Duration of tickfeeding before removal on transmission of Bb

Topics with information and discussion about published studies related to Lyme disease and other tick-borne diseases.
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inmacdonald
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Re: Duration of tickfeeding before removal on transmission o

Post by inmacdonald » Fri 28 Sep 2012 4:06

Dressage - Fancy equine footwork and the ability to avoid tripping over the hurdles.

Spanky JD. time line for onset of Borreliosis post Ixodid tick attachment to human skin, IDSA dogma restated 36 hours from attachment to disease transmission :::these corrections are gratefully acknowledged. Is the New IDSA ( year 2006) dogma correct inyear 2012? I think not.

My Revised post still raises issues of "accelerated" transmission of Borrelia infectomes ( a la Spielman 1993)
first raised as a discussion thread in year 2007, abandoned for 5 years, and re-activated for forum
consideration by Carina in Year 2012.

The spirit of the original Thread remains vital today , as it was in 2012. Not a question of how long by the stopwatch does it take for a competent vector of Bb to transmit Borreliosis to the human host;
but rather how SHORT an attachment results in transmssion of Bb from a competent vector to the human host. By any historical perspective, the time interval for "acccelerated transmission" [ of Spielman} has decreased dramatically since year 2007.

The time duration from Ixodid tick attachment to the appearance of Erythema migrans
has Shrunk appreciably in the interval 2007-2012.
The time duration of tick atachment to human infection of the erythema migrans NEGATIVE type
with disease disssemination to diverse organ systems remains unknown.


Evidence from current laboratory and clincal observations nullifies
long held beliefs. These must yield to new evidence with more sophisticated methods.

Best,
A

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Spanky
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Re: Duration of tickfeeding before removal on transmission o

Post by Spanky » Fri 28 Sep 2012 7:11

"inmacdonald":
Is the New IDSA ( year 2006) dogma correct in year 2012? I think not.
Well, I am of the opinion that "I think not", probably isn't good enough... so...you might want to roll up your sleeve, there...

But if you look at that section of the Guidelines that deals with the issue, the 36 hour statement, you will notice that it does contain citations to studies on which the statement is based. So, again, unless you are somehow able to dismiss the applicability of those studies as not standing for the principle stated, then...better roll up the sleeve.

You are the one saying that is wrong...that means you have the affirmative and the burden of proof.

In other words, theories and "I think" are nice and all...but prove it.

And there was a nice statement of the general principle contained in this thread previously, ironically, by someone who was intending to to supply material arguing for a shorter time period:
Infect Immun. 2003 December; 71(12): 6943–6952.
doi: 10.1128/IAI.71.12.6943-6952.2003
PMCID: PMC308935

Temporal Analysis of Borrelia burgdorferi Erp Protein Expression throughout the Mammal-Tick Infectious Cycle
Thus, it appears that during the first day or two of feeding, either very few bacteria are transmitted and are readily eliminated by the immune systems of most hosts or most of those bacteria transmitted are physiologically unable to establish disseminated infection.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC308935/

My impression has always been that the odds of contracting Lyme increase in relation to the length of time of attachment. To the extent that I have bothered with any of this, my impression was always that there was general agreement on that score. And mere transmission of some bacteria may not cause disease, as noted in the quotation, above.

So, it would seem that those that want to argue for a shorter time period are really arguing against the probabilities...(and I have never understood why this is such an issue for some).

ChuckG
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Location: Berkeley

Re: Duration of tickfeeding before removal on transmission o

Post by ChuckG » Sat 29 Sep 2012 1:53

They had the tick. 14 hours. Table 1. Convalescent serology is interesting.

http://jid.oxfordjournals.org/content/1 ... 6.full.pdf

The Journal of Infectious Diseases 1997;175:996–9
1997 by The University of Chicago. All rights reserved. 0022–1899/97/7504 – 0044$01.00

Duration of Tick Attachment as a Predictor of the Risk of Lyme Disease in an Area in which Lyme Disease Is Endemic

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Spanky
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Re: Duration of tickfeeding before removal on transmission o

Post by Spanky » Sat 29 Sep 2012 2:53

"ChuckG":
They had the tick. 14 hours. Table 1. Convalescent serology is interesting.
Well, yeah, but aren't we talking about the general rule?

The probability of contracting infection as a function of time of attachment?...and not suggesting that infection is absolutely impossible in shorter timeframes?

Seems that they acknowledge that possibility here:
As some infections will occur following tick attachment of a short duration, patient observations and education for development of symptoms of Lyme disease after any deer tick bite are necessary.
While noting the general findings, rule, here:
The incidence was significantly higher for
duration of attachment >72 h than for <›72 h: 3 (20%) of 15 vs. 1 (1.1%) of 94 (P  .008; odds
ratio, 23.3; 95% confidence interval, 2.2–242). PCR was an unreliable predictor of infection. Tick
identification and measurement of engorgement can be used to identify a small, high-risk subset of
persons who may benefit from antibiotic prophylaxis.
http://jid.oxfordjournals.org/content/1 ... 6.full.pdf

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