Анотация: Myeloblastosis-associated virus type 1 (MAV-1) is an exogenous avian retrovirus with oncogenic potential. MAV-1 was detected in young chicks hatching from eggs produced by an experimental genetic line of egg-type chickens. Transmissibility of MAV-1 had no/style> ;

ref=">ЉҐяяяя
яяяябy
љљљљ
аю­Ш·®?§(«р`­®?§џ¦ `Йµ®?§(«Їґ®?§Р5®¬¦®?§hЎ­ Ђ«¦®?§Р5®Ђ*¶®?§Р5®«¦®?§0хx
®?§АЙµ®?§wҐ®?§бy
0#ґбy
љљљљ s­®?§0хx
®?§иѕ{
Ш&ґ®?§Pъx
®?§0хx
®?§®?§ Кµ®?§xА¶®?§бy
)ґбy
љљљља{­®?§®?§ЂЄ¦®?§ пі®?§бy
 +ґбy
љљљља{­®?§0хx
®?§p…®®?§=x+ґ®`{лvАі«®?§АП« Ръx
®?§Ръx
®?§`Г­ @{©®?§АП« Ръx
®?§Ръx
®?§ЂГ­ r­®?§ n©®?§@ќЄ¬¶Тr�Г¶ШҐР{§®?§АїҐ®?§аЄ®?§ і«®?§@€®®?§ЂКµ®?§Р>®®?§ШШҐёґТr zЄШШҐёґТrЃ©р6ґЂ–Ш
®?§дy
®?§@|§®?§ d©®?§ЂІі®?§hЄ®?§Р2«Ш:ґ a­`Pa­®?§hЄ®?§0?®®?§hЄ®?§pµ®?§яяяя`­§0хx
®?§0хx
®?§0хx
®?§0хx
®?§Ђ7¶®?§ыx
®?§бy
а?ґбy
љљљљ0Џ®®?§ау­®?§@l©®?§Ау­®?§ ф­‚ЯТrPЉ®®?§5sђшk0хx
®?§ vҐ®?§s®®?§s®®?§аКµ®?§
®?§~
®?§hЭі®?§~
®?§hЭі®?§0хx
®?§~
®?§hЭі®?§®?§~
®?§hЭі®?§Pюx

®?§@{©®?§®?§®?§®?§�$н
РLґРІ«®?§Ђ#Є®?§
®?§
®?§0хx
®?§
®?§
®?§Ђx®®?§t been documented previously. This investigation was intended to partially characterize the virus involved and to study its transmissibility and oncogenicity in naturally and contact-infected chickens. Commercially produced white and brown layer pullets free of exogenous avian leukosis viruses were commingled at hatch with naturally MAV-1Цinfected chickens. The original MAV-1Цinfected chickens were discarded after approximately 8 wk, and the contact-exposed chickens were maintained in isolation for 36 wk. Young specific-pathogen-free (SPF) single comb white leghorn chickens were added to the group to study possible horizontal transmission of MAV-1 in young chickens. Upon weekly virus isolation attempts, MAV-1 was readily isolated from the contact-exposed white layers but not from the brown layers between 36 and 53 wk of age (18 wk in total). Three-week-old SPF chickens were readily infected with MAV-1 by contact as early as 1 wk postexposure. Throughout 22 hatches derived from the white and brown MAV-1Цcontact-exposed layers (between 36 and 53 wk of age), MAV-1 was frequently detected in the white layer progeny, whereas the virus was seldom isolated from the progeny produced by the brown layers during the same 18-wk period. MAV-1 induced a persistent infection in some of the SPF chickens that were exposed by contact at 3 wk of age. Gross tumors were not detected in any of the originally infected experimental chickens at 8 wk of age, in the contact-exposed brown or white layers at the termination of the study at 53 wks of age, or in the contact-exposed SPF chickens at the end of the study at 12 wk of age. Exogenous avian leukosis-related viruses may still be detected in egg-type chickens, emphasizing the importance of thorough screening before incorporation of experimental genetic material into commercial genetic lines of egg-type chickens.