Publication: Profiling disease burden and Borrelia seroprevalence in Canadians with complex and chronic illness
Open access: click here for free download
Authors: Victoria P. Sanderson, Jennifer C. Miller, Vladimir V. Bamm, Manali Tilak, Vett K. Lloyd, Gurpreet Singh-Ranger, Melanie K. B. Wills
Short summary
Participants experiencing a range of complex and chronic illnesses, including Lyme disease, autoimmune, and rheumatic conditions, were recruited from Atlantic Canada. They provided a blood sample and filled out standard questionnaires that asked about their symptoms, health-related quality of life, and functional restrictions or impairment. We then performed the conventional Lyme disease laboratory test (Borrelia IgG and IgM two-tiered serology) on the blood. Using the lab results and health data, we compared groups of participants looking for patterns or trends.
Major findings:
Participants reporting a diagnosis or suspicion of Lyme disease were profoundly affected across many domains of health-related quality of life.
Lyme-identifying participants were difficult to distinguish from other chronic, complex health conditions based on standard survey responses.
Laboratory testing for Lyme captured some, but not all, participants with confirmed or suspected Lyme disease.
Some participants with no known history of Lyme disease also returned positive Borrelia serology.
Borrelia seropositivity across complex and chronic disease cohorts was ~10%.
Aside from Lyme, the most common diagnosis associated with positive serology was fibromyalgia syndrome.
Deeper Perspectives
Who: This was a collaborative, international effort involving healthcare, research, and commercial diagnostic sectors, spearheaded by the G. Magnotta Lab at the University of Guelph and bolstered by the Lloyd Tick Lab at Mount Allison University. Participants attended a clinic in New Brunswick to meet with the study physician and donate blood samples. Galaxy Diagnostics (NC, USA) performed Borrelia serology, and all data analysis was done at the University of Guelph.
Study Workflow. (Generated by BioRender)
Why: On its own, this study provides an interesting snapshot of complex and chronic illness and Borrelia exposure in Atlantic Canada. However, it is also part of a bigger initiative at the G. Magnotta Lab to develop better diagnostic tools for Lyme disease. An important component of that research is having well-annotated cases so that we have a frame of reference for new techniques and developments. Profiling disease presentations and conventional test outcomes (serology) is key to that objective. In parallel, our lab is working to validate biomarker reservoirs and novel technological platforms which may be the basis for improved diagnostic tests. Eventually, they will be tested with participant specimens.
In the meantime, we can learn a lot using the questionnaires and tests that are already available. For example, many studies focus on the early stages of Lyme disease (tick bite, rash development etc.), but we were interested in the experiences of people with longstanding illness. People with lengthy and complex medical records often have more than one diagnosis (or “comorbidity”), which some studies try to exclude. Again, we were intent on capturing ‘real world’ experiences of people living with these conditions, so we did not restrict enrollment to straightforward cases. While this can make data analyses more challenging, it is more authentic. And let’s not forget that Canadians are not well represented in biomedical studies of Lyme disease. Most of what we know has emerged from the United States and Europe. There can be important differences in pathogen strains between regions that influence the accuracy of the tests, and how we experience disease, and we won’t have a better understanding of this unless we study it.
What we found:
Chronic and complex diseases were difficult to distinguish.
This is not a new finding, but it does underscore the challenges faced when trying to correctly identify diseases and offer appropriate care. This is especially true with conditions like fibromyalgia, myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS), and now long COVID that lack unique objective biomarkers*.
When we looked at participants who were positive for Borrelia IgG, approximately half of them had a diagnosis or suspicion of Lyme disease when they entered the study, and half did not. We could not tell the two groups apart based on their responses to the health questionnaires – they had clinically similar disease presentations as far as our survey results were concerned. The only feature that seemed to distinguish the seropositive, presumptive-Lyme group from seropositive “all other diseases” group was a reported history of tick bite or rash. Multisystem symptoms in the absence of early objective markers - bite or rash - were less likely to be attributed to Lyme disease.
*Studies are identifying biological abnormalities in these diseases, however there are no validated diagnostic tests available to the general public at the time of this writing.
10% of our chronic and complex illness study cohort was positive for Borrelia antibodies. Seroprevalence studies, which screen people for antibodies to Borrelia, can give an indication of pathogen exposure in a population of interest. This type of analysis has rarely been conducted in Canada. In our case, we focused on a broad spectrum of chronic illness, however it would be very interesting to perform baseline seroprevalence on the general population in same regions of New Brunswick where our participants reside. The few studies that have attempted to analyze seroprevalence in the Canadian Maritimes found a much lower number (only a fraction of 1%!) (1). By comparison, ~10% of the population is estimated to have Borrelia immunoreactivity in endemic regions of the United States (2).
The important caveat is that serology can’t tell us whether these are active infections, or past exposures to the Lyme pathogen that remain in the immune system memory. (This is one of the reasons that we are focused on developing new types of diagnostic tests.) Positive serology doesn’t necessarily mean that all the conditions and symptoms the participants reported are caused by Lyme disease. Likewise, negative serology doesn’t rule out Lyme disease. Studies from the United States that followed patients from the early, objective signs and symptoms of Lyme disease through a standard treatment regimen found that ~40% failed to seroconvert, or become positive on the diagnostic test (3). The authors concluded that seropositivity was not a reliable criterion for determining whether someone has post-treatment Lyme disease.
In addition to the known limitations of serology, we had further indications that it wasn’t working very well on our cohort (see below).
Serology test tiers did not align well.
The industry standard lab diagnostic for Lyme disease at the time this study was conducted used two different tests (“tiers”) to measure an individual’s antibody (immune) response to the Borrelia pathogen. The first test (an ELISA = enzyme linked immunosorbent assay) is like a screening assessment. The second test (a Western or immunoblot) adds specificity by looking for a set of bands that indicate that the immune system has reacted to several different parts of the bacteria. According to CDC (Centres for Disease Control) criteria, the two tiers need to be interpreted together to arrive at an overall result of positive or negative. In our study cohort, a number of participants were positive on only one tier (either the ELISA or the Western blot, but not both). While some degree of drop-off is expected between the first and second tier, ours was much steeper than the values that have been published for American samples. (Typically, other studies have found 60%+ agreement between Tier 1 and 2 4, while ours was ~25%). The same phenomenon of low agreement was previously reported by a different Canadian group (5). This might suggest that the tests are underperforming in a Canadian population, possibly due to differences in pathogen strain.
What’s next:
Our study emphasizes the difficulty in identifying Lyme disease based on clinical presentation or conventional laboratory testing. The G. Magnotta Lab is working on new strategies to directly detect the pathogen in humans that will not rely on the immune system for an indirect readout of infection. A direct detection platform should report active infection so that cases of Lyme disease will be better diagnosed, monitored, and managed in Canada and globally.
References
1. Hatchette, T. F. et al. Epidemiology of Lyme Disease, Nova Scotia, Canada, 2002–2013. Emerg Infect Dis 21, 1751–1758 (2015).
2. Krause, P. J. et al. Borrelia miyamotoi sensu lato seroreactivity and seroprevalence in the northeastern United States. Emerg Infect Dis 20, 1183–1190 (2014).
3. Rebman, A. W., Crowder, L. A., Kirkpatrick, A. & Aucott, J. N. Characteristics of seroconversion and implications for diagnosis of post-treatment Lyme disease syndrome: acute and convalescent serology among a prospective cohort of early Lyme disease patients. Clin Rheumatol 34, 585–589 (2014).
4. Maulden, A. B. et al. Two-tier lyme disease serology test results can vary according to the specific first-tier test used. J Pediatric Infect Dis Soc 9, 128–133 (2020).
5. Ogden, N. H., Arsenault, J., Hatchette, T. F., Mechai, S. & Lindsay, L. R. Antibody responses to Borrelia burgdorferi detected by western blot vary geographically in Canada. PLoS One 12, e0171731-13 (2017).