Friday, August 12, 2011

7 Tracking Lyme Disease in Dogs May Help Protect Humans: MedlinePlus

For the study,  a team led by Dr. Paul Mead, a CDC medical epidemiologist, used data from 46 states on human and canine Lyme disease prevalence.

Comparing the data, Mead's team found that when 1 percent or less of the dogs tested positive for Lyme disease, the risk of people becoming infected was low. However, when more than 5 percent of the dogs were infected, the risk to people was high.


Read More Here: Tracking Lyme Disease in Dogs May Help Protect Humans: MedlinePlus


Comment:

This is the kind of low cost surveillance data I think should have been collected all along - and let the vets do the data collection and reporting. I think it makes sense to use dogs to determine potential risk to humans because dogs roam around more and get in the tall grass - they go where the ticks are whereas people try to stay away from them. I consider a dog another potential piece of dragging white flannel flag.

7 comments:

  1. Hi Camp:

    Love your work, thanks! However, this report comparing canine/human cases? While studies like this could be good, this one is quite troublesome. You and your readers may want to read our article:

    Dogged by Discrepancies:
    The New CDC Lyme Disease Report Comparing National Canine and Human Cases

    © Georgia Lyme Disease Association, September 2011

    The CDC’s new report, Canine Serology as Adjunct to Human Lyme Disease Surveillance (Mead P, Goel R, Kugeler K.; Emerg Infect Dis. 2011 Sep.) attempts to define areas of human Lyme disease risk by correlating dog and human cases across the United States. While the concept is good, the conclusion is, unfortunately, based on flawed and subjective data.



    First, the test used to detect Lyme borreliosis in the national dog study was the C6 ELISA. Last year, a well-known researcher on the CDC's own Lyme disease diagnostic recommendations committee confirmed that, while the C6 may be specific for particular Lyme borrelia strains, it doesn't seem to detect others. Secondly, although the authors admit reporting practices may be subject to bias, they then go on to rely on human case numbers reported to the CDC for comparison. What they fail to point out are the major inconsistencies known in Lyme disease surveillance procedures among states. Statistical data are rendered useless when what is counted as a reportable Lyme disease case in some regions is routinely dismissed in others.



    Can true risk of Lyme disease really be assessed based on such data? The report sure doesn't jibe with what we hear from patients.

    See our website home page to read full article - GeorgiaLymeDisease.org

    Thanks, Camp O!

    Liz
    President
    Georgia Lyme Disease Association

    ReplyDelete
  2. Hi Liz,

    Welcome to Camp Other blog, and thank you for your comment.

    Thank you for pointing out more about the specifics of the research - I hadn't dug deeply into this one and was passing it on on general principle, because I think looking at canine surveillance can be a good indicator for where human cases can crop up.

    My best guess is that dogs are tested for Lyme disease more often than humans for a variety of reasons, and the controversy over human cases doesn't seem to extend to dogs. However, if the tests aren't accurate enough to pick up all strains of Bb, then the prevalence of the disease is not being accurately measured. This can be a bigger problem in the south, where (I think I read this in the Institute of Medicine tickborne illnesses workshop summary report) there is much greater genetic diversity of Borrelia burgdorferi. So using dogs to determine where human cases may crop up in the south might not work as well as it would in other areas.

    This is problematic - as is testing for Lyme disease in humans overall. And the issue with "Lyme-like" illness is that once it is "Lyme-like", it technically might not be Lyme disease for surveillance purposes, but relapsing fever instead. I think Borrelia lonestari is now being classified as a relapsing fever Borrelia strain, and I don't think it shows up on a standard ELISA or WB for Lyme disease - yet the symptoms are similar. I think Borrelia miyamotoi is another relapsing fever strain which brings up similar issues.

    It is problematic, too, that genetically relapsing fever Borrelia have great overlap in genetic identity to Borrelia burgdorferi sl, and I think there has been some research done to determine whether or not they could exchange genetic material. (I don't recall the outcome, would have to reexamine that.) But even if we set that aside, there is gene transfer and changes going on within the Bb that is responsible for Lyme disease, and this variation makes it harder to pick up during testing.

    In the northeast, over 50% of the people infected with Lyme disease in one huge study had the same strain with the same high virulence (Type C- A). Then after that, there were 3 strains which were seen. It didn't fall out into a lot of weird substrains. I think that in order to standardize tests - or attempt to - researchers try to get an aggregate of the most common types found into tests so they can find the highest number of cases. But what do you do about outliers? What about someone who doesn't fall into this category? What if some poor soul has lonestari, and it isn't showing up on the test?

    This is why Lyme disease and other Borrelia infections have been detected using clinical diagnosis, and serology is supposed to be additional data. A good medical detective should know what to look for in terms of history and presentation.

    Until we have more specific tests that Luft's research can help develop, I don't know how to improve this situation other than to try to come up with stricter reporting requirements for dogs and humans across the country - and to somehow standardize it and make sure more probable reports are made even if serology isn't clear but the clinical diagnosis reflects presence of Lyme disease.

    ReplyDelete
  3. Thanks for the welcome, Camp!

    I agree that relapsing fever is different and the illness shouldn’t be counted as a Lyme disease case. But the belief that southern Lyme disease is due to Borrelia lonestari is a common misconception. This was never proven. The CDC discarded the idea of the relapsing fever spirochete, B. lonestari, being the causative agent of our so-called, "Lyme-like illness" in the South. They only found B. lonestari in a single patient with an EM (who could have also been infected with Bb). CDC officials further confirmed that B. lonestari isn’t the culprit by email and on their website (although, the word doesn't seem to be reaching many state officials who continue to list B. lonestari as the causative agent of "STARI"). Our symptoms cannot be attributed to this.

    (By the way, Southern Tick Associated Rash Illness, or STARI, is inappropriately named. Lone star tick vectored Lyme disease was documented in the northern state of New Jersey back in the late 1970’s. In a four year study, the majority of ticks found in a New Jersey area during peak Lyme season were lone star ticks; less than 1% were “deer” ticks (during May, June and July). This makes it likely that numerous Lyme cases counted in the North are vectored by the lone star tick. A Canadian reported he contracted Lyme disease from a female lone star tick in 2004.)

    You have a good memory! Yes, the southern U.S. has far more diverse strains of Bb than thus far identified in the Northeast. Some scientists believe this fact suggests that Bb was in the South first and traveled north. Georgia Southern’s Dr. Jim Oliver has 275-300 southern strains of B. burgdorferi in the Institute of Arthropodolgy and Parasitology lab. Some are nearly identical to the B31 strain, most are a bit different. Two new species of Borrelia burgdorferi have been identified here - B. americana and B. carolinensis. It's currently unknown whether these are pathogenic. We have B. bissettii documented in the South and it's recently been implicated as a pathogen by Czech scientist Rudenko. (con’t)

    ReplyDelete
  4. Borrelia burgdorferi has been documented in lone star ticks for years. Many symptomatic southern patients do test positive for Lyme disease, including after lone star tick bites. Some have western blots positive by CDC criteria; as in the northeast, others show only a few positive bands that may or may not be specific for Bb. It is hard to determine whether this is due to individual immune system response or if these people may be infected with another Bb strain or species without changing the western blot criteria to match antigens from these specific strains/species. They may also have other borrelia and/or tick-borne infections.

    Researchers report that ticks in the South may transmit one or more of over a dozen illnesses, yet often medical providers only seem to be familiar with Rocky Mountain Spotted Fever. (Why isn’t tick-borne disease scientific research reaching medical professionals?)

    Although it is often reported that so-called STARI is "mild", there have never been any long-term, broad scale studies proving this. Southern Lyme patients have symptoms identical to Lyme disease, including swollen joints, fatigue, myalgias, arthralgias, arthritis, cardiac problems, bell’s palsy, and other neurological symptoms. Many suffer with chronic illness. CDC officials agree there's no research to support the "mild presentation" assumption. Conversely, we see some lone star tick bite patients who end up in wheelchairs after only a few years of their untreated erythema migrans rashes. Many are erroneously told, "We don't have Lyme disease in the South” and are denied proper treatment.

    Numerous people across the South report they test positive for Lyme and have all symptoms but are told their tests are "false positives". Cases are not reported, but are dismissed due to this myth that Bb isn’t endemic. For years, Georgia and other states did not use national reporting guidelines, making it literally impossible to determine true prevalence and causing doctors to think it’s rare. It’s a true problem, one that must be addressed so patients may be diagnosed and treated properly. (Con’t)

    ReplyDelete
  5. Switching gears to address dogs: except in “endemic” areas, I’m not sure if I think dogs may be tested more often than humans since animals cannot tell us when they feel bad. An engorged tick fell off my dog in fall 2010. She seemed slightly fatigued but I didn’t truly consider Lyme until this summer, while walking in the yard, she collapsed on her side twice. Because we (at Georgia Lyme Disease Association) get reports from hundreds of Georgians claiming they are infected with Lyme and I was infected here 20 years ago, I took the dog to the vet to request a LD test. (The vet said, “The CDC says we don’t really have the right ecological environment to have Lyme disease in the South.” Many patients inform us that Georgia physicians recite this same line, despite the fact that we absolutely do have the correct cycle – we have the white-footed mouse and several other competent reservoirs, Ixodes scapularis ticks, and Bb has been identified in thousands of tick, animal and human specimens from across the South for over 20 years.) I insisted on the test. It was NOT a C6. My dog has Lyme disease (+ IgG antibodies, which are far more unlikely to be a “false positive”). She’s never traveled outside the southeastern U.S.

    “This is why Lyme disease and other Borrelia infections have been detected using clinical diagnosis, and serology is supposed to be additional data. A good medical detective should know what to look for in terms of history and presentation.”

    Camp, the words you wrote above ring so incredibly true. Medical providers should be looking for Lyme disease and other tick-borne illnesses in humans in every part of the country.

    Keep up the GREAT work!

    Liz Schmitz
    President
    Georgia Lyme Disease Association

    ReplyDelete
  6. Liz,

    Getting back to your comment a bit late here -- sorry, I've been a bit preoccupied with real life lately and not online as much:

    You said,

    " But the belief that southern Lyme disease is due to Borrelia lonestari is a common misconception. This was never proven. The CDC discarded the idea of the relapsing fever spirochete, B. lonestari, being the causative agent of our so-called, "Lyme-like illness" in the South. They only found B. lonestari in a single patient with an EM (who could have also been infected with Bb). "

    I agree, and my statement about lonestari wasn't specifically aimed at the south when I wrote it -- I was thinking of lonestari in general. Both lonestari and miyamotoi may not show up as positive on a standard Lyme disease blood test, so it's important for everyone to consider them as a potential source of infection and not just Bb.

    I knew lonestari was found in NJ ages ago, and I wonder to this day how many people have lonestari or some other non-Bb strain of Borrelia who are ill and need treatment but do not receive it. Having a Borreliosis where there is no rash makes early diagnosis (and subsequent treatment) all the more difficult. Yet this is something all doctors need to be aware of in their practices.

    You said,

    "We have B. bissettii documented in the South and it's recently been implicated as a pathogen by Czech scientist Rudenko."

    I know about B. bissetti. It's in the south as well as in California. Apparently B. bissetti was found in CA during studies on samples from Lyme disease patients from a number of years ago. The B. bissetti from California is 97-100% genetically similar to the B. bissetti strains 25015, DN127, and 96... There is also B. bissetti from California that is 96-98% similar to those found in Czech Rebublic patient sera.

    I think ticks sightseeing on birds are responsible for this diversity.

    You said,

    "Numerous people across the South report they test positive for Lyme and have all symptoms but are told their tests are "false positives". Cases are not reported, but are dismissed due to this myth that Bb isn’t endemic."

    How do they determine the difference between a false positive and a false negative, though? Some of the false positives are also for conditions which require antibiotic therapy anyway - like syphilis (I doubt many people have this so much any more, but still, antibiotics can treat it) and Ehrlichiosis. If I were in a doctor's shoes, I would rather play it safe than sorry if I have a sick patient in front of me. There are a few viral conditions that can throw false positives, but if the patient in front of me has symptoms consistent with Lyme, I'd be considering and treating that.

    (more)

    ReplyDelete
  7. (For Liz - more)

    You said,

    "[...] I’m not sure if I think dogs may be tested more often than humans since animals cannot tell us when they feel bad. An engorged tick fell off my dog in fall 2010. She seemed slightly fatigued but I didn’t truly consider Lyme until this summer, while walking in the yard, she collapsed on her side twice. "

    My main point with this is that if dogs are lame and their behavior changes, vets do not go around telling them they are depressed or perhaps their symptoms are "all in their heads". Dogs tend to get believed more than humans have been, for whatever reason. And that is one reason why I wonder if carefully mapping where dogs which got infected picked up ticks may be a useful surveillance tool.

    Useful to a point though - it has its limitations. I think it may be even more useful to somehow more closely track bird migration patterns and begin de-ticking more birds and testing those ticks for bacteria, viruses, and parasites.

    "Medical providers should be looking for Lyme disease and other tick-borne illnesses in humans in every part of the country. "

    Yes. Especially now that it's clear birds contribute to the spread of new infections. Everyone has to be made more aware of these infections, especially doctors. The concept of "limited endemic area" is outdated. I think we have a good starting point on knowing which infections are out there, but it's hardly the entire picture. It's more like a guideline based on whatever surveillance has been done, and even then, due to budget cuts there has been less (and less recently completed) surveillance so we can't look to these maps as being totally accurate.

    ReplyDelete

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