95talongirl
New member
This was posted to the PDD yahoo group, and thought I'd share over here. IIRC, this was published on May, 2014.
This continues to be one of the most frustrating and misunderstood diseases in veterinary medicine. I still have not received a definite PDD diagnosis for Kimi, my late hawkhead parrot, who was ABV+. His proventricus was normal size, and there was no ABV found in his brain, where it usually can be found. So they are still doing testing since he DID test positive for ABV.
It is still something I hope that none of you ever have to experience. It was the worst few weeks of my life. I do feel that I should have gotten a second opinion, however. But that's a whole other story. Anyways, here's the article. Feel free to add anything else to this that you feel will help us all understand this devastating virus.
Avian Bornavirus Primer
Sharman M. Hoppes, DVM, Dipl. ABVP (Avian Practice); Texas A&M University College of Veterinary Medicine andChristal Pollock, DVM, Dipl. ABVP (Avian Practice); Lafeber Company Veterinary Consultant
Reviewers:Ian Tizard, BVMS, PhD, Dipl. ACVM, ScD; Texas A&M University College of Veterinary Medicine andNeil Forbes, BVetMed DECAMS FRCVS; Great Western Exotics, Swindon, United Kingdom
Key words: Bornavirus, ganglioneuritis, proventricular dilatation disease, PDD, psittacine, parrot
Macaws imported into the United States and Germany. During the early years, this disease was often referred to as “macaw wasting disease” (Payne 2012). Since that time, proventricular dilatation disease has been identified in over 50 different avian species including passerines like thecanary(Serinus canaria), honeycreepers, weaver finches, waterfowl, toucans, birds of prey, and psittacine birds (Hoppes 2013, Payne 2012, Smith 2010, Weissenböck 2009). Proventricular dilatation disease has been reported in captive parrots in North America, Latin America, Europe, Australia, Africa, Japan, and the Middle East (Sassa 2013, Last 2012, Doneley 2007).
Polyuria, hypotension, and cardiac abnormalities have also been reported. Avian bornavirus infection damages the Purkinje cells, which can potentially cause arrhythmias however this is usually a postmortem finding.
Table 1.Potential signs of neuropathic ganglioneuritis in the psittacine bird
Gastrointestinal singsCentral or peripheral nervous system signs
Weight loss
Crop stasis,regurgitation
Dilation of the proventriculus, ventriculus or intestines
Evidence ofmaldigestion-malabsorption
Diarrhea
Scant feces
Ataxia, weakness
Proprioceptive deficits
Tremors
Seizure activity
Blindness
Abnormal head movements
Figure 1.Maldigestion/malabsorption diarrhea in a parrot fed a seed-based diet. Photo credit - Dr. Gregory A. Rich.Click image to enlarge.
Figure 2.Radiographic evidence of proventricular dilatation (arrow). Photo credit - Dr. Sharman Hoppes.Click image to enlarge.
*Editor’s Note: Although death would seem to be the most objective of parameters, there are camps of PDD study that disagree vehemently with the statement that symptomatic avian bornavirus disease is invariably fatal and there are reports of birds with chronic disease living long, long lives.↑ top
Schubot Exotic Bird Health Centerthat have tested positive for ABV via PCR and serology for over 7 years that continue to be clinically healthy. Other individuals consistently tested negative for up to 6 years before becoming acutely ill. These birds only tested positive on PCR and serology at the terminal stages of disease.
PCR:Reverse transcription (RT) polymerase chain(PCR) testingof droppings, feathers, and blood has been evaluated in psittacine birds (Table 2) (Hoppes 2013, de Kloet 2011, Dahlhausen 2010). Positive ABV PCR test results do not mean the bird has or ever will develop clinical disease, and most PCR testing does not differentiate between ABV genotypes. Due to intermittent shedding, one negative PCR test result also cannot rule out ABV infection, particularly if the sample is not properly stored.
Serology:Serological testing has also been frustratingly inconclusive, with some ABV-infected birds failing to develop a detectable antibody response within weeks of dying of neuropathic ganglioneuritis (Table 2) (Herzog 2010). In other individuals there appears to be a positive correlation between the level of antibodies produced and the development of disease. Tests used to detect ABV titers have included indirect immunofluorescence, ELISA, and Western blot assay (Hoppes 2013).
Histopathology: Although crop biopsies are rarely performed in our practice (Hoppes), a crop biopsy is routinely performed by some avian veterinarians in suspect PDD birds. Surgical removal of a small, vascular, full thickness segment of the crop wall is approximately 70% reliable in identifying histologic signs consistent with neuropathic ganglioneuritis. Crop biopsy results also depend on the presence of segmental disease in the tiny piece of tissue collected. Additionally most birds without gastrointestinal signs are almost always negative via crop biopsy.
Current recommendation: A combination of cloacal or feather RT-PCR with a serologic assay may offer the best chance of identifying ABV infection.Birds with a high ABV load via PCR combined with high antibody titers appear to have the highest risk of developing clinical disease (Heffels-Redmann 2012), however there is there is no one combination of tests that can be used to reliably predict the progression from ABV exposure and shedding to clinical disease at this time. Multiple tests must be performed before a bird can be considered ABV negative. Ideally three negative PCR test results are needed for a bird to be considered negative.
Table 2.Laboratories in the United States that perform avian bornavirus diagnostic testing
PCRSerology
Avian BiotechXX
The Schubot CenterX
Veterinary Molecular DiagnosticsX
Figure 3.Profound emaciation in a cockatoo with neuropathic ganglioneuritis. Photo credit - Dr. Isabelle Langlois.Click image to enlarge.
Histopathologically there may be a lymphoplasmacytic ganglioneuritis involving the brain, spinal cord, peripheral nerves, splanchnic nerves, heart, and adrenal gland. In some instances, lesions can also be detected in the lungs or kidneys. Lesions may only be present in the brain and spinal cord in some neurologic cases.
Avian bornavirus can consistently be detected by PCR analysis in the tissues of birds that die of neuropathic ganglioneuritis. The virus may be found in all major organs or may be limited to the brain, spinal cord, and peripheral nerves. The vitreous humor can also be a source of ABV, even in apparently healthy carrier birds (Hoppes 2013).
This continues to be one of the most frustrating and misunderstood diseases in veterinary medicine. I still have not received a definite PDD diagnosis for Kimi, my late hawkhead parrot, who was ABV+. His proventricus was normal size, and there was no ABV found in his brain, where it usually can be found. So they are still doing testing since he DID test positive for ABV.
It is still something I hope that none of you ever have to experience. It was the worst few weeks of my life. I do feel that I should have gotten a second opinion, however. But that's a whole other story. Anyways, here's the article. Feel free to add anything else to this that you feel will help us all understand this devastating virus.
Avian Bornavirus Primer
Sharman M. Hoppes, DVM, Dipl. ABVP (Avian Practice); Texas A&M University College of Veterinary Medicine andChristal Pollock, DVM, Dipl. ABVP (Avian Practice); Lafeber Company Veterinary Consultant
Reviewers:Ian Tizard, BVMS, PhD, Dipl. ACVM, ScD; Texas A&M University College of Veterinary Medicine andNeil Forbes, BVetMed DECAMS FRCVS; Great Western Exotics, Swindon, United Kingdom
Key words: Bornavirus, ganglioneuritis, proventricular dilatation disease, PDD, psittacine, parrot
Macaws imported into the United States and Germany. During the early years, this disease was often referred to as “macaw wasting disease” (Payne 2012). Since that time, proventricular dilatation disease has been identified in over 50 different avian species including passerines like thecanary(Serinus canaria), honeycreepers, weaver finches, waterfowl, toucans, birds of prey, and psittacine birds (Hoppes 2013, Payne 2012, Smith 2010, Weissenböck 2009). Proventricular dilatation disease has been reported in captive parrots in North America, Latin America, Europe, Australia, Africa, Japan, and the Middle East (Sassa 2013, Last 2012, Doneley 2007).
Polyuria, hypotension, and cardiac abnormalities have also been reported. Avian bornavirus infection damages the Purkinje cells, which can potentially cause arrhythmias however this is usually a postmortem finding.
Table 1.Potential signs of neuropathic ganglioneuritis in the psittacine bird
Gastrointestinal singsCentral or peripheral nervous system signs
Weight loss
Crop stasis,regurgitation
Dilation of the proventriculus, ventriculus or intestines
Evidence ofmaldigestion-malabsorption
Diarrhea
Scant feces
Ataxia, weakness
Proprioceptive deficits
Tremors
Seizure activity
Blindness
Abnormal head movements
Figure 1.Maldigestion/malabsorption diarrhea in a parrot fed a seed-based diet. Photo credit - Dr. Gregory A. Rich.Click image to enlarge.
Figure 2.Radiographic evidence of proventricular dilatation (arrow). Photo credit - Dr. Sharman Hoppes.Click image to enlarge.
*Editor’s Note: Although death would seem to be the most objective of parameters, there are camps of PDD study that disagree vehemently with the statement that symptomatic avian bornavirus disease is invariably fatal and there are reports of birds with chronic disease living long, long lives.↑ top
Schubot Exotic Bird Health Centerthat have tested positive for ABV via PCR and serology for over 7 years that continue to be clinically healthy. Other individuals consistently tested negative for up to 6 years before becoming acutely ill. These birds only tested positive on PCR and serology at the terminal stages of disease.
PCR:Reverse transcription (RT) polymerase chain(PCR) testingof droppings, feathers, and blood has been evaluated in psittacine birds (Table 2) (Hoppes 2013, de Kloet 2011, Dahlhausen 2010). Positive ABV PCR test results do not mean the bird has or ever will develop clinical disease, and most PCR testing does not differentiate between ABV genotypes. Due to intermittent shedding, one negative PCR test result also cannot rule out ABV infection, particularly if the sample is not properly stored.
Serology:Serological testing has also been frustratingly inconclusive, with some ABV-infected birds failing to develop a detectable antibody response within weeks of dying of neuropathic ganglioneuritis (Table 2) (Herzog 2010). In other individuals there appears to be a positive correlation between the level of antibodies produced and the development of disease. Tests used to detect ABV titers have included indirect immunofluorescence, ELISA, and Western blot assay (Hoppes 2013).
Histopathology: Although crop biopsies are rarely performed in our practice (Hoppes), a crop biopsy is routinely performed by some avian veterinarians in suspect PDD birds. Surgical removal of a small, vascular, full thickness segment of the crop wall is approximately 70% reliable in identifying histologic signs consistent with neuropathic ganglioneuritis. Crop biopsy results also depend on the presence of segmental disease in the tiny piece of tissue collected. Additionally most birds without gastrointestinal signs are almost always negative via crop biopsy.
Current recommendation: A combination of cloacal or feather RT-PCR with a serologic assay may offer the best chance of identifying ABV infection.Birds with a high ABV load via PCR combined with high antibody titers appear to have the highest risk of developing clinical disease (Heffels-Redmann 2012), however there is there is no one combination of tests that can be used to reliably predict the progression from ABV exposure and shedding to clinical disease at this time. Multiple tests must be performed before a bird can be considered ABV negative. Ideally three negative PCR test results are needed for a bird to be considered negative.
Table 2.Laboratories in the United States that perform avian bornavirus diagnostic testing
PCRSerology
Avian BiotechXX
The Schubot CenterX
Veterinary Molecular DiagnosticsX
Figure 3.Profound emaciation in a cockatoo with neuropathic ganglioneuritis. Photo credit - Dr. Isabelle Langlois.Click image to enlarge.
Histopathologically there may be a lymphoplasmacytic ganglioneuritis involving the brain, spinal cord, peripheral nerves, splanchnic nerves, heart, and adrenal gland. In some instances, lesions can also be detected in the lungs or kidneys. Lesions may only be present in the brain and spinal cord in some neurologic cases.
Avian bornavirus can consistently be detected by PCR analysis in the tissues of birds that die of neuropathic ganglioneuritis. The virus may be found in all major organs or may be limited to the brain, spinal cord, and peripheral nerves. The vitreous humor can also be a source of ABV, even in apparently healthy carrier birds (Hoppes 2013).
