Using its huge reach that currently spans about half the hospitals and physicians in the U.S., Quest Diagnostics Inc. has determined that the incidence of Lyme disease is increasing. It tracked more than 6 million de-identified laboratory test results over the past seven years and concluded that the disease spiked between 2016 and 2017.
Incidents are rising in new areas outside of the northeastern U.S., where the disease has been more typically found, such as California and Florida. The disease has now been detected in all 50 states and the District of Columbia, which is thought to be connected to climate change as more regions become amenable to the blacklegged or deer ticks that carry the disease. The warming climate could also be conducive to longer seasons of tick-friendly temperatures, offering a longer window for exposure.
"There have been others that have suggested that changes in the environment impact that would allow the ticks to reproduce faster and bigger numbers. There's also more areas for mice and deer to live to support the blacklegged tick, which is the tick that carries [Borrelia burgdorferi]," Harvey Kaufman, senior medical director for Quest Diagnostics and head of the company's Health Trends research program, told BioWorld MedTech.
But he noted that more cases are also being seen in states that are already warm. That could indicate an extended tick season in those areas. Kaufman noted that in California and Florida, the tick season is now year-round, with no seasonal fluctuations in positive tests at all. A study of ragweed allergy season recently came to a similar conclusion, that a lengthening growing season is leading to a longer time frame for allergic reaction each year.
California saw its positive Lyme disease test results nearly triple at 483 infected patients from 2015 to 2017, while Florida saw its rate rise to 77 percent to 501 over the same period.
Quest analyzed the results of immunoglobulin G (IgG) antibody tests, which are produced in response to infection. It must be confirmed by an immunoblot, if positive or inconclusive. This is a standard procedure that's endorsed by the CDC.
This summer, the Secaucus, N.J.-based company also introduced a new DNA test service that identifies infection from Lyme disease as well as four other tick-borne infections from a single sample. It uses qualitative, real-time PCR to identify the DNA of the infectious agent. This is expected to prove useful when prior diagnostic efforts remain inconclusive. The antibodies associated with Lyme disease are more or less prominent over time in a given patient, which can make them particularly difficult to detect.
Lyme disease remains most prevalent in Pennsylvania, Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont. Together, these states accounted for 60.6 percent of the 2017 incidents of Lyme disease in the study from 2017. Pennsylvania had the highest absolute number of cases with more than 10,000, almost as many as the roughly 11,500 in all of the New England states combined.
"Lyme disease is a bigger risk to more people in the United States than ever before," said Kaufman. "Our data show that positive results for Lyme are both increasing in number and occurring in geographic areas not historically associated with the disease. We hypothesize that these significant rates of increase may reinforce other research suggesting changing climate conditions that allow ticks to live longer and in more regions may factor into disease risk."
More than 300,000 people contract Lyme disease annually, according to the CDC. It is spread via tick bites and is an infection from the bacterium Borrelia burgdorferi.
Typical symptoms of Lyme disease include a bullseye-shaped mark around the bite location and flu-like symptoms. It can be treated effectively with antibiotics, but even after treatment can result in at least six months of fatigue and other symptoms.
With the largest database of clinical laboratory results in the world, Quest routinely uses 44 billion de-identified lab test results to derive broader population health insights.
Quest has been doing Health Trends reports on population health trends since 2005, and prior to that launched an annual Drug Testing Index report. The Health Trends reports cover all sorts of diagnostic categories including opioid use, infectious diseases such as Hepatitis C and HIV, as well as cervical cancer. These are widely cited by the medical literature, physicians, payers and policy makers.
A few weeks ago, Quest added a new service that's driven by its de-identified population health data, known as Clinical Trials Connect. It enables companies conducting clinical trials to identify where clusters of patients with the indication under examination are located, and to connect with their treating physician to either recruit patients or even the physicians themselves as clinical investigators.