It could be salmonella too know. The symptoms are very similar, and likely salmonella is more common. Some seem to immediately jump to the PMV conclusion, but we had salmonella in 2019 and were told first it was PMV and learned after losing a few birds it was actually the more common Salmonella. Swollen elbow joint, limping, and respiratory was seen in the birds that we were able to treat. The ones who didn't make it had neurological issues similar to twisted neck. We treated with enrofloxacin/baytril until symptoms were gone and also supplemented with probiotic and watched them closely for any new diseases. I.e. yeast infection. If my memory is right I dont think PMV comes and goes. Salmonella/Paratyphoid or something else may.