Experimental infections, where a pathogen is introduced into the host body to see its effects in action, are considered the gold standard for assessing how vulnerable a host is, offering clear insights into how a pathogen causes disease and spreads through populations. This approach requires deliberately infecting live animals, which not only raises clear ethical concerns but also often proves impractical for many wildlife species, especially endangered ones, where conservation efforts take precedence. Scientists have found a potential solution to this problem.