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Viral Diseases

Short summary:
Historically viral diseases have not been recognized as. major causes of illness and death ... significant concern about viral diseases in wild birds has ...

Long summary:
Viral DiseasesPage 1Viral Diseases 139Section 4Viral DiseasesDuck PlagueInclusion Body Disease of CranesMiscellaneous Herpesvirusesof BirdsAvian PoxEastern Equine EncephalomyelitisNewcastle DiseaseAvian InfluenzaWoodcock ReovirusInclusion bodies in the liver of a bird that died of herpesvirus infectionPhoto by Lou SileoPage 2140 Field Manual of Wildlife Diseases: BirdsIntroduction to Viral DiseasesHistorically viral diseases have not been recognized asmajor causes of illness and death in North American wildbirds. Until relatively recently this may have been due toinadequate technology to culture and identify these organisms. Unlike bacteria viruses are too small to be seen underthe light microscope and they cannot be grown on artificialmedia. Nevertheless studies of infectious diseases causedby viruses have often predated discovery of the causativeagents by many years as evidenced by smallpox immunizations being used centuries before that virus was identified.The isolations of a tobacco mosaic virus in 1892 and footand mouth disease viruses in 1898 mark the development ofvirology as a distinct biological science. The era of modernvirology began in the postWorld War II years of 194550with the application of cell culture techniques to the study ofanimal viruses.For centuries gross and microscopic pathology associated with tissue alterations caused by viral infections havebeen recorded for species of domestic birds captive wildbirds and occasionally for freeliving wild birds. Howeversignificant concern about viral diseases in wild birds hasprimarily occurred since the 1970s. This timeframe isconsistent with an apparent increase of emerging infectiousdiseases and emerging viruses in other species includinghumans. It is noteworthy that this pattern exists for the diseases included in this section. Duck plague first appeared inthe United States in 1967 and the first major loss of wildwaterfowl from duck plague occurred in 1973. Eastern equineencephalitis erupted in a capt ...

Source: www.nwhc.usgs.gov