Scientists target blood-sucking pests
By Dennis O'Brien
BALTIMORE SUN
You don't have to read the headlines to know that they're nasty creatures. And the news is still bad for people who venture outdoors this summer: We're a long way from wiping out the 60 species of mosquito that spread West Nile virus and the deer tick that carries Lyme disease.
And despite research involving garlic, catnip, eucalyptus and volunteers willing to stand in tubs full of ticks, there is no infallible system for keeping the bugs out of your back yard -- and your bloodstream.
"There's a tremendous push being made to see if we can find something. But there's not many chemicals out there as candidates," said Jerome Klun, an entomologist with the U.S. Department of Agriculture's research lab in Beltsville, Md.
Beltsville researchers have been awarded $4 million in U.S. Defense Department grants to come up with repellents to protect troops from ticks and mosquitoes that transmit malaria, dengue and yellow fever overseas.
To that end, Klun and colleague John Carroll will create their own version of "Fear Factor" this fall when they and other volunteers douse their ankles in three kinds of repellent and step into plastic tubs filled with 100 lab-raised ticks each.
They want to know how many ticks ignore the repellent and crawl up their legs.
The experiment will run for six days as the researchers compare SS-220, an experimental repellent developed by Klun and other Beltsville researchers, with Picaridin, a commercially available repellent, and a solution containing the insect repellent chemical known as DEET.
Carroll, 59, said there's no danger that the ticks are carrying lyme disease. Not only are they lab-raised, they're also lone star ticks, a different variety from the deer ticks that transmit the disease.
Nor does the tub of ticks give him the creeps.
"When I'm out in the field, it's more risky than if I'm standing in a tub and I can see what's going on," he said.
The challenge is the complexity of the bugs.
The pests have 30 million years of evolution on their side, and they've developed unique sensors that zero in on the carbon dioxide and other chemicals we emit. Once they sense us, they use different approaches to get into our bloodstreams.
The female mosquito -- the one that bites -- approaches like a stealth fighter, and once she lands, a probelike cutting apparatus in her head finds our blood, which provides protein to nourish her eggs.
The wingless tick waits in the brush -- sometimes for days -- to snag a ride on a leg, arm, head or neck.
Males and females dig their mouths into our skin, and they can stay attached for days, sometimes leaving poison picked up from other animals as they siphon our blood.
Despite years of effort, scientists still aren't sure what constituent of our sweat and breath attracts the insects, and what best repels them.
Preliminary evidence confirms what many researchers suspect -- that some people are attractive to mosquitoes while others nearby remain un-nibbled.
Ethane, ethanol, acetone and isoprene -- chemicals found in varying amounts in sweat and exhaled breath -- might attract mosquitoes, studies show.
Some researchers are convinced that chemical changes in our sweat, often caused by our diets, play a key role.
Dr. Thiruchandurai Rajan, chief of pathology at the University of Connecticut Health Center, was inspired to check out the effects of garlic on repelling mosquitoes because a colleague's wife was feeding garlic to her horse.
In his experiment, dozens of human test subjects took garlic capsules or placebos and then inserted their arms into a mosquito cage to see whether it had any effect on the number of bites they received.
It didn't. Rajan still suspects that a longer experiment in which subjects eat more garlic for longer periods might show some improvement.
The question is whether eating so much garlic would be more effective at driving away insects or friends.
A big concern among health officials remains the tick's ability to spread Lyme disease and the mosquito's to spread West Nile virus.
West Nile virus, discovered in Uganda in 1937, infected 2,535 people in the United States last year and killed 98, according to the Centers for Disease Control and Prevention.
The virus has caused 260 U.S. deaths and infected 10,000 people since its arrival was documented in 1999.
Lyme disease, named in 1975 after it was first reported in Lyme, Conn., can cause heart trouble, fainting spells, vision problems and arthritis if left untreated.
There were 17,000 U.S. cases last year, according to Kim Mitchell, an epidemiologist with the Maryland state health department's Center for Veterinary Public Health, and CDC reports. Officials say those numbers could increase in the coming years.
Concern about pest-borne disease has spawned an explosion in the market for mosquito traps, zappers, foggers, UV lights, repellents and sprays.
Repellents alone generate about $100 million a year in sales, according to the market research company ACNielsen.
"We've seen tremendous growth," said Gordon Jones, a vice president of Biophysics Corp., a Rhode Island company that sells mosquito traps for $295 to $1,195.
The traps get rid of mosquitoes by converting propane to carbon dioxide, enticing them into a trap, where they are killed.
Running 24 hours a day, a trap will rid as much as 11/4 acres of mosquitoes in 30 days, Jones said.
In 2003, Consumer Reports found that the traps were effective, but its researchers recommended less expensive approaches first, such as repellents and protective clothing.
Only 30 percent of people who venture outdoors ever wear the stuff, surveys show.
"They don't like the way it smells, or they don't like the way it feels on their skin," said Brian Weekley, president of Minnesota-based Bugg Products.
Weekley, a chemical engineer, left the cosmetics industry 11 years ago to create an insect repellent with what he says is exactly the right blend of vanilla fragrance and the proven bug repellent known as DEET. Still, it's a hard sell.
"People are very skeptical about the repellent industry because there's so much folklore and junk out there," Weekley said.
Joel Coats, an Iowa State University entomologist, said it was folklore that attracted him to an oil extracted from catnip, an herb from the mint family named for its intoxicating effect on felines.
Coats is convinced that the oil is one of several botanical products that can repel mosquitoes and could one day be a replacement for DEET.
In 2001, Coats inserted groups of 20 mosquitoes into a glass tube and found that they consistently avoided portions of the surface treated with the oil. The university has patented a synthetic compound made from the catnip oil.
Although most studies indicate DEET is safe, some experts recommend it only in low doses because high doses might cause health problems, particularly when it's combined with other medications or insecticides.
In high concentrations, DEET is also a plasticizer -- if applied to the skin, it will soften plastic surfaces touched by those wearing it.
"If you use DEET in low concentrations, it's not so bad. But we think there's just as good, if not better, repellents out there," he said.
At Beltsville, much of the research is aimed at coming up with a replacement for DEET, the common name for N,N-diethyl-meta-toluamide. It was developed in the 1950s and is a key ingredient in repellents and insecticide sprays worldwide.
Still, DEET remains the gold standard for keeping away mosquitoes and ticks, and most experts say repellents laced with 20 percent to 30 percent DEET are safe.
"Beltsville researchers have been awarded $4 million in U.S. Defense Department grants to come up with repellents to protect troops from ticks and mosquitoes that transmit malaria, dengue and yellow fever overseas.
To that end, Klun and colleague John Carroll will create their own version of "Fear Factor" this fall when they and other volunteers douse their ankles in three kinds of repellent and step into plastic tubs filled with 100 lab-raised ticks each.
They want to know how many ticks ignore the repellent and crawl up their legs.
The experiment will run for six days as the researchers compare SS-220, an experimental repellent developed by Klun and other Beltsville researchers, with Picaridin, a commercially available repellent, and a solution containing the insect repellent chemical known as DEET.
Carroll, 59, said there's no danger that the ticks are carrying lyme disease. Not only are they lab-raised, they're also lone star ticks, a different variety from the deer ticks that transmit the disease."
To me, this part of the experiment seems almost beyond comprehension. That these men, John Carroll, and Jerome Klun, will voluntarily step into a tub of "lab-raised" ticks, and expose themselves to what I think could be, absolute infectedness w/ Lyme. This article also states that "there's no danger that the ticks are carrying lyme disease" because they are lab raised, and are lone star ticks????!!!!!
Geez, am I uneducated, or is this true?
What about all the other bacteria that most likely will be transmitted if one of these lab raised ticks decides to bite an ankle despite the repellent(s) applied?
Willies. Gives me the willies.
Julie
Ticks pick up diseases from the animals they bite, don't they? Like Rats, mice, birds and other rodents? Deer don't seem to get Lyme do they? IF they do, what about all the venison people eat, isn't this infected with the keets?
The odd thing is, don't Lone Star ticks carry TBD'S? Sheesh, why not give the money to Lyme research so they can find a cure for Lyme and research Lyme some more?
ICEY
How have they been feeding these ticks, I wonder?
Can you imagine standing in a tub full of these critters? I have a hard time just stepping outside during tick season.
Come to think of it, maybe that's why they having them stand in the tubs: to feed the ticks.
Gross, I know. Sorry. Just couldn't let that one by
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Tabby
hey ya Raski maybe this will do? 
if not, consider this a drive-by hello . . .
Julie
Some contols lonestar tick dosent carry Lyme duh.
Mg peroxide destroys.
We now make protective clothing that contains the above solution.
U.S. patent # 5,656,037.
We once used activated charcoal which traps the pathogens, but didn't destroy them, so disposal was an issue.
Sunblock? Use titanium dioxide (in sunblock) to repel?
For sure...encourage amphibians and reptiles in the areas most affected. They make FAR more melatonin than we do. They devour the insects/mice that transmit.
Bats won't work. I've asked a bat expert already.
Dog ticks transmit Rocky Mt. Spotted Fever. In the news today:
http://www.nejm.org
Good luck with using disease-free ticks!
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Do not take anything I say as medical advice. I am not a doctor, but I DID stay at a Holiday Inn Express!
oops!
Lymetutu
The total amount of mis-information is CRAZY....
I know I don't carry the credentials that these guys do....but...I can honestly say that my hard fought battle has earned an honorable degree in "TBI".
I can't believe how inaccurate this article is.
Amazing.....lol 
Trout
First: Lab animals, whether insects of little mice, etc., are RAISED BACTERIA FREE.
These specimens are grown by specialty labs and are easily checked for bacteria.
I used to identify bacteria in the gut of roaches.
These are not ticks from the wild. Just as the mice used in experiments do NOT contain Hantovirus, etc.
At least someone is TRYING to develop a better repellant. The inaccuracies here are irrelevant...they either are repelled, or they are not.
Why is this so difficult to understand?
The type of tick, at this juncture, is not important...I am sure if they find something that repells these ticks, they will try the product on Deer ticks, mosquitos, black flies, etc.
I say "Thumbs UP" to any REAL research, done at a REAL institution! The USDA does some very beneficial research.
I have a friend in Florida that got Malaria...yes, Malaria...IN PALM BEACH, and he almost died.
We need all the help we can get...
Thank you Julie for the article!
Peace, love and wellness,
JRW
What idiots!!!
I got sick the same week I found a lone star tick on my pillow upon waking. My dog, my husband and myself are sick. We are positive on the WB for Lyme, the FISH test for Babesia, and I have hme and hge of Ehrlichia.
We will never know where we got infected but it seems rather strange we all became ill after moving here where 98% of the ticks here are lonestar...
[This message has been edited by Lymied (edited 12 August 2005).]
But, below, where Mr. Carroll says what he says (the quote is below)>>>>>>>>>>>>>
"Carroll, 59, said there's no danger that the ticks are carrying lyme disease. Not only are they lab-raised, they're also lone star ticks, a different variety from the deer ticks that transmit the disease."
THAT is the part I take umbrage with. How many people will read this, look at the tick they just pulled off their self, their dog, their cat, their whatever, and say Hmmmm, it's a LONE STAR TICK. I can't possible contract Lyme from this lone star tick bite, because I read in the paper, that lone star ticks DO NOT TRANSMIT THE DISEASE (lyme, as referenced in the article I posted above in it's entirety).
I was once medically oriented (as a nurse) so I can comprehend the raising the ticks in a lab setting where they do not have any bacteria. But would I really believe that? It would be a huge Fear Factor moment for me.
And as for the incredibly inaccurate comment on lone star's not carrying Lyme, well. Hmmmmm.
Glad to hear your grief is good!!!
Julie