Processing procedures for recovering enteric viruses from wastewater sludges.

A powdered beef extract specially formulated for recovering viruses from environmental samples and designated as beef extract V was evaluated using indigenous and viral seeded wastewater sludge samples. When beef extract V was used to process activated and aerobically digested sludge solids, virus recoveries were shown to be similar to other methods that used commercially available supplemented beef extract. When used to process other sludge solids (primary and activated without primary clarification), cytotoxicity resulted in the BGM cell line used for virus assay.

The species concept and its application to tailed phages.

A recently proposed polythetic definition of virus species appears easily applicable to bacteriophages. Criteria for classification of tailed phages are evaluated. Morphology, DNA homology, and serology are the most important criteria for delineation of species, but no single criterion is satisfactory.

Factors affecting virus plaque confirmation procedures.

Direct plaque counts obtained by using the monolayer cell culture assay technique reliably confirmed the number of viruses isolated. Analysis revealed some significant differences in the false-positive rate, depending on the test method used or virus samples evaluated. Plaques from laboratory stock viruses showed a higher confirmation rate than sewage plaque isolates.

Isolation of enterovirus and reovirus from sewage and treated effluents in selected Puerto Rican communities.

Sewage treatment plant effluents were surveyed for viral contributions to gastroenteritis outbreaks in Puerto Rico. Of the 15 sewage treatment plants studied, all discharged their effluents upstream from water treatment plant intakes. No base-line data on the degree of viral challenge to these sewage treatment plants or the subsequent reduction of viruses before discharge existed.

Assessment of recovery efficiency of beef extract reagents for concentrating viruses from municipal wastewater sludge solids by the organic flocculation procedure.

This study was designed to assess the capacity of beef extract reagents to form flocs suitable for virus adsorption. Reagent comparisons resulted in the establishment of a modified organic flocculation procedure to concentrate viruses desorbed from sewage sludge solids with currently available modified powdered beef extracts. The method, based on supplementation with paste beef extract floc, achieved virus recoveries comparable to those obtained with powdered beef extract produced before a 1979 change in the manufacturing process.

Use of bituminous coal as an alternative technique for field concentration of waterborne viruses.

A filter system that sandwiches a bituminous coal preparation between two prefilters was comparable to those presently used to recover human viruses from large volumes of water. This filter was effective over a pH range of 3.0 to 7.

Comparison of commercial beef extracts and similar materials for recovering viruses from environmental samples.

Microbiological- and food-grade beef extracts, protein hydrolytic, enzymatic and autolytic digestion products, and whole protein materials were examined for their potential effectiveness for eluting adsorbed enteroviruses from membrane filters with observed efficiencies ranging from less than 1 to 69%. Concentration of enteroviruses from solutions of these protein and protein-derived products by organic flocculation ranged in efficiency from 2 to 125%. Both elution and concentration were dependent upon virus type, as well as nature, source, and production lot of the material being tested.

Round robin investigation of methods for the recovery of poliovirus from drinking water.

Six laboratories actively involved in water virology research participated in a methods evaluation study, conducted under the auspices of the American Society for Testing and Materials Committee on Viruses in the Aquatic Environment, Task Force on Drinking Water. Each participant was asked to examine the Viradel (virus adsorption-elution) method with cartridge-type Filterite filters for virus adsorption and organic flocculation and aluminum hydroxide-hydroextraction for reconcentration. Virus was adsorbed to filter media at pH 3.

A method for concentrating viruses recovered from sewage sludges.

Buffered 10% beef extract eluates of primary, activated, and anaerobic mesophilically digested sludges were concentrated 20-fold by the Katzenelson organic flocculation procedure after diluting the beef extract in the eluates to a final concentration of 3%. The weighted mean recovery of virions from the concentrates was approximately 58% of the numbers present in the unconcentrated buffered 10% beef extract eluates. Flocculation of eluates that contained buffered 10% beef extract at times produced poor flocs.

A method for recovering viruses from sludges.

Primary, activated, and anaerobic mesophilically digested sludges were salted with MgCl2 (divalent cations) or AlCl3 (trivalent cations) and acidified to bind indigenous unadsorbed virions to the sludge solids; the sludges were centrifuged, and the adsorbed virions were eluted from the solids with buffered 10% beef extract. The elution yields with this procedure were superior to those obtained from sludges that had been salted or acidified only. Homogenization of sludges prior to other treatment did not increase the numbers of virions recovered.

Concentration of poliovirus in water by molecular filtration.

The efficiency of concentrating poliovirus 1 from distilled water samples was determined by using a recirculating-flow molecular filtration system. The most efficient recoveries were achieved against members with a 10,000 nominal molecular weight limit pretreated with flocculated beef extract. This procedure yielded a mean virus recovery of 67%.

Survival of enteric viruses under natural conditions in a subarctic river.

The survival of enteric viruses was studied in the vicinity of Fairbanks, Alaska at selected stations along a 317-km section of the Tanana River. This section was located downstream from all known domestic wastewater sources and was effectively sealed by a total ice cover. The mean flow time through the region was 7.

Observations on the Occurrence, Distribution, and Seasonal Incidence of Blue-green Algal Viruses.

Phycovirus populations were found in 11 of the 12 waste stabilization ponds studied. These populations were comprised solely of blue-green algal (BGA) viruses. Two virus types were observed, one of which was related to the previously reported LPP-1 virus.

GROWTH CHARACTERISTICS OF THE BLUE-GREEN ALGAL VIRUS LPP-1.

Safferman, Robert S. (Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio), and Mary-Ellen Morris.

BLUE-GREEN ALGAL VIRUS LPP-1: PURIFICATION AND PARTIAL CHARACTERIZATION.

The blue-green algal virus LPP-1 was concentrated by ultrafiltration and purified by density-gradient and differential centrifugation. The virus contains DNA and has a sedimentation coefficient of 548S. Electron micrographs of purified viral preparations show that the polyhedral particles have short tails, which are approximately one-fourth as long as the diameter of the head.