title: The effect of delayed harvesting as well as freezing and thawing on biological properties of Newcastle disease virus.
abstract: Delayed harvest of Newcastle disease virus (NDV) from eggs was less infective (as expressed by its lower infectious titer and a higher number of virus particles per EID50) and more resistant to a temperature of 50 degrees C than the early harvest. On the other hand, little or no effect of delayed harvesting was found on neuraminidase, erythrocyte-fusing and immunogenic properties. Moreover, haemolytic activity of NDV was moderately enhanced when its harvesting from de-embryonated egg was delayed. Treatment of a fresh NDV preparation with repeated freezing and thawing cycles also caused a marked reduction in virus infectivity and induction of its haemolytic activity.
authors: Department of Veterinary Microbiology, Faculty of Veterinary Medicine, Academy of Agriculture and Technology, Olsztyn, Poland.
authors: E
authors: E
authors: Trybała
mesh_terms: D000818:Animals; D002645:Chickens / Q000276:immunology; D005615:Freezing; D006361:Heating; D006387:Hemagglutination, Viral; D006461:Hemolysis; D009522:Newcastle disease virus / Q000276:immunology / Q000472:pathogenicity / Q000502:physiology*; D013997:Time Factors; D014776:Virus Cultivation / Q000379:methods*