Background

Norovirus (NoV) can survive in buffer at a range of pH values. However, when variations to pH are combined with the enzymatic conditions typical in gastric fluid, NoV survival is less predictable. Added to this, the material on which expelled vomitus fluid lands, e.g., safety vinyl or carpet, might also affect the level of NoV survival in the environment.

Aim

This study aimed to assess survival of the NoV surrogate feline calicivirus (FCV) after application on to four material types in the presence of synthetic gastric fluid of varying pH values.

Methods

Synthetic gastric fluid of varying pH values (1.5, 2.5, 3.5 and 4.5) containing FCV (1 × 10⁶ plaque-forming units (pfu)/100 μL of gastric fluid) was seeded (100 μL) on to four material types: Formica, safety vinyl, cotton sheet and carpet tiles (2 cm × 2 cm) and left for 0, 30 and 60 min before recovering and identifying any viable viruses via plaque assay.

Findings

FCV survived in synthetic gastric fluid at pH values as low as 2.5 and in some cases as low as 1.5 for at least 30 min when associated with certain materials. Greater average numbers of viable virus were recovered from the more absorbent materials of cotton (1900 pfu/sample) and carpet (1600 pfu/sample) compared with Formica (360 pfu/sample) and safety vinyl (380 pfu/sample).

Conclusion

This study showed that FCV can survive in synthetic gastric fluids of low pH values for significant time periods especially on absorbent materials. This emphasises the importance of ensuring effective cleaning and decontamination procedures, particularly of soft furnishings and laundry, for infection prevention and control of NoV outbreaks.

中文翻译：

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诺如病毒替代物在合成胃液表面的存活。

 背景

诺如病毒 (NoV) 可以在一定 pH 值范围内的缓冲液中存活。然而，当 pH 值的变化与胃液中典型的酶促条件相结合时，NoV 的存活率就难以预测。除此之外，排出的呕吐物所落在的材料，例如安全乙烯基或地毯，也可能影响NoV在环境中的存活水平。

 目的

本研究旨在评估 NoV 替代猫杯状病毒 (FCV) 在不同 pH 值的合成胃液存在下应用于四种材料类型后的存活率。

 方法

将含有 FCV（1 × 10 ⁶噬菌斑形成单位 (pfu)/100 μL 胃液）的不同 pH 值（1.5、2.5、3.5 和 4.5）的合成胃液接种（100 μL）到四种材料类型上： 福米卡、安全乙烯基、棉床单和方块地毯 (2 cm × 2 cm) 并放置 0、30 和 60 分钟，然后通过噬菌斑测定回收和识别任何活病毒。

 发现

当与某些材料结合时，FCV 在 pH 值低至 2.5（有时低至 1.5）的合成胃液中存活至少 30 分钟。与福米卡（360 pfu/样品）和安全乙烯基（380 pfu/样品）相比，从吸水性更强的棉花（1900 pfu/样品）和地毯（1600 pfu/样品）材料中回收的平均活病毒数量更高。

 结论

这项研究表明，FCV 可以在低 pH 值的合成胃液中存活很长时间，尤其是在吸收性材料上。这强调了确保有效的清洁和去污程序（尤其是软家具和洗衣房）对于感染预防和控制新型冠状病毒爆发的重要性。