Live vaccines and viruses can infect the same cells in chickens, which can sometimes lead to new infections in flocks, revealed new research at the University of Illinois Urbana-Champaign. The findings, published in the journal, Virulence, could help design a better vaccine against viral diseases, like Marek’s disease, in people and poultry. “Marek’s disease is similar to varicella zoster virus (VZV) that causes chicken pox and shingles with how it replicates in the skin, is shed into the environment and enters the new host via the respiratory route,” explained University of Illinois Urbana-Champaign pathobiology professor Keith Jarosinski, who led the research.

“Both viruses have very similar genes and gene expression in the skin, so Marek’s disease in chickens is an excellent model for studying homologous VZV genes in the skin.” Marek’s disease is a highly contagious viral disease in poultry that can cause tumors to develop in various parts of the body, eye cancer, wing and leg paralysis and eventually death. It is spread through bird feed, bedding material, bird droppings, feathers and dead skin. The disease costs the poultry industry an estimated $1 billion each year. Undercovering interactions between viruses and vaccines Live vaccines are designed to actively replicate and stimulate the immune system. This type of vaccination is very good at training the immune system to recognize Marek’s disease, however, it does not lead to the complete eradication of the virus.