Avian Pacheco PVD

Description:
Pacheco's disease - This disease is caused by a number of closely related members of the herpesviridae. Herpesviruses are 120 to 220 nm in diameter and their genome has a double stranded DNA structure. Replication of the virus occurs in the nucleus of a cell. These viruses primarily infect lymphatic tissue (B or T cells), skin (epithelial cells) and nerve cells.
PDV was first recognized in Brazil where aviculturalists began seeing birds dying only a few days after becoming ill. The virus can start shedding in the feces and nasal discharge of an infected bird in as little as 3-7 days after infection. Considered highly contagious , PDV can spread rapidly through an aviary. Often the first sign that the disease is present is when a new bird is introduced to an aviary and healthy birds begin mysteriously dying. Pacheco's disease is often fatal and affects psittacines of all ages. New World psittacines seem to be more susceptible to the disease than Old World psittacines.
Transmission:
Transmission of PDV is generally through infected feces and nasal discharge. PDV remains remarkably stable outside the host body as a dust or aerosol. This dust or aerosol contaminates the air that is then inhaled by another possible host. Contaminated surfaces, food, and drinking water may also contribute to the spread of the disease. Birds can be asymptomatic carriers of Pacheco's virus. Some believe that any bird that has survived an outbreak of the disease should be considered as a possible carrier. PDV can be reactivated when the bird is under stress such as during breeding, loss of mate, or change and environmental changes. Once it is reactivated the virus is shed in large numbers in the feces of the infected bird.
Symptoms:
Symptoms include lethargy, diarrhea, ruffled feathers, sinusitis, anorexia, conjunctivitis, and tremors in the neck, wing and legs. Fecal material may become discolored with urates becoming green indicating possible liver damage has occurred. Birds generally die from massive liver necrosis characterized by an enlarged liver, spleen and kidneys. However, some birds die suddenly with no specific or observable symptoms. Seemingly healthy birds often die quickly from Pacheco's disease. Generally stress associated with relocation, breeding, loss of mate or climate changes can activate the virus and result in activation of the disease and it's symptoms as well as shedding large numbers of the virus in the feces.
Prevention:
Isolate all birds shedding PDV. Disinfect all contaminated surfaces with an oxidizer such as chlorine bleach (as Pacheco's virus is resistant to many disinfectants, alcohol does not work because it is not an oxidizer). It is also important to replace all air filters and clean vents and fan blades. A killed virus vaccine is available and can be given in a series of two injections, 4 weeks apart (yearly booster shots are required). Some species, such as cockatoos and Eclectus parrots, have had vaccination reactions such as granulomas and paralysis. Additionally, the vaccine may not protect against all forms of PDV. Only birds with high risk of exposure, such as pet store birds, should be vaccinated.Quarantine all new birds for 30-60 days and use PCR testing to determine whether or not birds are infected. Isolate birds who have been exposed to Pacheco's virus.
Treatment:
Acyclovir is effective against some strains of Pacheco's but may cause kidney damage. Acyclovir works best when treatment is started before symptoms appear.
Diagnosis:
PCR and sequence testing for specific PDV DNA. Histopathology.
Sample:
In live birds please submit both a blood sample and a cloacal swab sample for each bird. The Virus can be isolated from tissue samples of the liver, spleen or kidney submitted in a sterile container. Environmental testing using swabs of aviaries, countertops, fans, air-filters, nest-boxes, etc. is extremely effective when in determining the presence of Pacheco's virus DNA in the environment.
Handling:
Prior to shipping samples should be stored at 4 C. (refrigerator). Samples must be shipped in a padded envelope or box. Samples may be sent by regular mail, but overnight is recommended.