| comparison of avian cell substrates for propagating subtype c avian metapneumovirus. | avian metapneumovirus (ampv) is a respiratory viral pathogen that causes turkey rhinotracheitis (trt) or swollen head syndrome (shs) in chickens. ampv was first isolated in south africa during the early 1970s and has subsequently spread worldwide during the 1980s to include europe, asia, and south america. in 1996, a genetically distinct ampv subgroup c was isolated in the us following an outbreak of trt. vero cells are currently the best available substrate for ampv propagation but are of non-a ... | 2006 | 16194579 |