Over the last 3 years, we have been investigating the psittacid herpesvirus also known as the Pacheco's disease virus. This virus unapparently infects some birds which then shed the virus either continuously, in low concentrations, or intermittently. When other birds are exposed to this virus they may develop a severe disease that generally results in death. This disease is called Pacheco's disease. It occurs in outbreaks that may result in the loss of a single bird or many hundreds of birds.
Outbreaks are generally more severe in indoor aviaries.
An important adjunct means of controlling this disease, would be a diagnostic assay that would allow us to detect unapparently infected birds that may be sources of this infection. Our work has shown that the Pacheco's disease virus is not a single virus, but a complex of closely related viruses. To date, we have identified 13 virus variants. One variant appears to be the cause of most of the Pacheco's disease outbreaks, but the remaining 12 variants also cause significant disease. Our findings are significant, because many of the variants that we have identified may not be serologically cross reactive with the vaccine strain of the virus and therefore the vaccine may not protect against these viruses.