Development of real-time PCR to detect oral vaccine-like poliovirus and its application to environmental surveillance.

In order to perform environmental surveillance to track oral poliovirus vaccine-like poliovirus sensitively and conveniently, real-time PCR was developed and applied to a raw sewage concentrate. The real-time PCR method detected 0.01-0.

Continuity and change of Japanese encephalitis virus in Toyama Prefecture, Japan.

To determine the mechanisms of maintenance and evolution of Japanese encephalitis virus (JEV) in a temperate zone, we attempted to isolate JEV from mosquitoes and pigs in Toyama Prefecture, Japan. A total of 87 JEVs were isolated from female Culex tritaeniorhynchus mosquitoes and pigs during 2005-2009. The prevalence of JEV in Toyama Prefecture was seasonally late in comparison with that of the virus during 1966-1972.

Widespread circulation of echovirus type 13 demonstrated by increased seroprevalence in Toyama, Japan, between 2000 and 2003.

To confirm the magnitude of an echovirus type 13 (E13) outbreak in 2002 and to evaluate whether genetic and antigenic changes in E13 influenced the occurrence of the outbreak, we measured titers of neutralizing (NT) antibody against the Toyama, 2002-240-SF, and prototype Del Carmen E13 strains among inhabitants of Toyama before and after 2002. The rate of positivity for NT antibodies against both 2002-240-SF and Del Carmen in 2003 made a remarkable upturn in children 0 to 14 years old, compared to that in 2000. Titers of NT antibody against strain 2002-240-SF of inhabitants were slightly higher than those against Del Carmen, whereas anti-E13 rabbit serum raised against either strain Del Carmen or 2002-240-SF showed almost the same titer of NT antibody against both strains.

Frequent detection of noroviruses and sapoviruses in swine and high genetic diversity of porcine sapovirus in Japan during Fiscal Year 2008.

A molecular biological survey on porcine norovirus (NoV) and sapovirus (SaV) was conducted in Toyama Prefecture, Japan, during fiscal year 2008. Both NoV and SaV were detected from swine fecal samples throughout the surveillance period, indicating that these viruses were circulating in this region. NoV strains detected in this study belonged to three genotypes that are known as typical swine NoVs.

Detection of a novel recombinant norovirus from sewage water in toyama prefecture, Japan.

Recently, the recombination event of norovirus (NoV) has been reported with high frequency, suggesting that RNA recombination is a major driving force in NoV evolution. To assess the incidence of NoV recombination in a residential area, we conducted a molecular biological survey of NoVs existing in sewage water in Toyama Prefecture, Japan. Although GII/4 was predominantly detected in sewage water that was associated with a high frequency of outbreaks caused by this genotype, other genotypes, including two types of recombinant strain, were identified during the survey period.

Genetic changes of coxsackievirus A16 and enterovirus 71 isolated from hand, foot, and mouth disease patients in Toyama, Japan between 1981 and 2007.

We characterized the genetic diversity of the complete VP1 region of coxsackievirus A16 (CA16) and enterovirus 71 (EV71) isolated from patients with hand, foot, and mouth disease in Toyama from 1981 to 2007 to evaluate the relationship between epidemics and genetic changes. The predominant genogroups of CA16 changed from B to C in 1995-1998, and genogroup C further changed from subgenogroup C1 to C2 around 2002, and to C3 in 2005-2007. The subgenogroups of the EV71 isolates were classified into B1, B4, C1, and C3 in 1983-1994, and into C4 in 1997-2006.

Continuous presence of noroviruses and sapoviruses in raw sewage reflects infections among inhabitants of Toyama, Japan (2006 to 2008).

Various genotypes of norovirus (NoV) (genogroup I genotype 1 [GI.1], -2, -4, -5, -8, -11, -12, and -14; GII.3, -4, -6, -7, -10, -13, -14, and -15), and sapovirus (SaV) (GI.

Single base substitutions in the capsid region of the norovirus genome during viral shedding in cases of infection in areas where norovirus infection is endemic.

Norovirus (NoV) infections are the major cause of food- and waterborne nonbacterial gastroenteritis in Japan. Some individuals showed long-term excretion of the virus into feces in 29 outbreaks of acute nonbacterial gastroenteritis that occurred in Toyama Prefecture, Japan, in fiscal year 2006. In one of these cases, single base substitutions from A to G in the capsid region of the NoV genome were commonly detected in two individuals during virus shedding by direct sequencing of PCR products.

Evaluation of a two-dose administration of live oral poliovirus vaccine for wild and virulent vaccine-derived poliovirus type 1, 2, 3 strains in Japan.

We evaluated the efficacy of Japan's vaccination policy, a 2-dose administration of live oral poliovirus vaccine (OPV) against wild and virulent vaccine-derived poliovirus (VDPV) type 1, 2, 3 strains, by investigating the neutralizing antibody titers of residents in Toyama Prefecture, Japan. Seropositivities against the virulent type 1 and 2 strains were more than 90%, but the values against the virulent type 3 strains were approximately 60%. Also, while geometric mean antibody titers against virulent type 1 and 2 strains were more than 180, those against the virulent type 3 strains were 58-59, and 9-12, in particular, at 10 to 19 y of age.