Lyme Disease Awareness Month: All you need to know about tick-borne infection impacting 300k Americans each year
Lyme disease is a bacterial infection and is transmitted to humans through the bite of infected black-legged ticks
While Covid-19 may not go away in summer, but warmer weather means it is time to watch out for ticks and Lyme disease, the most common vector-borne disease in the US. May is the National Lyme disease Awareness Month, making it a perfect time to consider the dangers of the illness in what could be a particularly difficult season, thanks to the coronavirus pandemic.
What is Lyme disease and what causes it?
Lyme disease is a bacterial infection caused by the bacterium Borrelia burgdorferi and rarely, Borrelia mayonii. It is transmitted to humans through the bite of infected black-legged ticks, commonly known as a deer tick. The ticks that transmit Lyme disease can occasionally transmit other tickborne diseases as well. You are more likely to get Lyme disease if you live or spend time in grassy and heavily wooded areas where ticks carrying Lyme disease thrive, say experts.
The blacklegged tick (or deer tick, Ixodes scapularis) spreads the disease in the northeastern, mid-Atlantic, and north-central US. The western blacklegged tick (Ixodes pacificus) spreads the disease on the Pacific Coast.
How many are infected each year?
Each year, approximately 30,000 cases of Lyme disease are reported to the US Centers for Disease Control and Prevention (CDC) by state health departments and the District of Columbia. However, this number does not reflect every case of Lyme disease that is diagnosed in the US, which is substantially higher, shows analysis.
The CDC conducted two studies to understand how many people are actually diagnosed with Lyme disease each year. The first estimated the number of people who tested positive for Lyme disease based on data obtained from a survey of clinical laboratories. Researchers estimated that 288,000 (range 240,000–444,000) infections occur among patients for whom a laboratory specimen was submitted in 2008.
The second one examined the number of people diagnosed with Lyme disease based on medical claims information from a large insurance database. In this study, researchers estimated that 329,000 (range 296,000–376,000) cases of Lyme disease occur annually in the US. Based on the results of the two studies, the CDC suggests that the number of people diagnosed with Lyme disease each year in the US is around 300,000.
According to another study, state and local health departments reported a record number of cases of tick-borne diseases to CDC in 2017. The reported numbers of cases of Lyme disease, anaplasmosis/ehrlichiosis, spotted fever rickettsiosis (including Rocky Mountain spotted fever), babesiosis, tularemia, and Powassan virus disease all increased -- from a total of 48,610 reported cases in 2016 to a total of 59,349 reported cases in 2017.
The scientists say that reported cases capture only a fraction of the overall number of people with tick-borne illnesses. Even so, the number of reported cases of Lyme disease in the US has tripled since the late 1990s, they add.
What are the symptoms?
The typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. If left untreated, the infection can spread to joints, the heart, and the nervous system. Lyme disease is diagnosed based on symptoms, physical findings (for example rash), and the possibility of exposure to infected ticks. Laboratory testing is helpful if used correctly and performed with validated methods.
According to the CDC, early signs and symptoms can occur 3 to 30 days after a tick bite. “Fever, chills, headache, fatigue, muscle and joint aches, and swollen lymph nodes may occur in the absence of rash. Erythema migrans (EM) rash occurs in approximately 70 to 80% of infected persons. It begins at the site of a tick bite after a delay of 3 to 30 days (average is about 7 days). It expands gradually over several days reaching up to 12 inches or more (30 cm) across,” says CDC.
The later signs and symptoms can occur days to months after a tick bite. It includes severe headaches and neck stiffness, additional EM rashes on other areas of the body, and even facial palsy, which is the loss of muscle tone or droop on one or both sides of the face. A person may also experience arthritis with severe joint pain and swelling, particularly the knees and other large joints, intermittent pain in tendons, muscles, joints, and bones, heart palpitations, or an irregular heartbeat. Some of the other serious symptoms could be inflammation of the brain and spinal cord, nerve pain, and shooting pains, numbness, or tingling in the hands or feet.
Can it be treated?
Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. People treated with appropriate antibiotics in the early stages usually recover rapidly and completely. Antibiotics commonly used for oral treatment include doxycycline, amoxicillin, or cefuroxime axetil. People with certain neurological or cardiac forms of illness may require intravenous treatment with antibiotics such as ceftriaxone or penicillin.
However, it is broadly accepted that a sizeable number of patients experience treatment failure and continue to suffer long-term, debilitating symptoms, including pain, fatigue, cognitive dysfunction, and other symptoms. This is known as post-treatment Post-Treatment Lyme Disease Syndrome (PTLDS), for which diagnosis is not standardized and treatment remains controversial.
The prevalence and societal burden of PTLDS are unknown, say experts. Accordingly, the official numbers also do not reflect the prevalence of post-treatment Lyme disease. “Depending on the input assumptions, PTLDS prevalence estimates for 2016 ranged from 69,011 persons to 1,523,869. Prevalence in 2020 is predicted to be higher than 2016, and maybe as high as 1,944,189 cases,” says a study.
The CDC says it is not clear why some patients experience PTLDS. Some experts believe that Borrelia burgdorferi can trigger an “auto-immune” response causing symptoms that last well after the infection itself is gone. “Autoimmune responses are known to occur following other infections, including campylobacter (Guillain-Barré syndrome), chlamydia (Reiter’s syndrome), and strep throat (rheumatic heart disease),” says the CDC. Other experts hypothesize that PTLDS results from a persistent but difficult to detect infection.
Some also believe that the symptoms of PTLDS are due to other causes unrelated to the patient’s Borrelia burgdorferi infection.
Experts say you can get the disease twice because protective antibody immunity can wane after several years and one may also be infected by a different strain of Borrelia burgdorferi.
The best way to prevent Lyme disease is to avoid areas where ticks live, especially wooded, bushy areas with long grass. But if you cannot, it is important to take common-sense precautions in tick-infested areas.
Steps to prevent Lyme disease include using insect repellent, removing ticks promptly, applying pesticides, and reducing tick habitat. Since ticks attach easily to bare flesh if you are in an area where ticks are common, protect yourself and your children by wearing long sleeves and long pants. During outdoor activities, the CDC recommends walking in the center of trails and avoiding walking through tall bushes or other vegetation.
Since chemical repellents can be toxic, one must follow directions carefully when using them. The Environmental Protection Agency (EPA) has an online tool to help people select the repellent. “Use Environmental Protection Agency (EPA)-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone,” says the CDC.
One can use products that contain permethrin on clothing. Treat clothing and gear, such as boots, pants, socks, and tents with products containing 0.5% permethrin: it remains protective through several washings. Pre-treated clothing is available and may be protective longer.
It is critical that you check your clothing, yourself, your children, and your pets for ticks, and the reasons are multiple. Ticks can attach to any part of the body and are excellent at hiding in areas that we do not commonly see on our own bodies, such as underarms or behind knees. In most cases, the tick must be attached for 36 to 48 hours or more before the Lyme disease bacterium can be transmitted.
They are so tiny at their younger stages, it is possible for a tick to bite and move on before being discovered. Many that are infected by lyme disease may not even remember being bitten by a tick.
The CDC recommends using fine-tipped tweezers to remove an attached tick as soon as you notice it. If a tick is attached to the skin for less than 24 hours, the chance of getting Lyme disease is extremely small; however, other diseases may be transmitted more quickly, according to the CDC. Watch for signs or symptoms of Lyme disease such as rash or fever over the next few weeks, and see a healthcare provider if you notice any signs or symptoms, advice experts.