With the start of peak tick season, check here to spot some of the latest developments in diagnosis and treatment of Lyme disease.
Summer is officially in full swing which means patients will be enjoying outdoor BBQs, camping, hiking, and various other activities in nature. One important downside? Ticks. As any primary care physician knows, especially those in the Upper Midwestern and Northeastern parts of the US, tick season brings the looming danger of Lyme disease.
Catch up on 6 of the latest developments in Lyme disease diagnosis and treatment with our quick slideshow below.
Tests soon may be used to measure Borrelia burgdorferi infections directly, according to a recent review. Testing guidelines for Lyme disease adopted in 1994 were for antibody tests that provided indirect evidence of infection, but reliance on serologic testing has been suboptimal (cannot differentiate active infection, past infection, or reinfection). Review authors concluded that with new technical advances and knowledge, direct tests for early active Lyme disease are ready for practical assessment and future tests are probable.
According to the same review, the characteristics of an ideal direct test for Lyme disease are high sensitivity and specificity soon after a tick bite or infection at or before symptom onset; high sensitivity and specificity in later disease stages when extracutaneous infection has been established; short turnaround time (within 24 hours); applicability to easily obtained sample types (eg, blood, urine, saliva); and nonreactivity when active infection is absent. Authors concluded that as indirect serologic testing improves, direct nucleic acid and protein detections would complement the new techniques for more comprehensive diagnoses.
Researchers identified PGBb, a major component of the B. burgdorferi cell wall, as an immunogen that may contribute to the development and persistence of LA. The presence of the immunogen in the joints contributed to synovitis after antibiotics eradicated the pathogen, with PGBb detected in 94% of synovial fluid samples collected from patients with LA who received oral and intravenous antibiotics. B. burgdorferi also shed immunogenic PGBb fragments during growth, suggesting a role for PGBb in the immunopathogenesis of other manifestations of Lyme disease. This discovery could lead to new treatment options.
The cumulative prevalence of PTLD-characterized by incapacitating fatigue, pain, and neurocognitive dysfunction that continues for >6 months-is thought to be increasing in the US. Prevalence was estimated at between 69 000 and 1.6 million persons in 2016 and cases may increase to nearly 2 million in 2020. Delayed diagnosis and treatment are risk factors for PTLD, along with more symptoms and increased severity of acute Lyme disease.
IAGC injection appears to be an effective and safe second-line strategy for treating children with persistent LA, according to a recent study. Children treated with second-line IAGCs had baseline characteristics similar to those of children receiving second-line oral antibiotics alone, but had lower rates of antibiotic-refractory LA and faster rates of clinical resolution. IAGC injection was also associated with a reduced need for additional treatment.
A record number of casesoftickborne diseases were reported to the CDC in 2017, going from ~49 000 in 2016 to >59 000 in 2017. Disease-causing tickborne germs newly discovered in the US in the past 20 years include B. mayonii, B. miyamotoi, E. ewingii, Ehrlichia muris eauclairensis, Heartland virus, Rickettsia parkeri, and Rickettsia species 364D. In 2017, H. longicornis was reported in the US for the first time; as of April 9, 2019, no harmful germs have been found in these ticks in the US, but research is still ongoing.
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