What is lyme disease?
Lyme disease or Lyme borreliosis is an infectious disease caused by certain members of the genus Borrelia: screw-shaped bacteria (spirochetes) from three to eight micrometers in length. The vector is a disease which is transmitted by the sheep tick Ixodes ricinus and the deer tick Ixodes scapularis. The disease is named after the village of Lyme in Connecticut, where an epidemic outbreak of this disease in 1975.
Cause of infection
Mark sometimes wear bacteria of the genus Borrelia with him. A person can be infected with this by a tick bite. There are indications that the disease can be transmitted by other animals. The bacteria can also be transmitted through blood-to-blood contact. Because the bacterium is related to Treponema pallidum, the bacterium that causes syphilis, there is still debate whether Lyme disease can be transmitted through unprotected sexual contact. Despite the fact that there is research has been conducted, there has never been reported an infection in this way.
It is now clear that there are several variants of this bacterium exist, which cause very likely different disease symptoms. If skin symptoms often involve B. afzelii, B. garinii in neuroborreliosis. In the US, a move for which mainly causes joint pain; the species in Europe more often skin symptoms. Microbiology of Borrelia species is very complex and knowledge in this area there are numerous gaps. Per year, however, appear dozens of scientific papers on the subject.
Diagnosis and identification of the specific Lyme spirochetenstam is difficult because there is increasing more and more co-infections are transmitted along with Lyme. Lyme mutates itself.
Lyme disease symptoms
Lyme disease is a systemic disease with an erratic and in many forms that are becoming more diverse as more and more co-infections occur with other pathogens. The scientific information still shows gaps and partly contradictory. It is now possible to grow the bacteria and in a high percentage of the cases, it succeeds to establish the DNA of the bacterium by means of a PCR reaction. Still lacking a universally recognized gold standard for diagnosis. Incidentally, this also applies to the treatment, the definition of healing, or for the determination of the effect of treatment. With the increase in knowledge and techniques lyme borreliosis or becoming a 'normal' spirochetes infection that is detectable and treatable.
An infection with Borrelia burgdorferi often does not lead to symptoms of disease, such as from the occurrence of antibodies in people at risk (forestry workers) shows, of which there are many or contaminated (has been) with the spirochete, as evidenced by blood tests, but who never there some of have noticed. In the United States, HIV-positive without symptoms contrast rare. When there are symptoms occur, they are divided into three stages. The division in stages is somewhat arbitrary.
Stage 1: local skin infection; erythema migrans (EM)
The local skin infection usually begins as a red spot, often after 4 to 10 days and almost always within three months after a tick bite. The deviation extends in over the course of days to weeks out to a (5-40 cm in diameter) are more or less round or oval patch of red, often with central fading. The place is usually painless and does not itch usually is not elevated, except sometimes at the edges. Preferred Localization torso, legs, armpits and groin. This deviation is erythema (chronicum) migrans said. The local skin infection is sometimes a flu-like illness with malaise, fever, sore throat and muscle aches seen. This image can also be seen in a later phase of the disease.
As a typical erythema migrans (EM) is detected is almost certain to be Lyme borreliosis. Variations of the erythema migrans, however, occur. As erythema solid red can remain arise spot blisters or may have multiple rings around each be visible. Also, itching and pain may occur in a minority of cases. Multiple EM lesions have been described at the same time or recurrent EM lesions.
Half of patients with erythema migrans observed no tick bite. Some studies indicate that the non-standard (non-typical) forms of erythema migrans occur more frequently than the typical shape described above.
In patients with erythema migrans is typically a serological blood tests on Borrelia burgdorferi not necessary to make the diagnosis. In a fairly significant proportion of cases (30-50%) are in this phase of the disease is not yet detectable antibodies. Patients with erythema migrans, therefore, are to be dealt with without further testing with an antibiotic. Over the duration of treatment and dosage is no agreement among experts; the specified period may result from 10 to 21 days. In the acute phase may also lymphadenosis cutis benigna (Borrelia pseudo lymphoma) may occur, a pair of red subcutaneous bump at the site of the bite or remotely. Preferred location: ear, ear lobe, nipple, nose, scrotum.
Stage 2: early disseminated infection
After the tick bite Borrelia burgdorferi may get into the bloodstream, which leads to a disseminated infection. Contrary to what was previously thought, there are strong indications that the bacterium can disseminate all within forty-eight hours (spread) and include the central nervous system can infiltrate. In this demyelination (degenerative disappearance of the myelin sheath of nerve fibers) produces a disturbed stimulus conduction which among other can manifest as paralysis and / or sensory abnormalities.
Via the blood stream the bacterium is distributed in the body, but the bacterium is usually present in the blood stream only briefly. Although the bacteria can get into any organ, most of the genesis of disease in the nervous system, joints and heart. It turns out that the pointed half of the patients with a disseminated infection no tick bite or erythema migrans. As a result, it is possible that the signs of disease are not directly with an infection of Borrelia burgdorferi are associated.
Stage 3: chronic lyme borreliosis
One speaks generally of chronic Lyme disease in a disease duration of more than one year. All the above phenomena can have a prolonged course with symptom-free periods from weeks to years after the symptoms may return or get worse again. The symptoms can be swapped organ system.
There is strong evidence that Lyme borreliosis as the infection lasts more and more the characteristics of a chronic multisystem disease (compare Lues, also an infection with a screw-shaped bacteria). In addition to the specific phenomena in a variety of organ systems are in the chronic form of the disease, the general (also referred to non-specific) complaints in the foreground. In some people these symptoms include such things as flu-like symptoms, chronic fatigue (compare CVS), headache, transient temperature increase of a few hours, sweating, changing pain in muscles, tendons and joints (without objective local inflammation (compare fibromyalgia).
Regarding the need for further research and discussion in the group of chronic patients is disagreement among experts. This can give rise to violent conflicts between patients who believe they have Lyme disease and doctors that adhere to the strict criteria for diagnosis of the disease as described in some guidelines.
Diagnostics
The diagnosis of a Borrelia burgdorferi infection is not simple and in many cases there is difference of opinion among experts. Some experts strongly rely on laboratory research in the form of serological testing, because they consider that, where, in the case of a first test conducted sufficiently long after the infection, no serological signs (especially antibodies of the IgG class) of lyme borreliosis are found, it is virtually impossible that the symptoms are caused by Borrelia burgdorferi. In previous decades there was often pointed out that the tests could not detect all forms of the bacteria sometimes. However, nowadays this is less and less the case. Others emphasize that the tests do not provide security and believe that the diagnosis of lyme borreliosis should be based on careful mapping of the clinical signs in conjunction with additional research. They state that test results may be decisive never and that in many cases only a combination of data to the proper diagnosis may result. This position is losing as the testing methods are more reliable.
The additional research includes first of all serology of blood serum to various common Borrelia strains, if necessary supplemented by research into bacterial DNA, examination of cerebrospinal fluid, live blood analysis, psychiatric research, neuropsychological research and various types of brain imaging (MRI, SPECT, PET). DNA testing on the basis of PCR is particularly good to run on joint fluid and less on blood.
Lyme disease treatment
Shortly after a tick bite is 10-21 days 2x daily 100mg doxycycline mentioned most.
Lyme disease vaccine
In 1998 yielded the pharmaceutical company SmithKline Beecham (now GlaxoSmithKline) is a promising and highly effective vaccine. This vaccine consisted of a protein found on the surface of the bacterium Borrelia. Unlike a normal vaccine, this caused the production of antibodies which have been sucked up by the tick and the tick, in turn, made itself immune to the bacterium. This vaccine had an efficacy of 80%.
During the introductory period of the vaccine arose the suspicion that the vaccine would have undesirable side effects, especially arthritis. Further research showed that this association was not detectable, but public opinion turned against the vaccine and in 2002 the production of the vaccine was halted due to lack of demand.
There is referred to by pharmaceutical companies worked on second generation vaccines against Lyme, but these are not yet available. At the same time there researching the immune making carriers of the bacteria, especially rodents. If these animals can no longer carry the bacterium, character transfer him anymore. Testing with mice where these enter containing vaccine to eat, got turned out in 89% to be immune. There is even worked on modified rice plants that contain the vaccine and can be fed to mice. A promising approach is slightly different again-infecting mice with a modified virus that makes them insensitive for Borrelia, so as to break the life cycle of the bacteria.