We isolated two strains (A/Ishikawa/42/98 and 43/98) of influenza A (H1N1) virus, which are antigenically different from A/Beijing/262/95, from school children who had an influenza like illness in November, 1998 in Ishikawa Prefecture. Although the HI antibody prevalence rate against A/Ishikawa/42/98 was quite low in all age groups tested, this virus did not cause an outbreak until the end of 1999.
In our country, A/Ishikawa/42/98 like virus caused an outbreak after January, 2000, and was interestingly shown to possess similar HA antigenicity to that of A (H1N1) that had caused an outbreak in New Caledonia in May, 1999. Based on these observations, we speculate that A/Ishikawa/42/98 might so change in some unknown viral property during seasons from 1998/99 to 2000 as to cause an outbreak. The analysis of the viral property involved in the occurrence of the outbreak, therefore, seems to be important to prevent an occurrence of influenza outbreak

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We tested the antimicrobial activities of meropenem (MEPM), imipenem (IPM), panipenem (PAPM), piperacillin (PIPC), cefepime (CFPM), aztreonam (AZT), amikacin (AMK), and levofloxacin (LVFX) against 106 clinical Pseudomonas aeruginosa isolates and 64 clinical Acinetobacter spp. iso lates with reduced susceptibility to carbapenems. Using NCCLS breakpoints, the percentages of P. aeruginosa strains susceptible to AMK and Acinetobacter spp. strains susceptible to LVFX were found to be 51.1% and 55.6%, respectively, which represented the highest activity among 8 antimicrobial agents in each organism. Referring to the correlations among MICs of carbapenems, MEPM showed a higher activity than IPM and PAPM in both organisms; 29 of the 94 strains (30.9%) of IPMresistant P. aeruginosa were susceptible to MEPM. Further study for resistance mechanisms to carbapenems by the disk diffusion method using 2-mercaptopropionic acid revealed that 8 of the 64 Acinetobacter spp. isolates (12.5%) were metallo-β-lactamase producers, while none of 106 P. aeruginosa isolates were metallo-β-lactamase producers. PCR analysis using blaIMP-specific primers confirmed that 4 of the 8 metallo-β-lactamase-producing Acinetobacter spp. isolates detected by the disk diffusion method were carrying the bla_IMP gene. The identification of metallo-β-lactamase-producing Acinetobacter spp. isolates implies that metallo-β-lactamase genes have been disseminated among various gramnegative pathogens.

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A total of 1035 household dogs were examined for the presence of Giardia lamblia (G. lamblia) in their feces. Fecal samples from 151 (14.6%) of the dogs were positive for Giardia. The protozoan was more often detected in soft feces (26.4%) than in normal (10.0%) or diarrheic feces (13.7%) (p<0.001 and p<0.01, respectively). The forms of the organisms obtained from the 151 dogs were cysts (77.5%), trophozoites (9.9%), or both cysts and trophozoites (12.6%). Dogs kept indoors had a higher prevalence (18.5%) of Giardia than dogs kept outdoors (4.8%) (p<0.001). Giardia infection was also more prevalent in 1-6 months old puppies (21.7%) compared to other groups (2.4%-7.5%) (p<0.001). The prevalence of Giardia in dogs originally purchased from pet shops or breeding kennels was extremely high (21.5%) compared to that of dogs from individual households (4.3%) (p<0.001)
With regard to human public health, the high infection rate of Giardia in puppies and dogs kept indoors is a serious problem because G. lamblia in infected dogs may have zoonotic potential. No reports of human giardiasis transmitted from dogs have been made. However, the results of this study suggest that the risk of Giardia transmission from household dogs to humans is not negligible. Pet owners should be taught appropriate hygiene measures to prevent Giardia transmission from dogs to humans.

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The anti-biofilm effect of a newly developed antibacterial coating, a mixture of a silver citrate, soybean lecithin and liquid silicon at the ratio of 2: 2: 8, for silicon catheters was investigated in an in vitro experimental system using a modified Robbins device. The inhibitory effect against bacterial adherence, killing effect against adhered bacteria and durability of these anti-biofilm effects were examined using two strains of Pseudomonas aeruginosa and one of Escherichia coli. Almost complete inhibition of bacterial adherence was demonstrated in the case of one of two strains of P. aeruginosa andE. coli. The more resistant strain of P. aeruginosa OP 14-210 adhered at scattered sites of the silicon. with antibacterial coating, while mature biofilm developed on the surface of the silicon without coating.Using already adhered P. aeruginosa OP 14-210, we confirmed the killing effect of silver ion released by this new coating. These anti-biofilm effects did not change after treatment with artificial urine for at least 48 hours.

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A middle-scale epidemic of measles was occurred in Chiba Prefecture, from the beginning of the year in 2000 to September. The Chiba epidemiological surveillance of tuberculosis and infectious diseases committee conducted an investigation of the vaccination history of measles patients, to obtain the prevailing situation of measles and the efficacy of the vaccination. This report summarized results of the epidemiological investigation of measles vaccination history. A total of 1, 665 cases were reported during the period. The ratio of the under 1-year-old (who usually do not receive measles vaccine) to all reported cases was 11.4%. The ratio of the vaccinees for the reported cases was 11.8% and this ratio increased in the 5 years old or over. In particular, the 9-year-old age group (26.2%), and 10-14-year-old age group (23.3%) showed a higher ratio than the other age groups. These results indicate that early vaccine inoculation to the under 1-year old group and improvement of the vaccination rate are necessary to prevent measles epidemic. The results also suggest revaccination to higher age groups might be effective.

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A 62-year-male presented a high fever and a dry cough during a trip to Australia. He was admitted to a hospital as soon as be returned to Japan. The next day after returning to Japan, he was transferred to our hospital with septic shock and loss of consciousness. Neisseria meningitidis was cultured from his blood. N. meningitidis is rare in Japan. However its seems common, in some foreign countries. With these findings, it can be postulated that N. meningitides might be one of the etiological agents of the imported infectious disease.

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We report a case of a 53-year-old male with Vibrio cholerae non-O1 (serotype O19) infection, resulting in perforative pan-peritonitis. The patient had a history of gastric cancer and a gastrectomy was performed one year prior. The patient had previously been admitted with nausea and vomiting and was diagnosed with a sub-ileus condition. He was provisionally discharged when his condition improved and during that period he ate raw fish caught locally in Nagasaki Prefecture, and several hours later he experienced a sudden onset of severe abdominal pain and nausea and on diagnosis of pan-peritonitis an emergency resection of the transverse colon was performed. We subsequently isolated Vibrio cholerae non-O1 from the patient's peritoneal fluid and stool. He died of multiple organ failure three weeks later despite intensive chemotherapeutic care and treatment for shock and disseminated intravascular coagulation. The strain of Vibrio cholerae non-O1 isolated was non-toxigenic but hemolytic with hyper-producing of metalloprotease.

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