, and holistic approach to managing pests of all kinds by carefully combining various interventions (e.g., education, code enforcement, rodent proofing, poisoning) in ways that minimize environmental hazards and deficiencies that affect people's health.
The focus of this manual is on how to conduct a survey, although the other IPM components are covered briefly to establish their link to the survey. This manual is for classroom use and for the field training of program managers, environmental health practitioners, outreach workers, inspectors, and others who work in community-based rodent IPM programs.
This manual is also a reference on survey techniques and on the preparation of reports and maps.

# IPM Basics Definition and Philosophy
IPM requires a shift from the typical pest control efforts that often emphasize poisoning and trapping. With IPM, pests and disease vectors are managed by managing the environment. For IPM to succeed, the behavior and ecology of the target pest, the environment in which the pest is active, and the periodic changes that occur in the environment (including the people who share the environment) must be taken into account. In addition, the safety of the people, the environment, and the nontarget animals such as pets, birds, and livestock must be considered.
IPM is a decision-making process in which all interventions are focused on a pest problem and on the goal of providing the safest and most effective, economical, and sustained remedy. IPM is a comprehensive systems approach.
IPM is based on and should adhere to the sound biologic principles of population dynamics-the study of birth rates, mortality rates, and movement rates. An understanding of population dynamics is important because any successful strategy for the management of rodent populations depends on that understanding and on conducting appropriate interventions based on IPM principles. A 1976 CDC publication on urban rat control states that "political mechanisms must be able to administer the control procedures that are dictated by the principles . ...A corollary of the strategy of working with principles is that research should not continue in clear violation of population principles in expectation that a politically acceptable solution will be found."
Program and political support are essential in obtaining the necessary resources for an IPM program that takes into account the complex interplay of rodents, people, and environmental factors. The overall goals of IPM are to reduce or eliminate human encounters with pests and disease vectors and to reduce pesticide exposure.

# Program Components
The four key components of an IPM program are survey, tolerance limit, intervention, and evaluation. If a key component is omitted, success in managing or eliminating pests is reduced.
Surveys (inspection and monitoring): A measure of the magnitude of the pest problem and its environmental causes. Survey results determine the need for a rodent IPM program and the direction the program must take to manage the rodent problem. An urban rodent survey has four distinct phases:
1. premises inspection (comprehensive or sample) of defined areas (e.g., groups of blocks) to record infestations and their causative conditions;
2. preparation of maps, graphs, and tables to summarize survey results (may include photographs of field observations);
3. preparation of a report that includes an analysis of block and premises data, and premises prevalence rates for infestation and its causative conditions; and 4. recommendations to resolve the rodent infestation problem.
Surveys are especially useful in the development of educational interventions directed to the public (e.g., Web sites, television and radio programs, videos, newspaper articles, brochures, posters, exhibits).
Tolerance limit (action threshold): The level at which a pest causes sufficient damage to warrant public health attention and intervention.
Real or perceived damage can be aesthetic and can have economic, psychologic, and medical consequences. In 1972, CDC established tolerance limits for rodent infestation, exposed garbage, and improperly stored refuse. Details of these and other survey-based criteria are discussed later in this manual. The survey establishes the baseline on rodent infestation and on the causative conditions that support the infestation. The goal is to reduce both the infestation and the causative conditions to a level at which they no longer have an adverse effect on the community.
Interventions: Actions taken to prevent, reduce, or eliminate rodent infestations and their destructive effects. Survey data determine when, where, what, and whether interventions are necessary to prevent or eliminate a particular pest problem. Interventions are classified as educational, legal or regulatory, habitat modification, horticultural, biologic, mechanical, and chemical. These intervention categories typically form an IPM strategy. Most commensal rodent IPM programs emphasize educational and legal or regulatory interventions, and habitat modification.
The key to a successful IPM program is the elimination of the causes of infestation (i.e., food, water, and harborage). The judicious and careful use of pesticides (including toxicants) to manage pests is also important for success. A vital IPM "rule" for selecting rodenticides or other pesticides is that the product chosen should be the least toxic product that will be effective on a target pest. The product also must have a highly efficacious and readily available antidote that can be administered in a timely manner for both humans and pets if a rodenticide is inadvertently ingested. Widespread and indiscriminate use of pesticides, a problem Rachel Carson warned about in her 1967 book Silent Spring, has serious consequences for people, animals, and the environment.
Evaluation: The evaluation process (composed of periodic surveys) determines whether IPM interventions have been effective or whether they need to be repeated or modified. The initial survey of residential and commercial blocks and the periodic resurveys (monitoring) of a target community provides the basis for the evaluation of a program's progress.

# Characteristics of Urban Rodent Surveys
A health-related government agency or department typically manages a community-based vector control program. For the purpose of this manual, such agencies or organizations will be referred to as the "IPM authority." The responsible adult, whether a homeowner or a renter, who grants permission to inspect a premises or dwelling will be called the "householder."
The initial urban rodent survey is the data gathering phase of IPM program planning. Conducting the survey provides the IPM authority with an opportunity to inform residents about the program and to encourage their support when survey teams inspect their premises. An analysis of survey results will show the extent and severity of rodent infestations and their causative conditions and will delineate IPM program needs as well as the progress made in comparison with previous surveys.
To determine the magnitude of the rodent problem, determine priorities, and evaluate progress, the IPM program must maintain a premises and block records management system. The system should provide for sequentially reporting survey findings using standardized reporting forms.
The urban rodent survey involves an exterior inspection of premises to record significant data such as active rodent signs, rodent entries to buildings, and environmental deficiencies that provide food, water, and harborage. Although the Norway rat and the roof rat generally live outdoors, they do enter buildings that are not rodent proofed. The house mouse can survive outdoors, but it prefers indoor areas in an urban habitat. Whenever rodents find suitable food, water, and harborage, they become established and reproduce rapidly. Interior inspections of dwellings and buildings may be required if signs of infestation are obvious. Gaining access to interiors of premises is, however, generally more difficult, and the problems associated with the management and control of interior infestations are greater. Nevertheless, interior inspection is considered an essential component of an IPM program if clear evidence exists of significant interior infestation.
Two forms are required for an exterior urban rodent survey: a field inspection form and a summary form for office tabulations (Appendix A, Figures 1-4; Figures 1 and 3 are blank forms and Figures 2 and 4 are completed examples). These forms can be modified to serve the special needs of local programs. Although the use of check marks on a form may suffice to indicate the presence of deficiencies on premises, some programs use a coding system (e.g., letters, numbers, colors) to record more detailed information. Examples of such codes are furnished throughout this manual as an alternative to the checkmark system.
The survey forms provide the necessary data to plan and conduct a rodent IPM program. These data identify the need for rodent proofing, code enforcement, refuse management, cleanup of vacant lots, removal of abandoned automobiles and appliances, and other necessary interventions. The IPM approach emphasizes site-specific combinations of interventions to control or eliminate rodent populations.
In a more detailed version of the survey, a third form can be added for interior inspections. This form can be modified from the exterior inspection form to provide detailed data for each area or room within residential or commercial premises. This detailed information is useful in two ways: in determining where rodents may frequent and nest in particular areas of a premises or dwelling and in assessing rodent-related risks such as the potential for bites or food contamination.

# Basic Units in the Operational Program
For planning, operating, and reporting purposes, all rodent IPM programs use basic geographic units such as the following:
1. Premises (to record existing conditions). A premises is a plot of land with or without a building. It is the basic unit of a program in which survey items can be observed and recorded (e.g., environmental deficiencies, active rodent signs). Maintenance of a premises is usually the responsibility of a householder (unless multiple dwelling units are on a premises), superintendent, or manager who must maintain the environmental quality of the premises. For survey purposes, all premises are classified as residential, commercial, commercial and residential, or vacant lot. Schools, parks, churches, and parking areas are defined as commercial.
A premises may consist of an individual residence and its surroundings-whether attached (e.g., row house) or detached (e.g., a stand-alone home). A duplex house or a large apartment building and its surroundings are considered a single premises because they are usually under one ownership and are situated on one plot of land. The same criteria apply to a commercial premises with a major building and other structures. For larger aggregations of buildings, such as several apartment buildings under one or several ownerships, each numbered building and its surroundings are considered to be a separate premises. Reviewing municipal tax parcel maps may be helpful to clarify the physical (e.g., property lines) and administrative (e.g., ownership) data related to a particular property.
Where available, use of a geographic information system (GIS) to map properties can be helpful.

# Block (to classify conditions
). The block is a convenient unit for reporting infestations and causative conditions, recording interventions, and determining progress. In a target community, premises information should be aggregated for each block and filed according to assigned block numbers. A block is reported as infested as long as any active rodent signs exist on a single premises.
A block is ordinarily bounded by four streets, but some blocks are bounded by three or fewer, or may be irregular in form. In some cases, imaginary boundaries conforming to prevailing block sizes may be set to define a block.

# Census Tract (multiple contiguous blocks).
The census tract is an excellent unit for large-scale planning and reporting purposes. Some IPM authorities use zones, wards, or elementary school or health districts for reporting purposes.
4. Target Area (entire operational area of an IPM program). Large cities may have several target areas.

# Sample Versus Comprehensive Surveys
The block survey is considered comprehensive if all premises in all blocks in a defined target area are surveyed. In a sample survey, all premises on a block are inspected in a small but statistically valid number of blocks in a defined target area. Comprehensive surveys provide complete information on rodent infestation and sanitary conditions in a defined target area. Sample surveys are appropriate for defining an infestation problem and its causative conditions for a target area, but they are not appropriate for intervention purposes.
The sample survey is quicker to do than a comprehensive survey because all premises are inspected only within a randomly selected sample of the blocks in the proposed or actual target area. This type of survey is typically used to determine the need for a rodent IPM program; to define program needs and requirements for personnel, material, and equipment; and to later evaluate program progress.

# Personnel Requirements
Ideally, urban rodent surveys should be conducted by two-person teams, with the most qualified person recording the data and making decisions about questionable findings. Safety is also a factor in a team approach.
Survey teams, where possible, should be composed of experienced rodent control specialists, environmental health specialists, or other trained personnel. Knowledge of the area to be surveyed, when practical, can also be helpful, especially if a member of the survey team lives in the area to be surveyed. The survey teams should be guided by the exterior inspection form, which is to be completed during the inspection.
At least 3 to 5 days of classroom and field training are recommended for inspectors to ensure that their observational and recordkeeping skills are satisfactory.
To conduct interior inspections, additional classroom and field training is necessary.
IPM surveys are a detail-dependent process. The number of premises inspected per team per day will vary with experience, complexity of the built environment, and other variables. For example, large lots, multiple dwellings on a premises, difficult-toaccess alleys, and complex building designs need to be considered in determining the time required to conduct a survey.
In most communities, permission for entry onto premises must be obtained before conducting an inspection. People may resent the intrusion onto their properties unless they understand and accept the purpose of the inspections. Community support should be sought to enhance program success. This support can be gained by meeting with community representatives, church groups, and others in advance of the survey.

# Survey Procedures
Conducting an urban rodent survey involves four phases: preparation, public information and education, inspection, and analysis.  1). Evaluation is an essential component of the survey process. Taking photographs can be helpful in understanding particular infestation problems and can be used for training purposes is part of the evaluation process. Although inspections are generally conducted during daylight hours, we recommend that senior staff occasionally visit the target area at night to view conditions during the rodents' active period. These night inspections will add clarity to the relation between the rodents and their built environment. They will also provide a better understanding of the impact of poor refuse management. Infrared video cameras can be used to document rodent activity at night.

# Analysis.
Tabulating findings, analyzing data, and comparing achievements. Analysis of data provides the basis for developing work plans and for preparing reports with recommendations for eliminating infestations. Such reports often are supplemented by tables, graphs, maps, and photographs.

# Sample Survey Methodology
Initiating a sample survey requires maps, survey forms, and complete lists of blocks or premises of the target area. Each premises must be clearly defined and given a number so that it can be unambiguously identified on the map. Because of expected variations in block configurations, decide what constitutes a block for survey purposes. All field personnel must be aware of that definition.
The procedure for selecting the sample number of blocks for a random block survey follows:
1. Determine as closely as possible the number of blocks and premises within the target area or areas to be surveyed.
2. Determine the number of premises that will have to be inspected to ensure statistical validity (Table 1). Note: Sample sizes must adhere to the minimum standards; the reliability of the survey results depends on adherence to the standards.
3. Divide the number of blocks in a target area into the estimated number of premises. The equation below represents the average number of premises per block in the target area.
20,000 premises Example: -------------= 20 premises per block 1,000 blocks 4. Determine the number of blocks so that a sufficient number of premises (as obtained from Table 1) will be surveyed.
Example: If at least 500 premises need to be inspected, and the target area contains an average of 25 premises per block, then all premises on 20 blocks will need to be surveyed. 500 premises needed ------------= 20 blocks 25 (average premises per block) 5. Select the 20 blocks by using a table of random numbers (Appendix B, Table B-1), with each number representing a specific numbered block.
Note: When using this method, every premises on a selected block should be inspected, even if repeat visits are required.
Another survey method is to randomly select a sample of premises in the target area for inspection. For this method, a complete list of premises is needed, but such a list can be difficult to obtain. This particular method requires assigning every premises a number and identifying each premises on a map.

# Survey Crews and Equipment
Two-person teams are more efficient to conduct block surveys. Each team should carry the following items:
- a supply of field forms (exterior, interior, or both, depending on the needs of the program),
- mechanical lead pencils and lead refills (0.5millimeter leads, HB type),
- clipboards,
- flashlights (rechargeable type is recommended),
- gloves,
- forceps,
- hand lenses (5-10X),
- small plastic vials and zip-close plastic bags for field samples (e.g., dead rodent specimens, fecal droppings),
- black light to detect rodent urine stains,
- dog repellent,
- digital still cameras, and
- mobile phones or pagers (for communication between supervisors and inspection teams and for emergency situations). Note that a personal digital assistant (PDA) can be used instead of the field forms, lead pencils, and clipboards. Also note that infrared video cameras can be a valuable tool for filming rodents at night.
For indoor inspections, add the following items:
- small and large flashlights (headlamps, if practical),
- extendable inspection mirrors,
- dust masks or respirators,
- hard hats,
- portable vacuum cleaners with high-efficiency particulate air (HEPA) filters, and
- small ladders (4 feet ).
If a recording code (instead of a check mark) is to be used on the forms for more precise information about specific data categories, a copy of the codes should be taped to the clipboard for easy reference. The inspection forms can be relatively simple or can be greatly detailed depending on the needs of the survey. Inspection forms can be completed using PDAs and other portable computer equipment.
Each team should have a supply of outreach literature on the program to distribute to landlords and householders during the surveys.

# Premises Inspection-Exterior
Supervisors should hand out the block assignments before the teams leave the office. For multiple teams, the supervisor should remain in the immediate area to monitor the work of the teams and to provide support as needed.
A standardized survey process is more effective; for example, begin the survey of each block at the northeast corner and move clockwise. From this corner, the inspectors proceed around the block, inspecting each premises in the order established for the survey.
The two-member teams may work together on an inspection, or, if both are experienced, they may inspect alternate primeses and be available to assist each other as needed. Placing a chalk mark on the curb after a primeses has been inspected can be useful if a supervisor needs to locate the team; however, inspectors may use portable phones to maintain contact.
Each premises should be approached from its main entrance area and should not be entered by crossing yards. The inspector should request permission from a responsible adult to conduct an inspection. A brochure that explains the program can supplement the explanation of the program and the purpose of the inspection. Usually, only a few minutes are required to communicate effectively with householders. Occupants of the premises should be encouraged to join in the survey of the premises. This participation allows inspectors an opportunity to praise occupants for the well-maintained aspects of the primeses, such as a clean yard, and to tactfully call attention to active rodent signs or sanitation deficiencies.
Inspectors should wear clear identification that identifies them as a representative of the rodent IPM program. Wearing distinctive official uniforms also can be helpful in establishing identity with the program.
Before proceeding with the exterior inspection of a premises, write the number of dwelling units on the exterior inspection form (Appendix A, Figure 1, column 7. See the Instructions for Completing the Block Record (Exterior Inspection) Form section on pages FILL). The team should then proceed in a clockwise direction around the premises, inspecting the buildings, yard, and passageway(s) or other spaces, and recording all deficiencies on the survey form. The inspection pattern is as follows:
- front (the facade or surface of the building that contains the main entrance and its associated yard or other spaces),
- left side (left wall surface of building and its associated yard or other spaces),
- back or rear (the rear wall surface of the building and its associated yard or other spaces), and
- right side (the right wall surface of the building and its associated yard or other spaces).
Symbols can be used instead of check marks to record information. These symbols can also be used as a reference in the Remarks section or in the premises Address column of the form; for example, F: front (with main entrance to building), L: left side, B: back or rear, and R: right side.
Rodent signs should be observed at close range to determine infestation. Inspectors should look for active rodent runs or burrows in the yard, entry routes into buildings, burrows under walls or in ditch banks, rodent damage, fresh fecal droppings along foundations, and other evidence of infestation.
Before leaving a premises, inspectors should check the inspection form to make certain that all items have been completed. Having a supervisor or another field inspector recheck the survey findings on a subsequent day to verify results can be helpful (e.g., taking a 10% sample of the surveyed premises to ensure the recorded information is accurate and complete).
In some instances, householders may refuse permission for IPM staff to inspect their premises or dwelling. These refusals should be noted on the report form and referred to the supervisor. In other instances, no responsible adult may be at home to grant permission for inspection. In such cases, the policy of the IPM authority determines whether to conduct the exterior inspection.

# Premises Inspection-Interior
The term "interior inspection" generally applies to the main buildings on a premises and not to sheds or outbuildings (this delineation can be modified to meet the needs of the local IPM authority). Two-person teams are recommended for interior inspections. The work is detail-oriented, tedious, and often difficult to accomplish because of clutter, furniture, and crowded conditions.
Inspectors should check all rooms in the building for rodent signs and sanitation deficiencies. Kitchens, closets, bathrooms, attics, and basements are especially attractive to commensal rodents. All floor levels of the building should be inspected regardless of the suspected species. Norway rats are usually found in basements and on lower floors; upper floors and attic areas are especially attractive to roof rats; and house mice can be found nearly anywhere, including in cabinet drawers and above drop ceilings. Householders often can be helpful in providing specific information on a rodent infestation.
In some communities, the interior rodent population may be more difficult to manage or control than the exterior population. The exterior inspection form (Appendix A, Figure 1) can be modified for interior inspections. When doing so, information such as level/ floor, room type, and number of occupants as well as information on active rodent signs (droppings, holes, gnawed materials, and rub marks) should be included on the modified form. Information about rodent bites should also be collected.
Infestation rates (i.e., percent of apartments in a building with active rodent signs) are useful in comparing conditions or measuring IPM progress over time.
Inspection teams should follow standardized procedures for interior inspections. For example, in a multifamily apartment building, start in the basement, then work upward, inspecting apartments in numerical order, then inspect the attic or crawlspace, and finally the roof (if accessible). Enter each apartment through the front (main) door and inspect the wall that contains the main door as well as everything on or touching that wall for signs of rodents and potential rodent entries. Move clockwise to the next wall and continue until all walls are inspected. Next, inspect the floor area, including anything on or touching the floor. Last, inspect the ceiling area, including anything on or touching the ceiling. Each room should be inspected in the same manner. Closets should be inspected in association with particular walls of a room.
This standardized inspection method provides very specific data on rodent locations for intervention purposes. The data also simplify the tracking of specific changes over time and provide information for other inspectors.

# Instructions for Completing the Block Record (Exterior Inspection) Form
The Block Record-Exterior Rodent Inspection and Sanitation Form (Appendix A, Figure 1) is used to record information on rodent infestation and environmental deficiencies for each premises on a block. The form has space for recording information for 10 premises; additional forms can be used as necessary. Enter the page number in the space provided at the top right corner of the form (i.e., "1 of 2," "2 of 2"). If only one form is required for a block, use the same notation (i.e., "1 of 1") to clarify that only one page is required. In addition, enter the names of the inspectors at the top of the form in the space provided.
Other items at the top of the form should be completed by the supervisor or team leader before the teams enter entering the field. The location of a block should be indicated by writing the names of the streets that form the block in the block diagram space in the upper left portion of the form.
A copy of the assignment chart should be kept in the inspector's or supervisor's office.
Completed inspection forms (Appendix A, Figure 2) should be checked and initialed by the inspectors.
All columns of block data should be totaled and recorded on the appropriate line of the summary form (Appendix A, Figure 4 is a completed example). The summary form should be used to prepare progress reports, identify problems, and target resources.

# Premises Address
- As inspectors proceed clockwise around a block, they should write each street address in the left column. If an indoor inspection has been conducted at a particular address, the line number (1 to 10) in the "No." column should be circled.

# Premises Type
A premises must be classified in one of four categories (columns 1-4): residential, commercial and residential, commercial, or vacant lot. Only one of the first four columns should be checked.

# Column 1: Residential
Put a check in this column if the unit is a home or dwelling (defined as an enclosed space used for living purposes). A dwelling can be a single-family or multifamily unit. Enter the number of dwelling units in column 7 (No. of Dwelling Units).

# Column 2: Commercial and Residential
Put a check in this column if a premises is used for both commercial (see column 3 description) and residential purposes.

# Column 3: Commercial
Put a check in this column if the premises is used only for commercial purposes (including parking lots) or for other nonresidential purposes such as offices, churches, clubhouses, or schools. The type of premises (e.g., school) may also be written in the address column. Some IPM programs may decide to use a code for recording public properties, clubs, churches, or other types of nonresidential properties.

# Column 4: Vacant Lot
Put a check in this column for a lot with no structure on it. Note that a parking lot should be designated as "commercial."

# Premises Details
Use these four columns of the inspection form to record information that may be helpful in estimating population density and in determining resource needs for intervention purposes.

# Column 5: Food-Commercial
Put a check in this column if a regular, primary function of the premises is to prepare, sell, serve or dispense, or store food materials, including animal foods. Thus, restaurants, delicatessens, soup kitchens, bakeries, grocery stores, nursing homes and hospitals (where daily meals are served), pet stores, and grain warehouses should be included here. Both this column and column 2 or 3 should be checked.

# Column 6: Vacant
Put a check in this column if the main building on the premises is not in use, whether temporarily vacant, permanently abandoned, or boarded up and scheduled for demolition. Abandoned buildings generally are not considered habitable because of deterioration (e.g., broken windows, missing doors, vandalism, fire damage). If more precise information is desired, three symbols can be used in this column instead of a check mark: V: vacant and habitable, AO: abandoned and open, and AS: abandoned and sealed.

# Column 7: No. of Dwelling Units
Enter the number of dwelling units here. Determining the number of dwelling units on a premises should be based on the following definition:
A dwelling unit is a room or group of rooms located within a building or structure that forms a single habitable unit to be used for living, sleeping, cooking, and eating.
Multiple dwelling units (e.g., apartments) can exist on a premises. The number of mailboxes, meters, or doorbells is an indicator of the number of dwelling units on a premises. Only the number of habitable dwelling units on a premises should be marked; noninhabitable dwelling units should not be marked.

# Column 8: Sewers on Premises
Put a check in this column to record the presence of a sewer pipes or storm water drains on the premises. Sewers can provide harborage, and rats often travel between a premises sewer and the exterior portions of the premises. Evidence of harborage includes active burrows near manholes, catch basins, or broken sewer pipes, and fresh rub marks on broken downspouts that empty into sewers. If other sewer deficiencies are found, do not check them; use an asterisk and include a footnote under the Remarks section of the form.

# Food
These columns (numbers 9-12) provide information on food sources that must be eliminated.
Proper storage of refuse (also called municipal solid waste or MSW) requires the use of rodentproof containers of adequate construction, size, and number. Refuse is defined as a mixture of garbage and rubbish. Garbage consists largely of human food waste (organic, putrescible), but it includes offal, carrion, and animal feces (e.g., dog or horse). Rubbish is considered nonfood solid wastes (combustible and noncombustible, nonputrescible) such as metal, glass, furniture, carpeting, paper, and cardboard. Rubbish also includes wood chips and yard wastes.
In conducting rodent surveys, the following criteria for refuse storage are recommended.

# Approved Refuse Storage
- Refuse containers should be water tight with tight fitting lids that may be hinged; rust resistant; structurally strong; and easily filled, emptied, and cleaned. Standard refuse containers are 20-32 gallons (91-150 liters). Hinged containers with wheels can hold up to 95 gallons (430 liters). Bulk containers such as dumpsters have side handles or bail for manual handling or special attachment hooks and devices for automatic or semiautomatic handling.
- Bulk storage containers are generally acceptable and are often used in multihousing buildings, commercial establishments, and construction sites. Such containers often have a drain hole to facilitate cleaning. These drain holes are often 2-3 inches (5-8 centimeters) in diameter and are fitted with a removable hardware cloth screen or screw-on plug to prevent entry by rodents.
- Galvanized metal or heavy, high-grade plastic containers meet the guidelines under a in the Column 10 section.
- Cardboard boxes used for yard trash (essentially nonfood items) are acceptable.
- Plastic or moisture resistant paper bags used for refuse, properly tied and intact, placed at the curb or alley only on collection day and only during daylight hours are acceptable.

# Plastic Bags
Plastic refuse bags are widely used as liners in standard 20-32 gallon (91-150 liters) and larger refuse containers. These bags are required by many building managers for refuse placed in bulk containers and are used by many residents for yard trash.
To judge whether plastic bags are managed properly:
- Know the scheduled refuse collection days in the block being surveyed.
- Observe whether the storage site contains both acceptable bags and refuse containers or whether plastic bags appear to be the sole containers for storing refuse.
Plastic bags are not considered appropriate for overnight storage outdoors because nocturnally active rodents and other animals (e.g., cats, dogs) can easily gain access to their contents. Plastic bags should be considered acceptable only when placed outside during daylight hours for collection the same day.

# Approved Recyclable Storage
- Outdoor containers for recyclable items (paper, cardboard, plastic, glass, or metal cans) should be water-tight, strong enough to support the weight of items contained, and easy for sanitation crews to handle.
- Containers similar to those for refuse storage are generally acceptable for household recyclables, as are large plastic bags properly tied and intact and placed at the curb or alley only during daylight hours on collection day.
- In all cases, items stored should be free of food particles or other food residue.
To judge whether recyclables are managed properly:
- Know the scheduled recyclable collection days for the block being surveyed.
- Observe whether the recyclable items have been cleaned or rinsed or are otherwise free of food residue and that the plastic bags or other containers holding the recyclables are intact.

# Column 9: Unapproved Refuse Storage
Put a check in this column if garbage, rubbish, other refuse, or recyclable items are not stored in approved containers with tight fitting lids (or are not in tightly tied bags-where acceptable-during daytime only). Approved containers should be of the design described in the Approved Refuse Storage section. When properly placed in plastic or paper bags, securely tied, and regularly collected, yard trash and other inedible materials are approved. Yard trash is acceptable when placed in cardboard boxes or paper bags and regularly collected.
Put a check in this column if any of the following conditions are observed:
- Container that is not rodent and fly tight.
- Screw-on plug or rodent-excluding screen of an otherwise approved bulk container is not in place or is missing.
- 55 gallon (250-liter) drum. Such containers are often observed without a tight-fitting cover.
When filled, they are too heavy and bulky to handle.
- Nonstandard metal or cardboard containers that are not being used for regularly collected yard trash.
- Bin or stationary receptacle for refuse storage.
- Receptacle too small or too few receptacles for the amount of refuse.
- Overflowing receptacle or one with the cover off.
- Container(s) on a platform on the ground or with a shallow space (<18 inches  high) that offers harborage for rodents and possibly hides scraps of food spilled from the container.
- Burned refuse.
- Scattered refuse (including garbage, rubbish, or recyclables).
More-precise information can be obtained by using symbols instead of check marks to record specific deficiencies. Water and moisture reduction can also enhance IPM practices to control mosquitoes, cockroaches, and mold (especially indoors).

# Column 13: Standing Water
Put a check in this column if water accumulations that are accessible to rodents are found in containers such as buckets, pans, discarded tires, water bowls for pets, window pits of basements, and clogged rain gutters. For indoor inspections, check for water and other consumable liquids that are available overnight in open containers on tables or desks or in sinks, cooking pans, and buckets.

# Column 14: Condensate
Put a check in this column if condensate is available to rodents in, for example, collection pans under refrigeration or air conditioning units; from dripping or running water from a pipe onto the ground or pavement (or onto a basement floor indoors); or directly from the surface of, or dripping from, cold water pipes indoors.

# Column 15: Leaks
Put a check in this column if water is regularly leaking from, for example, a roof, pipe, or outdoor faucet onto the ground, pavement, or floor (indoors). For observed leaks, do not check the Standing Water category even if water has accumulated.

# Harborage
The seven survey items in this section (columns 16-22) pertain to the providing of harborage for rodents. Put a check in any column only if the inspector judges that a significant rodent harborage condition is evident.
For some surveys, quantifying the harborage present is helpful (e.g., using figures to indicate the number of abandoned vehicles and appliances or to estimate the number of cubic yards or cubic meters of large piles of rubbish, lumber, or clutter that is on the ground or on the floor indoors. These figures can be useful in estimating the resources needed for cleanup and for measuring progress in reducing the amount of harborage present.

# Column 16: Abandoned Vehicles
Put a check in this column if abandoned vehicles are in the yard, street, or alley. A vehicle is considered abandoned if the license tag is not current, if major parts are missing, or if high grass and weeds are growing around it. Abandoned vehicles observed in rodent-accessible garages should also be recorded. The summary line at the bottom of the form should note the number of premises with abandoned vehicles. The total number of vehicles may be entered directly below the column total if vehicles are counted for each premises.

# Column 17: Abandoned Appliances
Put a check in this column if appliances (such as refrigerators, stoves, or washing machines) are stored in the yard, in a dilapidated outbuilding, or at the edge of an adjoining street or alley. Put only one check mark regardless of the number of items observed; however, the number of appliances may be entered in the column instead of a check mark. The survey summary line should show the number of premises with abandoned appliances, not the number of appliances. The total number of appliances may be entered directly below the column total if appliances are counted for each premises.

# Column 18: Lumber or Clutter on the Ground
Put a check in this column if a significant amount (covering at least 1 square yard or 1 square meter) of lumber, firewood, or clutter is on the ground. These materials provide harborage for rodents. Clutter, either outdoors or indoors, is defined as disorganized storage of usable materials (not rubbish) that is not being used and which impedes inspections for active rodent infestation. A few scattered pieces of lumber or other materials should not be recorded, nor should lumber left on the ground as a result of recent building construction or demolition and is subject to early removal. If the amount is to be quantified, estimate the number of cubic yards (or cubic meters) to the nearest whole number. The number recorded in the Total row at the bottom of the column, however, is always the total number of premises with a deficiency. The total number of cubic yards (or cubic meters) of lumber or clutter may be entered directly below the column total for premises.

# Column 19: Other Large Rubbish
In both exterior and interior inspections, put a check in this column if there are discarded items of rubbish that are too large or otherwise not suitable for storage in approved refuse containers. These items include tires, automobile engines, large cans and drums, tree limbs, rubble, doors, mattresses, furniture, and other large items not listed in other columns. If the amount is to be quantified, estimate the number of cubic yards (or cubic meters) to the nearest whole number and enter the number directly below the column total.

# Column 20: Outbuildings or Privies
Put a check in this column only if the buildings on the premises are dilapidated or otherwise provide significant rodent harborage. A tight, well maintained building or an open, clean shed should not be recorded. Appliances, lumber, clutter, or large rubbish in an open shed should be reported in their respective columns if they furnish harborage. Always check this column when privies or outhouses are found.

# Column 21: Board Fences and Walls
Put a check in this column if dilapidated board fences, walls, or concrete slabs (e.g., patio slabs, broken sidewalks) are found because they can provide harborage for rodents.

# Column 22: Plant-Related
Put a check in this column if weeds or grass are more than 12 inches (0.3 meters) high and are sufficiently thick to hide refuse and provide harborage for rodents. Bushes and overgrown shrubbery that provide rodent harborage are also deficiencies that should be recorded. Note that roof rats are climbers and prefer to nest in trees, bushes, and attics of dwellings and outbuildings. Put a check mark in this column if dense growth such as ivy, honeysuckle, pyracantha, ground cover, dense shrubbery or vines, or palm trees provide harborage for rodents. Large planters indoors or outdoors may provide harborage for rodents, either in the soil or among dense vegetation. If more precise information is desired, symbols identifying types of dense growth may be used to record such deficiencies.

# Entry and Access
The two columns in this section (columns 23-24) are for recording the need for rodent-stoppage work to prevent rodents from entering structures.
A Norway rat can gain access to a structure through a hole the diameter of a U.S. quarter (0.96 inches or 24.3 millimeters in diameter) and a mouse can gain access through a hole the diameter of a U.S. dime (0.71 inches or 17.9 millimeters in diameter). Structural openings should be less than 34-inch (<19 millimeters) in diameter to exclude adult Norway rats, less than 12-inch (<13 millimeters) in diameter to exclude adult roof rats, and less than 14-in (<6 millimeters) in diameter to exclude adult mice. If openings are sealed (totally closed), cockroaches and other insects will also be excluded.
From a running start, a house mouse can jump up to 2 feet (0.6 meters) high, a Norway rat up to 3 feet (0.9 meters) high, and a roof rat up to 4 feet (1.2 meters) high. Therefore, openings up to 5 feet (1.5 meters) from the ground must be sealed or covered with mesh.

# Column 23: Structural Deficiencies
Put a check in this column if an actual or potential rodent entry to a building because of deterioration or structural defects is observed. Common defects include holes in crumbling masonry foundations, deteriorated fascia boards at the edge of roofs, and poorly fitted doors with gaps of sufficient size to permit rodent entry.

# Column 24: Pipe and Wiring Gaps
Check this column to indicate that a gap or hole associated with a wire, pipe, or other conduit penetrates the building exterior (including basement floor or roof ) and is sufficiently large to permit rodent entry. For indoor inspections, check this column if openings in interior walls, floors, or ceilings are found.

# Active Signs
Put a check in column 25 if active or fresh rodent signs are observed during exterior or interior inspections.
A premises is considered infested with rodents only if active signs are found (e.g., sightings, droppings, runways, rub marks, burrows or openings, gnaw marks, tracks). The infestation rate is calculated on the basis of the number of premises on a block with active rodent signs divided by the total number of premises on a block times 100.
If additional details are desired, symbols could be placed in or next to the column to distinguish signs attributable to Norway rats, roof rats, or house mice. Active rodent signs usually will be one or more of the signs listed below. More precise information can be recorded by using the following symbols instead of check marks:
B. Burrows: active burrow entrances do not have cobwebs or other blockages.

# D.
Fecal droppings or urine: fresh feces are dark and soft; old feces are hard or gray and brittle; urine may be wet, glossy, or sticky or may be a dried stain. A black light can help show rodent urine stains.
H. Gnawed holes, gnaw marks, or tooth marks: a freshly gnawed surface is usually light in color.
M. Rub marks: if fresh, they are black, soft, and greasy.
R. Runs: well traveled paths (Note: runs usually lead to food sources, water, and harborage).
T. Tracks: fresh foot tracks or tail-drag marks.
Z. Rodent hairs: often found on rub marks or at entry holes to buildings.

# Remarks
This section at the bottom of the form is for additional information.

# Interior Inspection Using a Modified Block Record (Exterior Inspection) Form
Much of the methodology for completing an interior inspection is the same or similar to that for an exterior inspection. A modified interior inspection form focuses exclusively on deficiencies found indoors. An interior form should include space for the premises address and the number of dwelling units at that address. The form's design should depend on the needs of the local IPM program, but suggested categories are listed in this section. Many of these categories are explained in the Instructions for Completing the Block Record (Exterior Inspection) Form; categories not explained in that section are explained below.

# Premises Type
- residential,
- commercial and residential, and
- commercial.

# Premises Details
- level or floor (where unit is located),
- room type (e.g., bedroom, bathroom, hallway, kitchen),
- number of occupants in unit, and
- sewer pipes or storm water drains on premises.

# Food
- unapproved refuse storage,
- exposed garbage,
- animal food,
- unapproved food storage (food material stored in open or unprotected boxes, bags, bins, or other containers or stored under storage conditions that are not rodent proof ), and
- other food and plants.

# Water
- standing water,
- condensate, and
- plumbing leaks.

# Harborage
- clutter or storage on the floor,
- other large rubbish,
- plant-related, and
- other harborage (small accumulations of material that may be viewed as providing harborage ).

# Entry and Access
- structural deficiencies and

# pipe and wiring gaps
Active Signs
- fecal droppings, urine;
- holes, gnawings, burrows;
- tracks, runs, rub marks; and
- rodent bites reported (This item is to capture information on whether the occupant has reported being bitten by a rodent within the 6-month period before the inspection. Information should be collected about the demographics of the victim, the biting incident, and the action taken by the health authority. Information about the rodent infestation, bites, circumstances, unsanitary conditions, food and water access, and harborage will be valuable in the effort to eliminate the infestation.
Note: Having the inspection team carry a small portable HEPA-filtering vacuum cleaner to remove rodent signs (e.g., droppings and nesting material) may be beneficial. The vacuum cleaner can also be used to remove potentially allergenic material from the dwelling.

# Remarks
The modified interior inspection form should also include a Remarks section to record additional information (e.g., heavy rat infestation in an apartment with very young children) that requires immediate attention or referral to another department.

# GIS and Mapping
GIS is a highly valued tool, as are maps of the target area or community. Maps help define the infestation problem and its causes as well as measure progress toward eliminating the problem. Maps of the target area are often used by programs to make block inspection assignments, show changing patterns in infestations and their causative conditions, and measure progress in addressing the rodent problem. Table 2 shows examples of the types of major deficiencies and associated map colors on a GIS map.
Maps may be prepared for other causative conditions, including water sources and entry and access routes. These maps can be used as a tool to determine priorities for corrective actions.
The goal of an IPM program should be to reduce rodent populations and their causative conditions to a level that they no longer have an adverse effect on the community. The following set of criteria should be achieved for a block or for the defined target area:
2% or less of the premises with active exterior rodent signs and either 15% or less of the premises with exposed garbage, or 30% or less of the premises with unapproved refuse storage.
These criteria are based on those used by the federal urban rat control program directed by CDC from 1972 to 1981 throughout the United States. About 80,000 blocks in 65 communities heavily infested with rats applied these criteria in their IPM efforts and attained an essentially rat-free and environmentally improved status. Hence, this set of criteria became widely accepted as the tolerance limit for a block, target area, or community. Local rodent IPM authorities may establish tolerance limits for other deficiency categories as needed. Tolerance limits will provide evaluative feedback to determine the direction to be taken by a rodent IPM program. Infestation is calculated as the number of premises with active rodent signs divided by the total number of premises on a block times 100.
Comprehensive surveys (i.e., premises-by-premises) to identify active rodent signs and their causative conditions should be conducted, at a minimum, twice yearly for all blocks that have not reached the tolerance limits for active rodent signs, exposed garbage, or unapproved refuse storage. Comprehensive inspections should continue until 80% or more of the blocks in a target area have achieved the established tolerance limit and have maintained that status for at least 1 year. Thereafter, a sample survey procedure may be used two or more times a year to verify the status of the target area blocks that have achieved the tolerance limit; for the other blocks, comprehensive inspections should be conducted at least twice yearly.
If the survey data indicate that conditions have deteriorated and that rates of active rodent signs, exposed garbage, and unapproved refuse storage have risen above the tolerance limit, appropriate IPM interventions will be required based on the analysis of the data.

# Interior Tolerance Limits
Interior inspections require visiting every room of every unit or every location of a structure on a premises. These visits provide inspectors with a detailed profile of the infestation and its causative conditions. One difficulty in this aspect of an urban IPM program is that inspectors are not likely to gain entry to all premises, units, or locations.
From the standpoint of good public health practice, the tolerance limit for rats or mice in human living quarters should be zero; that is, rodents should not live with people. To achieve and sustain a zero-tolerance limit for rodent infestation for one or more dwelling units, the same criteria should apply as that for exterior exposed garbage and unapproved refuse storage.
For interior surveys, the following additional broadscale tolerance limit should be established:
15% or less of the premises with rodent entry and access routes within 5 feet (1.5 meters) of grade or other low horizontal surfaces.
This tolerance limit for entry and access routes may not fully address the problem of rodent access to exterior premises, but it greatly increases the likelihood of achieving the zero tolerance limit for rodents in dwelling units, a key quality-of-life issue. This limit also promotes the application of rodent-stoppage interventions that are essential to reducing interior infestation.
The urban rodent survey is an essential tool in the IPM effort to manage rodent problems. The survey provides precise information about infestations and their causative conditions, and it measures progress toward their elimination.
This manual should serve as a basis for designing and conducting valid surveys to determine the magnitude of infestation problems and their causes, for implementing interventions, and for measuring progress. The survey, however, is only a framework for the many activities of a rodent IPM program. An IPM program cannot succeed without the commitment of the local health authority, other professionals, and the public.
 6  4 0 8 6 - - 4 3 - - 2        2 648 Ruskin St.        3 650 Ruskin St.       4 652 Ruskin St.      5 654 Ruskin St.      6  - - - - - - - - - - - - - - - - - - - - - - - 7 661 Biko St.        8 663 Biko St.       9  - - - - - - - - - - - - - - - - - - - - - - - 10 1243 King St.      TOTAL 7 0 0 1 0 0 33 1 7 6 2 2 2 0 2 0 1 1 1 2 3 2 4 1 5 N B i k o S T R u s k i n S T King Ave

# Chavez Ave
Remarks (continue on back of form as necessary):
City:

# Example
To select at random 20 blocks from a total population of 427 blocks in the area to be surveyed, assign the numbers 1 through 427 to the 427 blocks. To assign these numbers, use a map of the area so that each block is clearly defined.
Because 427 is a three digit number, combine three columns in the table and read them together. (For a two-digit number, combine and read two columns; for a four-digit number, combine and read four columns.) A column is a single-digit list of vertical numbers. In this table, columns are grouped in pairs.
- Select a starting point on the table randomly.
- If the number at the starting point is 427 or less, select the block having that number.
- If the number of the starting point is greater, continue down the horizontal rows until the number 427 or less is reached, and select that number.
- In either case, continue down the rows and, if necessary, down the columns beginning at the top of the page until 20 numbers of 427 or less have been located.
- This list will be the 20 blocks surveyed.

# NOTES:
Ignore any number over 427 because only 427 blocks exist in the total population to be surveyed. Having the same number 427 or less more than once does not matter. Continue until 20 numbers are selected.
Assuming 20 blocks will be chosen from a total population of 427 blocks, the selection process can be illustrated as follows:
- Suppose the randomly chosen starting point is the number formed by vertical columns 25-27 (remember that each digit is a column) in the 28th horizontal row of the third page of random numbers (page B-4).
- This number is 724, which is more than 427, so continue down the same columns by horizontal row until the number 081 is reached. Block 81 would be the first block chosen.
The other 19 blocks chosen would be 361, 373, 61 (ignore 533 because it is over 427), 164, 224, 118 (ignore 876 and 948), 300, 9 (ignore 565 and 613), 140 (ignore 724, 453, and 717), 38 (move to the top of the page, vertical columns 28-30 for the remaining numbers) 401, 225, 233, 328, 5, 184, 117, 376, and 114.
- The last nine blocks chosen (beginning with 401) are found in the numbers formed by combining columns 28-30 in row 1 on the same page.

# Appendix A-Survey Forms
Integrated Pest Management: Conducting Urban Rodent Surveys

# Appendix B-Selecting a Random Sample
Suppose there is a finite population from which we wish to draw random sample of N elements. One method of creating a random sample would be to assign a number to each number of the population (e.g., block), put a set of numbered tags corresponding to the elements into a box, shake the box, and draw N tags from it. The numbers on these N tags would correspond to the elements to be selected. This method could be satisfactory, but it would require considerable labor to prepare the tags.
Instead of preparing numbered tags, we can use a table of random numbers. Such a table consists of numbers chosen in a fashion similar to drawing numbered tags out of a box. The table is so created that all numbers 0, 1... 9 appear with approximately the same frequency. By combining numbers in pairs, we have numbers from 00 to 99; by combining the numbers three at a time we have numbers from 000 to 999. The numbers can be combined as much as necessary.