Travel History

Medical topics with questions, information and discussion related to Lyme disease and other tick-borne diseases.
Post Reply
hv808ct
Posts: 256
Joined: Wed 30 Jul 2008 4:11

Travel History

Post by hv808ct » Fri 18 Sep 2015 15:06

Joseph D. Forrestera. Epidemiology of Lyme disease in low-incidence states. Ticks and Tick-borne Diseases 6 (2015) 721–723.

Our analysis revealed that over 80% of cases in the low-incidence states studied were associated with recent travel to a high-incidence state. Notably, these cases had similar epidemiologic characteristics to cases from high-incidence states, with a slight male predominance and bi-modal age distribution. In contrast, cases in patients without travel-related exposure occurred predominantly among females aged 30–59 years; epidemiologic characteristics that are different than those expected based on the epidemiology of Lyme disease patients as a whole. While the diagnosis of patients with compatible clinical features and recent travel to high incidence areas is relatively straight forward, patients without a travel history pose a diagnostic dilemma for the health care provider in a low incidence area. The situation is complicated by the predictive value of both clinical features and laboratory testing in a low pre-test probability setting. In this setting, the negative predictive value of testing is quite high; if a patient’s test is negative it almost certainly means that the patient does not have Lyme disease. Conversely, a positive test has a low predictive value, meaning that even patients with a suggestive skin lesion or positive serology may be misdiagnosed with Lyme disease.

The importance of obtaining a travel history cannot be overemphasized since it allows providers in low-incidence areas to recognize patients at higher risk of disease.

…when evaluating surveillance data, cases detected in low-incidence areas do not necessarily correspond to endemic transmission of Lyme disease and should be evaluated carefully. Tests that have not been validated by the U.S. Food and Drug Administration should be avoided, as these may increase the chance for misdiagnosis.

Clinicians and public health professionals should strongly consider the possibility of misdiagnosis of Lyme disease without travel-related exposure in low-incidence states, helping ensure that patients with other illnesses are appropriately diagnosed and patients with true Lyme disease receive appropriate antibiotic therapy.

duncan
Posts: 1370
Joined: Wed 5 Sep 2012 18:48

Re: Travel History

Post by duncan » Fri 18 Sep 2015 15:32

Is this another study that alludes to a lack of confidence in the 2T system?

What do they meany by "health care provider"?

dlf
Posts: 294
Joined: Sun 7 Apr 2013 15:36

Re: Travel History

Post by dlf » Fri 18 Sep 2015 18:36

Thanks hv808ct for providing a few details from the article. The abstract is quite devoid of them. I am posting a link to the pubmed listing mainly because the list of authors on this is lengthy and notable. Forrester was not the only author.


Ticks Tick Borne Dis. 2015 Jun 12. pii: S1877-959X(15)00112-0. doi: 10.1016/j.ttbdis.2015.06.005. [Epub ahead of print]
Epidemiology of Lyme disease in low-incidence states.
Forrester JD1, Brett M2, Matthias J3, Stanek D3, Springs CB4, Marsden-Haug N5, Oltean H6, Baker JS7, Kugeler KJ8, Mead PS8, Hinckley A9.
http://www.ncbi.nlm.nih.gov/pubmed/26103924


duncan, I think the answer to your first question is yes.

However, similar to the Lantos study about 80% of the patients in a low transmission area with positive serology being false positive, this one also seems to allude to much more than a comment on two-tier serology. Given the authorship it might allude to much more.

Could it be a way of limiting recognition of the further emergence and expansion of Lyme into broader and new areas?

Could it be a justification for the CDC to change the U.S. surveillance definition of endemicity and the case definitions so that any emerging areas could no longer be determined from statistics derived from cases?

If so, does that mean that they want to move to a very costly form of surveillance requiring tick and small mammal confirmation before any human cases are recognized, thereby ensuring very few new areas will be acknowledged due to lack of resources for this surveillance?

Could it be a way of dismissing any and all species and strains of Borrelia that are non-reactive to BB strain B31 as a potential cause of illness?

Are they trying to reinforce the advice that further limits physician acceptance for high-complexity testing performed in CLIA licensed laboratories?

Could it be a way to inject an enormous level of uncertainty into each and every diagnosis of Lyme disease being made?

Given the general lack of knowledge among physicians about Lyme and other tick-borne diseases in areas of historically low transmission due to lack of experience and expertise, are they trying to ensure that cases that don't conform exactly to Steere's disease model can't be diagnosed as Lyme?

Are they trying to ensure that the population of patients suffering from undiagnosed borreliosis spend a lifetime dealing with increasingly complex chronic illness, thereby putting a very large strain on health care and public resources?

Are they sending a conflicting message to physicians that they need to employ vigilance in diagnosis, when most patient visits are limited to 5 minute appointments pretty much assuring that the patients will be dismissed with the standard, "I don't know what you have, but it definitely isn't Lyme"?

Lots of questions, but for the most part this series of articles that have come out recently seem to ignore one very big factor.

Although not yet being recognized for increased prevalence for human cases, areas of historically low transmission are highly unlikely to remain areas of low transmission. In fact since 2011, in some areas the jump in cases in another population has grown exponentially.

Incidence of Lyme in our furry canine companions has grown year by year. Yet human studies that are currently being published are based on information that is at least five to ten years old.

http://www.capcvet.org/parasite-prevalence-maps/

You can check your state and any others for yearly incidence. As an example (a gift for Dr. Lantos, if he is still occasionally looking on the site) , here are the yearly figures for North Carolina and specifically the incidence in Durham where Duke U. is located. The 2015 figures are only year to date. The others are for the full year. Looks like 2013 and 2014 were landmark years.

North Carolina 2015 (year to date) 3016 dogs positive (1 out of 47 dogs tested) Durham 140 (1 out of 48 dogs tested)
North Carolina 2014 - 3570 dogs positive (1 out of 46 dogs tested) Durham 171 (1 out of 55 dogs tested)
North Carolina 2013 - 2119 dogs positive (1 out of 51 dogs tested) Durham 125 (1 out of 57 dogs tested)
North Carolina 2012 - 630 dogs positive (1 out of 68 dogs tested) Durham 30 (1 out of 90 dogs tested)
North Carolina 2011 - 554 dogs positive (1 out of 62 dogs tested) Durham 13 (1 out of 63 dogs tested)

duncan
Posts: 1370
Joined: Wed 5 Sep 2012 18:48

Re: Travel History

Post by duncan » Sat 19 Sep 2015 13:37

Dogs are the canaries in the coal mines. Sadly, children are, too - children in every state and every country. They are the ones most likely to play amid the tall grasses and run through the underbrush and leaves.

In lieu of children stats - since even if they are available, claims of false positives seem suddenly at-the-ready - I would think any TBD researcher would take very seriously those canine infection rates, and use them as a barometer of sorts.

Post Reply