Lyme disease is carried by ticks, and is a pretty well-known problem — around 300,000 cases are likely diagnosed in the US every year, according to the Center for Disease Control and Prevention — but there's still a lot we don't know about it. Lyme disease is more complex than it looks, and the first few months of 2019 have brought some studies that are changing our understanding of tick-borne diseases and Lyme.
People with Lyme disease contract it from the bite of a tick infected with a particular bacterium, often after traveling through tick-friendly areas like forests and prairies, and it can cause issues like joint pain, flu-like symptoms and a distinctive bulls-eye rash (though you can have Lyme even if you don't see a rash). It's treated with antibiotics. However, between 10 and 20% of people who are bitten suffer from symptoms long after the disease has been treated, and scientists aren't entirely sure why. "Some scientists believe the bacterium can persist in the body, but others dismiss the idea. This dispute, combined with patients whom doctors often can't help, has created a fractious field unlike almost any other," noted Science in a review of Lyme disease research funding in 2019.
New science is helping to solve this conundrum, and cast more light on Lyme in general. Here's where Lyme research stands right now.