Fever and chills, muscle and joint aches, headaches, exhaustion! If that is how you feel, and you live or play in rural, suburban and even peri-urban parts of the northeastern United States, then one or more tick-transmitted infections should, at least, be considered as a possible cause. Tick bites can result in transmission of bacteria, protozoans, rickettsias and even viruses. In the northeastern United States, tick-transmitted pathogens can cause:
Although each of these diseases also have their own unique diagnostic symptoms, and can be detected using appropriate blood tests, acute disease often is described as a summer-time flu.
Lyme disease was first identified in 1975, and since then the disease has continued to increase, both in the number of people afflicted and in the geographic distribution. National surveillance for Lyme disease began in 1982, when 491 cases were reported. In 2004, the latest year for which statistics are available, there were 19,804 human cases verified by the Centers for Disease Control and Prevention. More than 60,000 cases are reported each year in Europe.
The early stages of Lyme disease is usually marked by one or more of the following symptoms:
Erythema migrans (EM) is a red circular patch that appears usually at the site of the tick 5 days to 1 month after the bite of an infected tick. The patch then expands, often to a large size. Sometimes many patches appear, varying in shape, depending on their location. Common sites are the knee, thigh, groin, trunk, and the armpits. The center of the rash may clear as it enlarges, resulting in a bulls-eye appearance. The rash may be warm, but it usually is not painful. Not all rashes that occur at the site of a tick bite are due to Lyme disease (i.e. an allergic reaction to tick saliva at the site of the bite which can be confused with the rash of Lyme disease). Allergic reactions to tick saliva usually occur within a few hours to a few days following the tick bite, but usually do not expand and normally disappear within a few days.
Some symptoms and signs of Lyme disease may not appear until weeks, months, or years after a tick bite:
In rare cases, Lyme disease acquired during pregnancy may have possibly lead to infection of the fetus and to stillbirth, but adverse effects to the fetus have not been conclusively documented.
Lyme disease is often difficult to diagnose because its symptoms and signs mimic those of many other diseases. The fever, muscle aches, and fatigue of Lyme disease can easily be mistaken for viral infections, such as influenza, infectious mononucleosis or chronic fatigue syndrome. Joint pain can be mistaken for other types of arthritis, such as rheumatoid arthritis, and neurologic signs can mimic those caused by other conditions, such as multiple sclerosis. At the same time, other types of arthritis or neurologic diseases can be misdiagnosed as Lyme disease.
Diagnosis of Lyme disease depends upon:
Lyme disease is treated with antibiotics under the supervision of a physician. Several antibiotics are effective. Usually they are given by mouth but may be given intravenously in more severe cases. Patients treated in the early stages with antibiotics usually recover rapidly and completely. Most patients who are treated in later stages of the disease also respond well to antibiotics. In a few patients who are treated for Lyme disease, symptoms of persisting infection may continue, making additional antibiotic treatment necessary. Varying degrees of permanent damage to joints or the nervous system can develop in patients with late chronic Lyme disease. Typically these are patients in whom Lyme disease was unrecognized in the early stages or for whom the initial treatment was unsuccessful. Rare, indirect deaths from Lyme disease have been reported.
Currently, the Infectious Disease Society of America does not recommend antibiotic therapy for patients bitten by Ixodes scapularis ticks estimated to have been attached for more than 48 hours.New guidelines for physicians are being developed for release later in 2006. These may include findings from a newer study suggesting that a single 200-mg dose of doxycycline administered within 72 hours after a recognized Blacklegged tick bite was 87% effective in preventing Lyme disease transmission.
(Ref. Nadelman RB, Nowakowski J, Fish D, et al. Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite. N Engl J Med 2001; 345:79-84).