http://aem.asm.org/cgi/content/full/73/6/1687
Significance of Fomites in the Spread of Respiratory and Enteric Viral Disease<sup>
</sup>
some extract. free full article
Worldwide annually there are 1.7 million deaths from diarrheal<sup> </sup>diseases and 1.5 million deaths from respiratory infections<sup> </sup>(56). Viruses cause an estimated 60% of human infections, and<sup> </sup>most common illnesses are produced by respiratory and enteric<sup> </sup>viruses (7, 49). Unlike bacterial disease, viral illness cannot<sup> </sup>be resolved with the use of antibiotics. Prevention and management<sup> </sup>of viral disease heavily relies upon vaccines and antiviral<sup> </sup>medications (49). Both vaccines and antiviral medications are<sup> </sup>only 60% effective (39, 49). Additionally, to date there are<sup> </sup>no vaccines or antiviral drugs for most common enteric and respiratory<sup> </sup>viruses with the exception of influenza virus and hepatitis<sup> </sup>A virus (HAV). Consequently, viral disease spread is most effectively<sup> </sup>deterred by preclusion of viral infection.<sup> </sup> Increases in population growth and mobility have enhanced pathogen<sup> </sup>transmission and intensified the difficulty of interrupting<sup> </sup>disease spread (14). Control of viral disease spread requires<sup> </sup>a clear understanding of how viruses are transmitted in the<sup> </sup>environment (27). For centuries it was assumed that infectious<sup> </sup>diseases were spread primarily by the airborne route or through<sup> </sup>direct patient contact, and the surrounding environment played<sup> </sup>little or no role in disease transmission (19, 27). Up until<sup> </sup>1987 the Centers for Disease Control and the American Hospital<sup> </sup>Association focused on patient diagnosis due to the belief that<sup> </sup>nosocomial infections were not related to microbial contamination<sup> </sup>of surfaces (19). Over the years studies have changed the perspective<sup> </sup>on viral transmission to include a more complex multifactorial<sup> </sup>model of disease spread (27). There is now growing evidence<sup> </sup>that contaminated fomites or surfaces play a key role in the<sup> </sup>spread of viral infections (3, 7, 38, 71).<sup> </sup>
Viral transmission is dependent on interaction with the host<sup> </sup>as well as interaction with the environment (60). Viruses are<sup> </sup>probably the most common cause of infectious disease acquired<sup> </sup>indoors (7, 71). The rapid spread of viral disease in crowded<sup> </sup>indoor establishments, including schools, day care facilities,<sup> </sup>nursing homes, business offices, and hospitals, consistently<sup> </sup>facilitates disease morbidity and mortality (71). Yet, fundamental<sup> </sup>knowledge concerning the role of surfaces and objects in viral<sup> </sup>disease transmission is lacking, and further investigation is<sup> </sup>needed (52, 60, 61). The goal of this article was to use existing<sup> </sup>published literature to assess the significance of fomites in<sup> </sup>the transmission of viral disease by clarifying the role of<sup> </sup>fomites in the spread of common pathogenic respiratory and enteric<sup> </sup>viruses.
FIG. 1. Factors influencing virus survival on fomites.
FIG. 2. Respiratory virus inactivation rates (K<sub>i</sub>).
Several different viruses cause respiratory infections, including<sup> </sup>respiratory syncytial virus (RSV), human parainfluenza virus<sup> </sup>(1 thru 4) (HPIV), influenza virus (A and B), human coronavirus<sup> </sup>(SARS, OC43, and 229E), rhinovirus, and adenovirus (serotypes<sup> </sup>4 and 7) (18). It is generally accepted that respiratory viruses<sup> </sup>are spread person to person via aerosol transmission (7, 27).<sup> </sup>Nevertheless, current scientific evidence also suggests that<sup> </sup>fomites are an important vehicle in the spread of respiratory<sup> </sup>viruses (7). By using an aerosolized source, HPIV1 was found<sup> </sup>to infect only 2 of 40 children at a distance of 60 cm (37).<sup> </sup>Therefore, HPIV transmission by aerosol was considered improbable;<sup> </sup>however, transmission may have taken place by surface contamination<sup> </sup>or close contact (37). Respiratory viruses cause sneezing and<sup> </sup>coughing, which expel an estimated 10<sup>7</sup> infectious virions per<sup> </sup>ml of nasal fluid (18). Nasal secretions can travel at a velocity<sup> </sup>of over 20 m per second and a distance greater than 3 m (about<sup> </sup>10 feet) to contaminate surrounding fomites (42, 57, 78).<sup> </sup> Viruses have been isolated on fomites in day care centers and<sup> </sup>homes (influenza A virus) (12), offices (parainfluenza virus)<sup> </sup>(S. A. Boone and C. P. Gerba, submitted for publication), and<sup> </sup>hospitals (coronavirus, parainfluenza virus, and RSV) (23) using<sup> </sup>PCR. A hospital in Taiwan used reverse transcriptase PCR to<sup> </sup>detect coronavirus on hospital phones, doorknobs, computer mouses,<sup> </sup>and toilet handles during an outbreak of severe acute respiratory<sup> </sup>syndrome (SARS) (23). Studies have proven that RSV, HPIV, influenza<sup> </sup>virus, coronavirus, and rhinovirus can remain viable on fomites<sup> </sup>for several hours to several days (Tables 1 and 3) (5, 7, 9,<sup> </sup>51). Avian influenza virus was detected on several surfaces<sup> </sup>for over 6 days (73). Studies have demonstrated that RSV, influenza<sup> </sup>virus, parainfluenza virus, and rhinovirus can survive on hands<sup> </sup>for significant periods of time and that these viruses can be<sup> </sup>transferred from hands and fingers to fomites and back again<sup> </sup>(Tables 1 and 2) (5, 7, 33, 51). After a 10-second exposure,<sup> </sup>70% of rhinovirus was transferred from donor to recipient hands<sup> </sup>in the 1978 study by Gwaltney et al. (30). Also, Gwaltney et<sup> </sup>al. demonstrated that subjects with cold symptoms had rhinovirus<sup> </sup>on their hands, and the virus was recovered from 43% of the<sup> </sup>plastic tiles they touched (30). Contaminated hands frequently<sup> </sup>come into contact with portals of entry, and so the potential<sup> </sup>for viral infection from contaminated fomites and hands exists.<sup> </sup>A study by Hendley et al. (36) found that 1 in 2.7 hospital<sup> </sup>grand round attendees rubbed their eyes and 33% picked their<sup> </sup>nose within a 1-hour observation period (36). Indirect evidence<sup> </sup>from clinical and laboratory studies clearly supports the involvement<sup> </sup>of fomites in respiratory virus infection. However, direct evidence<sup> </sup>supporting respiratory virus transmission or infection is still<sup> </sup>scarce. A study by Gwaltney et al. (29) observed that 50% of<sup> </sup>subjects developed infections after handling a coffee cup contaminated<sup> </sup>with rhinovirus. The study also demonstrated that rhinovirus<sup> </sup>self-inoculation can result from rubbing the nasal mucosa with<sup> </sup>contaminated fingers and could lead to infection (29).
Significance of Fomites in the Spread of Respiratory and Enteric Viral Disease<sup>
</sup>some extract. free full article
Worldwide annually there are 1.7 million deaths from diarrheal<sup> </sup>diseases and 1.5 million deaths from respiratory infections<sup> </sup>(56). Viruses cause an estimated 60% of human infections, and<sup> </sup>most common illnesses are produced by respiratory and enteric<sup> </sup>viruses (7, 49). Unlike bacterial disease, viral illness cannot<sup> </sup>be resolved with the use of antibiotics. Prevention and management<sup> </sup>of viral disease heavily relies upon vaccines and antiviral<sup> </sup>medications (49). Both vaccines and antiviral medications are<sup> </sup>only 60% effective (39, 49). Additionally, to date there are<sup> </sup>no vaccines or antiviral drugs for most common enteric and respiratory<sup> </sup>viruses with the exception of influenza virus and hepatitis<sup> </sup>A virus (HAV). Consequently, viral disease spread is most effectively<sup> </sup>deterred by preclusion of viral infection.<sup> </sup> Increases in population growth and mobility have enhanced pathogen<sup> </sup>transmission and intensified the difficulty of interrupting<sup> </sup>disease spread (14). Control of viral disease spread requires<sup> </sup>a clear understanding of how viruses are transmitted in the<sup> </sup>environment (27). For centuries it was assumed that infectious<sup> </sup>diseases were spread primarily by the airborne route or through<sup> </sup>direct patient contact, and the surrounding environment played<sup> </sup>little or no role in disease transmission (19, 27). Up until<sup> </sup>1987 the Centers for Disease Control and the American Hospital<sup> </sup>Association focused on patient diagnosis due to the belief that<sup> </sup>nosocomial infections were not related to microbial contamination<sup> </sup>of surfaces (19). Over the years studies have changed the perspective<sup> </sup>on viral transmission to include a more complex multifactorial<sup> </sup>model of disease spread (27). There is now growing evidence<sup> </sup>that contaminated fomites or surfaces play a key role in the<sup> </sup>spread of viral infections (3, 7, 38, 71).<sup> </sup>
Viral transmission is dependent on interaction with the host<sup> </sup>as well as interaction with the environment (60). Viruses are<sup> </sup>probably the most common cause of infectious disease acquired<sup> </sup>indoors (7, 71). The rapid spread of viral disease in crowded<sup> </sup>indoor establishments, including schools, day care facilities,<sup> </sup>nursing homes, business offices, and hospitals, consistently<sup> </sup>facilitates disease morbidity and mortality (71). Yet, fundamental<sup> </sup>knowledge concerning the role of surfaces and objects in viral<sup> </sup>disease transmission is lacking, and further investigation is<sup> </sup>needed (52, 60, 61). The goal of this article was to use existing<sup> </sup>published literature to assess the significance of fomites in<sup> </sup>the transmission of viral disease by clarifying the role of<sup> </sup>fomites in the spread of common pathogenic respiratory and enteric<sup> </sup>viruses.
FIG. 1. Factors influencing virus survival on fomites.
FIG. 2. Respiratory virus inactivation rates (K<sub>i</sub>).
Several different viruses cause respiratory infections, including<sup> </sup>respiratory syncytial virus (RSV), human parainfluenza virus<sup> </sup>(1 thru 4) (HPIV), influenza virus (A and B), human coronavirus<sup> </sup>(SARS, OC43, and 229E), rhinovirus, and adenovirus (serotypes<sup> </sup>4 and 7) (18). It is generally accepted that respiratory viruses<sup> </sup>are spread person to person via aerosol transmission (7, 27).<sup> </sup>Nevertheless, current scientific evidence also suggests that<sup> </sup>fomites are an important vehicle in the spread of respiratory<sup> </sup>viruses (7). By using an aerosolized source, HPIV1 was found<sup> </sup>to infect only 2 of 40 children at a distance of 60 cm (37).<sup> </sup>Therefore, HPIV transmission by aerosol was considered improbable;<sup> </sup>however, transmission may have taken place by surface contamination<sup> </sup>or close contact (37). Respiratory viruses cause sneezing and<sup> </sup>coughing, which expel an estimated 10<sup>7</sup> infectious virions per<sup> </sup>ml of nasal fluid (18). Nasal secretions can travel at a velocity<sup> </sup>of over 20 m per second and a distance greater than 3 m (about<sup> </sup>10 feet) to contaminate surrounding fomites (42, 57, 78).<sup> </sup> Viruses have been isolated on fomites in day care centers and<sup> </sup>homes (influenza A virus) (12), offices (parainfluenza virus)<sup> </sup>(S. A. Boone and C. P. Gerba, submitted for publication), and<sup> </sup>hospitals (coronavirus, parainfluenza virus, and RSV) (23) using<sup> </sup>PCR. A hospital in Taiwan used reverse transcriptase PCR to<sup> </sup>detect coronavirus on hospital phones, doorknobs, computer mouses,<sup> </sup>and toilet handles during an outbreak of severe acute respiratory<sup> </sup>syndrome (SARS) (23). Studies have proven that RSV, HPIV, influenza<sup> </sup>virus, coronavirus, and rhinovirus can remain viable on fomites<sup> </sup>for several hours to several days (Tables 1 and 3) (5, 7, 9,<sup> </sup>51). Avian influenza virus was detected on several surfaces<sup> </sup>for over 6 days (73). Studies have demonstrated that RSV, influenza<sup> </sup>virus, parainfluenza virus, and rhinovirus can survive on hands<sup> </sup>for significant periods of time and that these viruses can be<sup> </sup>transferred from hands and fingers to fomites and back again<sup> </sup>(Tables 1 and 2) (5, 7, 33, 51). After a 10-second exposure,<sup> </sup>70% of rhinovirus was transferred from donor to recipient hands<sup> </sup>in the 1978 study by Gwaltney et al. (30). Also, Gwaltney et<sup> </sup>al. demonstrated that subjects with cold symptoms had rhinovirus<sup> </sup>on their hands, and the virus was recovered from 43% of the<sup> </sup>plastic tiles they touched (30). Contaminated hands frequently<sup> </sup>come into contact with portals of entry, and so the potential<sup> </sup>for viral infection from contaminated fomites and hands exists.<sup> </sup>A study by Hendley et al. (36) found that 1 in 2.7 hospital<sup> </sup>grand round attendees rubbed their eyes and 33% picked their<sup> </sup>nose within a 1-hour observation period (36). Indirect evidence<sup> </sup>from clinical and laboratory studies clearly supports the involvement<sup> </sup>of fomites in respiratory virus infection. However, direct evidence<sup> </sup>supporting respiratory virus transmission or infection is still<sup> </sup>scarce. A study by Gwaltney et al. (29) observed that 50% of<sup> </sup>subjects developed infections after handling a coffee cup contaminated<sup> </sup>with rhinovirus. The study also demonstrated that rhinovirus<sup> </sup>self-inoculation can result from rubbing the nasal mucosa with<sup> </sup>contaminated fingers and could lead to infection (29).
