No abstract

No abstract

A method for estimating the leptospiricidal activity of therapeutic antiserum for Weil's disease was improved by using the intracutaneous method in guinea pigs. The neutralization curves between the leptospiral suspensions for challenge and the antisera were shown to be linear over a wide range of the dosis of the pathogen. Although the reproducibility of the neutralization experiments was high, a significant divergence was observed among the slopes in various test samples. However , the trouble due to such a discrepancy in the slope may practically be reduced if such an antiserum preparation that has a regression coefficient close to the mean of those of various neutralization lines constructed by many different products is adopted as the reference. A practical method for the potency test was suggested .

Experimental leptospirosis with Leptospira icterohaemorrhagiae Shibaura strain was studied in guinea pigs. When the pathogen was inoculated intracutaneously to the back of the animals, localized haemorrhage was observed at the inoculated site before the appearance of general haemorrhage. The severity of the local lesion increased progressively until the 7th day of inoculation. The minimum infective dose (MID) or the 50% infective dose (ID50) of the leptospiral suspension was determined by the appearance of the macroscopic local haemorrhage 7 days after inoculation. The MID thus determined was almost comparable with the value determined by the development of general symptoms and signs by conventional ip inoculation. The number of the pathogen per ID50 varied between 6 and 35 in five experiments. The local haemorrhage was effectively protected by active or passive immunization. Microscopically, haemorrhage at the inoculated site was found mainly in the dermis, directly beneath the epidermis in particular, and accompanied with leakage of the pathogen. The pathogen was also detected abunduntly in the thickened epidermal layer covering the inoculated area as well as in the epithelial matrix of hair-follicle, probably due to the proliferation of the pathogen at the site. 298 Vol. 27 MORI et al.

Involvement of the nervous system by the human T-lymphotropic virus type I (HTLV-I) was demonstrated in the tropics and Japan in two chronic neurological disorders, tropical spastic paraparesis (TSP) {l] and HTLV-I-associated myelopathy (HAM) {2]. HAM and HTLV-I-positive TSP are recognized as clinically and pathologically identical diseases [3], and the name HAWTSP is now used for this disorder {3a].In previous reports, treponemal infections have been suggested as a suspected cause of TSP by serological and pathological studies {4]. In subsequent investigations to evaluate this hypothesis, Rodgers-Johnson and colleagues { 57 noted that Treponemu pertenue and Treponemu pallidum were unlikely to be etiological candidates for TSP. Samples were also tested for the presence of antibody to Bowelia burgdorferi, a causative agent of Lyme disease, which was recognized as a multisystem disease involving neurological complication [67. Rodgers-Johnson and colleagues [5] were able to demonstrate that 25% of Jamaican patients with TSP had antibodies to B. burgdofleri. In Japan, some cases of Lyme disease have been reported since 1987 [7].We recently examined 2 patients who had facial diplegia and elevated serum antibodies to B. burgdorferi in the Kagoshima prefecture, one of the areas in Japan in which HAWTSP is most prevalent {8]. Neuroborreliosis apparently exists in this area, and consequently, it would be important to know whether B. burgdorferi might play a role in the development of HAWTSP in Japan.Serum samples were obtained from 20 patients with HAWTSP (15 women and 5 men) from the Kagoshima prefecture. Their ages ranged from 23 to 76 years (mean, 52). The two groups of control subjects consisted of 20 healthy carriers of HTLV-I (15 women and 5 men; age range, 21 to 75, mean, 52) and 20 seronegative healthy individuals (1 5 women and 5 men; age range, 2 1 to 76, mean, 52). The serum samples from these groups were tested by immunofluorescence assay using B. burgdorferi (IFA-Bb) from Ixodes ricinus as the antigen. Positive samples in IFA-Bb were examined by the Treponema pallidum hemagglutination test (TPHA) to exclude syphilis or other treponemal infections.Only one of the HAWTSP patients was positive by IFABb. However, this patient was also positive by TPHA, indicating a previous syphilis infection. All samples from the control groups consisting of healthy carriers and healthy individuals were negative when tested by IFA-Bb and TPHA.The present results clearly demonstrate that there is not a causal relationship between B. burgdorferi and HAWTSP in Japan. However, since some differences of clinical features are known to exist between HAWTSP in Japan and in the Caribbean basin 131, the possibility remains that these differences may be influenced by infection with B. burgdofleri, which may act as a cofactor.