Detection of norovirus antigens from recombinant virus-like particles and stool samples by a commercial norovirus enzyme-linked immunosorbent assay kit.

The commercial norovirus enzyme-linked immunosorbent assay kit was evaluated for its reactivity to recombinant virus-like particles and the detection of natural viruses from stool samples of Japanese infants and children with sporadic acute gastroenteritis compared to reverse transcription-PCR. The kit had a sensitivity of 76.3% and a specificity of 94.9%. Our results clearly indicated that the kit allows the detection of the most prevalent genotype, GII/4. In order to increase the sensitivity of the kit, the reactivity with norovirus of GII/3 and GII/6 genotypes needs to be improved.

Interleukin 8 in the human colostrum.

We investigated the postpartum changes in colostral interleukin (IL) 8 concentrations during the first 3 postpartum days and examined the IL-8 production of colostral cells at the levels of both protein and mRNA. Colostrum samples were obtained from healthy mothers after full-term delivery. Colostrum, supernatants, and cell lysates of cultured colostral cells were assayed for IL-8 by enzyme-linked immunosorbent assay. Reverse-transcription polymerase chain reaction was used to test uncultured colostral cells for the production of IL-8 mRNA. The colostral IL-8 concentrations, especially high on day 1 postpartum, declined abruptly during the first 3 postpartum days (mean 19.7, 10.0, and 3.0 ng/ml on days 1, 2 and 3 postpartum, respectively). Colostral cells apparently produced and secreted IL-8 in in vitro culture without stimulant, although in smaller quantities than with lipopolysaccharide stimulation. The majority of uncultured colostral cell samples expressed IL-8 mRNA, suggesting a role of colostral cells, at least in part, as a source of colostral IL-8.

Molecular epidemiology of viral gastroenteritis in Asia.

Acute gastroenteritis is one of the most common diseases in humans, and continues to be a significant cause of mortality and morbidity worldwide. Recently the estimates of mortality associated with diarrhea declined, however the majority of deaths still occur in developing countries and thus urgent intervention is needed for the prevention of these diseases. In Asian countries it is very important to study the distribution, transmission and characteristics of prevalent viruses in order to produce viral vaccines. The viruses which cause gastroenteritis are primarily from four distinct families - group A rotaviruses, caliciviruses, enteric adenoviruses and astroviruses. Rotavirus is a common virus that causes severe gastroenteritis in children <5 years of age. The reassortant viruses with animal virus, or directly animal viruses are isolated in humans. The future development of a safe and effective vaccine against rotavirus, along with the expansion of understanding of the distribution of types in Asia and an availability of rapid diagnostic tests, could reduce mortality and might be able to prevent severe gastroenteritis. Calicivirus is a causative virus of acute gastroenteritis in children and has been known to contaminate food causing viral outbreaks affecting people of all ages. Recently, the understanding of calicivirus and the improvement of detection techniques has increased the total frequencies of diarrheal viruses. For the future control and prevention of diarrheal diseases it is necessary to examine the molecular epidemiology of caliciviruses as well as rotaviruses.