In world leprosy nowadays, a favorable epidemiologic trend has been provided due to the best effort of the worldwide campaign with chemotherapy providing a bright but one-sided look at the future. However, the numbers of new patients are still higher than those under chemotherapy, leaving a concern over the remaining non-human source of infection. To overcome that plausibility, overall understanding of the etiology of the disease should be improved. The author discussed this by the analyses of historical and scientific legitimacy of the current idea about the etiology of leprosy that have unreasonably rejected the possibility of dual infections in relation to that of Mycobacterium leprae. The analyses also consider the author’s ongoing effort to know the feasibility of artificial culture of M. leprae by improving of the former methods reported by Skinsnes et al. and has been rejected as it contained Mycobacterium scrofulaceum, without attention to the coexistent M. leprae at that time. The bacillus thus maintained with the modification of the medium still shows PGL-1 immunoreactivity and the pathogenicity to cause neuropathy in mice. These strongly suggest the coexistence of the above two bacilli throughout past years. The genomic study is in progress to prove that hypothesis, the genomes should be alike in nature if proven.

To evaluate the serogrouping-based diagnosis of diarrheagenic Escherichia coli, a total of 1,130 strains of E. coli isolated in several countries were studied. The strains were regarded as enterovirulent on the basis of their O-antigens determined using a commercially available kit containing 43 antisera, and the presence of diarrhea-associated genes (eae, stx, aggR, est, elt, ipaH) was evaluated by PCR. Two hundred sixty-three strains of 1,130 (23.3%) were identified as diarrheagenic based on the presence of at least one pathogenic gene. The probability that E. coli identified as diarrheagenic on the basis of serogrouping actually possessed some pathogenic gene was highest for serogroup O119 (78.4%); other serogroups with a positive rate for pathogenic genes higher than 60% were O111 and O126. No target genes were detected among the strains belonging to serogroups O1, O29, O112ac, O143, O158 and O168. Our results suggest that, in practice, serogrouping is useful for the identification of diarrheagenic E. coli in a very limited number of serogroups.

Klebsiella pneumoniae is the leading cause of liver abscess in diabetic patients in Taiwan. We report the case of a diabetic patient with a history of four episodes of K. pneumoniae liver abscess within 3 years. The patient later developed Streptococcus bovis bacteremia originating from a colon tumor with complications of endocarditis, osteomyelitis, and silent splenic abscess. Occult colon tumor may have played an important role in our case, with recurrent infection arising from colonizers of the gastrointestinal tract. As our case shows, the possible association between occult colon tumor and K. pneumoniae liver abscess in diabetic patients should be surveyed.

A 4-year retrospective population-based survey was conducted in two cities in Akita Prefecture, Japan, to estimate the incidence rate and the cumulative risk of hospitalization potentially associated with rotavirus diarrhea. At monthly occasions of the 3-year-old checkup, we asked each parent if his or her child had ever been hospitalized because of rotavirus diarrhea. Based on 3-year follow-up of the four consecutive birth cohorts (1996-1999), we calculated the incidence rate and the cumulative risk of rotavirus-associated hospitalizations by the age of 3 years. The incidence rates of rotavirus-associated hospitalization in 1-year-old children in Akita city and Honjo city were 9.7 and 16 hospitalizations per 1,000 children per year, respectively, whereas 1.9% of children in Akita city and 3.3% of children in Honjo city were hospitalized by their third birthday because of rotavirus-associated diarrhea. The burden of rotavirus diarrhea in this region of Japan, and probably across the nation, appears substantially large.

The accumulation kinetics of the abnormal form of prion protein (PrP^Sc) in spleens and brains of scrapie (Obihiro-1)-infected mice at various times after intracerebral (i.c.), intraperitoneal (i.p.), or oral inoculation were studied. PrP^Sc was first detected by Western blotting with anti-prion protein antibodies on days 70 and 116 after i.c. (3 μg) in spleens and brains, respectively. Although the amount of cerebral PrP^Sc gradually increased to the maximum level on day 152 after i.c. inoculation, splenic PrP^Sc established the maximum level on day 116 after i.c. inoculation then registered slight decreases up to day 152 with further incubation. The detectable levels of cerebral PrP^Sc by Western blotting were established on day 231 or 259, whereas those of splenic PrP^Sc were detected on day 94 or 93, after i.p. and oral infection, respectively. The splenic PrP^Sc decreased slightly thereafter. These results indicate that splenic PrP^Sc increased before cerebral PrP^Sc established a detectable level in a manner independent of the inoculation route.

Hepatitis B virus (HBV) surface antigen (HBsAg) is one of the most important serological markers of current HBV infection. However, there are significant antigenic variations of HBsAg caused by genotypic diversity as well as mutation of the HBV genome. It is predictable that amino acid substitutions occurring in the HBsAg “a”determinant of a particular HBV genotype will affect the sensitivity of some diagnostic kits, since all the diagnostic kits currently available utilize monoclonal and/or polyclonal antibodies against the “a” determinant. One possible concern is that there may be a significant variation in the sensitivity of HBsAg diagnostic kits to HBsAg encoded by HBV of different genotypes, which might result in a failure to detect HBsAg of a particular HBV genotype. In this study, we assessed the reactivity of HBsAg specimens derived from three different HBV genotypes (A, B, and C) that are prevalent in Japan by 10 commercially available EIA (enzyme immunoassay), CLIA (chemiluminescent immunoassay), and CLEIA (chemiluminescent enzyme immunoassay) diagnostic kits. Specimens included both clinical samples and recombinant HBsAg. Our results showed that all the diagnostic kits evaluated were able to detect HBsAg irrespective of HBV genotypes. At the same time, it is apparent that some, but not all of the kits showed clear differences in sensitivity to the three HBV genotypes.

In order to establish immunological detection methods for severe acute respiratory syndrome coronavirus (SARS-CoV), we established monoclonal antibodies directed against structural components of the virus. B cell hybridomas were generated from mice that were hyper-immunized with inactivated SARS-CoV virion. By screening 2,880 generated hybridomas, we established three hybridoma clones that secreted antibodies specific for nucleocapsid protein (N) and 27 clones that secreted antibodies specific for spike protein (S). Among these, four S-protein specific antibodies had in vitro neutralization activity against SARS-CoV infection. These monoclonal antibodies enabled the immunological detection of SARS-CoV by immunofluorescence staining, Western blot or immunohistology. Furthermore, a combination of monoclonal antibodies with different specificities allowed the establishment of a highly sensitive antigen-capture sandwich ELISA system. These monoclonal antibodies would be a useful tool for rapid and specific diagnosis of SARS and also for possible antibody-based treatment of the disease.

Erythema infectiosum (fifth disease) is the major clinical manifestation of human parvovirus B19 (HPV B19) infection. HPV B19 is known to be associated with adverse effects on fetuses such as hydrops fetalis, aplastic anemia, intrauterine fetal death, and chronic anemia in immunocompromised individuals. The objective of this study was to assess seroprevalence to HPV B19 in three different groups in Shiraz, Iran. The first group included 91 to-be-married girls. The second group included 184 pregnant women and the third group consisted of 184 neonates, who were born to the women in the second group. Specific IgG and IgM antibodies to HPV B19 were measured using ELISA technique. Results showed that the prevalence for IgG to HPV B19 was 56 (61.5%), 127 (69%), and 127 (69%) for the first, second, and third groups, respectively. Overall, 183 out of the 275 (66.5%) women of childbearing age had IgG to HPV B19. The seroprevalence for IgM to HPV B19 was 2.2% for the second group. There was no detectable IgM in umbilical cord sera or in the first group blood samples. In conclusion, approximately one-third of individuals in the study who were of childbearing age were at risk for primary HPV B19 infection.

We investigated a measles virus (MV) outbreak that occurred at a junior high school in Yamagata, Japan between January and February, 2004. We received throat swab specimens from three patients at this school and carried out virus isolation with Vero/hSLAM cells and virus genome detection by reverse-transcription polymerase chain reaction. As a result, we isolated the virus from one patient and succeeded in amplifying the MV genome from the others. Further sequence analysis of the N gene revealed that these viruses were completely identical, and that their genotype could be characterized as type D9, which has not been reported in Japan previously. We also identified D9 viruses in two students at other junior high schools in Yamagata. These results suggested that D9 strains were imported from a region outside Japan. The genotypes of MVs found in Yamagata have changed in recent years, with D5 predominating in 2001 and H1 predominating in 2002 and 2003 as reported as national surveillance data. Therefore, we should monitor carefully to be sure that D9 strains do not become the next predominant virus. The more the number of measles cases decrease, the more important become the roles of public health laboratories, which genotype MVs and monitor their circulation and transmission pathways.

Enterococci are one of the leading causes of nosocomial infections. In recent years, enterococci have become increasingly resistant to a wide range of antimicrobial agents. From April to October 2001, a study was conducted to speciate and determine the antimicrobial susceptibility of 50 isolates of enterococci from bacteremic children. These isolates were tested for antimicrobial susceptibility to the commonly used antibiotics. Screening for vancomycin resistance was done by the agar screen method, and the results were confirmed by determining the minimum inhibitory concentration (MIC) using the agar dilution method. It was observed that 33 isolates were Enterococcus faecium, followed by E. faecalis (10), E. durans (4), and E. dispar (3). Seventy-two percent of strains were resistant to ampicillin, 46% to amoxicillin + clavulanic acid, 72% to ciprofloxacin, 54% to doxycyclin, and 74% to erythromycin. Sixty-six percent of isolates showed high-level gentamicin resistance and 42% showed high-level streptomycin resistance. Four strains showed raised MIC to vancomycin (8 μg/ml). It was concluded that multidrug resistant E. faecium is emerging as an important agent of bacteremia in children.

This study aimed to determine the levels of the macrolides-lincosamides-streptogramins B (MLS_B) resistance phenotype in Staphylococcus aureus and coagulase-negative staphylococci (CNS) isolates from clinical samples. A total of 521 strains of staphylococci, comprising 230 S. aureus and 291 CNS isolates from various clinical samples, were identified by conventional methods. The double-disc test was applied by placing erythromycin and clindamycin discs on these isolates to investigate the inducible and constitutive MLS_B resistance phenotypes and MS phenotype. Among the S. aureus strains, 24.3% showed the constitutive and 7.8% the inducible phenotype, while there was no MS phenotype. In the CNS strains, 40.2% showed the constitutive and 14.7% the inducible MLS_B resistance phenotype, and 18.2% had the MS phenotype. In both S. aureus and CNS strains, the constitutive MLS_B resistance rate was found to be higher than the rate of inducible resistance. By applying double-disc tests on a routine basis to detect inducible MLS_B resistance, clindamycin can be effectively used on staphylococcal infections. Additionally, it can be used to survey the MLS_B resistance of staphylococci strains from specific geographical regions or hospitals.

The aim of this study was to determine the neopterin levels and peripheral blood lymphocyte subgroups in HBeAg-positive and -negative chronic hepatitis B patients. A total of 89 patients were included in the study. The mean serum neopterin level of patients with chronic hepatitis B was significantly higher than that of the control group. In HBeAg-positive chronic hepatitis B patients, the mean serum neopterin level was significantly higher than that of anti-HBeAb-positive patients. There was no significant correlation between the serum neopterin levels and alanine aminotransferase and HBVDNA levels in HBeAg-positive chronic hepatitis B patients. There were no significant differences between the control subjects and patients with HBeAg-positive or anti-HBeAb-positive hepatitis in terms of the percentage of peripheral blood CD4⁺ or CD8⁺ or the ratio of CD4⁺/CD8⁺ lymphocytes. Our results suggest an association between elevated neopterin concentrations and HBeAg-positivity in patients with chronic hepatitis B. However, there appears to be no association between the neopterin levels and either hepatocyte damage or viral replication status.

We report the results of a prospective study conducted among asymptomatic children of slum dwellers in Kolkata, eastern India, to assess the prevalence of Cryptosporidium parvum during the period of October 2002 to July 2003. Of the 609 fecal samples examined, C. parvum was detected in 14 (2.3%). The study indicated that poor sanitary conditions may be cofactors for the cryptosporidial disease burden among slum dwellers. The implications of asymptomatic infections have been discussed.

A 53-year-old man visited Mt. Arashima-dake in Fukui Prefecture, and was infested by a tick-like organism. He visited a local clinic on July 12, 2004, complaining of high fever, general fatigue and rash. After several days without definite diagnosis, he was admitted to the Fukui Prefectural Hospital, where he was treated with minocycline hydrochloride for 10 days until recovery. His clinical symptoms on admission were high fever (39.6°C), erythematous eruption, eschar on the right upper arm, and regional lymphoadenopathy. The epidemiological status and some clinical findings strongly suggested spotted fever (SF), and SF was confirmed based on the finding that his sera were reactive only to antigens of the SF group rickettsiae in the indirect immunoperoxidase analysis. This case is the first official report of SF rickettsiosis in Fukui Prefecture, the northern part of central Japan.

We obtained rabies-specific egg yolk antibodies (IgY) by immunizing hens with recombinant His-tagged nucleoprotein and phosphoprotein (rN, rP) of the rabies virus (CVS-11 strain) expressed in Escherichia coli. The anti-rN and rP IgY were shown to bind specifically to the respective proteins of the CVS-11 strain of rabies virus by Western blotting, immune fluorescent assay and immunohistochemistry, indicating that IgY to rabies recombinant proteins could serve as a reagent for diagnosis of rabies virus infection.