How do #pathogens become more virulent? Read on for a tale of #ancient bones, #ancientDNA, and a very modern danger in the chicken industry… 🧵1/14 The culprit is Marek’s Disease Virus – a cancer-causing herpesvirus of chickens that causes mortality in >90% of unvaccinated birds. Highly transmissible and persistent in the environment, the #poultry industry spends 💵$bns controlling this disease. 2/14