Media Home Page | Contact Us
CDC Telebriefing Transcript
Waterborne-Disease Outbreaks on the Rise
November 21, 2002
CDC MODERATOR: This is Jennifer Morcone from the Press Office. I'm joined today with Sherline Lee, that's S-h-e-r-l-i-n-e L-e-e, and Michael Beach.
Sherline will be making some opening comments about drinking water surveillance and Michael will be speaking about recreational water.
MS. LEE: Thank you very much. First, we would really like to take this opportunity to acknowledge the state, territorial and local health departments that contributed to this report as well as our collaborators at the US EPA and CDC.
Many of you are familiar already with the waterborne disease outbreak surveillance summaries and the surveillance system.
But in brief, waterborne disease outbreak reports are voluntarily reported to CDC on an annual basis by the state, territorial and local public health agencies that are responsible for the detection and investigation of waterborne disease outbreaks.
These outbreaks are analyzed and then summarized and published by CDC and EPA in the MMWR every two years.
The investigation of outbreaks allows us to study problems associated with water in a comprehensive fashion. The data gathered through the surveillance system are useful for identifying major deficiencies in providing safe drinking water and recreational water, and also help us assess whether current guidelines or regulations are adequate to protect the public against disease.
For example, in drinking water, through these investigations we gather information on source water contamination, water treatment and water distribution system deficiencies or other factors that may contribute to outbreaks.
For recreational water, we gather information on the environmental conditions in fresh and marine waters, water treatment in swimming pools and water parks and the behavioral factors that contribute to the occurrence of outbreaks.
This type of information may not be provided always through the study of isolated cases.
What we are reporting today is that the number of both drinking water and recreational water outbreaks reported in 1999 and 2000 has increased from the number reported in 1997 and 1998. Regarding drinking water, the first important finding from this report is that the drinking water outbreaks increased from 17 outbreaks in 1997 and 1998 to 39 in 1999 and 2000. The observed increase in drinking water illness outbreaks largely reflects problems associated with drinking water from small private wells that are independently owned and operated.
We would like to point out that outbreaks in regulated drinking water systems have not increased, indicating that efforts by the drinking water industry, public health officials, and regulatory agencies have been successful in preventing illness.
Our second finding is that many of these drinking water outbreaks are also preventable. We urge the public to actively think about the water they drink. Whether the water comes from a tap or from a bottle, the public should find out where the water they are drinking comes from, and whether it has been made safe to drink.
The drinking water messages we would like to get out to the public are, first, if your water comes from a public water system, find out if a consumer confidence report or CCR exists for your water system, and for help, visit the EPA Web site, and we'll give that URL out later, or call the EPA safe drinking water hotline at 1-800-426-4791.
If you are an owner or user of a private well, make sure that your well is properly constructed, maintained and tested. Please contact your local health department, the EPA safe drinking water hotline, or visit the EPA Web site. [Addendum: http://www.epa.gov/safewater/dwinfo.htm and/or http://www.epa.gov/safewater/pwells1.html]
If you have general water and health concerns, please visit the CDC Web site. [Addendum: http://www.cdc.gov/ncidod/dpd/parasiticpathways/drinkingwater.htm]
CDC MODERATOR: Thank you, Sherline.
Michael, would you like to make some comments about recreational water?
DR. BEACH: Welcome, everyone. I'd just like to point out, as Sherline mentioned, in this summary, we document 59 new outbreaks associated with recreational water use that have affected over 2000 people. Thirty-six of these outbreaks have actually been of diarrheal illness, with fifteen occurring in '99, twenty-one in 2000, and that's now the highest number we've had reported since the system started reporting back in 1978, and these data really continue the trend which we've seen, which is an increasing number of recreational water outbreaks of diarrheal illness being reported since the mid 1980's.
This trend is really heavily influenced by outbreaks in disinfected venues, you know, such as swimming pools, with the parasite, Cryptosporidium parvum now accounting for almost 70 percent of the outbreaks. This makes really good biological sense because, as some of you know, cryptosporidium is chlorine-resistant. So once the pool water becomes contaminated, you know, normal pool levels of chlorine aren't going to kill this particular bug.
In the freshwater settings, we find that the toxin-secreting e.coli strains account for almost 30 percent of outbreaks reported, and I think what we've got to keep in mind here is that having chlorine-resistant bugs out there now, and the popularity of swimming in untreated water such as lakes and rivers and the ocean, makes public education critical to reducing the spread of recreational water
illnesses. We really would like swimmers to--they really need to know and understand that they shouldn't swim when they're ill with diarrhea, that basically swimming water is not drinking water. They should really be trying to reduce the amount of water they swallow, which is a very common practice. And they should try and improve their hygiene by taking regular bathroom breaks while they're swimming, changing diapers in rest rooms instead of at the poolside, so that, really, we can wash up afterwards appropriately, and really transition to taking that cleansing shower before we swim rather than afterwards.
We also document a number of outbreaks of diarrheal illness and skin infections in disinfected venues that were caused by chlorine-sensitive germs like shigella, pseudomonas, and so on, that you'll see in some of the tables there. The fact that we see these outbreaks really underscores the need for improved pool maintenance, since most of these really shouldn't have occurred if the disinfectant levels were kept at appropriate levels.
So we're really calling for a continued vigilance in training pool staff so they understand the critical importance between disinfection, keeping the pool clean and maintained, and really good swimmer health. We want staff to be checking disinfectant levels not just early in the morning when they're opening the pool, but during heavy swimmer use, when disinfection is really needed most.
But although we see this increasing trend--again, that's over the past 15 years or so--in the number of outbreaks being reported for diarrheal illness, I want to remind everyone to keep perspective. Hundreds of millions of swimming visits occur each year. Clearly, everyone's not getting ill. But I think by combining improved pool operations and staff training with increased public awareness and education about, you know, those key issues--you don't swim when you're ill with diarrhea, don't swallow the water, and we need improved hygiene--we hope to reverse the trend in the future.
We're not looking to reduce the popularity of swimming. This is a national pastime. We really want to transition the public from the status-quo swimming practices they have now to responsible swimming practices.
So I think for further information about CDC's Healthy Swimming project, there's a website, healthyswimming.org, and you can find further information there. Thank you.
CDC MODERATOR: Great. We can open it up for questions now.
AT&T MODERATOR: Our first question will come from the line of Candace Rondeaux, from St. Petersburg Times. Please go ahead.
QUESTION: Oh, hi, there. I'm calling from, actually, the state where we seem to have the most outbreaks both for drinking water and recreational water. And I'm trying to understand two things: One, whether or not maybe there's something implied here in the way we regulate our recreational pools; and whether or not there's something else going on here in Florida that we need to be looking out for as citizens.
DR. BEACH: I think from a recreational water standpoint, I think we'd really like to caution looking at the numbers of outbreaks and comparing them to other states' because there are so many factors that contribute to this reporting. To some extent, what we find is that in states that are doing a very good job of detecting outbreaks and investigating them, they have an apparent increase in the number of outbreaks. But that's really because they're doing a good job of investigating, not necessarily that that particular state is more prone to having outbreaks than other states.
DR. LEVY: Candace, yes, generally that's the case. Florida is a state with very good surveillance. So as Michael said, what tends to happen is you see what look like large numbers, but you can't really compare to other states.
AT&T MODERATOR: Thank you. Our next question will be from the line of John Lauerman, from Bloomberg News. Please go ahead.
QUESTION: Thanks for taking my question. I was wondering if you could talk about, or if you could give us some trends in the number of people who are sickened and/or killed by waterborne disease in this study period.
DR. LEVY: Michael, do you want to answer for waterborne, or Sherline?
DR. BEACH: I mean, for recreational water I think the trend is not just in this particular two-year period. The trend is over the past 15 years that we've seen a steady increase in the number of outbreaks being reported. And I think the reason for that is probably a combination of both--that it's probably real in, for instance, emergence of new germs like cryptosporidium that are chlorine-resistant certainly have moved that illness so that we pick it up more in the chlorinated venues. In addition, I think we're doing--more resources are being put into recreational waterborne disease outbreak investigations and the public is starting to think a little bit more about what they drank or where they swam versus what they ate last night.
MS. LEE: John, we do have the data on the deaths. However, I would like to actually provide that to you in follow-up.
CDC MODERATOR: Next question? Thank you.
AT&T MODERATOR: Our next question will be from Adam Marcus, from HealthScout. Please go ahead.
QUESTION: Hi. The Natural Resources Defense Council says that raw sewage is to blame for a lot of the coastal problems. Is that true--runoff of raw sewage into coastal areas?
DR. BEACH: You're talking about recreational water?
DR. BEACH: I think that that certainly plays--raw and treated sewage, because some of these germs survive partially through the disinfection process in wastewater treatment. But this surveillance system actually does not pick up a lot of outbreaks from ocean venues, and we always get questions about that. And our response is, really, that we know that ocean usage is associated with illness because studies have shown that repeatedly. The reason we perhaps don't pick that up is that it's geographic in reference, we think. If you have large beaches that bring in people from very wide areas, and then they disperse at the end of the day, that type of an outbreak is much more difficult to pick up and it probably goes below the radar screen. As we think most of these outbreaks--it's really kind of a tip-of-the-iceberg thing. We don't detect most of what's occurring out there, particularly with diarrheal illnesses.
AT&T MODERATOR: Thank you. Our next question will be from Karen Taylor Mitchell, from Safe Tables. Please go ahead.
QUESTION: Hi. I'm wondering what connection is being made between the origin of the disease that you're seeing in terms of shigella, E. coli, some of those things, and the fact that they're brought into the pools and the bodies of water by people who are infected in the first place by food-borne disease. What kind of programs are being done to try to reduce the number or waterborne illnesses by front-loading and stopping it at the source?
DR. BEACH: Right. I think, really, a lot of this has to do with coordination of messages, and that trying to get the messages out on particular bugs, it's not only, you know, be careful about what you eat. For instance, in a shigella sort of thing, what we're trying to do is coordinate responses so that if there are shigella cases starting to show up, what we do is not just think about the restaurant they came from or the day care, but we're also alerting other--basically trying to get a message out about the health of the community to interested parties, and that if there's a shigella outbreak, pool operators and the lake-swimming operators need to know at the same time.
As well as, if there's a swimming-pool outbreak, we need to let other people in the community, including day care operators, know that this is, I think, a multifaceted approach, where the community has a stake in its own health regardless of where it is, from a day care setting or a pool setting or a food setting, we know that when it starts in one place, it usually ends up in the others. And we've seen this repeatedly, where it may start out in a pool, get into day care, and becomes community-wide; or vice versa.
And so it's a coordinated message response so that we keep people in the loop. Illinois right now is kind of setting up an informal network to really send out messages to a wide variety of people, from physicians to pool operators and so on, where they will get messages about the health of the community so that they can understand better where we need to put the messages to try and stop these things and the front end, as you say.
CDC MODERATOR: The next question?
AT&T MODERATOR: Thank you. Our next question is from Karen Jacobs, from Reuters. Please go ahead.
QUESTION: Hi. My question is for Mr. Beach. I was wondering if you have any figures on recreational water illness outbreaks for '97-'98. You mentioned that the evidence shows that they been increasing over the past 15 years. I was wondering if you had any concrete figures.
DR. BEACH: Right. I think what I'd refer you to, which is graphics--pictures worth a thousand words. Page 23 shows a histogram increasing from the mid-1980s through this particular report, and I think that gives you a good feel for the numbers there.
MS. LEE: Karen, this is Sherline. We have the advantage of being in Atlanta. So the figure for 1997 for rack water was seven outbreaks, and the 1998 was 25 outbreaks.
AT&T MODERATOR: Thank you. We now have a follow-up from the line of John Lauerman from Bloomberg. Please go ahead.
QUESTION: Thanks for taking my question again. You mentioned that you'd like to determine whether this is a result of better surveillance or an actual true increase in waterborne disease. And I'm wondering how you're going to determine that, when will you know, et cetera?
DR. BEACH: Did you want to answer that Sherline? Okay, I can say I'm not--if I did say that, it was a misstatement. I don't know that we're going to be able to sort that out. So this is not like a study in progress or anything. It's a supposition that we probably have a combination of factors contributing to this increase. But it's very hard to sort that sort of thing out.
One comment I would like to make in reference to an earlier one on sewage in the coastal areas leading to illnesses, I think that that is always a factor when sewage is being released. But we also want the public to be thinking not only about what sewage and environmental contamination is occurring, but also who are you swimming next to, and making sure that we have the messages about not swimming when we're ill with diarrhea out there.
MS. LEE: John, I just want to jump in and clarify your last question regarding the deaths. The deaths due to drinking--deaths among those who are drinking water are very rare. So I can give you again, as I said, the exact count in the follow-up.
CDC MODERATOR: And can get those for you after the call. We don't have them handy. Next question?
AT&T MODERATOR: Thank you. We do have a follow-up from the line of Candace Rondeaux, from St. Petersburg Times. Please go ahead.
QUESTION: I just noticed as I was paging through your report here, one of the things you mention, and I'm hoping maybe you just can talk about or elaborate on a little bit is this idea that there's sort of a gross inattentiveness to pH levels and chlorine levels and how important it is to maintain these in pools and spas. I mean, what do you think that's about and what do you think we can do about that?
DR. BEACH: I think what it's about is, in many cases, a lack of staff training, so that there's a key link in their mind that the single barrier to preventing the spread of illness is the disinfection and filtration. And we need to get those individuals trained more readily and get them thinking about it more often. It's very common to check very early in the morning when work is starting at that, but this needs to be done on a regular basis and, you know, basically when people are in the pool. That's when you need the protection. And I think what we're looking towards is improving that training so that the link is there in people's minds.
We're undergoing a study here, hopefully for release next year, where we'll be looking at state inspections and how that relates to giving us a feel for violations and how often is this occurring.
Florida is a key player in that particular study. So we'll be releasing that next year some time.
AT&T OPERATOR: And we do have a question now from the line of Adam Marcus from Health Scout. Please go ahead.
QUESTION: Not a question, but I hate to "beat a dead horse," but with the death issue in the report, I see two deaths linked to drinking water and four linked to recreation water. Is that just a sampling of the total?
MS. LEE: It's out of all the outbreaks reported.
QUESTION: So the figures are two and four for those periods?
MS. LEE: Right.
AT&T OPERATOR: Thank you. Our next question will be from the line of Keith Mulvahill [ph]. Please go ahead, from Reuters Health.
QUESTION: Hi. I just want to have Sherline comment a little more on the increase seen in drinking water. I guess it sort of reverses the trend. Do you have any explanation for that?
MS. LEE: I think this was alluded to in the press statement but again believe is contributing to a lot of these outbreaks are problems in the private wells. These wells are not regulated and the maintenance and the testing is left up to the owner, and we would really like to encourage the public to do something about it, and there are actually very good resources, which I did mention, and that is the Safe Drinking Water Hotline, and there's a Private Well Annual that they can actually request or download off the EPA Web site.
QUESTION: Okay. So I mean, is there more people drinking well water, or is it people are just not taking care of it properly? More of that happening?
MS. LEE: We cite several statistics from different sources and there are more people who are drinking well water each year. There are approximately 30,000 new wells drilled each year, and of course we don't know whether these are all private wells but we would suspect that many of these people are drinking water from what we consider private wells.
AT&T OPERATOR: Thank you. Once again, ladies and gentlemen, if you have a question, please depress the one. We have a follow-up from Carol Taylor Mitchell from [inaudible]. Please go ahead.
QUESTION: Hi. In talking about the death statistics that you've given, I know that with foodborne disease, they tend to be distorted by a couple of things. Number one, oftentimes, when you have a death from Shigella, or e.coli, or something like that, in somebody who has a preexisting condition, the death is listed as the preexisting condition, the cause of death rather than the pathogen.
Another thing is that the death is not really indicative of the hospitalizations and serious illnesses. So I wonder if you could address with the first, whether you see that as a similar problem with waterborne illnesses, and second, if you have any statistics as to the number of hospitalizations and/or serious illnesses created by these disease?
DR. BEACH: Sherline, do you have anything to say or should I--
MS. LEE: The number of hospitalizations we didn't total but it is actually provided in the document. Again, I can give you the exact numbers. But we depend on the states to report that to us, so, as we said, I'm not sure how sensitive we are, or how sensitive the surveillance system is, cause it really depends on what the state decides to put in their reports.
Regarding the issue of overall underreporting--Deborah, do you have a comment you wanted to add?
DR. LEVY: This is Deborah Levy and I oversee the surveillance system. It really depends on the focus in the health department as to what they're able to investigate. For example, for some reason, outbreaks tend to cluster, and when a state has limited resources, it's sometimes difficult to actually go in and investigate fully, all of these. It also depends on physician reporting the illnesses and the deaths.
I think the surveillance is not very sensitive to accuracy in terms of numbers in that way. So yes, the problem might be somewhat similar to the foodborne surveillance. The two surveillance systems tend to operate in the same way, in that states investigate them and then report them to us, and we're basically limited to what comes in on the report forms.
AT&T OPERATOR: Thank you. Once again, ladies and gentlemen, if you'd like to ask a question, please press the one. And we have no questions in queue. Please continue.
CDC MODERATOR: Okay. Thank you very much for joining us today.
Michael or Sherline, are there any trailing comments you'd like to make?
MS. LEE: No. Just thank you for the opportunity again. We really welcome this opportunity to talk to the public about their water.
CDC MODERATOR: And we'll add the full URL to the Web sites that Sherline has made reference to in the transcript. If anyone would like them, please feel free to call the Press Office at the close of this call.  639-3286.
Thank you, everyone.
AT&T OPERATOR: Thank you, ladies and gentlemen. That does conclude you conference for today. Thank you for your participation and for using AT&T Executive Teleconference Services. You may now disconnect.
This page last updated November 21, 2002
Department of Health and Human Services