Changes

*The complement fixation test can be used to identify Eastern or Western EEV in infected mouse or chicken brains, cell culture fluid or amniotic-allantoic fluid

*The complement fixation test can be used to identify Eastern or Western EEV in infected mouse or chicken brains, cell culture fluid or amniotic-allantoic fluid

*Virus may be identified in brain tissue or cell culture using direct immunofluorescent staining.  

*Virus may be identified in brain tissue or cell culture using direct immunofluorescent staining.  

*EEE and WEE viral RNA in mosquitoes and tissues may be detected by reverse-transcription PCR.   

*EEE and WEE viral RNA in mosquitoes and equine tissues may be detected by reverse-transcription PCR.   

*ELISA can be used to detect virus in brain tissue.  An antigen-capture ELISA, developed for EEE surveillance in mosquitoes, can be used where virus isolation and PCR facilities are unavailable (1).

*ELISA can be used to detect virus in brain tissue.  An antigen-capture ELISA, developed for EEE surveillance in mosquitoes, can be used where virus isolation and PCR facilities are unavailable (1).

*Virus isolation is the most definitive diagnostic method for EEE or WEE.  Brain is preferred, but virus has also been isolated from the liver and spleen. Samples of these tissues should be taken in duplicate, one set for virus isolation and the other placed in formalin for histopathology. Viral isolation specimens should be sent frozen unless they can be received refrigerated within 48 hours of sampling.  Unless clinical signs persist for more than 5days prior to death, EEE virus is frequently isolated from equine brain tissue.  WEE virus, however, is rarely isolated from tissues of infected horses.  Newborn mice, chicken embryos and a number of cell culture systems can be used for virus isolation.  Virus may also be isolated from cerebrospinal fluid (CSF) of acutely infected horses.

*Virus isolation is the most definitive diagnostic method for EEE or WEE.  Brain is preferred, but virus has also been isolated from the liver and spleen. Samples of these tissues should be taken in duplicate, one set for virus isolation and the other placed in formalin for histopathology. Viral isolation specimens should be sent frozen unless they can be received refrigerated within 48 hours of sampling.  Unless clinical signs persist for more than 5days prior to death, EEE virus is frequently isolated from equine brain tissue.  WEE virus, however, is rarely isolated from tissues of infected horses.  Newborn mice, chicken embryos and a number of cell culture systems can be used for virus isolation.  Virus may also be isolated from cerebrospinal fluid (CSF) of acutely infected horses.