Archive for the ‘Lyme Disease’ Category

STARI or a Lyme Disease variant?

Thursday, October 31st, 2013
Here's the spirochete you definitely don't want to have..it causes syphilis.

Here's the spirochete you definitely don't want to have..it causes syphilis.

There continues to be considerable controversy over the extent of Lyme Disease  in the United States. Its cause is a spirochete, a skinny, long bacteria that is coiled and looks like a microscopic spring. Historically this family of "bugs" was known to have a member that caused syphilis, a scourge of mankind for thousands of years. Then in 1975 a new disease made its first appearance with a cluster of cases in both children and adults in Lyme, Connecticut. Over fifty cases were reported in the first two years of the epidemic, the black-legged tick Ixodes scapularis was found to be the vector that transmits the disease to humans and  in 1982 the spirochete Borrelia burgdorferi was identified as the bacteria responsible for the rash, arthritis, cardiac and neurological manifestations of what was eventually termed Lyme disease. The World Health Organization calls the illness Lyme borreliosis and it is widely found in Europe from Turkey to Sweden with nearly 65,000 cases a year, some differences in signs and symptoms and another tick species as the transmitting agent.

Lyme disease has clearly spread from its origin in the northeast US and is now an illness that affects hundreds of thousands yearly. The Center for Disease Control and Prevention (CDC) has  a website with extensive information on Lyme Disease,  and links to frequently asked questions about the illness. Among those bits of information is the blunt statement that Lyme disease, to a great extent, only occurs in three endemic regions of this country. Those cases occur in the area from northeast Virginia to Maine and some north-central states, including Wisconsin and Minnesota.

But it also can be spread by another tick much further west, especially in California where a different black-legged tick, Ixodes pacificus is the vector. And the CDC's own interactive map of Lyme disease cases from 2001 through 2012 shows it has struck in Florida, Texas and a number of other states, albeit without the number of cases seen in the east and northeast portions of this country.

Humans aren't the only species affected; dogs can get Lyme disease also and the incidence of the illness has markedly increases. A canine vaccine is available. Horses, cattle and cats can also get Lyme, but much less commonly.

A major issue is whether Lyme disease or something quite similar occurs in the South. The debate on that started twenty-five years ago and continues to today.

In 1988, Dr. Edwin Masters, a family practice physician in Missouri and amateur forester, gave a talk on Lyme disease to a forestry association. He had extensively prepared for his lecture and subsequently began to see cases of what he thought was Lyme disease in his own practice. Many had a rash similar to Lyme victims elsewhere (erythema migrans, abbreviated as EM). Some had swollen joints, neurological signs and symptoms and positive blood tests for Lyme disease using the test most commonly available then. Masters reported his cases to the Missouri Department of Health, but found that his reports were ignored.

He didn't give up at that point, but carefully photographed the EM rashes his patients presented with and stored blood samples. In the North the CDC said just having the reach was diagnostic, but denied that was true in the South.

A 1999 paper published by scientists from Amsterdam and New York said that there are ten different species of the spirochete bacteria that is called Borrelia. At that time three were known to cause disease in humans.

A multi-part 2009 blog post in Psychology Today's Emerging Diseases series (written by Pamela Weintraub, the Executive Editor at Discover Magazine) was titled "Rebel with a Cause: The Incredible Dr. Masters." It details the last thirty years of the live of the physician who championed the cause of Southern Lyme disease.

The Lone Star tick appears to be the vector for Lyme-like diseases in the South.

The Lone Star tick appears to be the vector for Lyme-like diseases in the South.

A 2013 Discover Magazine In-Depth report Ticked: The battle over Lyme Disease in the South, tells the story well (I downloaded it for $1.99). In brief, many people who live in the South have had a Lyme-like illness that the Lyme and Tick-Borne Diseases Research Center at Columbia University calls STARI, Southern Tick-Associated Rash Illness. From the CDC's conservative viewpoint this is not Lyme Disease since it has never been clearly proven to be caused by the spirochete Borrelia burgdorferi sense stricto (that translates to "In the strict sense")  and, according to the CDC doesn't cause the major complications associated with that illness. Their 2011 webpage on STARI says patents bitten by the Lone Star tick can sometimes develop an EM rash like those of Lyme disease victims, but the skin manifestations of STARI are slightly different and arthritis, cardiac or neurological complications don't occur.

Kerry Clark, a PhD associate professor in the Department of Public Health at the University of South Florida, took up the cudgel for Southern Lyme disease after Masters' death. He is a medical entomologist at USF who had collected and studied ticks for years. After giving a Lyme disease talk in Georgia three years ago, he was approached by a woman from an Atlanta suburb who told him there were many similar cases in her town. Clark collected many ticks from the patchy woodland areas infiltrating the area; most were juvenile (nymph phase) or adult Lone Star ticks.

Several days later he found one engorged tick on his own scalp. Since he has had fatigue, intermittent mental "fuzziness," twitches and a strange recurrent pounding headache.

Clark recently published a major study in the International Journal of Medical Sciences (easily available on the National Library of Medicine website) with the title "Lyme Borreliosis in Human Patients in Florida and Georgia, USA." It gives demographic, clinical and lab data on ten such patients with suspected Lyme disease. Clark and his associates used a newly developed test developed specifically for the genospecies Borrelia burgdorferi. Worldwide this includes more than 20 different "bugs" with seven in North America, but in the past only one had been generally accepted as responsible for Lyme disease. With DNA confirmation, they reported finding other closely-related spirochetes in patients' blood and skin as well as in Lone Star ticks.

My first take was this was an impressive article, but I am aware of those who would treat many patients with a variety of symptoms for "chronic Lyme disease" over extended periods of time using repeated doses of expensive intravenous antibiotics. And there is another subset of physicians, including, unfortunately, one of Clark's co-authors, who use treatment modalities which I view with great skepticism.

If other academic laboratories confirm Clark's work, perhaps we can get to definitive answers and make available tests that help determine when and how to treat patients with atypical Lyme disease.

Having seen diagnoses come and go (e.g., the virus that supposedly caused chronic fatigue syndrome was eventually found to be a lab contaminant), I'm waiting for those confirmatory studies.

 

 

 

 

 

 

 

babesiosis, caused by the parasite Babesia microti —

a pathogen similar in type and impact to the one that causes

malaria. Ticks in the South also carry other diseases, including

Rocky Mountain Spotted Fever and ehrlichiosis, caused by two

kinds of related bacteria.

 

 

The Columbia University Lyme and Tick-borne Disease Research Center's website has a nicely balanced discussion of STARI, Southern Tick-Associated Rash Illness, sometimes called Masters Disease in honor of the now-deceased Missouri family physician who initially reported cases of what was felt to be a Lyme Disease-like illness.

Discover magazine, which I subscribe to, has an In-Depth publication available for $1.99 on the controversy concerning a Lyme disease-like illness in the south. It's well written by Wendy Orent, a PhD anthropologist/science writer who teaches at Emory University; she has also published a controversial book on plague.

Orent was also involved in a debate about the possibility of an H5N1 (bird flu) epidemic.  According to Orent, there was no legitimate basis to assume that any large-scale epidemic would ensue as a result of the H5N1 virus.

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Lyme Disease Redux

Monday, September 23rd, 2013

Yesterday's edition of The New York Times had an article by an experienced academic physician that called for a new Lyme disease vaccine, Dr. Stanley A. Plotkin, a professor of pediatrics at the University of Pennsylvania said new CDC data had been released showing a ten-fold greater incidence of the disease than was previously thought. He explored the history of the vaccine put on the market in 1998 by a major US pharmaceutical company, then called SmithKlineBeecham (now it's become GlaxoSmithKline).

I looked for that news release from the CDC and found their old numbers in an August, 2013 online site (30,000 cases a year reported by state and DC health departments) had been superseded by new preliminary figures coming from three different databases. So instead of the numbers we've thought represented human cases, 96% of which occur in thirteen states in the Northeast and upper Midwest, we have 300,000 cases a year, still heavily concentrated in those regions.

The white-footed mouse is the main reservoir for Lyme disease.

The white-footed mouse is the main reservoir for Lyme disease.

In 2011 Richard Ostfeld, a senior disease ecologist working at the Cary Institute in New York published an excellent book, Lyme Disease: The Ecology of a Complex System, aimed at a mixed readership of scientists and nonscientists. I've mentioned this before but should reiterate his finding that white-footed mice were a highly significant reservoir (host animal) for the bacteria that is then transmitted to humans by, in this country, one particular insect-like species, the black-legged tick.It's actually an arachnid, cousin to spiders and scorpions. There are other host species and a variety of predators, weather/climate conditions and habitat factors also play a role.

His work predicted a surge in cases of Lyme disease in the spring of 2012, based on an acorn crop boom-and-bust cycle. The town of Whitman, MA, published an online summary of this prediction quoting the Cary Institute's press release. In brief that mouse species' population soars in a year with an abundant acorn crop and falls markedly when acorns are scarce. The organism that causes Lyme disease is a bacterial species called Borrelia burgdoferi, The white-footed mouse is a superb host for that bug; the mouse doesn't get sick; the bacteria multiplies and there is an abundant supply of B. burgdorferi waiting to spread to other animals. Those mice are also frequently bitten by the tick in question, especially around their ears.

In the seasons of acorn abundance the mouse population soars and the ticks, which need a blood meal three times in their life span (once in the larval storage, once as a nymph and once as an adult), have plenty of mice to feed on.

But then comes a lean crop year for the acorns and the B. burgdorferi infected ticks have to find other blood sources for their next meal. Any mammal will do, but humans are certainly among those available. If we are camping or hiking through an area where the tiny tick nymphs or abound, we may never notice the bite. We may not even be wearing any  bug spray or perhaps have more skin exposed than is safest. The nymphs are cold-blooded, so the countryside has to warm up from Winter's blasts before they are ready to feed. If it's a milder cold season (and with global warming that may be the case), the nymphs may be out looking for a meal as early as April.

Forest ecologists from the Cary Institute noted 2010's crop of acorns was very heavy;  mouse population numbers rose appropriately. Then, in the fall of 2011, their research site had a marked acorn scarcity. Mouse numbers plummeted leading to a prediction from the group of at least 20% more human cases of Lyme disease.

Let's return to Dr. Plotkin's article in the New York Times. Eight years ago he almost lost an adult son to a cardiac complication of a Lyme infection. Alec D. Plotkin was walking his dog on an August day in Pennsylvania when he abruptly lost consciousness and collapsed. In 2011 his father (Dr. Plotkin) published an article, "Correcting a Public health Fiasco: The Need for a New Vaccine against Lyme Disease," in the Journal Clinical Infectious Diseases. At that time the yearly US case estimate was (reported cases only) roughly 20,000, but as Dr. Plotkin noted, "the extent of underreporting is unknown." He mentioned that the state of Connecticut's statistics would imply that 1% of its entire population could develop the ailment over a ten-year stretch and that nine of sixteen countries in Europe, where Lyme disease is caused by a different variant of B. burgdorferi, had data showing an increased case incidence over time.

But you may or may not have the pathognomonic rash.

But you may or may not have the pathognomonic rash.

On Septmeber 19, The New York Times published the obit of Dr. Stephen E. Malawista, who, as chief of rheumatology at Yale School of Medicine had, with his postdoctoral student, Allen C. Steere, defined Lyme disease. In the fall of 1975 two women from Lyme, CT and Old Lyme had developed joint swelling, peculiar rashes and neurological complaints undiagnosable by their local physicians. Each went to Yale seeking answers.

Researchers there noted that the clinical picture, which was originally felt to be juvenile rheumatoid arthritis, had occurred in clusters and at a rate 100 times that expected for JRA. It also was clustered in warm-weather months. Dr. Malawista suggested the name Lyme arthritis and he and his team made the eventual linkage with tick bites. In 1982 Dr. Willy Burgdorfer found the bacterium responsible and Yale scientists wnet to work to develop a vaccine.

It was finally licensed in 1998, but a series of events, detailed by Dr. Plotkin in his medical article, led to it being removed from the market four years later. In brief: the CDC's Advisorty Committee on Immunization Practices (ACIP) gave greater emphasis to protective clothing, tick repellants and, in the event of an infection, consistent early diagnosis and antibiotic treatment, than to the vaccine, even for those at high risk. Then it was only tested in adults and more in the group who got the vaccine than in the control group experienced some transient joint soreness...but not actual arthritis (typically red,hot, swollen, painful joints. The marketing of the drug was inappropriately directed at a lay, not a medical audience. A class action suit was brought against Glaxo, the drug company which produced the vaccine and, in spite of later studies showing no increase in Lyme-related joint disease, was settled by Glaxo for $1 million in 2003. Only the lawyers involved got any money.

By then the vaccine was off the market.

It's clearly time for it to come back, perhaps in a new version, perhaps developed by a different company, but, in any case a human Lyme disease vaccine is needed.

 

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Lyme disease: the battle continues

Wednesday, July 3rd, 2013
Stay away from ticks

Stay away from ticks

In April of 2012 I wrote a series of posts on tick-borne diseases. This is my 315th post so when the subject of chronic Lyme disease (called post-treatment Lyme Disease syndrome {PTLDS} by the CDC) came up in a well-balanced article in The New Yorker I needed to revisit what I had written 14+ months ago before I could determine if there was anything new on the subject.

It delineates the ongoing controversy which basically comes down to whether chronic Lyme disease actually occurs. Most academic physicians and organizations deny that this exists, but a large group of patents with a multitude of long-term symptoms have interacted with physicians who are willing to treat such an entity. They've formed an International Lyme and Associated Diseases Society who "argue that the traditional approach to diagnosis and treatment, put forth by most American physicians, all but guarantees failure."

A pamphlet from a group formed to fund-raise and increase awareness, the Lyme Action Network, is titled "It Might Be Lyme." The multitude of symptoms under this rubric is astounding as is the conclusion that years of (often intravenous and horrendously expensive) antibiotic therapy is needed to ensure a cure of the ailment.

The author of the New Yorker article was recently interviewed by Terry Gross on NPR. He comments that our current state of knowledge of the illness is incomplete, but notes that the symptoms of many of those who are said to have "chronic Lyme" are vague, commonplace and difficult to attribute to this disease when there are no positive tests and/or they don't live in region of the country known to have Lyme disease.

Let's start with a comment. I found only one medical article that shifted my point of view even a tad bit.

A research group headed by a Johns Hopkins-associated physician with infectious disease training published a study of patients with PTLDS symptoms in a journal I've never heard of before: Quality of Life Research.

His group enrolled 63 patients with the skin manifestation of Lyme disease and systemic symptoms (therefore people with pretty clear-cut diagnoses to fit the ailment) in a prospective cohort study. They followed this group and the control subjects for six months and saw each of them five times. After conventional treatment with a three week course of the antibiotic doxycycline all signs of Lyme disease went away, but after six months slightly over a third of the patents had new-onset fatigue, one fifth had widespread pain and 45% had neurocognitive problems (thinking issues that relate to a particular part of the brain).

This is the first article I've seen that prospectively followed patients with Lyme disease, but my caveats are: it was a small group (63 patients) with obvious Lyme disease and the followup period is relatively short.

I'd like to see a considerably longer prospective study of a much larger group.

Don't wait until the tick has finished its meal

Don't wait until the tick has finished its meal

The introduction to the article mentions that Lyme disease is caused by a spirochete bacteria (therefore a long, coiled member of the same family as the syphilis, but there hasn't been human to human spread that I'm aware of and of course, Lyme is not  a venereal disease). It is  the most common vector-borne (transmitted by a blood-sucking insect or arachnid (mites or ticks) infectious disease in North America. In 2009 nearly 40,000 cases were reported in this country, but most feel that there are likely at least 100,000 cases a year.

There are four other, less prevalent, illnesses that the deer tick vector can transmit, but funding for control of ticks is regarded as low especially when compared to that in Massachusetts for mosquito control in an effort to prevent other ailments, especially West Nile virus and eastern equine encephalitis.

Many academic physicians with infectious disease training feel strongly that Lyme disease should be treated with antibiotics for a month or less in most cases with an exception made for those who develop Lyme arthritis (who may require up to three months of treatment).

After realizing I hadn't done my due diligence, it was time to read lots of background material, including the article in The New Yorker. I downloaded the Kindle edition of Lyme Disease: The Ecology of a Complex System, a 2010 book written by Richard Ostfield, a Ph.D. field biologist.

This is a fascinating opus written from a different point of view, one of a scientist working at the Cary Institute of Ecosystem Studies, a private, not-for-profit in New York state with research focusing on the interactions among organisms that influence the risk of human exposure to vector-borne diseases.

Dr. Ostfeld outlines the natural history and ecology of LD and shows it is a much more convoluted ailment than I had realized. I had thought that the bacterium, the vector and the host were those I had read about, namely Borrelia burgdorferi, the black-legged tick and the white-footed mouse. But just focusing on the potential host species, chipmunks and shrews may carry the microorganism and the tick bites or tries to bite other animals, some of which are "less-efficient/competent reservoirs." So white-tailed deer and robins, depending on their abundance or lack thereof, may play a role in the likelihood of your catching LD, as may the terrain (e.g., densely forested versus subdivided into patches).

We had dinner recently with friends and one of the number was a physician who works for the CDC and has lectured extensively on Lyme disease. He feels quite strongly that the viewpoint of many of those who espouse long-term antibiotic therapy for LD is influenced by financial reward and that data is lacking to prove that this entity exists.

Allen Steele, the doctor who first discovered Lyme disease, now a rheumatologist at Massachusetts General Hospital, is the country's foremost Lyme disease researcher. These days he finds himself distrusted and sometimes harassed by those who feel Lyme disease often has chronic manifestations. A June 2, 2013 article in the Boston Globe highlighted the issue with its title "Drawing the lines in the Lyme disease battle."

I certainly don't agree with a fringe view  I found claiming that the LD bacterium was weaponized for bio-warfare.

At the end of my reading I side with the more traditional, academic view of Lyme disease. I think the other group has yet to prove its case.

 

 

 

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Tick-borne Disease part four: the chronic Lyme Disease controversy

Monday, April 30th, 2012

Sometimes you need an expert panel to resolve a controversy

A March 27, 2012, Wall Street Journal article, "This Season's Ticking Bomb,"predicted that the unusually warm weather most of the country has been experiencing meant we would also see many more cases of tick-borne diseases, If you click on the link, be sure to look at the section called "View Interactive" to get to a series of suggestions on reducing your family's risk of tick bites.

The article itself talked mainly about Lyme disease. There is an International Lyme and Associated Diseases Society (ILADS), but much of their Lyme disease website information was from 2006.  They are on one side of a major medical controversy, how to care for patients who have had Lyme disease and continue to have problems, especially with short-term memory, fatigue, or musculoskeletal issues, well after they have been appropriately treated with short-term antibiotics.

Two articles were published on this subject in 2007-8: the first one, "Chronic Lyme Disease: an appraisal"  is available online; the other, "A Critical Appraisal of Chronic Lyme Disease," appeared in the New England Journal of Medicine.

The real question is whether the bacteria involved, Borrelia burgdorferi, remains in the body of a patient after relatively short-term antibiotic therapy and if a considerably longer course of drug treatment is warranted. The ILADS says, "Yes" to both questions and refers back to a Harvard & Tufts study published in the Annals of Internal Medicine in 1994.

The most recent CDC online information states that 10 to 20% of those who receive standard therapy for Lyme disease will have some lingering symptoms. However they term this "Post-treatment Lyme disease Syndrome." I found that European cases of Lyme and similar diseases are usually caused by our Borrelia borgdorferi's cousins; data from that literature may not be relevant here.

In November 2006, the Attorney General of Connecticut (CAG) pushed the Infectious Disease Society of America (IDSA) into a detailed review of their Lyme Disease guidelines by starting an investigation to decide if they had violated existing antitrust laws. By April 2008, the IDSA and the CAG agreed to end the probe by convening a review panel, with members from Duke, the NIH, Dartmouth, the U.S. Navy, Baylor, Tulane and other centers, to decide if the original guidelines had been based on sound medical/scientific evidence and if they needed changes. An MD, PhD medical ethicist screened panel members for any conflict of interest. A public hearing was held to include other viewpoints. The Final Report of the Review Panel was published in April, 2010.

Some will think the decision ties their doc's hands.

It basically upheld the 2006 IDSA guidelines, but added 1). In some cases (non-pregnant adults or kids 8 or older who've had a tick of the Lyme-carrying species attached for 36+ hours in an area with high infectivity rate of ticks with B. burgdorferi), a single dose of doxycycline (if they have no allergy to this drug) may be given  if the tick was removed within 72 hours; 2). Antibiotics are appropriate for adults and children 8 or older with early, uncomplicated Lyme disease; 3).  "Reports purporting to show the persistence of viable B. burgdorferi organisms after treatment with recommended regimens for Lyme disease have not been conclusive or corroborated by controlled studies." and 4). "The risk/benefit ratio from prolonged antibiotic therapy strongly discourages prolonged antibiotic courses for Lyme disease.

And at the end of the report, they mentioned a disease I'd never heard of; I'll do some more reading and write about it later.

 

 

 

 

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tick-borne disease part 3: Vanilla Lyme

Sunday, April 29th, 2012

I'm finally ready to write about Lyme disease and will start with the basics; it results from the bite of a tiny tick and causes well over 20,000 cases per year in the US. It's most common in the North-East and the Middle-West, most frequently affects kids under 16 (especially girls--ticks can hide in long hair) and can be prevented (DEET to keep ticks away; post-hike "tick checks"); prompt antibiotic treatment is indicated if signs or symptoms/history suggest this entity.

you have to look closely

I'll save the controversy about post-treatment Lyme disease syndrome, AKA Chronic Lyme Disease, for another post as that issue deserves its own discussion.

We first heard about Lyme disease some years back when a relative was afflicted by a severe case of the illness. One of the best resources I've subsequently found on Lyme came from an emeritus at the place I got my formal medical training, the University of Wisconsin, now termed UW-Madison. Dr. Kenneth Todar, a PhD in the Department of Bacteriology, has a superb online textbook and his chapter on Lyme Disease is an extremely helpful reference.

The initial realization of the disease itself happened thirty-seven years ago. The website for NIAID, the National Institute of Allergy and Infectious Diseases has a great, though somewhat convoluted, detailed history of Dr. Willy Burgorfer's isolation of the spirochete bacteria that would eventually be named for him.

In brief, there had been a 1975 outbreak that resulted in a considerable number of children living in or near the town of Lyme, Connecticut, being diagnosed with juvenile rheumatoid arthritis. The Yale physician looking for the cause of these Lyme disease cases realized most occurred in children who spent time in wooded areas and whose initial symptoms occurred in the midst of the tick season, summer. He thought the deer tick might be involved and, eventually, Dr. Burgdorfer  found the spirochetes in deer ticks sent to him from the affected area.

IDSA,  the Infectious Disease Society of America, has a one-pager titled "Ten Facts You Should Know About Lyme Disease" and the New York Health Department has a similar short discussion of Lyme Disease.

one example of a typical rash

To reiterate the concepts I think are crucial:  the groups involved, kids under 16 with more girls than boys, plus adult men;. the areas of the country: 93% of cases occur in ten states: Connecticut, Delaware, Maryland, Massachusetts, Minnesota, New Jersey, New York, Pennsylvania, Rhode Island and Wisconsin; the fact that early diagnosis is clinical (antibodies develop later); the tiny size (two mm) of the tick nymphs which usually are the agents for transmission of the bacteria; the difficulty in diagnosis unless the characteristic rash is present; and the need for prompt antibiotic treatment in prevention.

Symptoms begin to show anywhere from a few days to a month after the bite, but, in most cases, the tick itself has to remain attached for a day and a half to transmit the bacteria and there is no person to person spread of this disease. Early signs, in the absence of the characteristic rash, are very non-specific.

There is a sizable percentage of patents with Lyme who have long-term sequelae. I'll write about them next time.

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Tick-borne diseases: part one: Colorado ticks and related diseases

Saturday, April 21st, 2012

a well-fed tick

The Wall Street Journal recently published an article titled "This Season's Ticking Bomb,"  discussing the rise of tick-borne diseases, especially focusing on Lyme disease. It said two factors have been important contributors to this global trend: people have moved into turf harboring animal species which often carry ticks and, simultaneously, some kinds of those animals, e.g., squirrels, deer and mice, have increased their numbers.

I must confess I haven't worried much about Lyme disease since our 1999 move to Fort Collins, Colorado, where our back porch is at an altitude of 5,206 feet. Then I found an online 2012 fact sheet from Colorado State University; its subject, "Colorado Ticks and Tick-borne Diseases" gave me pause until I read, "No human cases of Lyme disease have originated in Colorado."

I was amazed to find that ticks here are especially common at higher altitudes; I would have guessed the opposite was true.

We have two species of Colorado ticks that are most relevant to humans: the American dog tick and the Rocky Mountain wood tick. They are three-host blood-feeding parasites, moving from rodents or other small mammals to dogs or deer typically and then, when available, on to human hosts. We're more likely to encounter them in spring or early summer on paths through grassy areas or the brushy zones near the edges of field and woods.

I initially was concerned about the risk of Rocky Mountain spotted fever (RMSF), but it's actually fairly rare here and most common in North Carolina, Oklahoma, Arkansas, Tennessee and Mississippi. From 2,000 to 2,500 cases occur a year in the US with those five states accounting for 60%. They see 19 to 77 cases a year per million while Colorado has 0.2 to 1.5 cases per million. The CDC webpage on RMSF notes the overall incidence of the disease has gone up considerably since 1920, but the fatality rate has plummeted. But in eastern Arizona, through 2009, over 90 cases were noted in a previously RMSF-free area. Ten percent of those who developed RMSF died and there was a marked association with communities with free-roaming dogs.

Colorado Tick fever is seen more frequently in my state than any other infection related to tick bites. It's a viral disease with up to 15% of our campers being exposed, but is not as serious as many other tick-bite-caused illnesses. It usually goes away without causing complications, but 5-10% of those infected with the virus can develop encephalitis, meningitis or, rarely, hemorrhagic fever. Children are more prone to severe acute disease and more likely to have the nervous system complications, but most kids who contract this illness get well quickly. About 70% of adults over 30 may have prolonged symptoms.

make your body a no-tick zone

Half of those who develop Colorado tick fever have a so-called "saddle-back" temperature curve with initial fever then normal temperature followed by a single fever recurrence.

 I'm in the prime zone for this disease; it normally occurs in those living or traveling to altitudes of 4,000 to 10,000 feet. So it's important for me and others living or visiting here to wear protective clothing, use DEET as a tick repellent, do a "tick check" after a day outdoors and, if any are found to remove them properly with blunt tweezers.

 

 

 

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