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Disease-Spreading Ticks on the Move as Climate Changes

In Lyme Disease, Uncategorized on September 9, 2012 at 11:15 am
Posted by David Braun of National Geographic in Tales of the Weird on September 7, 2012
A female blacklegged tick converting its blood-meal into thousands of eggs. Credit: NSF/Graham Hickling, University of Tennessee

A female blacklegged tick converting its blood-meal into thousands of eggs. Credit: NSF/Graham Hickling, University of Tennessee

One more reason to be nervous about climate change: Tick species are on the march.

The blood-sucking, disease-spreading parasites are expanding into new territories as wildlife populations, forest habitats and weather patterns change across North America, biologists have found.

“This year’s mild winter and early spring were a bonanza for tick populations in the eastern United States,” the National Science Foundation said today. “Reports of tick-borne disease rose fast.”

While Lyme disease is the most common tick-borne disease in the Northeast and Upper Midwest, new research finds that it is not the greatest cause for concern in most Southeastern states, the NSF said in a news statement about a research paper in the journal Zoonoses and Public Health.

“The majority of human-biting ticks in the North–members of the blacklegged tick species–cause Lyme disease, but these same ticks do not commonly bite humans south of mid-Virginia,” the NSF explained.

Biologist Graham Hickling of the University of Tennessee, co-author of the Zoonoses and Public Health paper, says many patients in Southeastern states, who become sick from a tick-bite, assume they have Lyme disease, but the odds of that being the case are low.

“Ticks in the eastern U.S. collectively carry more than a dozen agents that can cause human disease,” says Hickling.

“Here in Tennessee we regularly collect lone star ticks that test positive for Ehrlichia, [a tick-borne bacterial infection]. Lone stars are an aggressive species that account for most of the human bites that we see in this region. So ehrlichiosis has to be a big concern, yet most people have never heard of it.”

In contrast, explains Hickling, there have been no confirmed reports to date of the Lyme disease pathogen among the sparse populations of blacklegged ticks found in Tennessee.

Spotted Fever Rickettsiosis and Ehrlichiosis

“The Southeast is dominated by different tick species than the ones that attack humans in the North,” says Ellen Stromdahl, an entomologist at the U.S. Army Public Health Command and lead author of the paper.

“The lone star tick is by far the most abundant tick in the Southeast, and which species of tick bites you is critical because different ticks carry different diseases. In the Southeast you are unlikely to be bitten by the blacklegged ticks that spread Lyme disease,” Stromdahl says.

Most bites in the Southeast are from the tick species that spread spotted fever rickettsiosis and ehrlichiosis, but not Lyme disease, the NSF said. “A complicating factor for public health officials is that tick species are on the move, as wildlife populations, forest habitats and weather patterns change across the continent. This spring the Tennessee Department of Health, for example, reported a 500 percent increase in tick-borne rickettsiosis.”

“Identifying health risks in the face of changing climates will be critical in coming years.”

“Identifying health risks in the face of changing climates will be critical in coming years,” says Sam Scheiner, National Science Foundation program director for the joint NSF-National Institutes of Health Ecology and Evolution of Infectious Diseases (EEID) program, which funds Hickling’s research. This study will inform public health officials about what diseases are found in which areas, so they can minimize human health problems.”

Hickling’s work is also in collaboration with scientist Jean Tsao of Michigan State University and is part of an EEID project to identify the ecological factors leading to distributions of tick species and pathogens–in particular, where the Lyme disease tick and pathogen are found.

Lyme-infected blacklegged ticks are expanding south through Virginia, and lone star ticks are moving north, the NSF said in its statement. “The bite of the lone star tick can create a bulls-eye rash that appears like that of Lyme disease, but the rash isn’t caused by the Lyme bacteria. The scientists say that this almost certainly leads to misdiagnosis of some patients in mid-Atlantic states, where both tick species are common.”

The best way to distinguish Lyme from other tick-borne diseases is to be vigilant for tick bites, and whenever possible save any tick that manages to bite you. “Store the tick in your freezer or in a vial of alcohol so it can be identified if you become ill,” the NSF recommends.

Nymphal Blacklegged Ticks of the Northeast

In the Northeast, the NSF release explained, Lyme disease awareness campaigns have focused public attention on the nymphal blacklegged tick–which is responsible for most disease transmission and which is tinier than the adult form. “While nymphal blacklegged ticks and nymphal lone star ticks–which also bite humans–can be distinguished, the two are often confused by the public. In one study, 13 of 20 patients reporting tick bites to physicians were given antibiotics on the assumption that they were at risk for Lyme disease, yet 53 of the 54 ticks removed from those same patients were lone star ticks, which do not spread Lyme disease.”

“Where you live determines which tick species is likely to bite you.”

“Where you live determines which tick species is likely to bite you,” says Tsao, “and therefore which diseases you’re most likely to contract.”

The NSF says biologists are happy that recent treatment recommendations have begun to emphasize the importance of considering the tick species and its infection status as part of the diagnostic process. “Their advice: Stay open-minded about which tick-borne diseases are most common in your area–and save the tick that bites you.”

This blog post was based on publicity material provided by the National Science Foundation, an independent federal agency that supports fundamental research and education across all fields of science and engineering.

Lyme Disease

(From the Centers for Disease Control and Prevention)

The Lyme disease bacterium, Borrelia burgdorferi, is spread through the bite of infected ticks. The blacklegged tick (or deer tick, Ixodes scapularis) spreads the disease in the northeastern, mid-Atlantic, and north-central United States, and the western blacklegged tick (Ixodes pacificus) spreads the disease on the Pacific Coast.

Ticks can attach to any part of the human body but are often found in hard-to-see areas such as the groin, armpits, and scalp. In most cases, the tick must be attached for 36-48 hours or more before the Lyme disease bacterium can be transmitted.

Most humans are infected through the bites of immature ticks called nymphs. Nymphs are tiny (less than 2 mm) and difficult to see; they feed during the spring and summer months. Adult ticks can also transmit Lyme disease bacteria, but they are much larger and may be more likely to be discovered and removed before they have had time to transmit the bacteria. Adult Ixodes ticks are most active during the cooler months of the year.

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Which Bug Repellent Is Best?

In DEET, Lyme Disease, Uncategorized, West Nile Virus on September 2, 2012 at 11:05 am

Bucks - Making the Most of Your Money

August 30, 2012, 4:17 PM
By ANN CARRNS

If your family is like ours, you’ll be spending time outdoors this Labor Day weekend.

And if you’re a mother like me (read: a worrier), you’re well aware of news reports

about the abundance of ticks this year,

and about an increase in cases of West Nile virus in some parts of the country.

That means we’ll be spraying ourselves and our children with bug repellent, to ward off both ticks

and the pesky mosquitoes that carry West Nile.

(Generally we avoid slathering our offspring with chemicals.

But we make an exception in this case,

if they’re going to be out in nature for extended periods of time). But which repellent is best?

Consumer Reports has updated a test of widely available repellents that work on both deer ticks and mosquitoes that carry West Nile,

along with cost information on a per-ounce basis. The six top-rated products are $2 an ounce or less.

The data on costs is from 2010, according to Consumer Reports, but all the products are currently available.

(And a quick check online suggests prices are about the same, or in some cases, lower.)

Just how much chemical you are comfortable exposing yourself

and your children to is up to you. The four top-ranked brands

— Off Deep Woods Sportsmen II, Cutter Backwoods Unscented, Off Family Care Smooth & Dry,

and 3M Ultrathon Insect Repellent — all contain DEET in varying concentrations from 15 percent to 30 percent,

and were able to repel mosquitoes for at least eight hours.

DEET is effective, and the Environmental Protection Agency says it is safe when used as directed,

but you shouldn’t use it on babies under 2 months old. The American Academy of Pediatrics advises

against using products with more than 30 percent DEET on children.

The fifth- and sixth-ranked products — Repel Plant Based Lemon Eucalyptus and Natrapel 8-hour with Picaridin —

don’t contain DEET, but provided long-lasting protection as well.

The lower-ranked products also repelled mosquitoes effectively, but generally for shorter periods of time,

and some had other drawbacks, like a tendency to stain clothing.

The upshot, Consumer Report says, is that “most of the tested products will do the job if you’re

going to be outside for only a couple of hours, but look for a highly rated product to protect you on longer excursions.”

The E.P.A. has information on its Web site to help you choose a repellentbased on your specific needs,

although it doesn’t include cost data. General information about West Nile is available

from the Centers for Disease Control and Prevention.

Are you stepping up your use of bug repellent due to West Nile?

http://bucks.blogs.nytimes.com/2012/08/30/which-bug-repellent-is-best/?src=rechp

Tick bites can make you deathly allergic to meat

In Lyme Disease, Uncategorized on August 13, 2012 at 8:15 pm

http://grist.org/list/tick-bites-can-make-you-deathly-allergic-to-meat/

 

By Sarah Laskow

Photo by The Adventures of Kristin & Adam.

If there weren’t enough reasons to be totally terrified and grossed out by ticks (they drop on your head from the trees, they suck your blood, they burrow into your skin, they transmit a terrible disease you’ll never be fully rid of), the bite of a lone star tick can trigger allergies that mean eating a hamburger can lead to anaphylactic shock.

Helen Chappell writes in Discover Magazine about her experience with this relatively unknown danger, and her account is pretty dire:

Tick saliva is “a really good provocateur of an immune response, even outside of an infection,” Commins told me, though they are not yet sure whether it’s bacteria carried in tick saliva or the saliva itself that is responsible. But they believe that something in some ticks’ saliva stimulates the human immune system to produce antibodies to a sugar present in mammalian meat, though not poultry and fish, called galactose-alpha-1,3-galactose (alpha-gal for short). The next time an unsuspecting meat lover chows down on a hamburger, those antibodies could rally a systemic allergic reaction.

Except not right away. Maybe not until hours later.

You can have a steak for dinner and not know anything’s amiss until the middle of the night. Add to that the fact that different kinds of meats — or even different cuts of the same kind of meat — can cause more or less severe reactions, and you’ve got a recipe for confusion.

Now, normally, we’ll all in favor of people eating less meat, but no one should have to undergo a near-death experience to get to that place. Ugh, ticks!

 

Source

 

Sarah Laskow is a reporter based in New York City who covers environment, energy, and sustainability issues, among other things. Follow her on Twitter.

 

 

‘Robo-mosquitoes’ in Margaritaville?

In Dengue Fever, Lyme Disease, Uncategorized on August 13, 2012 at 8:43 am

BY DAVID REJESKI AND ELEONORE PAUWELS

Most Europeans see the United States as the land that embraces genetic engineering. So imagine the surprise when a British firm — Oxitec — ran into the buzz saw of public opinion trying to introduce a genetically modified (GM) mosquito in Key West to eradicate the dreaded Dengue virus.

Within a few weeks of a public meeting to discuss the mosquito release, a petition against the initiative had more than 100,000 signatories. [The entire population of Monroe County, which encompasses The Keys, is only about 75,000.] Key West inhabitants have branded Oxitec mosquitoes with names like “Robo-Frankenstein mosquitoes,” “mutant mosquitoes,” and “Super bugs,” using rhetoric lifted from movies like Jurassic Park and The Hunger Games.

Are people overreacting? Maybe. But a closer read of many of the comments posted on the petition website provide a deeper insight into the resistance and some key lessons for future technologies dependent on genetic engineering.

•  Trust. Whether the public trusts new technologies often depends on whether the public trusts their developers or those responsible for ensuring public safety. The comments contain numerous references not just to Oxitec, but to agriculture giant Monsanto, the Food and Drug Administration (FDA), and British Petroleum: “I am fed up with Monsanto and other biotech companies,” said one.

Given the complexity of most emerging technologies, many people will fall back on this simple trust test, and most corporations, and increasingly, government organizations, will lose.

•  Nature. Many people saw the GM mosquitoes as a violation of nature’s order, commenting, “Why do all these big companies all seem to think that they know what’s better than Mother Nature?” “You can’t mess with Mother Nature and not have something bad happen; they don’t know what they’re doing!”

Commenters pointed to a number of examples, including invasive species common in Florida, such as the melaleuca plant (originally introduced to dry out swampy land) and giant pythons, and other unwelcome visitors like Africanized honeybees, the Mediterranean fruit fly (a scourge in California) and Asian beetles and carp. People emphasized that a true “test release” is impossible. “Once living organisms are released into the environment they cannot be recalled, nor do we know what results and impacts may occur,” one commenter said.

•  Permission. Decades of research on risk perceptions have shown that people differentiate between “voluntary” risks, which we willfully undertake, and “non-voluntary” risks, which are imposed upon us. People will smoke themselves to death while fighting against a nearby factory emitting pollutants.

In this case, Key West inhabitants clearly saw the government and the company imposing their will on the population. “We were never asked if we wanted GMOs released into our environment . . . there is very little democracy left if we have no voice,” one commenter said. Another asked, “Who wants to be a human Guinea pig?” Another added, “We are not lab rats!”

Interestingly, the other side of the risk equation, Dengue fever, was never mentioned. This may be because the actual number of cases in Florida totaled seven in 2011 and 58 in 2010, according to the Centers for Disease Control and Prevention. In the tropics and subtropics, as many as 100 million people are infected yearly, but for many people in Florida, Dengue fever is an abstraction; Oxitec and their mosquitoes pose the risk.

Clearly, there was a significant lack of information about impacts and uncertainties in the Key West case. Some people asked: “Where is the unbiased, third-party, peer-reviewed research on effectiveness and safety of GM mosquitoes?” But given the biases, trust deficit, and dynamics of the situation, it is doubtful whether more information would have reduced public opposition.

As scientists work on more dramatic modifications of organisms in areas like synthetic biology, the Key West case should serve as a lesson, as should the growing public opposition to GM foods in states like California, Michigan, Oregon, Washington and Vermont.

Getting the science right won’t help if we get the public engagement wrong.

David Rejeski is the director of the Woodrow Wilson International Center for Scholar’s Science & Technology Innovation Program. Eleonore Pauwels is a research scholar with the program.

http://www.miamiherald.com/2012/08/13/2945313/robo-mosquitoes-in-margaritaville.html

Rhode Island Lawmakers Push Lyme Disease Strategy

In Lyme Disease, Uncategorized on July 21, 2012 at 5:08 pm

July 15, 2012

PROVIDENCE, R.I. (AP) —

A group of lawmakers is pushing for a national strategy to combat

Lyme disease aimed at speeding advances in diagnosis, treatment and prevention of the sometimes serious illness that infects tens of thousands of people every year.

“The tick problem is growing. The Lyme disease problem is growing,” said Sen. Jack Reed, D-R.I., a cosponsor of the bill in the U.S. Senate. “This requires resources.”

The legislation provides for the establishment of an advisory committee made up of researchers, patient advocates and agencies, as well as the coordination of support for developing better diagnostic tests, surveillance, research and other efforts.

“The key with the bill is to get everyone in the room, get all of the best available science and then aggressively attack this hideous disease that has ruined so many lives,” said Rep. Chris Smith, R-N.J., the sponsor in the House who has pushed similar legislation in the past.

Reed and Sen. Richard Blumenthal, D-Conn., who introduced the Senate bill, said they hope to pass a bill this year.

“It is essentially designed to create awareness and understanding in public healt

h agencies about the urgent and immediate need to act more effectively against a disease that truly has reached epidemic proportions,” Blumenthal said.

Lyme disease is the sixth most common reportable disease in the United States, and the second highest (behind chlamydia) in the Northeast, said Dr. Ben Beard, director of vector-borne diseases at the federal Centers for Disease Control and Prevention.

In recent years, Lyme disease cases have increased around the country. Some of that may reflect improved testing and reporting, Beard said. But he said researchers also believe there has been a real growth in cases, possibly because of more deer and the spread of suburbia into previously uninhabited places.

This year, 8,400 cases have already been reported, the CDC said. Lyme experts believe the number of actual cases is likely larger, in part because tests for the disease are unreliable.

Lyme disease is named after Lyme, Conn., where the illness was first discovered in 1975. It’s transmitted through t

he bites of infected deer ticks, which are about the size of a poppy seed. Those infected often develop a fever, headache and fatigue, and sometimes a tell-tale rash that looks like a bull’s eye centered on the tick bite. Most people recover with antibiotics, although some symptoms can persist. If left untreated, the infection can cause arthritis or spread to the heart and nervous system.

Treatment can be tricky, especially in cases that aren’t caught early.

Reed said the bill would ultimately result in more federal money aimed at Lyme disease, welcomed news to Thomas Mather, a professor and director of the University of Rhode Island’s Center for Vector-Borne Disease, which runs the TickEncounter Resource Center.

A grant from the U.S. Department of Agriculture in 2006 helped start his program, which works to reduce tick-borne illnesses including

Lyme disease. Mather said it’s difficult to get the money he needs to keep the work going, and he hopes enacting a federal strategy will make that easier.

“We’re really looking for ways to sustain these activities,” he said. “Mostly what’s needed are more resources.”

The Infectious Diseases Society of America, an influential doctor’s group that sets guidelines for treatment of Lyme disease, has opposed similar legislation in the past. In 2009, it raised concerns about whether such a panel might be slanted and not adequately represent the views of the scientific community.

It has not yet taken a position on the pending legislation.

If the legislation passes, Lyme disease would be the latest in a string of diseases to be targeted with a national strategy, the most recent being Alzheimer’s disease.

Smith has scheduled a Congressional subcommittee hearing on Tuesday about challenges in diagnosing and managing Lyme disease.

http://www.eagletribune.com/local/x1301512142/Rhode-Island-lawmakers-push-national-lyme-disease-strategy

First Westchester County, NY West Nile Mosquitoes of 2012

In Lyme Disease, Uncategorized, West Nile Virus on July 21, 2012 at 5:04 pm

Updated: July 20, 2012 8:35 PM
By NEWSDAY.COM

An undated file photo of a mosquito, a

Photo credit: Getty Images | An undated file photo of a mosquito, a carrier for the potentially lethal virus West Nile.

Lab tests have confirmed the first mosquitoes contaminated withWest Nile virus in Westchester County this summer, county health officials said Friday.

The “batch” of mosquitoes — found in Mamaroneck — was sent to a state Department of Health laboratory for testing.

“We expect to find mosquitoes that carry West Nile virus at about this time, so we hope confirmation of their presence reminds residents to take precautions” including using mosquito repellent and wearing protective clothing, Sherlita Amler, Westchester County’s health commissioner, said in a statement.

The midsummer find mirrors results last year, when health officials confirmed the first infected mosquitoes in early August. Overall, 32 batches of mosquitoes tested positive for West Nile virus last year in Westchester County.

Across the river, health authorities in Rockland County found contaminated mosquitoes in late June, at least a month earlier than has been typical. The infected mosquitoes were found in Haverstraw and Ramapo, according to the Rockland County Health Department.

The lab tests prompted a response from County Legis. Ken Jenkins, D-Yonkers, who blamed County Executive Rob Astorino for trimming the health department’s budget. Because of budget cuts,Jenkins claimed, in 2011 Westchester County applied larvacide to 20,000 fewer catch basins than it did in 2010.

“In matters like public health and safety, I think we have to always move forward with an abundance of caution and vigilance,” Jenkins said in a statement. “Last year, the number of inspections and larvicide applications were reduced sharply from the previous year because of funding cuts by theAstorino Administration, and this short-sighted approach could lead to deadly consequences.”

West Nile virus was first identified in New York in 1999, and since then the virus has spread across the continental U.S. Although most people don’t realize they’ve been exposed, the virus can have serious consequences for the very young or old and people with existing health conditions or compromised immune systems.

West Nile fever, the less-severe form, can lead to symptoms similar to the common cold or flu, including headache, nausea, sore throat and swollen lymph nodes, according the Centers for Disease Control.

More serious infections can have debilitating symptoms, such as confusion and loss of consciousness, tremors, muscle weakness and vision loss.

Stagnant water is the best breeding ground for the virus, and Amler urged people to “remove standing water from gutters and play equipment, empty buckets and other containers around your property, and turn over children’s pools after their use.”

The health department offered a list of tips and recommendations:

Avoid the outdoors in the early evening when mosquitoes are active and feeding. Use insect repellents when outdoors during these times, following the repellent directions. Adults can apply insect repellents with up to 30 percent DEET onto their own hands and then rub the repellent onto their children. Products containing DEET are not recommended for use on children under two months old.

Wear long pants, long-sleeved shirts and socks when outdoors in areas where mosquitoes are feeding.

Check around property for cans, containers and ceramic pots and discard or turn them over.

Check and remove standing water from children’s toys, pools, wheelbarrows and play houses.

Remove discarded tires.

Drill holes in the bottoms of all recycling containers that are left outdoors.

Change the water in birdbaths at least twice weekly.

Sweep driveways after it rains to clear puddles.

Keep storm drains and gutters clear of leaves and debris.

Clean and chlorinate swimming pools, outdoor spas and hot tubs and drain water that collects on their covers.

Residents who notice large areas of standing water on public property that could serve as potential mosquito breeding grounds should report it to the Westchester County Department of Health by calling 914-813-5000 or emailing the Health Department at hweb@westchestergov.com

 

http://newyork.newsday.com/news/health/first-westchester-west-nile-mosquitoes-of-2012-id-d-1.3850766

Mosquito Warning for Montanans

In DEET, Lyme Disease, Uncategorized, West Nile Virus on July 21, 2012 at 5:01 pm

Posted: July 19, 2012 10:59 AM by Melissa Anderson (Helena)

Mosquitoes are loving the recent weather conditions in Montana, and while the pesky insects are mostly annoying, they can also spread a dangerous virus.

Montana health officials are cautioning people to be aware that mosquito bites can carry West Nile virus, and besides using mosquito repellent, there are some other ways people can protect themselves.

Lewis & Clark County public health nurse Mike Henderson said, “You can prevent bites of course by covering up your skin. Long sleeves, long pants, especially at dusk and dawn. And if we can take measures to prevent where mosquitoes are going to be able to breed. Drain any standing water around your place at least once a week.”

Infection by West Nile virus occurs in about three to 14 days after being bitten and while most people who get bit won’t have any symptoms, some people may develop a headache, fever, fatigue and joint stiffness.

http://www.kxlh.com/news/mosquito-warning-for-montanans/

Predators, Prey and Lyme Disease

In Lyme Disease on June 23, 2012 at 6:25 pm

http://green.blogs.nytimes.com/2012/06/18/predators-prey-and-lyme-disease/

JUNE 18, 2012, 3:00 PM

Predators, Prey and Lyme Disease

By KELLY SLIVKA

Deer ticks are aptly named, in a sense; a Northeastern deer can carry over 1,000 of these ticks on its body. But as far as humans are concerned, the ticks might be more relevantly called mouse ticks. That’s because white-footed mice and other small mammals, not deer, are now known by scientists to be major carriers of Lyme disease.

Lyme disease is spreading in the Northeast and the Midwest, and according to the national Centers for Disease Control, the number of annual cases over the past decade has been increasing. However, no one is quite sure why. In a new study published in the Proceedings of the National Academy of Sciences, researchers tried to figure out what is driving the proliferation of Lyme disease in human populations by studying populations patterns in animals that interact with ticks. Their study suggests that large predators like coyotes and foxes that aren’t typically associated with Lyme disease transmission may have a big impact on the spread of the disease.

The life cycle of deer ticks depends on interactions in the entire ecosystem in which the ticks dwell, said Taal Levi, the study’s lead author, who did the research while a doctoral student at the University of California Santa Cruz and is now an ecologist at the Cary Institute of Ecosystem Studies in New York.

Ticks rely on “bloodmeals” from other animals to move through their three life stages: larva, nymph, and adult, Dr. Levi said. When the ticks hatch into larvae, the bacteria that causes Lyme disease, Borrelia burgdorferi, is not present.

For a tick larva to grow into a nymph, its next life stage, it needs blood. If the larva gets its blood meal from a mouse already carrying B. burgdorferi, the larva picks up the bacteria and becomes a carrier itself. It grows into a nymph and waits for its next host so it can get the blood meal necessary to grow into an adult tick. “Sometimes one of those nymphs doesn’t bite a small mammal but bites a person, and that’s where we get the disease,” Dr. Levi said.

While people used to blame deer for the spread of Lyme disease, Dr. Levi said that scientific evidence has indicated that deer probably aren’t significant transmitters of B. burgdorferi bacteria because their systems tend to quickly flush it out. But “some hosts, like white-footed mice, don’t clear it at all,” he said, which means the bacteria hang around long enough to be transmitted to ticks.

Dr. Levi hypothesized that because these small animals are prey, their abundance – and the spread of the Lyme disease bacteria within them – depends on the abundance of their predators. In the study, he and his colleagues did a computer analysis of known cases of Lyme disease and population data for red foxes — a key predator of rodents — in four states with a high prevalence of the disease: Minnesota, Wisconsin, Pennsylvania and Virginia. For good measure, they also compared deer populations with the tally of Lyme disease cases in Wisconsin, Pennsylvania, Virginia and New York.

The models showed higher numbers of Lyme disease cases in places where there are fewer foxes. They detected no significant relationship between numbers of deer and numbers of Lyme disease cases.

The researchers also ran computer programs comparing Lyme disease cases with coyote populations in the states where they modeled red fox populations. As coyotes have spread through the Midwest and Northeast, they have tended to displace foxes, Dr. Levi said.

But coyotes don’t generally pack themselves as tightly into an area as foxes, meaning that there tend to be fewer coyotes in an area than there were foxes. “If you replace fox habitat with coyote-occupied habitat, you lose a large number of predators, and those predators you’ve lost consumed a high number of mammals,” Dr. Levi said. So the models showed a significant relationship between high numbers of coyotes and high numbers of Lyme disease cases.

So: more coyotes equals fewer foxes, which means fewer predators, which means more small animals are running around that could be carrying the bacteria for Lyme disease. More bacteria is therefore transmitted to more ticks, which then transmit the bacteria to humans. It’s complicated.

In fact, it’s so complicated that Maria Diuk-Wasser, an epidemiologist at the Yale School for Public Health who was not involved in the study, said she was skeptical about the connections drawn between top predators and Lyme disease cases in the study.

Modeling patterns can show relationships between data, but not necessarily the causes of the relationships, she pointed out. For example, to say that there’s a correlation between the number of coyotes in an area and the number of cases of Lyme disease reported there is different than saying that a high number of coyotes in an area causes more cases of Lyme disease in humans.

“What they say is plausible,” Dr. Diuk-Wasser said. But she said she wanted to see more experimental studies performed out in the field to support the models. The models in the study use historical population data recorded by hunters and state wildlife management services rather than data collected specifically for the study.

Dr. Diuk-Wasser said that birds are also major carriers of Lyme disease bacteria and might be even more significant carriers than rodents because of the distances they can easily travel.

Given the health implications, “understanding the ecological mechanisms that drive Lyme disease in nature is very important,” she said.

Long Tick Season in Affected Areas

In Lyme Disease on May 7, 2012 at 8:01 am

 

It could be a long tick season in affected areas; tips for staying safe

May 1, 2012

Shortly after her first child was born, Colleen Safford left Manhattan for a 10-acre spread north of the urban jungle to create a new life for her growing family — a life immersed in the outdoors.

But along with the woods and grassy fields came a drawback of country life in the Northeast: the black-legged tick, which can carry the Lyme disease bacteria.

“I wanted grass stains for my kids instead of cement scrapes,” said Safford, who owns a dog boarding business on her property in Chatham, N.Y., about two hours north of New York City. “I wanted them to have an intense outdoor experience, and Lyme disease came with it. But it’s worth it.”

There were 30,158 cases of confirmed and probable Lyme cases reported in 2010, according to the federal Centers for Disease Control and Prevention, with 94 percent of those cases being reported from 12 states in the Northeast and upper Midwest.

The disease may be spreading, according to a study released in February in the American Journal of Tropical Medicine and Hygiene. It showed a clear risk across much of the Northeast, from Maine to northern Virginia; a high-risk region in the upper Midwest, including parts of Wisconsin, Minnesota and Illinois; and “emerging risk” regions including the Illinois-Indiana border, southwestern Michigan and eastern North Dakota.

The mild winter this year could increase the number of Lyme cases. Adult ticks have been active earlier than usual and people have been getting outside sooner than they typically do, increasing the exposure season, said Paul Curtis, a natural resources professor and tick expert at Cornell University.

Nobody suggests staying indoors this summer. But nature enthusiasts, hikers, gardeners and people who work outside in high-risk areas need to guard against ticks.

“If you’re engaged in outdoor activities and you do regular tick checks, you’ll be able to find them,” said Phillip Baker, executive director of the American Lyme Disease Foundation. “Once they take a meal, they get bigger. If they’re still there the next day and it’s still less than 48 hours, you can pick them off. That gives you a bit of a safety measure.”

Only an infected tick attached to your body for about 36 to 48 hours can make you sick, he said.

Lyme disease causes flu-like symptoms including fever, chills and achy joints, and often a distinctive bull’s-eye rash. Most people recover quickly when treated early with antibiotics, but untreated infections can cause more serious conditions like Bell’s palsy, arthritis and neurological problems.

Besides tick checks, the American Lyme Disease Foundation recommends wearing light-colored, tightly woven clothing to make it easier to see crawling ticks; avoiding sitting directly on the ground or on stone walls; walking in the middle of established trails rather than at the edges; tucking pants into socks, and shirts into pants; and wearing covered shoes.

For sun lovers and others who don’t want to cover up, there are spray repellents that Baker said work “pretty well.”

There also is clothing made with the insect repellent permethrin bonded to the fibers.

Other ways to help prevent Lyme disease, according to the CDC, include bathing after being outside, to help spot ticks or wash of ones that haven’t attached yet; checking outdoor gear and pets for ticks; and running clothing through a hot dryer for an hour to kill any ticks.

In New York’s Columbia County, where Safford lives, Lyme is a part of everyday life.

“People talk about it like you would talk about a common cold up here,” Safford says.

“You just need to be aware that it’s in your environment and err on the side of caution in terms of your checking, but not allow it to hinder or affect your lifestyle.”

Her two older children — Sayer, 5, and Orla, 3 — attend a school where they spend most of the day outside tending to gardens and animals, and the family of five often hikes on weekends. Only Sayer has been treated for Lyme, twice when he was 4.

Boys ages 5 to 10 have the highest number of reported Lyme disease cases, according to federal figures.

Safford says she uses natural repellents against Lyme and checks her children’s bodies nightly at bath time, removing any ticks that are found. Ticks are especially fond of bodily creases such as armpits, the back of the knee, the groin and the nape of the neck.

“We just say, ‘tick check,’ and they lift up their arms and I look through their scalp and hair,” Safford says. And she and her husband scan each other. “It’s very romantic,” she joked.

___

Online:

CDC Lyme site: http://www.cdc.gov/lyme/

American Lyme Disease Founndation: http://www.aldf.com/

http://wapo.st/ticks2012

Cayenne Tick Responsible for Equine Piroplasmosis Outbreak

In Lyme Disease, Uncategorized on October 7, 2011 at 12:07 pm

Read the magazine story to find out more.
Photo: Cayenne tick.
ARS scientists have identified the cayenne tick as the predominant vector of Equine piroplasmosis in horses in a 2009 Texas outbreak. Photo courtesy of Jim Occi, BugPics, Bugwood.org.

For further reading


By Sharon Durham
October 3, 2011The cayenne tick has been identified as one of the vectors of equine piroplasmosis in horses in a 2009 Texas outbreak, according to U.S. Department of Agriculture (USDA) scientists.

The United States has been considered free from the disease since 1978, but sporadic cases have occurred in recent years. In October 2009, in Kleberg County, Texas, a mare was presented for veterinary care with clinical signs of infection, including poor appetite and weight loss. Subsequent investigation and testing confirmed the original case and indentified more than 290 additional infected animals on the ranch.

Research leader Donald Knowles, entomologist Glen Scoles and veterinary medical officer Massaro Ueti with the Agricultural Research Service (ARS) Animal Disease Research Unit, in Pullman, Wash., and collaborator Robert Mealey with Washington State University in Pullman have been working on the project with USDA’s Animal and Plant Health Inspection Service (APHIS) and the Texas Animal Health Commission (TAHC).

ARS is USDA’s principal intramural scientific research agency, and the research supports the USDA priority of promoting international food security.

The researchers’ goal was to assess and prevent the spread of the Texas outbreak, which could have serious international trade implications if it is found to have spread beyond the ranch where the outbreak occurred. Part of their initiative was to identify the tick species responsible for the new outbreak.

Only two U.S. tick species—Dermacentor variabilis and Rhipicephalus (Boophilusmicroplus—had previously been shown experimentally to be vectors of Theileria equi, the microbe that causes equine piroplasmosis, according to Scoles.

The cayenne tick, Amblyomma cajennense, had not previously been shown to be a competent vector. Adult cayenne ticks were collected from positive horses on the outbreak ranch and allowed to re-attach and feed on a noninfected horse. Scoles led the study showing these ticks successfully transmitted T. equi. The results will be published in the October issue of Emerging Infectious Diseases.

Knowles, Ueti and Mealey are treating some of the South Texas horses with imidocarb dipropionate. Tests conducted thus far by the team have been promising and trials are ongoing.

Read more about this research in the October 2011 issue of Agricultural Research magazine.

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