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Martin, the two main considerations in wheezing cats are infection with the feline herpesvirus (FHV-1) and feline asthma. FHV-1 is expected to go into remission within 1-3 weeks but can recrudesce (relapse without cure in between events) periodically. It's a more upper respiratory disorder which is more likely to cause the choking you've witnessed. Asthma is a more chronic and persistent lower respiratory disorder. These conditions are approached very differently and so Trevor's vet will want to carefully auscultate (listen to) and X-ray Trevor's thorax (chest) in an attempt to clarify which of these disorders or if another less common disorder is present. Please respond with further questions or concerns if you wish.