Why does size matter for viruses – A new paradigm on viral size

Abstract

Size and shape are the two immutable laws that govern all life forms including viruses. In this study we postulate and evaluate the hypothesis that there exists a strong association between viral geometry and features of viral disease outbreaks. Data on viral disease outbreaks were retrieved from WHO and CDC public domains for a period of twelve years to assess the relationship between viral size and epidemiological factors such as number of outbreaks, case fatality rate, proportion of emerging infectious diseases and transmission routes. We observed a significant correlation between viral size and frequency of disease outbreaks (rho=-0.82, p=0.004), case fatality rate (rho=0.48, p=0.03) and genome size (r=0.79, p<0.001). Viral sizes were significantly different among diverse transmission routes (p<0.001). The proportion of emerging infectious diseases were significantly different between viruses with size <10(5) and >or=10(5)nm(3) (21% vs 64%, p=0.046). In conclusion, this preliminary evidence shows that viral size plays a substantial role in the epidemiology of viral diseases. Our data suggests that small size viruses are associated with more number of outbreaks than large size viruses. Large size viruses are associated with high case fatality rate and can be potential emerging pathogens. Viral size may be crucial for niche selection and specified transmission routes in the susceptible host. Hence, viral geometry should not be neglected in epidemiology and modeling of viral diseases, and planning vaccine strategies.