analysis of a 348 base-pair segment of open reading
By Ulloa, Juan Carlos, Adriana Matiz, Leonardo Laro and
The researchers of this paper used stool samples from children suffering from diarrhea in three locations around Colombia. The samples were probed by EIA, and those positive samples were confirmed through RT-PCR. On average, 4% of the stool samples tested in each site were positive for astrovirus. Assuming that the ORF2 site on the genome, a 348 base pair region, was highly conserved amongst all 8 astrovirus serotypes, this region was used to determine relationships between all serotypes based on differenbt analytical procedure. Through the region's analysis, serotypes could be placed into 2 groups of four based on the number of mutations per strain in each serotype and through neighbor joining. However, analysis of the 116 amino acid fragments from this region did not provide enough for differentiation between the serotypes. Molecular characterization techniques in which the researchers located sites of glycosylation, phosphorylation, and myristoylation did not show differences in the location of these processes in any of the serotypes. Thus, any sort of antigenic differences in the genomes must occur outside the ORF2 segment.
2) "Detection of enteric viruses and bacterial indicators in German environmental waters."
By Pusch, D., D.-Y. Oh, S. Wolf, R. Dumke, U. Schröter-Bobsin,
M. Höhne, I.
In this study, the researches examined the prevalence of astroviruses, along with other viruses, within the surface waters. The researchers used a lake outside of Leipzig, Germany, which was downstream of a sewage treatment plant. In order to analyze the prevalence of the virus, viral DNA was extracted from many different water samples and a nested PCR was used. These samples were taken from points along the course of the pipeline from the treatment facility to the lake: near the exit of the facility, midway through the pipeline, and at the lake. Between 24% and 42% of the samples taken along this pathway turned out positive for astroviruses, with the percentages decreasing as the samples were taken further from the treatment facility. This meant that astroviruses were the second-most prevalent virus in these waters, behind only enteroviruses and ahead of noroviruses, hepatitis A virus, rotaviruses, and adenoviruses. These numbers also meant that the treatment process removed a large amount of the virus from the water; sewage which had not yet been treated had 73% of the samples test positive for astrovirus. The percentage of positive results peaked in the winter time, due to the seasonal nature of the disease. The researchers also discovered that serotype 1 and 2 occurred most frequently in the water.
3) Development of antigen-capture enzyme-linked immunosorbent assay and RT-PCR for detection of turkey astroviruses."
By Tang Y, Ismail MM, Saif YM. In Avian Disease 49(2):182-8. (2005) Web access to article
Two new antigen-capture enzyme-linked immunosorbent assays
(AC-ELISAs) and two reverse transcription-polymerase chain reactions
(RT-PCRs) to detect turkey astroviruses were developed in this study.
Both RT-PCRs showed better specificity and more powerful detection of
turkey astroviruses compared with earlier data, which was based on electron-microscopy.
For example, the RT-PCR was able to detect 10.9% higher rate of turkey
astrovirus from stool samples than EM. The development of these new
diagnostic tools are important because electron-microscopy often can
not distinguish between astroviruses and other small round viruses.