LYME disease: The growing threat of ticks calls for a response in Public Health

Borrelia burgdorferi is the bacterium transmitted by ticks (see Ixodes scapularis, one of the tick species that can transmit the disease) causes Lyme disease or borreliosis, whose symptoms include fatigue, pain, loss of memory or concentration and, in some patients, inflammatory arthritis, articular, muscular, lupus … pains. Its incidence is increasing by 10% in Europe, yet Lyme disease remains poorly and hardly diagnosed and therefore sometimes untreated. In the United States, while the CDC estimates 30,000 new cases each year, the actual incidence would be 10 times higher.

A complex diagnosis: because the symptoms may appear in the following months or years after the bite, because they are polymorphic and common to other diseases, the diagnosis Clinical Lyme disease remains complex. Today, this diagnosis is mainly based on serology. Finally, the bacterium Borrelia burgdorferi, and the other bacteria involved, and the badociated pathologies are still poorly understood by primary care physicians. Lyme disease accounts for the majority (82%) of reported cases of tick-bite diseases.

Multiple factors likely contribute to increased incidence of Lyme disease, such as increased tick density and geographic expansion

10% to 20% of cases refractory to treatment: Although most cases are treated successfully, 10% to 20% of patients report persistent symptoms after effective antimicrobial therapy. These virus infections are also likely to cause severe illness and death. The example is given with the Powbadan virus (POWV), recognized in 1958, which causes a febrile illness, followed by progressive and severe neurological disorders, resulting in death in 10 to 15% of cases and long-term symptoms in 70% cases. These "intractable" and fatal cases call for a better understanding, prevention, detection and management of infection.

These limits in the various axes of fight against tick-borne diseases have led researchers to explore,

• new diagnostics innovative with different platforms likely to bring a clinical benefit . The authors refer to multiplex serological platforms capable of detecting antibodies vs. more than 170,000 distinct epitopes, allowing researchers to identify 8 pathogens. In addition to its ability to simultaneously detect multiple pathogens, this test provides better detection of pathogens in specimens collected early in the disease.

Non-serological platform technologies can also improve diagnostic capabilities, including identifying emerging pathogens. 2 "new" viruses have been identified, the Heartland virus and the Bourbon virus, by next-generation sequencing

Clinical implementation of these new generation diagnostics will be essential to better understand the determinants of epidemiological and clinical trends. the full clinical scope of the tick-borne disease. They will facilitate the appropriate clinical care for infected patients, and the testing of vaccine candidates and new therapeutic products

• Vaccines to prevent the disease: a vaccine against Lyme disease has already been developed, but it has been removed from the market and is no longer available. Future modes of protection could include vaccines specifically designed to create an immune response to a pathogen, or to target pathogens within the ticks that carry them.

Only by improving diagnoses, by developing new preventive treatments and vaccines, will public health officials be able to stem the growing threat of tick-borne diseases.

In the meantime, there are basic preventive measures: wearing insect repellents and loose clothing while walking in the woods.