New data concerning turkey rhinotracheitis

Turkey rhinotracheitis (TRT) is an acute infectious and contagious avian di sease found all over the world. It is caused by avian pneumovirus (APV), wh ich has two superficial glicoproteins: G and F, that are the main antigen d eterminants. Examinations of the nucleotide sequence in the G protein codin g gene found in TRT virus isolates allowed to distinguish two subgroups - A and B. Both viral subgroups have direct tropism to the ciliated epithelium of the respiratory tract, but serotype A seems to be more pathogenic. Both serotype A and B provide enough immunity against all TRT virus isolates. T he highest level of immunity is obtained from vaccination in the form of ae rosole.