Around 30,000 cases of Lyme disease are reported each year to the U.S. Centers for Disease Control and Prevention. But that number only tells part of the story; Many cases of Lyme disease are not reported. When researchers look at insurance claims and population data, the estimates soar to more than 300,000 cases annually in the United States.
Ticks carrying Lyme disease are all over the country, but they are most commonly found in the eastern U.S. In a recent study conducted by the Entomological Society of America, researchers surveyed nine of the national parks on the East Coast and found ticks carrying the disease in every park tested.
Lyme disease is caused by a bacteria spread through the bite of a deer tick, also known as a black-legged tick. Symptoms are often similar to the flu, including fever, chills, muscle aches, fatigue, and joint pain. Some people also develop a rash or Bell’s palsy, which is facial drooping, according to lymedisease.org. Because these symptoms are also present in many other diseases, Lyme disease is frequently misdiagnosed or not diagnosed until it develops into a chronic condition, called Post-Treatment Lyme Disease Syndrome.
Early detection is important. When treated early, with antibiotics, people usually recover without any lasting problems. But according to researchers at Northeastern University, 10 to 20 percent of people with Lyme disease will continue to have problems despite being treated with antibiotics, including fatigue, arthritis, muscle pain, and cognitive difficulties.
Microbiologist Kim Lewis and his team at Northeastern believe they know why. In a study published in 2015 in Antromicrobial Agents and Chemotherapy, they found through laboratory experiments that _Borrelia burgdorferi,_the bacteria that causes Lyme disease, forms “persister cells,” a phenomenon also found in other hard-to-treat or antibiotic resistant infections.
These cells become dormant and are not affected by the initial round of antibiotics, only to activate once antibiotics have cleared the system. Then, they flourish, causing chronic infection.
Lewis continued his research in 2016, looking at different treatments for Lyme disease that would eradicate the initial infection and the dormant cells. One such treatment is called pulse-dosing, where an initial dose of antibiotics kills the active disease cells, then dormant cells are given time to activate and additional doses of antibiotics are given. Lewis’ team found that it can take four rounds of antibiotics to kill all the persisters. Some medical schools are now experimenting to determine whether pulse-dosing works in humans. Another treatment is combining different antibiotics to kill both active and dormant cells. This method has worked in test tubes but testing on humans has not yet begun.
As with many other illnesses, Lyme disease affects people in different ways. Some might experience mild, flu-like symptoms for a few days and then recover. Some develop a target-like rash, while others experience no rash or have a red or bluish oval-shaped rash. Some experience symptoms for years. Scientists at the Raboud University in the Netherlands are trying to understand what causes different reactions to the bacteria. In a study published in 2016 in Cell Host and Microbe, they analyzed blood drawn from healthy Western Europeans from the Human Functional Genomics Project and found that both age and genes affect how the disease manifests. Because the immune system weakens with age, Lyme disease can be more serious in the elderly. People with a genetic variation that causes an increase in lactic acid in the cells might also have more serious reactions.
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