Which strain was virulent?

To determine which strain was virulent, specific context is needed, such as the type of organism or study in question. In many cases, virulence is assessed through factors like pathogenicity, the ability to cause disease, and specific genetic traits. For example, in bacterial studies, strains like E. coli O157:H7 are often highlighted for their virulence due to their ability to cause severe illness. In viral contexts, strains like H1N1 or certain variants of SARS-CoV-2 have demonstrated increased virulence.