The interplay between Caenorhabditis elegans larval development and Orsay virus infection

larval development and infection by its natural enteric pathogen Orsay virus (OrV). We show that OrV can replicate efficiently during molting periods and that infection initiated in more developed larvae leads to significantly higher viral loads and broader intestinal cell infection. Conversely, OrV infection perturbs the expression of developmental regulators and alters the timing of larval transitions: it accelerates the first molt and delays the subsequent stages, ultimately resynchronizing overall developmental timing. These findings suggest that developmental transitions create windows of altered antiviral capacity. Our work highlights trade-offs between developmental progression and immune competence, offering new insights into how host-pathogen interactions are shaped by development.