A relative bought a kitten around a month ago. Before buying him, they saw videos of him playing and looking lively and well, and they also saw him in person before taking him home.
Around a month later, the kitten has been diagnosed with pyothorax.
Is it likely that the kitten would already have had pyothorax when he was bought, or could it have developed during the month afterwards?
I don't have any more details than this as it isn't my kitten, and I don't know what health checks, if any, were done before he was bought.