[Enhancement of norovirus detection rates in oysters and other food samples by using bacterial treatment].

Factors such as low recovery rate and food contaminants may be responsible for the difficulty of detecting Norovirus (NV) by PCR in foodborne outbreaks. To detect NV more efficiently, we introduced a bacterial treatment, in which concentrated samples were incubated overnight with Klebsiella oxytoca at 35 degrees C before RNA extraction using the standard protocol. Recovery rates of NVs (G I/8 or G II/13) added to food suspensions in the modified method were compared with those in the standard method by quantification of NV RNAs using real-time PCR. Recovery rates in the modified method were 8.6% for G I/8 and 11.6% for G II/13 in 18 oyster samples and 13.9% for G I/8 and 19.6% for G II/13 in 15 other food samples, while those in the standard method were 0.3% for G I/8 and 0.5% for G II/13 in the oyster samples and 1.9% for G I/8 and 7.9% for G II/13 in the other food samples. These results indicate that the bacterial treatment increase the recovery of NV from foods such as oysters, suggesting that the modified method will be useful for NV detection in food samples.

[Effects of hand hygiene on feline calicivirus inactivation and removal as norovirus surrogate treated with antiseptic hand rubbing, wet wipes, and functional water].

As a preventive action plan against gastroenteritis caused by the Norovirus (NV), we studied hand hygiene effects using with three hand rubbing products, four wet wipe products, and two functional water types using Feline Calicivirus as a Norovirus surrogate. After treatment using antiseptic hand rubbing products containing chlorhexidine, quaternary ammonium, and povidone-iodine, high inactivation detected by TCID50 was observed compared to products containing povidone-iodine, although no difference was seen in viral removal measured by the amount of viral genome copies in real-time-PCR. Among wet wipes soaked in chlorhexidine, quaternary ammonium, benzoic acid and PHMB, two groups showed viral inactivation and removal. Two products were more effective for functional water, viral decrease was seen in rinsing in running electrolyzed acid water and handwashing by soap. Results underscore the importance of selection in hand washing metheds (alternative soap and also) in preventing viral gastroenteritis.

[Effects of handwashing on Feline Calicivirus removal as Norovirus surrogate].

Viral gastroenteritis caused by Norovirus (NV) mainly appears during the winter season. In fact, outbreaks and patients with NV gastroenteritis are the major cause of community disease in the winter. Strategies to avoid gastroenteritis caused by NV are thus needed. No effective method for evaluating virus inactivation and removal exists for of NV, which cannot be cultured using cell-lines. Trials using Feline Calici Virus (FCV; a member of the calicivirus family) as a NV surrogate have been conducted by culturing FCV in CRFK cells. By washing one's hands, about 99% of the viruses can be removed, compared with simply rinsing one's hands in running water. Washing one's hands with alcohol, chlorhexidine, quaternary ammonium, or 3 other kinds of hand soaps (containing povidone-iodine, triclosan, and isopropylmethyl phenol, respectively), was also effective for removing viruses. These results suggest that washing one's hands may be an effective method of preventing viral gastroenteritis.

Multiple viral infections and genomic divergence among noroviruses during an outbreak of acute gastroenteritis.

An epidemic outbreak of both norovirus (NV) and astrovirus (ASV) occurred on a research ship surveying Tokyo Bay, causing acute gastroenteritis in 26 of its 37 crew members. The presence of viral pathogens in fecal specimens was analyzed, and noroviruses were identified by reverse transcription-PCR in 18 (48.6%) of these specimens. In addition, astroviruses were identified in 14 (37.8%) of the fecal samples from the affected crew members, and multiple viral infections of both NV and ASV were observed in 6 cases. The genogrouping of the NV-positive samples was then examined by dot blot hybridization, and it was determined that all of the isolates were from genogroup II (GII). No bacterial pathogens were subsequently isolated from fecal specimens. Furthermore, a variety of NV strains were identified by sequencing and single-stranded conformational polymorphism (SSCP) analyses of PCR products from the fecal samples. One recombinant NV isolate, Minato/14, was identified as a recombinant NV strain of GII/6 and GII/1. The other NV isolates from this outbreak were classified into three NV genotypes (GII/1 [Minato/10], GII/4 [Minato/33], and GII/5 [Minato/6]). Furthermore, ASVs in positive samples were determined to belong to serotypes 1 and 2 by sequencing analysis. Our findings thus indicate that coinfections with NV and ASV, including a number of NV genotypes, persisted during an outbreak of gastroenteritis in a closed environment.

[Comparison of the number of Norovirus genome copies in patients and healthy persons].

In viral gastroenteritis outbreaks occurred by Norovirus (NV), NV was detected not only from patients but also from healthy persons who have taken the same food, and also detected from healthy staff members working at community places such as hospital, school and nursing home. The number of fecal NV genome copies of patients, healthy persons and food handlers are examined by real-time PCR method, to investigate foodborne gastroenteritis and person to person transmission outbreaks. There is no significant difference on the number of NV genome copies in feces between patients, and NV-detected healthy persons. Those result indicate asymptomatic carrier of NV who were working as food handlers or staff members at community places will become an origin of food-borne gastroenteritis or person to person transmission outbreaks.

[Community gastroenteritis caused by adenovirus type 41].

Viral gastroenteritis is caused mainly by NV (Norovirus). Rotavirus, Astrovirus and Adenovirus are the major cause of gastroenteritis in humans although there are rare cases. From the end of June to the beginning of July 2002, we had an endemic of community gastroenteritis by Adenovirus. In our investigation, the patients were separated into 3 groups. On comparison of the viruses from each groups we observed that they had the same characteristics. In conclusion, we found that the infection was caused by person to person contact and not by food.

[An epidemic of rotavirus infection in a nursing home for the elderly in Japan].

An outbreak of diarrheal disease in a Japanese home for aged is reported. Out of 202 residents, 47 cases complained of diarrhea (23.3%) during a month. Clinical symptom were diarrhea (100%) vomiting (40.4%) and fever (31.9%). Fecal examination of 9 cases revealed positive A-group rotavirus antigen. Bacterial and small round shaped virus infection was excluded. Examination of rotavirus antibody, CF titer was positive in about 50% in each age group but the titer decreased year by year. In Japan, rotavirus infection has been epidemic only in nursing home for baby and titer of antigen has been believed to be sustain by repeated provocation. However, Japanese situation is changing to be west Europe and north America.