Dr. Murai Éva szerk.: Parasitologia Hungarica 24. (Budapest, 1991)

Stages of Lyme borreliosis The course of Lb can be divided into stages. ECM is the first stage, the second one is characterized by neurological and cardiac symptoms, while the third stage is equal to arthritis (135, 152). Our data show that it is very difficult to fit the various manifestations into stages. ECM and ACA are exceptions. Although ECM may have signs indicative of systemic infection, our data suggest that ECM remains a localized infection in most patients even when it is left untreated. The other extreme is ACA. It is a chronic, progressive illness in each case. To fit organ manifestations into stages is questionable because all the other symptoms may have acute, subacute and chronic forms. The incubation period can influence the appearance of symptoms. For example, in ACA the long latency period is coupled with a chronic progressive course. The same phenomenon can be observed during the early period of ECM. The longer the time that elapsed after tick bite, the higher the risk of complications. Similarly, acute BS has a tendency for spontaneous recovery, while symptoms appearing after a longer period - e.g. ACA-associated polyneuritis - have a chronic progressive course. Arthritis is also a good example: there seems to be a shift from the large joints to the small ones as the incubation period lengthens. Large joint arthritis has a fluctuating but basically benign outcome, while small joint arthritis is a progressive and always chronic manifestation of Lb. Theoretically, this phenomenon may be explained by the fact that Bb must adapt to the host and this takes time. Adaptation can also be seen in vitro. For example, a strain which had grown well in our own culture medium could hardly be multiplied in the Statens Seruminstitut. The normal Bb concentration could only be achieved after the 4th-5th passage. Inversely, a Danish strain, growing well in the Danish culture medium, could be cultured effectively in Hungary only after several passages. The same phenomenon is likely to exist in vivo. Bb isolated from ACA grew slower than another strain cultured from ECM (6). There are three possibilities concerning the relationship between the pathogen and its host. If the adaptability of the spirochete is poor, Bb remains in the skin and will invariably be eliminated, even in untreated patients. In rapidly generalized infections with acute onset and a usually benign outcome the host's defense mechanisms overcome the pathogen. The third possibility is the case of the slowly adapting Bb. During the long adaptation period the microbe "learns" how to evade the host's defence mechanism. Serology Our data show that IFA is a reasonably good method for borrelia antibody testing (77). Especially in the early cases it can be false negative because of the low antibody titer, and in the treated cases no seroconversion can be detected. Sometimes it is obviously false positive, but high titers are seldom misleading in the everyday clinical practice. Of course, this statement holds true only of the well controlled methods. A technique which gives a false positive result in 20% of cerebrovascular diseases or in multiple sclerosis (100, 101) is unsuitable for diagnostic purposes,