Transcript of Get Ready Report podcast Episode 10: “Zoonotic Diseases, Part 2"

Interview with Lonnie King, DVM, director of the National Center for Zoonotic, Vector-Borne and Enteric Diseases at the Centers for Disease Control and Prevention. This podcast is the second part of an interview with King and the Get Ready campaign. The first part of the interview is also available as a podcast and transcript.

Getting back to the pets. We love our pets, is it okay for them to lick our faces?

We love our pets and the benefits that we get from this human animal bond that we now are really appreciating is helping our psychological well being. For seniors, it really helps with giving them companionship, so there is great benefits to having animals as part of our life. Here, again, I think you have to use good common sense. They do potentially and can potentially transmit diseases like toxoplasmosis and salmonella — through reptiles and turtles or birds, basically small turtles. The(se pets) do carry salmonella and round worms and hookworms. These kinds of problems with internal parasites or worms used to be fairly commonly transmitted, especially children who were playing outside. That is one of the things we worry about. Cat scratch fever from an organism called “bartonella.” I think it’s a matter of not being so overly concerned that you don’t have the wonderful benefits of our pets as companions and the richness they add to our lives, but (of) just understand(ing) that they are a potential source of threats, not a great high risk, but you need to use the precautions that we talked about.

What about petting zoos? They are tremendously educational and fun, but can we pick up diseases at them?

I agree they are educational, and kids really enjoy them but I think you have to use common sense. Young children in particular are at the highest risk because they are in there with close exposures and if they touch these animals and they are eating food or putting their hands in their mouth, things like salmonella and cryptosporidium and E coli, even staph and strep, are concerns with these petting zoos. So I think you have to really use special precautions for young children in particular. Most of the petting zoos now that are set up right have trained operators. They have transition areas (where) it’s important that foods not be brought in and there is immediate opportunities to wash your hands after you go through on e of these zoos. CDC, by the way, has published in MMWR a compendium of measures to prevent diseases associated with animals in public settings. It’s a good resource for people to take a look at, and the CDC Web site on Healthy Pets, Healthy People (http://www.cdc.gov/HEALTHYPETS/) is another very good contact for people to gain information about pets and dogs and cats, and hamsters, reptiles, rodents, etc., and how we need to handle them carefully.

We’ve been hearing a lot lately about avian influenza virus or bird flu, which is found mainly in birds and is highly contagious among poultry, and we now know that infections with these viruses can occur in humans. Should we be worried?

We are always concerned, and when people talk about influenzas there are actually four different types to be concerned about: One is what we have every year circulating around, your annual influenzas that people get vaccinated for and the influenza virus constantly changes. That virus goes from person to person. Getting vaccinated and understanding how you might be exposed in public places to this virus. You have a disease called “low-pathogenic avian influenza,” which is found very commonly in domestic birds and also in wild birds. These viruses are constantly changing and on the move frequently, but they are lowly pathogenic. So they are being carried, but they’re not causing clinical disease. And we have high-pathogenic avian influenza, which is what we see today in H5N1. It describes the proteins on the surface of this virus, and it is highly pathogenic. (This) means it is devastating for populations of birds — mostly domestic, chickens and poultry but also for wildlife. We constantly watch this very carefully because there has been 125 to 150 human cases where this high pathogenic influenza (that) is actually passed from birds to people. (Editor’s note: Interview conducted July 2008) Fortunately, it has not gained the characteristic to be able to be passed from person to person. When that happens, then you have the fourth phase, which we call pandemic influenza like we’ve seen in 1918 and 1919. (Those) were the years where there was a huge amount of deaths and sickness. There have been two other kinds of circulation of influenzas, pandemic type, not as devastating as the 1918 one, but people have to remember that the origin of these new influenzas are actually probably in southeast Asia or China where there is a constant circulation and exchange of this virus between birds and oftentimes pigs and people. (T)here you actually have a pool of amplification and change, and that’s where the new viruses emerge that can either move around the world as low pathogenic in birds or highly pathogenic where they are devastating in birds and then into people (who) can then transfer from person to person. So it is a constantly changing group of viruses that drift and shift, and we watch them very closely. So the real issue is not from birds to people, although if you were living in an endemic area you would have to worry about that. It’s when it changes the characteristic and then it becomes a human disease where it goes from person to person

Therefore we don’t need to worry about catching bird flu from eating poultry and eggs?

In areas where the disease may be endemic, where the virus actually may be in meat or eggs, it’s a matter of cooking those products to the right temperatures that will kill influenza. So we really would be at low risk if we handle those products properly. And frankly with H5N1 we don’t have that in the United Sates. It is just very limited in terms of human disease, but cooking and handling the product properly is the key.

Getting back to pets, can they catch diseases from us?

They can. You hear a lot now about a disease called “methicillin resistant staphylococcus arueas,” or “MRSA,” which is a real concern not only to animal populations, but to human populations where this type of staph is building up a resistance that we see in animals and in humans. There are good recorded incidences where people will actually transfer this disease to pets. There have been certainly incidences where human tuberculosis in a person actually being transmitted to household pets as well.

What about dog bites?

Dog bites are a real public health problem in this country and around the world and while they’re not zoonotic in terms of transferring a virus or bacteria directly to people they can cause tremendous problems. The last estimate that I saw estimated that there were almost 5 million bites a year and 800,000 of these required medical care. Some of these were emergency visits, and hospital visits. And they are quite painful and quite costly. They are a major problem especially with kids handling pets. Pets that are running without leashes and you can actually get some of the bacterial infections from bites. Cat bites in particular can be very nasty with a bacteria called pasteurella. So it is a very significant public health problem that sometimes we don’t think of as zoonoses. But here again, it’s the interaction of people and animals that have caused these problems.

Interview conducted July 2008 by Teddi Dineley Johnson, The Nation’s Health, APHA

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