WASHINGTON-As model Bella Hadid opens up about Lyme disease and other health issues, her ordeal brings up many questions. What exactly is Lyme disease, and how is it contracted and spread? How is the illness diagnosed and treated? What does it mean when someone has “chronic Lyme”? Is there a vaccine for Lyme disease? To help us with these questions, I spoke with Dr Leana Wen, an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health. She previously served as Baltimore’s health commissioner.
Dr Leana Wen said that Lyme disease is a bacterial infection. The bacterium Borrelia burgdorferi is the most common cause. In rare cases, Borrelia mayonii may cause the illness also. In the United States, Lyme is the most common disease spread by vectors, which are animals like mosquitos and ticks that spread infections. Lyme disease is transmitted through the bite of a particular tick, the black-legged tick (Ixodes scapularis and Ixodes pacificus). There are three stages of Lyme disease. The first stage is early localized disease that begins within a day to four weeks after the tick bite. People develop flu-like symptoms such as headache, muscle aches and fatigue. Some develop a characteristic “bull’s-eye” rash known as erythema migrans. The second stage occurs three to 12 weeks after the initial infection. This is the “early disseminated” stage in which people have more widespread symptoms. 
These can include dizziness, chest pain, palpitations, arthritis and facial nerve paralysis.

 The third stage is “late disseminated” disease, which can occur months after infection. Here, again, there is a constellation of symptoms. They include ongoing joint pain, fatigue, depression, palpitations, and other neurological, rheumatological and cardiac involvement.