Content warning: This article contains depictions of animal suffering and inhumane treatment of animals.

A teen in British Columbia recently became critically ill after becoming infected with H5N1. H5N1 is a highly pathogenic strain of bird flu.

Outbreaks of avian influenza, or bird flu, in livestock and flocks on industrial-scale chicken and dairy farms — so-called factory farms — in the United States are raising alarm bells for public health across the world.

Mainstream commercial animal agriculture is conducted in an intensive way in often cramped and unhygienic environments. These conditions are ideal for new viruses to jump from animals to humans.