Transcription:
Mosquito-borne Disease Prevention

Melanie Cole (Host):  Mosquitos cause more human suffering than any other organism. Over 1 million people worldwide can die from mosquito-borne diseases every year. Not only can mosquitoes carry diseases that affect humans, they can also transmit several diseases and parasites that dogs and horses can be very susceptible to. The Vector-Borne Disease Laboratory at Maine Medical Center Research Institute is dedicated to the control of emerging tick and mosquito-borne diseases. My guest today is Chuck Lubelczyk. He's a vector ecologist at Maine Medical Center Research Institute. Welcome to the show, Chuck. So, tell us about mosquitoes. What are the most common vector-borne diseases that you're seeing with mosquitoes these days?

Chuck Lubelczyk (Guest):  In the northeastern U.S., we have big problems with both West Nile Virus and Eastern Equine Encephalitis virus, both of which are veterinary as well as human health problems but we also have issues with canine heart worm, which is transmitted by mosquitoes, as well.

Melanie:  Wow. People have heard of West Nile Virus, so let's start with that. What is it and what kind of mosquitoes? How do we prevent it?

Chuck:  West Nile Virus is a flavivirus that has actually come over from Africa. It arrived in the U.S. in 2000 and is actually associated with many mosquitoes; however, commonly, the mosquitoes that transmit it are ones associated with an urban or suburban environment. So, it tends to be a problem in large cities and urban areas.

Melanie:  So, people say try and get rid of standing water and things. Give us your best advice. I mean, you're the expert. Tell us what you tell people every single day about mosquitoes.

Chuck:  Yes. If you have even a small amount of water, a quarter of an inch of water, building up, that's enough breeding habitat for mosquitoes to start in and around your homes. The other effective thing, if you're going to get rid of your water, is to make sure that your window screens are in place and in decent repair because they're going to be a very good barrier to having them come into your home and bite you while you're sleeping.

Melanie:  What about things like birdbaths? I mean, if you keep replacing that water and birds are in and out of it, is that protective? Do they eat the mosquitoes in there?

Chuck:  Birds don't. If you're going to have a birdbath, the best place to put your birdbath is so it's out in the open sun. It tends to heat the water up enough that mosquitoes don't tend to like it a whole lot but frequently changing the water in your birdbath will help to get rid of any mosquitoes that are deposited in there.

Melanie:  People don't realize, sometimes, if they're bitten by a mosquito. What are some of the signs of West Nile Virus that if you've been out or you've been out somewhere and you've gotten some bites on you that you should look out for?

Chuck:  West Nile Virus in many cases is not as serious a disease other mosquito-borne diseases. Many people that have what are called "summer flu-like symptoms" any of those chills, fever, headaches; there are also severe neurologic complications, as well, in extreme cases. Primarily, a lot of it is sort of your flu-like symptoms and, possibly, some neurologic problems in severe cases.

Melanie:  Tell us about some other mosquito-borne disease, and I'm going to jump right into this one because Zika is what everybody's hearing about in the news, Chuck. So, tell us what is the Zika virus and what are the mosquitoes? How do we know if we've been bitten by one of those mosquitoes?

Chuck:  So, the Zika virus is sort of the latest in a cast of characters that have been emerging in the last 10 years or so, coming in with mosquitoes that are being brought in by human transport. These mosquitoes tend to arrive in many port cities or areas where you have a lot of shipping containers or used tires coming in with water in them where the mosquitoes breed, they escape and get started in new areas, such as areas of South America coming over from Africa. In many cases, these mosquitoes are very urban in nature and so, particularly the aedes aegypti mosquito is really centered in core urban areas with a dense human population. The other mosquito, the Asian tiger mosquito, aedes albopictus, also has similar habitats and is generally found more in developed areas where they take advantage of very small bodies of water such as soda cans, pet food bowls, tires, buckets, cups, anything like that that can allow a mosquito to breed, these guys take advantage of it.

Melanie:  There seems to be a worldwide panic about Zika. Do you think that it's going to invade quite as much as people are thinking that it's going to? Can mosquitoes go from area to area very easily?

Chuck:  Well, for those of us in the Northeast or the upper Midwest of the United States, Zika virus is really transmitted by two mosquitoes that are very tropical or warm weather associated. Currently, aedes aegypti, the most common vector for Zika, is really a tropical weather mosquito. It doesn't really occur north of Florida in the U.S. Aedes albopictus, however, is a slightly more temperate mosquito but does occur as far up in latitude as New Jersey, or so, commonly. It really hasn't established itself too much in the extreme Northeast, yet, but it is one that is on the radar for us. So, we would be concerned to look for it.

Melanie:  So, what are some other mosquito-borne diseases that we should worry about, and you mentioned even at the beginning heart worm for dogs? People don't think of mosquito-borne diseases as affecting our animal friends. So, what is heart worm?

Chuck:  Heart worm is a parasitic disease that the larval heart worms are transmitted by mosquitoes into the bloodstream of animals, and it primarily affects dogs. There is, however, an effective vaccine but the mosquito that carries it, the genus anopheles, is a very widespread mosquito that tends to get more press as a vector of malaria in many parts of developing worlds but, at least in North America, is a vector of this disease called “canine heart worm”.

Melanie:  Is there a prevention for that?

Chuck:  There is a vaccine that dogs can have that will mitigate the effects of heart worm.

Melanie:  Okay. Now, we've also, over the years, Chuck, heard about yellow fever and dengue. I mean, there are all these things we've heard that mosquitoes can do, so what are those? Do we have to still worry about those?

Chuck:  No, not so much yellow fever. Dengue certainly is a problem in the tropics and dengue is sort of like the old Zika. The Zika are a couple years old. Dengue really started picking up about a decade ago and it does cause very serious disease transmitted by the same mosquitoes that transmitted Zika virus as well as another virus called “chikungunya” that was in the press about two years ago. I think the real take home message is that these diseases appearing one at a time are just a general symptom of a pattern of emerging mosquito-borne diseases and how these mosquitoes now will travel. They certainly can travel and we assist in that travel by moving them from continent to continent or country to country.

Melanie:  That's fascinating. Now, people see DEET and they see all of these repellants everywhere and I think this industry, with Zika, has really grown a lot in the last few months. So, do these work? Are they a good fight against mosquitoes besides standing water?

Chuck:  You can use DEET very effectively to repel mosquitoes. The interesting thing about DEET is, you can simply apply a lower concentration for it to be very effective. A Twenty-eight percent concentration DEET in a product will be as effective as higher concentrations which might result in more skin or allergic reactions in people. So, if folks are going out looking for a spray and they are going to apply something with DEET, they can keep it to under 30% concentration for a very effective repellant.

Melanie:  What do you tell people, Chuck, when they find out what you do and they ask you about their children and using repellant on their children? Is DEET safe for kids?

Chuck:  DEET is safe for kids. In many cases, you should apply the DEET directly to clothing and allow it to dry. There is another compound as well called “permethrin”, which is also effective and is applied only to clothing but also works to repel ticks and mosquitoes. If you use these directly on your clothing, they should provide an effective barrier without having to have these compounds touch the skin.

Melanie:  So, you could put that directly on your clothing over your clothing?

Chuck:  Yes.

Melanie:  Okay. So, that's a really great idea if parents are nervous about putting it directly on the skin of their children.

Chuck:  Yes and, really, these do have to be reapplied because you certainly can either sweat them off, or, if it's raining and you're outside, of course, these can wash off, but the benefit is that they can be reapplied over the course of several hours. They don't need to be reapplied right away.

Melanie:  So, Chuck, give us your best advice about mosquito-borne diseases and some of the panic that's going on and, really, the more common ones that we've heard about like West Nile and heart worm. What do you tell people every day when they ask you about this?

Chuck:  What we tell people is that, especially if you're living in northern North America, our season for mosquito-borne diseases really starts late summer. Both West Nile Virus and Easter Equine Encephalitis virus tend to be late summer diseases. August and September are the primary times you have to be careful of them. Heart worm in dogs certainly can be an issue going throughout the entire summer season; however, most people can really effectively manage mosquitoes or manage mosquito bites by simply wearing long sleeves. Long sleeves provide a very effective barrier and you can even buy much of the tropic-weight fabric, which is equally effective at keeping mosquitoes from biting you, but isn't as burdensome wearing them in warm weather. So, we really do advise people to think about buying long-sleeved clothes, even lightweight fabric but then also treating those clothes with some kind of repellant, either permethrin or DEET.

Melanie:  Chuck, just tell us about the Vector-Borne Disease Laboratory at Maine Medical Center Research Institute. It's fascinating what you do.

Chuck:  Well, our lab works a lot on surveillance diseases and the vectors--both ticks and mosquitoes-- that carry them. We also work on a lot of basic research dealing with things such as the impact of climate change but also novel strategies such as the use of botanical pesticides, which might be more environmentally benign to control both ticks and mosquitoes in areas near the coast.

Melanie:  Thank you so much for being with us. You are just a wealth of great information. You're listening to MMC Radio. For more information you can go to MMC.org. That is MMC.org. This is Melanie Cole. Thanks so much for listening.