[Spotted fever group rickettsiosis in Chiba Prefecture].

In Chiba Prefecture, the first patient of infection with spotted fever group Rickettsia was found in 1987, thereafter nine patients were detected serologically by the end of 1990. Patients were found in the villages of Amatsukominato, Katsuura and Ootaki, which were located in southern part of Chiba Prefecture. The illness occurred from June to October. On the other hand, patients with Rickettsia tsutsugamushi were seen from October to September. Difference of prevalent seasons of these two types of rickettsiosis is important to make a clinical diagnosis and serological identification of this spotted fever group rickettsiosis. Antibody of the patients showed the highest titer to YH strain of Rickettsia and showed high cross-reactivity to other spotted fever group rickettsiae. For the diagnosis of the patient serologically, it was confirmed that any strain of spotted fever group Rickettsia were useful.

[Spotted fever group rickettsiosis and vectors in Kanagawa prefecture].

Primer pairs for PCR were designed from the gene encoding the 17,000-molecular-weight genus-common antigen of Rickettsia japonica, Rickettsia rickettsii, Rickettsia conorii, Rickettsia typhi and Rickettsia prowazekii. Primers R1, R2 were designed for amplifying the genomic DNA from spotted fever group (SFG) rickettsiae and epidemic typhus rickettsiae. Primers Rj5, Rj10 were designed for amplifying the genomic DNA from only R. japonica. Using the primers R1, R2, about a 540-bp fragment was observed by amplifying the genomic DNA from R. japonica, R. rickettsii, R. conorii, Thai tick typhus TT-118, Rickettsia sibirica, Rickettsia montana, Rickettsia askari, R. typhi, R. prowazekii and Katayama strain isolated from the patient infected with SFG rickettsiae. Using the primers Rj5, Rj10, the 357-bp fragment was observed by amplifying the genomic DNA from R. japonica and Katayama strain. Therefore, the Katayama strain was identified to belong to R. japonica. With primers R1, R2 and Rj5, Rj10, 537 bp and 357 bp bands were amplified from blood of the patients infected with SFG rickettsiae in Kanagawa prefecture. These findings indicate that the causative agent of SFG rickettsiosis in these two patients was R. japonica. The ticks, Ixodes ovatus and Haemaphysalis flava, were collected by out field research in Kanagawa prefecture. With primers R1, R2 and Rj5, Rj10, 537 bp and 357 bp were amplified from these ticks. This indicates that I. ovatus and H. flava were the vector of R. japonica in Kanagawa prefecture. Also, with the primers R1, R2, about a 540 bp fragment was amplified but with primers Rj5, Rj10, no fragments were amplified from I. ovatus and H. flava. Therefore, these ticks may have SFG rickettsiae other than R. japonica and epidemic typhus rickettsiae.

[Incidence of antibodies in raccoon dogs and deer inhabiting suburban areas].

We evaluated the incidence of antibodies against canine distemper (CD) virus, canine parvovirus, Toxoplasma gondii (T. gondii), Aujeszky's disease virus, porcine reproductive and respiratory syndrome virus, Rickettsia tsutsugamushi, Rickettsia japonica, and Coxiella burnetii in 30 raccoon dogs and 5 deer captured in suburban areas in Kanagawa Prefecture. Among the raccoon dogs, anti-T. gondii antibody was detected in 1 animal (3.3%) and anti-CD virus antibody in 9 (30.0%). However, antibodies against the other pathogenic microorganisms were not detected in the raccoon dogs. The deer had none of the examined antibodies.

[Serotype-specific amplification of Rickettsia tsutsugamushi DNA from clinical specimens by nested polymerase chain reaction].

Polymerase chain reaction (PCR) with nested primer pairs was used to diagnose Tsutsugamushi disease and identify the Rickettsia tsutsugamushi serotype. The primer pairs used for PCR were designed on the basis of the nucleotide sequence of the gene that encodes the 56-kDa antigen. Five serovariants, the Gilliam, Karp, Kato, Kawasaki, and Kuroki strains of Rickettsia tsutsugamushi were detected and identified by nested PCR. The serotypes of patients registered during 1990 to 1992 in Kanagawa Prefecture were identified by nested PCR. Sixty percentage of patients showed Kawasaki types, 20% Karp types, and 20% Kuroki types. This result suggested that the recent Tsutsugamushi disease were mostly caused by Kawasaki types in Kanagawa Prefecture.

[Epidemiology of Tsutsugamushi disease and typing of isolated Rickettsia in Chiba Prefecture].

In Chiba Prefecture, the first patient of Tsutsugamushi disease was found in the southern part in the 1950's, but after that no patient was detected until 1982. After 1982, patients have been noticed again, the number of patients has been increasing year by year. The number of serologically confirmed cases was 152 and 157 in 1989 and 1990, respectively with indirect immunofluorescence assay. About 90 percent of the patients were found in November and December, prevalently in the southern part of the prefecture. On the other hand, a few patients were found yearly in a harf of towns and villages in this prefecture. The number of isolated strains of Rickettsia tsutsugamushi from patients was 4, i.e., TR6030, TR6310, TR6311, and TR6324 in 1986 and 3, TR1811, TR1827 and TR1829, in 1991. Six isolates except TR6303 reacted with anti-Kawasaki monoclonal antibody but not with other strain specific monoclonal antibodies. Therefore, these 6 isolates were determined as Kawasaki type strain. An isolate. TR6303, reacted with anti-Kuroki monoclonal antibody at a titer of 1:2560 and anti-Karp monoclonal antibody at a titer of 1:320. This result suggested that the recent Tsutsugamushi disease is mostly caused by Kawasaki types in this prefecture.

[Tsutsugamushi disease (scrub typhus) in Japan: epidemiological aspects].

Epidemiological aspects of tsutsugamushi disease (scrub typhus) in Japan in 1998 were analyzed using questionnaires. Four hundred and sixteen scrub typhus cases were reported in 24 prefectures in 1998. The annual number of the patients in 1998 was similar to those in the preceding three years. There was no sex difference. The patients at the age of 51 or greater accounted for 72% of the total cases. Patients engaged in farming and forestry accounted for 32% and 14% cases, respectively. Fifty-six, 21 and 19% were reported in Kyusyu, Kanto and Tohoku-Hokuriku districts, respectively, 96% of the total cases being reported in these 3 districts. Most cases were reported from April through June with some from October through December in Tohoku-Hokuriku districts, while most cases were reported from October through December in other districts, including Kyusyu and Kanto districts. Thus, there was a difference in epidemic seasons among the districts. Serotypes of scrub typhus rickettsia were analyzed by serum antibody titers in the Kyusyu district. The novel Kawasaki and Kuroki types were major strains; however, no geographical difference was seen within the Kyusyu district. Interestingly, 24 cases were diagnosed only by the new serotypes not by the classical serotypes (Kato, Karp and Gilliam) in serological tests. This result suggests that further investigations are required to determine the prevalent serotypes in each district and to improve the serological tests. This was the first comprehensive report of epidemiology of scrub typus in entire Japan. Information obtained in the present study provides deep insight into prediction, diagnosis, treatment and prevention of scrub typhus in Japan.

[Tsutsugamushi disease (scrub typhus) in Japan: clinical features].

Clinical features of tsutsugamushi disease (scrub typhus) were analyzed, based on 416 cases reported in Japan in 1998. Three major clinical symptoms: eschar, fever and rash were found in 87%, 98% and 92% of the cases, respectively. Elevated levels of CRP, GOT, GPT and LDH were observed in 96%, 85%, 78% and 91%, respectively. These clinical and laboratory findings were observed in the majority of the cases and considered important for diagnosis. Disseminated intravascular coagulation developed in 21 cases, indicating that scrub typhus can be life threatening. Lymphadenopathy was observed in 51% of the cases. Enlarged lymph nodes were limited to the local sites in 75% of these lymphadenopathy cases and most of these sites were adjacent to eschars. Most eschars were scabbed and located in the abdomen and the lower half of the body, especially the feet. This suggests that these parts are frequently exposed to tsutsugamushi mites. Furthermore, the skin is soft in these parts and covered by cloth. These factors may make it possible for mites to keep biting without being noticed for several hours, long enough for rickettsial transmission. Interestingly, eschar and rash were absent in 14% and 8% of the cases, respectively. This result suggests that the cases without the unique symptoms may have been misdiagnosed as common cold or other febrile illnesses. One hundred and fifty-four suspected cases were not scrub typhus cases by the serological tests. The three major clinical symptoms were present in approximately a half of these negative cases, eschar being observed in approximately 70%. This may suggest the presence of new type of scrub typhus can not be diagnosed by the present laboratory tests. Clinical features of scrub typhus in Japan were well revealed, and information obtained in the present study is useful for improving clinical diagnosis. It should, however, be stressed that there were cases that could not be correctly diagnosed only by the clinical symptoms, suggesting that it is important to improve the serological tests.

Power spectral analysis of auditory evoked response.

Five normal hearing adults were examined for power spectral analysis of AER to 1000-Hz pure tone. Major frequency components of responses to stimuli at 50 dB hearing level exist at 1 to 14 c/s. The power spectra of responses to stimuli at 10 dB hearing level are greater than those of the SBA in the frequency components between 3 and 9 c/s; furthermore, the total power of 3 to 9 c/s indicates a clear difference between the 2. Incidentally, at 512-msec analysis time, the total power of 3 to 9 c/s of the AER are significantly greater than that at 1024-msec analysis time, whereas those of the SBA show little discrepancy at the 2; thus at 512-msec analysis time, the total power of 4 to 9 c/s yields a clear difference between the AER and the SBA responses averaged over 50 stimuli even at 10 dB hearing level.

Specific amplification of Rickettsia japonica DNA from clinical specimens by PCR.

The gene encoding the 17,000-molecular-weight genus-common antigen (17K genus-common antigen) has been cloned and sequenced from Rickettsia japonica. The primer pair used for PCR was designed from this sequence. A 357-bp fragment was observed by amplifying the genomic DNA from R. japonica and also the DNA from blood clots of patients with spotted fever group rickettsiosis. The results indicated that this method is suitable for the diagnosis of spotted fever group rickettsiosis in Japan.

Molecular epidemiology and phylogenetic analysis of Sapporo-like viruses.

Sapporo-like viruses (SLV) are a causative agent of gastroenteritis in humans. SLV-specific primers were newly designed in capsid protein-coding region and 529 fecal samples collected from gastroenteritis patients were tested. Thirty-five samples (6.6%) were found to be positive by reverse transcriptase-polymerase chain reaction (RT-PCR). Out of 35 positive samples, 25 were classified into a genogroup SG-I, typified by the Sapporo virus, and 9 were classified as a genogroup SG-II, typified by the London virus. Interestingly, one sample could not be classified into any genogroup, which suggests that it may be part of a new SLV genogroup. The RT-PCR used in this study appeared to be capable of widely detecting SLV genogroups, and it was seen to be powerful enough for molecular epidemiological as well as phylogenetic studies on SLV.

Occurrence of rickettsiosis of spotted fever group in Chiba Prefecture of Japan.

Acute- and convalescent-phase sera were obtained from a patient with suspected tsutsugamushi disease in July 1987, in Amatsukominato located in the southeastern area of Chiba Prefecture, and showed negative serologic reactions with Rickettsia tsutsugamushi, while the convalescent-phase serum reacted positively with R. montana and a Japanese isolate of spotted fever group rickettsia at IgM and IgG titers of 1:320 and 1:640, respectively, in the indirect immunofluorescence test. These findings showed that a rickettsiosis of the spotted fever group occurred also in Chiba Prefecture like in the southeastern areas of Shikoku and Kyushu islands of Japan.

Emerging rickettsial infections in Sri Lanka: the pattern in the hilly Central Province.

OBJECTIVES: To identify different rickettsial infections using a specific immunofluorescent technique in patients clinically diagnosed as 'typhus fever' in the Central Province of Sri Lanka, and to define the clinical picture, assess the severity of infection and to determine the pattern of geographical distribution of the infections of the hospital-based patients. METHODS: A specific indirect immunofluorescent antibody technique was used on the sera of two groups of patients in laboratories in Japan and Thailand. RESULTS: We serodiagnosed infections with Orientia tsutsugamushi, Rickettsia typhi and spotted fever group in 56 of 118 clinically investigated patients. There were eight infections with O. tsutsugamushi, two with R. typhi and 10 spotted fever group patients with IgM antibodies suggestive of acute infection. Nineteen patients had antibodies against these three rickettsial species, suggestive of past exposure, co-infection or cross-reactivity of antigens. Discrete, erythematous maculopapular rash was common to all three types of infection except for five patients who had no rash. Five patients positive for spotted fever antibodies developed fern-leaf type skin necrosis with severe illness. Duration of the febrile period ranged from 4 to 23 days with defervescence occurring after specific antibiotic treatment. CONCLUSIONS: The study has shown the presence of different types of rickettsial infections in the Central Province of Sri Lanka. The characterization of the clinical picture and the severity of infection provide useful information for the proper management of the patients in the future.