Canada
The range of ticks able to carry Lyme disease has expanded from a limited area of Ontario to include areas of southern Quebec, Manitoba, northern Ontario, southern New Brunswick, southwest Nova Scotia and limited parts of Saskatchewan and Alberta, as well as British Columbia. Cases have been reported as far east as the island of Newfoundland. A model-based prediction by Leighton et al. (2012) suggests that the range of the I. scapularis tick will expand into Canada by 46 km/year over the next decade, with warming climatic temperatures as the main driver of increased speed of spread. Mexico
A 2007 study suggests Borrelia burgdorferi infections are endemic to Mexico, from four cases reported between 1999 and 2000. United States
In 2019, according to the CDC, there were approximately 35,000 confirmed and probable cases in the U.S. with incidences occurring in almost every state. The CDC is currently conducting research on evaluation and diagnostics of the disease and preliminary results suggest the number of new cases to be around 300,000.Lyme disease is the most common tick-borne disease in North America and Europe, and one of the fastest-growing infectious diseases in the United States. Of cases reported to the United States CDC, the ratio of Lyme disease infection is 7.9 cases for every 100,000 persons.
Resolution of MRI white matter hyperintensities after antibiotic treatment has been observed.Tryptophan, a precursor to serotonin, appears to be reduced within the central nervous system in a number of infectious diseases that affect the brain, including Lyme. Researchers are investigating if this neurohormone secretion is the cause of neuropsychiatric disorders developing in some people with borreliosis. Immunological studies
Exposure to the Borrelia bacterium during Lyme disease possibly causes a long-lived and damaging inflammatory response, a form of pathogen-induced autoimmune disease. The production of this reaction might be due to a form of molecular mimicry, where Borrelia avoids being killed by the immune system by resembling normal parts of the bodys tissues.Chronic symptoms from an autoimmune reaction could explain why some symptoms persist even after the spirochetes have been eliminated from the body. This hypothesis may explain why chronic arthritis persists after antibiotic therapy, similar to rheumatic fever, but its wider application is controversial. Diagnosis
Lyme disease is diagnosed based on symptoms, objective physical findings (such as erythema migrans (EM) rash, facial palsy, or arthritis), history of possible exposure to infected ticks, and possibly laboratory tests. People with symptoms of early Lyme disease should have a total body skin examination for EM rashes and asked whether EM-type rashes had manifested within the last 1–2 months. Presence of an EM rash and recent tick exposure (i.e., being outdoors in a likely tick habitat where Lyme is common, within 30 days of the appearance of the rash) are sufficient for Lyme diagnosis; no laboratory confirmation is needed or recommended.