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

similarly to that which indicated a 30% seropositivity ratio for healthy blood donors (108). ' Borrelia antibody testing in the CSF has higher sensitivity and specificity in neuroborreliosis (64,148,149). Intrathecal production of borrelia-specific antibody can be detected in almost every case (9, 98, 107, 163). However, it must be remembered that intrathecally produced antibodies against irrelevant viruses are frequently found in multiple sclerosis (37). That is why intrathecal production of borrelia antibodies should not be accepted as a proof of neuroborreliosis without some reserve (113,123). All of the serological methods give false positive or false negative results in some cases (65,94, 96, 98,116,122). Which factors exert any influence on seropositivity? One of them is time. The highest antibody titers can be measured in the late form of Lb, especially in ACA. On the other hand, only 35% of ECM patients had elevated antibody titers. Seroconversion usually occurred 4-6 weeks after the first symptoms of infection had appeared. Another major factor influencing seropositivity is the generalization of infection. The chance of generalization is increasing with time but generalization does not take place in every case. The appearance of borrelia antibodies takes at least 6 weeks (95, 134). Three weeks after the onset of ECM only an IgM response can be detected even by the very sensitive capture ELISA (13). In spite of this fact, two weeks (!) after tick bite we found elevated IgG titers in a considerable portion of patients. Sixty per cent of this fast-responding group had ECM, so the probability of false positivity is low. We are convinced that fast antibody response seen in a certain part of the patients supports our opinion mentioned earlier, namely that the outcome of the infection is determined soon after the tick bite. Fast response is a sign of systemic infection even in cases when clinical symptoms are missing. This theory is supported by the results of an animal experiment in which intraperitonealfy infected mice (generalized infection from the first minute) produced IgG antibodies on the 5th (!) day (10). Antibody response has been shown to be prevented by antibiotic treatment. No one knows the reason why no antibody production is induced against Bb surviving the antibiotic treatment (29,133). Therapy Several years before the first isolation of Bb, some investigators suspected that the causative agent of ECM and BS was a penicillin-sensitive spirochete. The first Lb cases were treated with antibiotics suitable for the treatment of syphilis. Steere administered 250,000 IU of penicillin G or 250 mg tetracycline or erythromycin q.i.d. against ECM. Although the last one proved to be ineffective, the others significantly shortened the illness and reduced the risk of complications. Arthritis developed in one-third of the penicillin treated patients, and the joint symptoms were less severe than in the untreated group (140). When the unstable penicillin-G was exchanged with Phenoxymethylpenicillin, a compound of better absorptive properties, complications occurred in less than 10% of patients (142). Penicillin adminis-