Biomedical subjects
Publications and source records attributed to Motohiko Ogawa.
Rhipicephalus turanicus tick colony infected in the laboratory with Rickettsia massiliae showed that the rickettsia is transovarially and transdatially tramsmitted. The expression of rOmpB did not change with temperature or the stages of the tick life cycle. In contrast, rOmpA was less expressed during the larval stage.
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We report results on the seroprevalence of antibodies to Coxiella burnetii in cattle and healthy people in Korea. Upon agreement with dairy owners, serum samples from 414 dairy cattle were collected between March and June 2001 and samples from 205 people for health screening were collected between April and December 2002. The sera were analyzed for the presence of anti-C. burnetii phase II antibodies using an indirect microimmunofluorescence test; strong fluorescence at a 1:32 dilution was regarded as positive. The overall seroprevalence of C. burnetii in cattle in Korea was 25.6%, with regional variation from 8.9 to 59.3%. Of the positive serum samples, 75.5% had antibody titers >or=1:256. By contrast, only 1.5% of people in a rural area were seropositive, and most of the positive samples had low antibody titers. In conclusion, this study showed that relatively high seropositivity of C. burnetii in dairy cattle, accordingly, the studies on the high-risk groups are needed to evaluate the seroprevalence for this organism in Korea.
Simkania negevensis has been associated with bronchiolitis in infants and community-acquired pneumonia in adults. Reports of exposure to this microorganism are only available from Israel, North America and Western Europe. Currently, no standard method for diagnosis of S. negevensis infection has been established nor have prevalence rates been shown in Japan. For the first time we demonstrated the ability of the microimmunofluorescence (MIF) test to detect S. negevensis-specific immunoglobulin G and exposure to S. negevensis in Japan. The positive rate in healthy volunteers was 4.3% (25/588), with rates increasing with age. Results indicate the usefulness of the MIF test as a serological method for detecting S. negevensis-specific antibodies. A standard serological test for infection with S. negevensis is needed.
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A Japanese traveler returning from Kenya became ill, presenting with fever and a prominent, generalized rash without an eschar. Results of the immunofluorescence antibody assay of the patient's sera performed in Japan were compatible with illness due to a spotted fever group (SFG) rickettsia, and a presumptive diagnosis of African SFG rickettsiosis, probably either Mediterranean spotted fever (MSF) or African tick-bite fever (ATBF), was rendered. To further define the disease diagnosis, sera were examined in France by Western immunoblotting combined with cross-adsorption, which confirmed the diagnosis of MSF but not of ATBF. Because of the need to further characterize the epidemiologic and clinical features of the two African SFG rickettsioses, clinicians are encouraged to contact a specialized laboratory when encountering such cases.
We report a case of severe Chlamydophila (Chlamydia) psittaci pneumonia rapidly diagnosed by detection of antigen in sputum with an immunochromatography assay. The patient was admitted to our hospital because of shock, disturbance of consciousness, accidental hypothermia, and multiple organ dysfunction syndrome, and he recovered after administration of intravenous erythromycin and high-dose methylpredonisolone therapy. Psittacosis was confirmed by detection of 16S rRNA gene of C. psittasi in sputum with multiplex-polymerase chain reaction analysis. Serological responses to C. psittasi, C. trachomatis, and C. pneumoniae were also evaluated, and serological cross-reactivity was observed between each species. We consider that the commercially available immunochromatography assay for Chlamydia species can be helpful for rapid diagnosis of Chlamydia infection of the respiratory tract. Hereafter, further examination will be necessary regarding pretreatment of specimens or detection sensitivity and specificity.
Tsutsugamushi disease has been a notifiable disease in Japan since the implementation of the Infectious Diseases Control Law in April 1999. In order to assess the role of public health laboratories in detecting Tsutsugamushi disease, a questionnaire regarding routine testing of suspected cases of Tsutsugamushi disease was sent to 73 regional public health laboratories (47 prefectural laboratories and 26 municipal laboratories) in July 2001. The response rate was 92% (67/73 laboratories). It was found that most prefectural laboratories are well prepared to routinely receive and test specimens of suspected Tsutsugamushi disease cases. Additionally, we found that some regional public health laboratories are using two or more detection methods to improve the accuracy of their routine tests. In southern Japan. Kawasaki and Kuroki strains, strains endemic to the region, are widely used in addition to Kato, Karp, and Gilliam strains, the standard strains used for serum antibody tests in Japan. For the years 2000 and 2001, we found that for some prefectures, the annual number of cases confirmed by regional public health laboratories was nearly equal to the annual number of cases the prefecture reported to the National Notifiable Diseases Surveillance System. In these prefectures, it appears that an effective communication network has been established between physicians, public health laboratories, and local health centers, ensuring laboratory confirmation and proper notification.
The purpose of the present study was to develop an optimal method for culturing Simkania negevensis. Centrifugation was effective for the propagation of S. negevensis, but sonication was not effective. The addition of cycloheximide to the culture medium significantly decreased the number of inclusions. Pretreatment of host monolayers with diethylaminoethyl-dextran or polyethylene glycol was detrimental. The most optimal conditions were centrifugation of the inocula onto untreated Vero cells, and culture in RPMI 1640 medium containing 10% fetal calf serum without cycloheximide or antimicrobial agents.
Detection of Coxiella burnetii, the etiologic agent of Q fever, is important for diagnosis of Q fever. PCR-based methods have been widely used for the detection mostly because isolation of C. bumetii is time-consuming. Recent reports showed that PCR-positive rates of Q fever infection widely differed. We have evaluated the PCR and nested PCR assays currently used in Japan. The nested PCR assay detected as few as 6 microorganisms and was 10 times more sensitive than the regular PCR assay. The nested PCR assay did not show any non-specific bands with 12 other bacteria, whereas the PCR assay showed some extra bands for 5 of the 12 bacteria. These results suggest that the nested PCR is more sensitive and specific than the PCR in the detection of C. burnetii. However, nested PCR generally has a risk of cross-contamination during preparation of the 2nd PCR. Using blood specimens serially collected from an acute Q fever patient, the PCR and the nested PCR assays gave very similar results, suggesting that sensitivity of the PCR assay is at an achieved level of the detection for clinical specimens although the nested PCR assay is more sensitive. It is recommended that both the PCR and nested PCR assays should be performed for the detection of C. burnetii to obtain reliable results.
Three patients developed acute Q fever after returning from an inspection tour of farms and abattoirs to Australia. Serum levels of antibodies to Coxiella burnetii and the presence of C. burnetii-DNA in blood samples were examined for more than 100 days. Four-fold raises of IgM and IgG antibodies against C. burnetii phase 2 were observed within the first three weeks in all the three cases. Maximum titers of IgM and IgG antibodies were 1,024-2,048 and 512-4,096, respectively. According to the temporal diagnostic criteria of acute Q fever in the convalescent serum: the IgM titer of > or = 64 and IgG titer of > or = 512 against phase 2, patient A, B and C were determined to be antibody positive for 45, 199 and 122 days, respectively. The result suggests that this standard is practical and reasonable for diagnosis of acute Q fever. C. burnetti-DNA was detected in the sera and buffy coat samples of patient A who developed high fever, severe thrombocytopenia and liver disfunction, but not in those of patient B and C. This study provides useful information for optimization and standardization of Q fever diagnosis in Japan.
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In vitro inhibitory effects of tea polyphenols on Chlamydia trachomatis and C. pneumoniae were investigated. A product of tea polyphenols, Polyphenon 70S was used. Chlamydial strains used were C. trachomatis D/UW-3/Cx and L(2)/434/Bu, and C. pneumoniae AR-39 and AC-43 strains. HeLa229 cells and HL cells were used for cultivation of C. trachomatis and C. pneumoniae, respectively. In the post-inoculation method, no inclusions of C. trachomatis were observed at 0.5 mg/ml of Polyphenon 70S. However, the toxicity of Polyphenon 70S was noted in HeLa229 cells and HL cells at a concentration of 0.25 mg/ml. In the pre-inoculation method, no toxic effects of Polyphenon 70S on the cells were noted. Complete inhibition of C. trachomatis D and L(2) was noted at concentrations of 1.6 and 0.4 mg/ml, respectively. With C. pneumoniae strains, the end points were 0.8 and 1.6 mg/ml for AR-39 and AC-43, respectively. Our findings encouraged the application of tea polyphenols for topical usage.
After an inspection tour to farms and abattoirs in Australia and New Zealand, three Japanese persons simultaneously developed febrile illnesses in Japan. They generally had slight fever and general fatigue, followed by thrombocytopenia and hepatic dysfunction. However, no respiratory symptoms were observed. In one of the cases, severe thrombocytopenia (1.3 x 10(4)/microliter) and high fever up to 40 degrees C were observed. These clinical symptoms were compatible with Q fever. All of the cases showed four hold-elevations of IgM and IgG against Coxiella burnetii phase II between acute and convalescent sera by a serological test. C. burentii-DNA was also detected in the serum of one patient. Minocycline was highly effective in all cases. This report illustrates the typical clinical courses of acute Q fever.
Surveillance for scrub typhus was conducted in Japan in 1998 using a questionnaire. A total of 462 cases were reported. Scrub typhus occurred in both the fall and spring in the northern part of Honshu (the main island), and in the fall in the central part of Honshu and on the island of Kyushu. The occurrence of the disease varied with age, gender, and activity. Seventy-six percent of the patients were more than 51 years old, and 36% and 16% of the patients were engaged in farm work and forestry, respectively. Fever, rash, and eschar were detected in 98%, 93%, and 97% of the patients, respectively. Elevated levels of C-reactive protein, aspartate transaminase, and alanine transaminase were detected in 96%, 87%, and 77% of the patients, respectively. Disseminated intravascular coagulation developed in 34 cases and had a unique regional distribution. This study shows the status of scrub typhus in Japan in 1998 and provides important information for diagnosis and prevention.