What is Pacheco's Disease?

Pacheco’s disease in birds is caused by the herpesvirus and is susceptible predominantly to birds in the Psittacine family (various types of parrots, macaws, Amazon parrots, parakeets, cockatoos, cockatiels, lovebirds, lorikeets and conures), though it has rarely been found in other avian families. It can cause viral hepatitis in some species and internal papillomatosis in other species. It can be fatal for some species while other species seem to have a resistance to the disease.

Pacheco’s disease is a disease in birds which is caused by herpesvirus.  The viral infection at the root of this disease is susceptible mainly to birds in the psittacine family.

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Symptoms of Pacheco's Disease in Birds

Historically, it seems that Old World Psittacines are more resistant to the disease than New World Psittacines. Here are some of the symptoms you might notice:

  • Lethargy
  • Diarrhea
  • Ruffled feathers
  • Sinusitis
  • Anorexia
  • Conjunctivitis
  • Tremors of the neck, wings and legs
  • Discoloration of urine and feces are possible in some birds

Some of this symptoms will present in varying degrees of severity and at various stages of development.

Types 

There is only one type of Pacheco’s disease in birds and it is quite deadly. In fact, there are many cases in which birds on a particular day have been found dead after having been seemingly normal the previous day. The deceased avian apparently had no visible signs prior to death so medical assistance could not be obtained. This disease is rarely seen by veterinary professionals before they expire and birds can expire within hours after certain clinical signs present.

Causes of Pacheco's Disease in Birds

This disease is caused by a number of viruses within the Herpesviridae family which are closely related. After it was discovered in Brazil, it was found to be fatal to infected birds within days. Research has revealed that the virus can be shed in the feces and nasal discharge of infected birds within 3 to 7 days of infection, making Pacheco’s disease extremely contagious, enabling the virus to infect an aviary quite rapidly. Some birds have shown evidence of infection within 4 to 5 days of exposure. While the disease is primarily transmitted through contact with contaminated feces and nasal discharge, the virus shows remarkable stability outside the host in the form of a dust or aerosol.

Inhalation of this dust or aerosol is an additional method of transmission. The virus is also potentially transmittable via contaminated food and drinking water as well as by other contaminated surfaces. This disease is also transmitted vertically; for example transmitted from mother to embryo, so extra care must be taken in the breeding process as mothers can be carriers of the virus while not being “infected” themselves.

Diagnosis of Pacheco's Disease in Birds

Because some birds never display clinical signs or the symptoms noted above, your veterinary professional may not get involved before the disease kills the host. Most vets confirm diagnosis of deceased birds by post-mortem testing ( after the bird has died). Either dead or alive, your vet will likely do PCR (Polymerase Chain Reaction) testing to isolate the entity guilty of infecting your bird. He will be looking for specific Avian Herpesvirus (AHV) DNA. If your bird has expired, the virus can still be detected in the liver, kidneys, intestines or feces.

It is vital for the health and safety of your aviary that you proceed with the testing to confirm the diagnosis even if your bird has died as precautions may be needed to protect your remaining birds. The remaining birds in your aviary will need to be tested for presence of the virus and any new birds in your aviary will need to be isolated and observed for a minimum of 6 weeks before introduction into your aviary. 

Treatment of Pacheco's Disease in Birds

There is no treatment for Pacheco’s disease in birds as the disease has such a rapid and high morbidity rate. Many birds expire before symptoms and clinical signs present, making treatment impossible for those afflicted birds. Those who live until clinical signs present have historically died within a couple of days. Once this disease is discovered in your aviary, it is very important to test other birds for the virus, whether they show symptoms or not. Isolation is essential for those birds who test positive for the virus at least until it can be determined if they are infected or carriers of the virus.

Some birds who test positive may never show signs of the disease and still others may be able to develop an immunity to it but this may take 60 to 90 days to happen. Retesting after 60 to 90 days later will likely show you which birds should be considered permanently infected. These birds should be expected to show the clinical signs of the disease, as well as shed the virus in their feces and nasal discharge as noted above, and isolation steps taken.

Recovery of Pacheco's Disease in Birds

Since Pacheco’s disease in birds is so contagious, spreading rapidly to other similar birds and has such a high rate of morbidity, it is vital that you consider methods of prevention in an attempt to protect the other birds in your aviary. As noted above, once this disease has been discovered within your aviary, then you must take necessary steps to determine the extent of the infection and isolate the birds who are permanently infected so that those birds not testing positive for Avian Herpesvirus (AHV) can have a better chance of remaining virus-free.

Also, it is also vital that you test any new birds coming into your aviary and “quarantine” them for a period of at least 6 weeks before introducing them to the aviary population.  This is a very dangerous virus/disease for birds, especially those in the Psittacine family, making it vital for you to take whatever steps necessary to protect your remaining aviary population.