Persistence of the 2009 Pandemic Influenza A (H1N1) Virus in Water and on Non-Porous Surface

Abstract

Knowledge of influenza A virus survival in different environmental conditions is a key element for the implementation of hygiene and personal protection measures by health authorities. As it is dependent on virus isolates even within the same subtype, we studied the survival of the 2009 H1N1 pandemic (H1N1pdm) virus in water and on non-porous surface. The H1N1pdm virus was subjected to various environmental parameters over time and tested for infectivity. In water, at low and medium salinity levels and 4°C, virus survived at least 200 days. Increasing temperature and salinity had a strong negative effect on the survival of the virus which remained infectious no more than 1 day at 35°C and 270 parts per thousand (ppt) of salt. Based on modeled data, the H1N1pdm virus retained its infectivity on smooth non-porous surface for at least 7 days at 35°C and up to 66 days at 4°C. The H1N1pdm virus has thus the ability to persist in water and on glass surface for extended periods of time, even at 35°C. Additional experiments suggest that external viral structures in direct contact with the environment are mostly involved in loss of virus infectivity.

Effect of Envelope Proteins on the Mechanical Properties of Influenza Virus

“…Compared with the classical icosahedral viruses, including the picornaviruses, the environmental persistence of influenza virus is less but not negligible (52)(53)(54). In order to persist within the infected host cell, the influenza virus requires flexibility of its envelope to enable dynamics in membrane curvature during the viral life cycle, including host cell receptor binding, viral fusion with the host endosome, and budding during viral assembly.…”

Environmental Stability of Swine and Human Pandemic Influenza Viruses in Water under Variable Conditions of Temperature, Salinity, and pH

“…This result may be an artifact of how the human and swine viruses tested in our study were propagated; it has been shown that both human and avian viruses grown on MDCK cells are more stable at higher temperatures than are the same viruses when grown in chicken eggs (24). At higher temperatures, all the viruses assessed, regardless of their subtype and origin, were quickly inactivated, especially at temperatures higher than 28°C; this is similar to the reduction in persistence seen for a 2009 pandemic H1N1 and a 1999 seasonal H1N1 from Ͼ150 days at 4°C to just 2 days at 35°C (22). While swine viruses persisted significantly longer than human viruses at 10°C (P ϭ 0.045) and 23°C (P ϭ 0.010) in this study, such differences were not consistent across the broader range of temperatures evaluated, and given the small sample sizes, the statistical power is low.…”

“…To be transmitted and maintained, viruses must remain infectious. It has been well established that IAVs persist longest at cold temperatures (12,13,17,22,23); human and swine viruses analyzed in this study lasted longest at 4°C, and results were consistent with those previously reported for pandemic virus A/Paris/2590/2009 (H1N1), which had a reported Rt value of 178 days at 4°C (22). The swine and human viruses included in this study, however, demonstrated greater persistence at low temperatures than did a suite of viruses of avian origin that were previously analyzed (12).…”

Survival of Viruses in Water

“…As an example, the survival of poliovirus in water was historically extensively studied [16][17][18][19] before the number of studies declined in recent years in parallel with the eradication of the disease worldwide. On the other hand, there has been an increase in respiratory diseases linked to viruses carried by waterfowl, such as influenza [1,20,21], and studies on these viruses have been increasingly numerous. Likewise, following the terrorist threats of the early 2000s, more studies have been dedicated to potential biowarfare agents [6,22].…”

“…It has been universally demonstrated that higher temperatures mean faster viral inactivation. At low temperatures above freezing, viruses may survive for extended periods of time, often longer than the duration of the study [18], and sometimes for several years [21]. At higher temperatures, the viral population will be reduced by several orders of magnitude in a few days [28].…”