Thursday, December 16, 2010 425 440 0966

Centers for Disease Control and Prevention

Managing Rodents and Mosquitoes

Through Integrated Pest Management



Hello, I’m Cynthia Good. Welcome to today’s program, “Managing Rodents and Mosquitoes through Integrated Pest Management.” Over the next 90 minutes we’re going to look at the threats, both re-emerging and new, that rats, mice and mosquitoes pose to cities and rural areas. And we'll examine the most effective strategy for managing these pests – Integrated Pest Management.

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In recent years many urban communities have experienced a resurgence of the rodent problem. In some communities more than 50 percent of the premises are infested with rats and mice. In 1993, the rodent-borne Hantavirus pulmonary syndrome made national headlines when it claimed several lives in the desert Southwest. And more recently mosquitoes have been responsible for the spread of the occasionally lethal West Nile Virus.

For centuries rats and mosquitoes have carried numerous diseases that threaten our health and the quality of our lives. They are not just a nuisance. These diseases pose fresh challenges for our environmental public health services workforce. Today we will learn how to best protect ourselves from these sometimes deadly pests by applying a systems approach we call 'Integrated Pest Management or I-P-M for short. Now let's look at a short animated piece, created here at CDC specifically for this program that illustrates some of the conditions that would favor rodent and mosquito infestation.



To help us understand I-P-M strategy, we have assembled a panel of experts.

Joining me today is Dr. Stephen Frantz, Principal Officer of Global Environmental Options and former Director of Vector Biology and Comprehensive Management at the New York State Department of Health. Dr. Frantz is one of the nation's leading experts on rodent control and integrated pest management.

Also with us today is Dr. Gary Clark, Chief of the Dengue Branch in the Division of Vector-Borne Diseases at CDC's National Center for Infectious Diseases. Dr. Clark is an expert in mosquito-borne diseases.

With us too is Dr. Virginia Caine, Director of the Marion County Health Department in Indiana. Dr. Caine is also the President-Elect of the American Public Health Association. Our congratulations on your new post.

And finally, Dr. Patrick Meehan, Deputy Director for Program of CDC's National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry which are presenting today's broadcast.

Welcome to you all. And now let's look at the objectives for today's broadcast.

This program has four principal objectives:

One… describe environmental factors associated with pest infestations.

Two… describe the current practice of health departments to manage pest infestations.

Three… describe Integrated Pest Management and its importance in managing pest infestations.

And four…describe CDC’s promotion of I-P-M.

In the course of the program we’ll also be showing you the contact numbers you can use to call us or fax in your questions.

You’ll be glad to know that continuing education credit is available to you for participating in this broadcast. To receive credit, you need to register and complete the evaluation form. We’re offering C-M-E, C-N-E, CHES, and regular C-E-U credit for this broadcast.

Specific information on how to get credit is on the broadcast website ( I’ll also give you more information about accreditation at the end of the broadcast.

Now let’s get started. Here’s Dr. Richard Joseph Jackson, senior advisor to the Director of the Centers for Disease Control and Prevention and former Director of the CDC's National Center for Environmental Health, with some introductory remarks.


This special program on integrated pest management or IPM focuses on two important threats to health: mosquitoes and rats and mice. These pests have existed with humans and affected our health since the beginning of time. In medieval Europe rodents were responsible for transmitting plague, the terrible Black Death that killed one third of the population. And for centuries mosquitoes have been responsible for the spread of many diseases. We’ve long recognized that to protect our health we need strong public health programs to manage rats and mice and mosquitoes, and that’s why these programs are an integral part of public health practice. So we’ve had these strong programs in the past; what happened? Why are we paying more attention to these pests now? What happened is that rats and mice and mosquitoes have continued to be and will always be a public health threat but efforts towards their control have diminished, have gone down perhaps because we thought these were problems of the past. All that changed when West Nile Virus and Hantavirus came on the scene and healthy young adults began dying from these illnesses. And then the terrorist attacks in 2001 got us thinking about how the plague bacillus could be used by terrorists. These events got out attention and showed us that we need to do more to manage rats, mice and mosquitoes. They are and they always have been more than just a nuisance for many people.

So what should we do? We need to take a long range comprehensive approach to the problem. A comprehensive approach that combines biological, cultural, physical and chemical tools in a way that minimizes threats to our health and to the environment. That’s what we mean by IPM. Instead of sitting back and waiting for calls or complaints or reports of rat bites or mosquito-caused illnesses, we need to focus more on prevention and on changing behaviors.

Here’s our action plan. Number one, we have to work with the community. These problems are too complex for any one group to manage alone. Number two, we’ve got to identify the root causes, things like food supplies and breeding grounds for these pests. Number three, we have to track the illnesses, we have to perform the inspections; we have to conduct surveillance. Number four, we have to improve sanitation and we have to enforce the public health codes. Number five, we are going to need to use pesticides, but we ought to do it effectively, carefully, and intelligently. And finally, we need to measure our success because unless we can demonstrate that we are having an impact, sooner or later we will lose support for the program.

I’ll give you an example of how this works. Let’s ask ourselves why are rats and mice a problem? Usually it’s because we humans are providing them with the food, water and shelter that they need. We put out plastic trash bags full of leftover food, leave them out, or we put food in dumpsters where the trash is overflowing. We tolerate tumbled down buildings and abandoned vehicles where rats and mice take shelter. And even if we leave pet food and water out for long periods of time, it can attract them. These kinds of things make it easy for rats and mice to live with us, and it explains why in a recent survey in a major American city 20 percent of the buildings were infested with rats and mice. In some of the neighborhoods, more than half of the buildings were infested. Rats and mice spread disease, they contaminate food and they destroy property. They bite 10,000 people a year, mostly children and the elderly. In fact, they’ve even started fires by gnawing on electrical wires, and sometimes these fires have resulted in serious injury and death.

We’re not controlling these problems or practicing good public health if all we do is put out poison after someone complains. What is effective is working with other agencies and organizations and with decision makers and with the community to change our behaviors. These actions will help eliminate the conditions that make it easy for rats and mice to survive.

In the case of mosquitoes, our focus in the past has been on spraying areas where mosquitoes are a nuisance and where tourism might be affected. In the United States we’ve been successful at managing mosquitoes. But we need to keep in mind that mosquito-borne diseases are still among the world’s leading causes of illness and death. Spraying to kill adult mosquitoes may be good public relations, but if you really want to do good public health work, we’ve got to reduce the numbers and survival rate of the larvae. That is the baby mosquitoes. More communities need to be better prepared for new and emerging threats such as West Nile Virus, and one of the most important actions to take is to work with the community to eliminate standing water. Primary sources of standing water are containers such as old tires, plugged rain gutters, and low lying areas along rivers and creeks and ponds where water can stagnate.

We have tended to think of this issue as a rodent and a mosquito problem, but it’s really our problem. It’s a human problem. An IPM approach is required to address it. We recognize that there are limited resources and there are other competing health priorities, and this has had a significant impact of how health departments manage the problem. And many health departments rely on pesticides, but they are just a small part of the solution. And in fact, widespread indiscriminate use of pesticides creates it own problems. In fact, the biggest hindrance to managing mosquitoes is that most environmental public health programs are understaffed and overworked.

Our purpose today is to highlight the importance of integrated pest management. We recognize to successfully apply an IPM approach; we need to improve the capabilities of all of us in the public health workforce. And this broadcast is designed to bring attention to both of these important issues: IPM and workforce development. Our panel of experts will tell you more about the environmental factors associated with rat, mouse and mosquito infestations, and it will give you an overview of the current practices that health departments are using to manage these pests and highlight the important contribution that IPM can make. And finally, it will show you how CDC is working with you in the public health services workforce to make IPM a reality.



Before we talk about Integrated Pest Management, can you start us off, Stephen, by telling us why rats and mice pose such a serious threat to our health and well-being?


Cynthia, rats and mice have always been among the most destructive animals on the planet. In scientific terms, we call them zoonotic pests or vectors. Pests because they can harm and annoy us. And vectors because they carry zoonotic disease organisms transmissible to humans. The biggest threats are the 'commensal' species, from the Latin meaning 'sharing the table', which in some cases they almost literally do. These animals depend almost exclusively on the built environment and agriculture to survive and thrive.

Nobody feels comfortable seeing rats and mice in their home or even running about in the street. We know that they are a vector for many diseases such as plague and Hantavirus pulmonary syndrome, but recent studies also show that mice can be a trigger for asthma attacks. In addition to biting, bringing disease and causing stress, they also consume and contaminate tons of food and cause tremendous physical damage to structures and material goods. Keeping a rodent-free environment is a constant and daily challenge.


Can you give us some historical background on efforts to control rodents?


By the beginning of the 20th century, US government agencies had acquired considerable expertise in successful rodent management. The key to success was environmental management that focused on eliminating food sources, water, and harborage. However, by the 1940s, new poisons for rodent control began to eclipse good environmental management. Today, we place far too much reliance on poisoning. In fact, sustainable, safe, rodent management has been lacking for several decades.


Have there been any major efforts since the 1940s and 50s aimed at rodent management?


Yes, there have. One of the most important efforts was the federal urban rat control program run by CDC from 1972 to 1981. This program awarded grants to more than 65 cities and counties throughout the US to control rats and mice. These programs were required to conduct comprehensive premises surveys of the communities they served to assess the rat problem and determine its causative conditions. The interventions that followed emphasized public health education, community sanitation, code enforcement and, to a lesser degree, poisoning. Communities played an active role in that process. Over the life of the program, more than 80 thousand blocks that had been heavily infested became rat-free and environmentally improved. That means that the causative conditions that support infestation were significantly reduced or eliminated. This is what I-P-M is about. It's a comprehensive systems approach to the problem that is effective and sustainable without compromising the health of people and the environment.


It sounds like the program was very successful. And what's the situation today?


Unfortunately, since 1981 when the federal program ended there's been a resurgence of the rodent problem in many communities. As a result, these communities have had to make hard choices about how to spend limited resources and the presence of rats and mice apparently have not ranked high. In 1999, an American Housing Survey found that more than 8 million housing units in the US had rat and mouse infestation.

On top of this, budgets for programs aimed at improving housing conditions and aging housing stock, especially in low-income neighborhoods, are now either tight or being slashed. Solid waste management, street and building maintenance, affordable housing for the needy are also cash strapped programs. Today, most rodent control programs are complaint-oriented and are limited to poisoning and sometimes, trapping. Undoubtedly, rodents are taking advantage of this situation.


In fact, CDC's National Center for Environmental Health recently sent a camera crew to a number of cities around the country to document the problem and the efforts to address it. Let's take a look at what they discovered.


Rats and mice present a public health risk to the residents of the community because they have been associated with the transmission of diseases. Traditionally and perhaps the most well known are the plague outbreaks in Europe in the 17th, 16th century. More recently Hantavirus has been a significant concern for residents in many communities, and they’re also an economic pest that we see significant problems in our commercial food establishments where they are responsible for the destruction of a lot of food that subsequently gets thrown out as a result of contamination by their feces or their urine.

Rats and mice present a health and safety risk to our community primarily because of the possibility of transmission of rodent-borne disease. That’s first and foremost of our concern. Secondly, the economic impact. They have a potential economic impact on food establishments, restaurants, supermarkets, that sort of thing. And finally, quality of life. We want to make sure that our citizens have a good quality of life and rodents certainly detract from that, and we want to improve the quality of life as well.

Rodents, like people, need food, shelter and water, all of which are supplied in our home.

The greatest concern about the rodent problem is two fold. One is, we have neglectful landlords who are not responsible for their properties, or not taking responsibilities. The other aspect is that we have tenants who are not educated about rodent infestation.

They get into everything. They leave their droppings behind everywhere and it’s awful in the morning sometimes when you open up the cabinets and you find what foods they got into, and it can be very expensive because you’re tossing food out that maybe you just bought that morning for the children.

As a population group, Native Americans certainly stand a much more higher likelihood and pronounced possibilities of being exposed to vector-borne diseases, as well as other diseases because as a population group, we are still very intimately connected to mother nature. We still consume a lot of the wildlife, the plants and therefore vector-borne diseases certainly creates a greater chance for exposure to these kinds of diseases.

Plague is endemic to the Southwest. It presents a significant problem here in the greater Albuquerque area. I believe that one of the biggest problems we have is the suburbanization and the migration of people into the natural habitat.

The rats and mice problem is because they’ve had a large amount of the Hantavirus on the Indian reservations, and those are deadly.

Just the fear that if they cannot get into the food, they’re going to start coming after us, you know, and at nighttime, when you hear these scuttles, you’re thinking, oh my God, where are they? Where are they and please hope that they don’t come into my children.


So clearly there are a lot of issues that must be addressed. Stephen, how do we go about this?


Cynthia, as I alluded to already, today many communities rely almost exclusively on complaint or nuisance-based management techniques to attempt to control rodents. When you use this approach you can initially get a sharp drop in the population of the target species below the tolerance limit. However, generally the effect is only temporary. Since you're not affecting the breeding structure of the population it inevitably rebounds usually to previous levels. The real answer is Integrated Pest Management. The primary objective of I-P-M is the permanent reduction of targeted pests to levels of virtually no concern, i.e. the ‘tolerance limit’. You can't do this simply by poisoning and trapping. The first priority must be to modify the habitat in such a way that populations are prevented from multiplying again to previous levels. Trapping and poisoning should only be supplemental interventions in achieving a new, lowered population equilibrium.

I-P-M requires a paradigm shift from typical pest control efforts. With I-P-M, you manage the environment to manage the pest or vector. This means we must take into account the behavior and ecology of the target pest, in this case rats and mice; the environment where they are active; and the periodic changes that occur in that environment. At the same time, we must ensure the safety of people as well as non-targeted animals, such as livestock, pets, birds, and the environment.

Integrated Pest Management is therefore a decision-making process in which all necessary activities are brought to bear on the vector or pest with the goal of providing a remedy that is: the most effective, safe, economical, and sustained. These four criteria clearly separate I-P-M from typical pest control practices. I-P-M has as its goal the long-term, effective resolution of the problem.


So tell us then, what are the components of I-P-M?


There are four key components: inspection and monitoring; tolerance limit; interventions; and evaluation. Let's look at them one at a time.

The inspection and monitoring system allows us to periodically measure the magnitude of the problem and its environmental causes.

The tolerance limit is the population level at which the pest causes sufficient damage to warrant intervention. Damage can be: esthetic and nuisance, economic, or medical and psychological.

Interventions are the actions taken to eliminate or reduce the pest population and its destructive effects. There are several common intervention categories that might be used singly or, more typically, in combination to form an I-P-M strategy. Educational Interventions modify human behavior; Legal Interventions include the development, promotion, and enforcement of regulatory codes, ordinances.

Then we have Physical Interventions which provide alternative approaches to housekeeping, storage practices, improved sanitation and rodent-proofing of structures. Closely linked to physical interventions are cultural interventions which primarily deal with landscape design and maintenance. It includes preventing access routes to buildings through overhanging foliage and removing or thinning dense groundcover.

The next category is biological interventions. Predators, parasites, or pathogens for a target population can also be introduced as part of an I-P-M strategy. For some vector and pest species like mosquitoes, we have some very effective biological agents. However, for commensal rodents, there are at present no biological agents that don’t also pose a risk to non-target mammal species. We have mechanical interventions…devices such traps which capture the target species dead or alive.

We also have chemical interventions or pesticides. The bulk of chemical interventions for rodents are lethal rodenticides though there are some relatively effective repellent compounds used to prevent rodent gnawing, such as plastic coated cables.

The final and probably most critical component of an I-P-M plan is an effective evaluation process. From the results of the evaluation process, we can determine whether the I-P-M interventions need to be repeated or modified. If the outcome is completely successful then we shift to monitoring only.



Thanks, Stephen. Now let's talk about I-P-M and mosquitoes. Gary, how big of a problem do we face?


Cynthia, mosquitoes are rightly considered among the most dangerous animals on the planet. Malaria alone kills more than a million people each year. But although malaria, yellow fever, and dengue are important priorities in the international community, until recently mosquito-borne diseases had almost become public health curiosities in the United States. This was not always the case, however.

Less than a hundred years ago there were an estimated 600 thousand cases a year of malaria. But, in the 1940s, thanks to a variety of programs orchestrated by the Office of Malarial Control in Atlanta, malaria and other mosquito-borne diseases were effectively eliminated. The Office of Malarial Control gave rise to what we know today as the Centers for Disease Control and Prevention. CDC continues to work closely with state and local mosquito control or abatement programs, but is not directly involved in local mosquito control activities. In the U.S., this is generally a local responsibility performed by city or county governments or public or private mosquito control programs.


Why do we need mosquito control since malaria has been eradicated?


Malaria, dengue, and yellow fever are diseases that circulate between mosquitoes and humans with little or no involvement of other vertebrates. But there is another class of diseases, called zoonotic diseases, that are transmitted by mosquitoes and involve birds and other vertebrate animals as well as humans. West Nile Virus is one of these. The natural cycle of West Nile virus involves certain species of mosquitoes which transmit the virus to susceptible bird species which act as amplifying hosts. Humans can be infected with pathogens like West Nile if they are bitten by an infective mosquito that previously picked up the pathogen while taking blood from an infectious bird or mammal. In this scenario, humans are “accidental” or “dead end hosts” since these viruses do not multiply to high enough levels to infect other female mosquitoes that bite infected humans. So while humans are essential for the maintenance of malaria, yellow fever, and dengue, they are not necessary for the transmission and maintenance of zoonotic disease cycles, like West Nile virus.

Prior to the detection of West Nile virus in the United States in 1999, there were four important mosquito-borne zoonotic diseases transmitted in various parts of the country. They are St. Louis encephalitis, eastern equine encephalitis, western equine encephalitis, and La Crosse encephalitis.


Is it fair to say though that in recent years the threat from mosquitoes has been increasing again?


Yes, especially in northern areas of the country. However, areas with persistent, recurring zoonotic diseases have continued to maintain integrated mosquito management programs, especially since the 1975 epidemic of St. Louis encephalitis which caused around 21 hundred human cases and one hundred seventy deaths.

In many parts of the southern US, mosquito control programs have been maintained and enlarged due to an increased demand for fewer mosquitoes in expanding urban, suburban and recreational areas. Fortunately, the programs that have the ability to manage nuisance mosquitoes also possess the ability to reduce the density of mosquitoes that transmit viral diseases.


What's been the impact of West Nile virus on mosquito control?


The detection of West Nile virus in New York City in the summer of 1999 changed the way many communities viewed their mosquito control needs, even though the epidemic initially remained localized to four states in the Northeast. Since then the disease has spread rapidly across the country. By 2002 it was reported in 44 states. So far this year it has been seen again in a majority of states and is still increasing. In 2002 the number of human cases of West Nile infection surged dramatically to over 4,000. The peak months of infection were August and September. Many of those infections occurred in moderate-size cities and towns, and though case numbers have been low, rural areas with low human densities have experienced a high incidence of West Nile disease as well.


The camera crew from the National Center for Environmental Health has been following the response to West Nile in various communities around the country. Let see what they found.


Mosquitoes present a risk to the residents of our community because they carry disease. Mosquitoes are what are known as a vector, and they can transmit disease either directly or as an intermediate host from other animals. In particular, the disease that’s prevalent in our community is West Nile Virus. West Nile Virus the mosquitoes can catch from birds, primarily, but also from other animals. And then when they bite humans, they can transmit the disease to human beings. Our greatest concerns related to the mosquito problem involve the possibility of the spread of disease from the mosquitoes to humans. The problem is that mosquitoes are fairly ubiquitous and it is difficult to avoid getting bitten by a mosquito. It’s also not possible to tell whether a particular mosquito is carrying disease or not. So prevention remains key.

My greatest concerns about the mosquito problem in the Albuquerque area are the fact that we have this large reservoir of mosquitoes here that simply need the addition of vector-borne disease organisms to produce a disease state in the Albuquerque area. It’s a problem just waiting to happen.

Mosquitoes present a significant risk because of their ability to transmit arboviral diseases to humans and other mammals such as horses. In California we are especially concerned with well known arboviral diseases that have caused epidemics such as St. Louis Encephalitis Virus, as well as Western Equine Encephalitis Virus, and in this year and last year, West Nile Virus. My greatest concern in this community is that West Nile Virus infected birds will migrate here and mosquitoes will then feed on them and then will subsequently bite humans and other mammals such as horses. It is highly possible, if there are a lot of infected birds, that West Nile Virus could be a problem in our state. Another concern is studies at the University of California Davis have shown that ten of the most common mosquito species in California are capable of being infected and transmitting West Nile Virus.

Mosquitoes are a problem in this area. A lot of the reason is because we’re a farm right in downtown Albuquerque and that’s a pretty unusual situation. But we irrigate and we have a few ponds around here and lots of horses and mosquitoes seem to really like that. I’m concerned about mosquitoes for a couple of reasons. One, I’m a horse woman and I have 30 horses here and West Nile Virus, of course, is a big concern to us. But I’m also a mom and a family person and so I’m concerned about my family, too.

The most effective way of controlling the mosquito population is to locate breeding sites and to actually control the mosquito larvae. They’re most concentrated, they’re more accessible and they’re not as mobile as adults are.


So lots of different species presenting lots of different challenges. Gary, how can Integrated Pest Management be effectively applied to the management of mosquito populations?


As Stephen pointed out, the cardinal rule is “manage the environment to manage the pest.” We need to understand the relationship between mosquitoes and the environment.

In the mosquito life cycle, the adult female always looks for a habitat associated with water to lay her eggs. Depending on the species, this could be a bucket with water, a storm drain, a salt marsh, the flood plain of a river, or a tree hole with water. About 2 days after the eggs are laid, they are ready to hatch. A small larva or wriggler comes out and begins to feed on bacteria and organic materials in the water. At the end of four larval stages the mosquito transforms into a pupa and from an aquatic into a terrestrial creature. After about 2 days in the pupal stage, the adult mosquito emerges onto the water’s surface and is soon able to fly. The entire process from the egg hatching to the emergence of the adult mosquito can take as little as 7 days, under optimal conditions of food and temperature.

For Integrated Pest Management, applying interventions during the larval or aquatic stage of mosquito development has proved to be the most effective method of control. To do this we employ various physical and chemical approaches to treat the unique aquatic habitats where different mosquitoes reproduce. Pesticides used for larval control are known as larvacides.

There is always interest in biological interventions, namely the use of biological organisms or their byproducts to manage mosquitoes. Fish that eat mosquito larvae are the most extensively used biocontrol agent. Biocontrol has the potential of becoming a more important tool and playing a larger role in the future but more research is needed.

Adulticides are another method of chemical intervention that is used in aerosol form. Although less efficient than larvacides, they do sometimes represent an important part of any I-P-M program. During epidemic periods or when mosquitoes are produced in adjacent jurisdictions, it may be the only option for mosquito control. But the perceived ‘need’ for such spraying should be very carefully assessed in terms of public health and the environment. They typically are applied as an Ultra-Low Volume spray dispersed either by truck-mounted equipment or from aircraft. This is the common image that many people have of mosquito control but it is just one intervention of an I-P-M program. Let's hear one caution about the use of pesticides.


Integrated pest management is an effort to reduce the use of pesticides in a mosquito controlled program because while pesticides are effective in mosquito control, they also can have long term harmful effects in the environment and to human health. In our county we have been working with experts and citizen groups to reduce or eliminate any unnecessary use of pesticide, and to use other non-chemical measures where possible for reducing the mosquito problem.

You can’t be outside enjoying the evening air. The children cannot play comfortably. You have to buy sprays and whatever for your yard and for the air and for your children. That can be expensive, too.


Clearly, public education about mosquitoes is another important component of I-P-M. Residents can prevent the pots and other artificial containers in their backyards and patios from becoming prime mosquito habitats. Any of these containers, ranging from buckets to tires to children’s toys to boat covers, if filled with water and left unattended for only a week, can produce mosquitoes, resulting in higher densities at the residence – the site where people are most commonly bitten by mosquitoes, including those that transmit West Nile virus. Other habitats such as catch basins, discarded tires, roadside ditches, and intermittent streams in urban areas require local government management efforts. Let's hear what one local health officer has to say about public education.


It’s very important for communities to be aware of pest controls, and safe ways to control pests including not using pesticide through preventive measures. So the health department reaches out to communities through the internet on our website, through public service announcements, through appearances at community meetings, through flyers, through an informational hotline, and any way we can to get the word out about ways that people can prevent mosquito-borne diseases. Mosquito control requires the cooperation of everyone in the community. In order to get rid of standing water, homeowners need to do their part. In order for catch basins to have larvacide applied, every municipality needs to make sure that the catch basins are cleaned. Without the involvement of communities, homeowners, and everyone, it will be difficult to prevent mosquito-borne diseases.


In addition, residents need to be aware of the effectiveness and value of physical barriers or interventions. Originally window screens were one of the important innovations which helped eradicate malaria in this country and they continue to be effective today. Using chemical repellents too is an important way in which people can prevent themselves being bitten by mosquitoes.


How widely has I-P-M been adopted as an approach to mosquito management, especially since the arrival of West Nile virus?


We have seen a major expansion of integrated mosquito management programs. With CDC support and technical assistance, communities with existing vector mosquito control programs are extending their capabilities to locate the sources of vector mosquitoes, monitor them, and prevent adult mosquitoes from emerging from these habitats. Many programs are also expanding their abilities to monitor adult mosquito densities and West Nile virus activity. Many communities that only did nuisance mosquito control prior to the arrival of West Nile are now expanding their capabilities, and many communities that did nothing to control mosquito populations are beginning to develop comprehensive I-P-M programs.



Thank you, Gary. Now let's hear what CDC is doing to promote the use of Integrated Pest Management as an important tool to manage rodents, mosquitoes and other pests. Pat, tell us what CDC is doing in this area.


I'd be glad to, Cynthia. But before I begin, I'd like to put I-P-M in a broader context. An important mission for CDC is to build the infrastructure of environmental public health services in the United States. This includes working to improve the environmental public health workforce and its capacity, and to build strategic partnerships with federal, tribal, state, and local governmental agencies, the academic community, and national and community-based non-profit organizations. From a prevention perspective, our ability … or lack of ability … to deliver environmental public health services directly impacts on the success of our efforts to manage vector-driven problems.

You have heard from my colleagues about the spread and impact of West Nile virus. Rats and mice are also very capable of spreading disease, as witness the Old World plague pandemics of the Middle Ages. Rat-borne disease wiped out a third of the European population, perhaps 20 million people, in a single century. In our own time, Hantavirus pulmonary syndrome has taken several lives in rural communities of the US, and now there is concern about the spread of monkeypox that has been linked to pet prairie dogs and imported rats.

Rats, mice, mosquitoes, and other pests often serve as sentinels for unhealthy housing conditions and associated health risks. And experience tells us that Integrated Pest Management is the most efficient and effective way to eliminate or manage these pests as well as prevent the spread of disease and injury from them.

However, applying this systems' approach requires a greater commitment from the public health community and the general public than currently exists. This is the reason for our broadcast today. It is to bring attention to problems such as West Nile virus and Hantavirus pulmonary syndrome and to promote I-P-M as the essential vector management system to successfully address these problems.

It is in this larger framework, that I'd like to share with you what we are doing at CDC. First of all, we are working with a number of national and local organizations interested in vector management to develop guidelines for sustainable integrated mosquito management. These guidelines will address the components of a successful integrated mosquito management program based on research findings and best practices. When completed in the next few months the guidelines will be available on the CDC website. Last year, in the July 26 issue of the Morbidity and Mortality Weekly Report, CDC published guidelines on Hantavirus pulmonary syndrome. And, in the future, CDC will also be posting new guidelines on the Control of Commensal Rodents Using Integrated Pest Management. These too will be available on CDC's website.

We also are exploring ways to obtain political and public health commitments to develop: One, long-term sustainable vector management programs which include priority funding; And two… methods to identify areas of high risk.

CDC supports two innovative demonstration projects in New York City and Philadelphia to promote the long-term management of commensal rodents. These programs conduct comprehensive semi-annual premises' surveys, have strong community education and outreach components and vigorously address sanitary deficiencies, especially through code enforcement to reduce rodent infestation. They distribute rodent-proof garbage cans, conduct interior and exterior rodent proofing, and promote or sponsor neighborhood clean-up campaigns. The New York City program also is studying the relationship between mouse allergen and asthma episodes. As a result of the success of this demonstration program, New York City recently expanded its commitment to rodent management. In Philadelphia, program staff are trained to identify and address other environmental public health hazards such as leaded paint, mold and the lack of working fire detectors.


Thanks, Pat. The National Center for Environmental Health camera crew visited both the New York and Philadelphia demonstration projects, so let's take a look at how those are working.


In the City of Philadelphia, we’ve received special funds to conduct a demonstration project which involves doing interior and exterior inspections of premises to determine the magnitude of the rodent infestation which is a very big component of integrated pest management. Once we’ve determined the magnitude of the problem and the causative conditions, then we can adequately educate the community on how to solve the problems. Our measurement of success is twofold. Number one is to reduce the prevalence of rodents in the premises by measuring the presence or absence of rodents during survey, and our second component of measuring our success is actually looking to see if the causative conditions, such as abandoned automobiles, animal food, exposed garbage, are present from survey to survey.

Well, we have an integrated pest management program in place within the city and obviously what we’re doing is really trying to prevent infestations and conditions conducive to infestations. We have a very aggressive enforcement program. We have exterminations conducted when necessary, and we have clean ups. We clean up lots to eliminate conditions that are conducive to such infestations.

Currently the Department of Health tracks rodent complaints through a data base. This captures information such as complaint and address and allegation. Also it captures why the inspection has failed. This is important to us because then we can map out by density the reason that the inspection failed. If it failed due to active rodent signs, it’s much more significant than it failed for a hole in the door. This way we can target our resources on those areas that really need it rather than those that just complain the most.

Some of the techniques that are used are stoppage, which is a process whereby you close every hole in the surrounding property or around the property to prevent rodents from entering the property. And another component is cleaning of all surfaces: floors and countertops, and also using plastic containers to house foods.

The Health Department havs come to speak to a lot of the community residents about problems with the rats. The Health Department have come in and helped out the people by covering up the holes. They have fumigated, they have also talked to landlords to get the basements and also the yards cleaned up. Then if the landlords don’t do their job, then the Health Department comes and fines them which is something that’s really good about them. Before, we couldn’t sit down in the front because the rats used to come out and attack us all the time. They will come out of nowhere. My apartment – I couldn’t even – the kids have to be locking all the doors up because they will come out in the kitchen and come in and scare the kids and stuff like that. Now we can sit in the front. I don’t see any at all. I mean nothing at all. They don’t come out of my apartment anymore. The basements are clean. The landlords were actually being pushed before because of the rat problem because the basements and the yards were, you know, full of garbage. Now the landlords actually cleaned up everything, so now they’re maintaining all the cleaning in the building and stuff like that.

For a long time, community residents had to walk up and down Grove Street and pass rat carcasses, literally 5, 6, 7 rat carcasses on any given day in the streets, on the sidewalks. And people felt like it was not only disgusting but dangerous for their children. Community residents were complaining about getting bitten by rats while they slept, having things in their apartment destroyed, their trash cans chewed through on the block. So we started working on that issue and what we wanted to focus on was both things that an individual tenant could do to tackle the problem, but also things that landlords could do, and then look for systemic solutions to the problem of rat infestation, and that work really led us to collaborate closely with the Department of Health on a project to educate landlords and tenants about ways to prevent rat infestation, and the Department of Health has been doing stuff like providing new trash cans to landlords and providing other materials to help fight rat infestation and we’ve seen really terrific results of the collaboration. About five years ago community residents were talking a lot about a vacant piece of land up on the corner of Grove Street and Myrtle Avenue, about half a block away from here. It was abandoned; it was full of rusting cars, boats, dead animals. It was an eyesore and it was a danger. Community residents really felt strongly that we needed to do something to fix that; at the very least, clean it up, at the very best, create a park for community residents and their children to use. So we purchased the property and we’re in the process of creating the park the community residents planned and designed at a series of community meetings over the past two years.


Pat those are very comprehensive projects. What's the lesson that they provide?


Our expectation is that these demonstration programs will be replicated in other communities across the country since they clearly demonstrate the value of the I-P-M systems approach. At the same time, we hope that through this broadcast, with its focus on vector driven problems and the effectiveness of I-P-M in resolving them, that we are presenting a powerful case to both public health authorities and the public, as to why they need to adopt I-P-M practices to better protect our communities.



Thank you, Pat. And now I'd like to turn to the final member of our panel. Virginia, as Director of the Marion County Health Department you've worked on the frontlines dealing with these threats from mosquitoes and commensal rodents. What has been your experience in dealing with these pests?


Thank you, Cynthia. The Marion County Health Department serves nearly one million people. Our county ranks as one of the largest in the nation and includes the city of Indianapolis.

Our Health Department’s comprehensive rodent control program dates back to the early 1970s when we were the recipient of a federal grant to manage the urban rodent problem. Our focus was on eliminating those environmental conditions that allow rats and mice to survive and multiply. I am proud to say that over these many years, we continue to apply integrated pest management principles to control rats and mice. In 1972, nearly 40 percent of the premises in some Indianapolis neighborhoods were infested with rats; today it is less than six percent; and for much of the county, it is less than two percent.

When the federal grant program was discontinued in 1981, we recognized the importance and need to continue this comprehensive program by using local funds. Today the program operates almost exclusively with local tax dollars. Our program remains multi-faceted and deals with the biological, cultural, and environmental aspects of rodent infestation in a way that has long-term benefits for our community. The use of rodenticides and trapping play a much smaller role than it does in many communities where the approach often is complaint-oriented and highly dependent on the use of poisons and trapping. Such programs lack surveillance which is critical to determining the magnitude of the problem and successfully addressing it.

Eliminating the conditions that attract rodents and allow them to survive and multiply is the major focus of our effort. We routinely remove millions of pounds of refuse from vacant lots and abandoned buildings. We exercise strong code enforcement where necessary, and we work closely with community-based organizations, especially in conducting clean-up campaigns. We even have a tool loan program to help with the clean-up of neighborhoods.

Now, I’d like to talk about mosquito management. The Health Department’s mosquito management program began well before the threat of West Nile virus. Marion County remained mosquito-borne disease free until the West Nile outbreak in the year 2000. One reason for our success in controlling mosquito populations has been our diligence in larviciding. This continues to be the cornerstone of our program.

Since the West Nile virus outbreak, we have become even more diligent in our approach. In addition to stepping up our larviciding efforts, night crews have also been judiciously spraying against adult mosquitoes and we work closely with the community by providing them with essential information about the mosquito problem and its prevention. Timely response to citizen complaints is a top priority, and all calls are responded to within 24 to 48 hours. We even provide mosquito fish upon request for those areas where they are judged to be environmentally safe.

We have enjoyed considerable success in managing both rodent and mosquito populations, and that's because we apply I-P-M principles in all that we do to manage these pests. Our experience tells us that there is no short-cut. If we want to prevent disease and improve the quality of life of our citizens, we must find the resources to address these problems in a comprehensive way. Our citizens deserve nothing less.



Thank you, Virginia. In a moment we’ll take your questions and comments about I-P-M, so please keep those lines ringing and the faxes coming in. Before we take your questions, here’s some important information.

For those of you interested in continuing education credits for this program – you must register and complete an evaluation in order to receive credit. We’re offering C-M-E, C-N-E, CHES, and regular C-E-U credit based on one and a half hours of instruction.

Here’s how to get credit!

The CDC Training and Continuing Education Online System is simple to operate. Use this address to access the system:

W-W-W dot P - H - P - P -O dot CDC dot GOV forward slash P - H - T - N ON-LINE, all one word.


If you have any problems with the online system, refer to the extensive help system or you may also ask for assistance by phone or e-mail. Call us toll free at 800- 41- TRAIN, that’s 800- 4-1-8- 7-2-4-6. This toll free number is available Monday through Friday from eight a-m until four thirty p-m Eastern Time.

Our e-mail address is C - E at CDC dot GOV. The registration and evaluation forms will be active on the online system until October 18, 2003 for the satellite broadcast and live webcast, and for up to three years for the archived webcast and videotape; but we recommend you complete the process sooner rather than later. Please try to wrap it up in the next few days if possible, while it’s fresh on your mind.


And now let's go to our first question from [STATE].


I’m afraid that’s all the time we have for your questions. However, if you weren’t able to get through to our operators or think of a question later, you can still send them to this e-mail address: I-P-M at C-D-C dot gov. Answers will be posted on our website beginning next week.

We hope the information we presented today on managing rodents and mosquitoes through Integrated Pest Management will prove useful to you whether you’re a policymaker, practitioner, or interested observer. Since CDC is presenting this broadcast, I'd like to ask Dr. Pat Meehan to say a few final words. Pat?


Thanks Cynthia. I'd like to congratulate those communities that have made the effort to adopt I-P-M principles and practices. You are an inspiration by your example. And I would like to encourage others to follow suit based on the information we have presented in this broadcast.


Thanks, Pat. Before we go, here are a few final housekeeping reminders. Please be sure to visit the program website ( and give us your comments about today’s program.

While you're there you can also obtain your continuing education credit by filling out the form at this address: (

If you’d like to view today’s program again, you can do so by logging on to CDC website ( and following the links to the archived webcasts.

We’d also like to remind you that if you have questions or contributions to make about environmental health services to please join CDC’s Environmental Health List-Serv. Instructions on how to do this can be found at the environmental health services website ( on the screen.

My thanks to all our panelists for joining us today. And thank you too for taking the time to be with us to discuss the important topic of Managing Rodents and Mosquitoes through Integrated Pest Management. We wish you the best of luck.

Next week the Public Health Training Network brings you the first of two programs on another very critical public health concern. Join us Tuesday, September 23rd at 2 pm Eastern for “Preparing for the Return of SARS: Are we ready?”

Until then, on behalf of everyone at CDC and the Public Health Training Network, I’m Cynthia Good wishing you a good day from Atlanta.

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