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D5244-92 – Standard Test Method Technical Guide
📐 Scope and Key Definitions
This practice covers a uniform procedure for concentrating viruses from water samples using a virus adsorption-elution cartridge filter method. It applies to drinking water volumes of 400 L or more, and is also suitable for sewages, effluents, and surface waters without technical modifications. While designed for human enteroviruses, it may be used for other enteric viruses such as adenovirus, rotavirus, Norwalk virus, astrovirus, and calicivirus upon specific testing.
| 🟦 Term | 📏 Definition |
|---|---|
| Enterovirus | Genus of Picornaviridae, 22–30 nm, positive single-stranded RNA, acid stable, ether resistant. |
| Cell Monolayer | Single layer of cells grown on a glass or plastic surface. |
| Plaque | Area of clearing caused by cytopathic effects of virus on a cell monolayer. |
⚙️ Procedure Overview and Parameters
The procedure employs a negatively charged cartridge filter to adsorb viruses from water. Viruses are released by passing a beef extract-glycine reagent at pH 9.0 through the filter. The eluted viruses are further concentrated by organic flocculation, achieved by lowering the pH to 3.5, separating the resulting floc, and solubilizing it in a small volume of phosphate solution.
| ⚡ Parameter | 📐 Value |
|---|---|
| Sample Volume (drinking water) | ≥ 400 L |
| Elution pH | 9.0 |
| Flocculation pH | 3.5 |
⚠️ Safety Note: Only adequately trained personnel should perform these procedures. Follow safety precautions recommended by the U.S. Public Health Service Center for Disease Control for work with potentially hazardous biological organisms.
📊 Key Measured Properties and Significance
This practice is used for recovering plaque-forming enteric viruses in conjunction with cell culture assay systems. Enteric viruses of public health significance are present in the aquatic environment and have been detected in treated water supplies. They are responsible for a wide range of illnesses, from hepatitis to gastroenteritis. The consistency of this practice was determined from method evaluation studies with poliovirus-seeded drinking water samples.
💡 Tip: Although specifically developed for human enteroviruses, this practice has been validated with poliovirus-seeded drinking water to ensure reliable recovery for cell culture analysis.
❓ Frequently Asked Questions
🔍 What types of viruses can be recovered?
Human enteroviruses are the primary target, but other enteric viruses like adenovirus, rotavirus, Norwalk virus, astrovirus, and calicivirus may also be recovered with specific testing.
💡 What is the principle of the procedure?
Viruses are adsorbed to a charged filter, eluted at pH 9.0, and concentrated by organic flocculation at pH 3.5.
⚡ What are the critical pH values?
Elution uses pH 9.0, and flocculation is performed at pH 3.5.
📌 How much sample volume is required?
For drinking water quality samples, volumes of 400 L or more are processed.