Dr. Danielle Lang with a budgerigar during this study.

Project Title:

Development of novel techniques for diagnosis and treatment of Macrorhabdus ornithogaster in budgerigars (Melopsittacus undulatus)

Principal Investigator:

Jennifer Langan, DVM, DACZM, DECZM (Zoo Health Management)

Additional Investigator(s):

Danielle Lang, DVM, MS; Katie Delk, DVM, DACZM; Matthew Allender, DVM, MS, PhD, DACZM; and Sathya Chinnadurai, DVM, MS, DACZM, DACVAA, DACAW

Principal Investigator Institution:

Brookfield Zoo Chicago (Brookfield, IL), University of Illinois College of Veterinary Medicine (Urbana, IL) 

About the Project:

Main points about the project/summary:

This recently completed research project funded by AAV’s 2023 Avian Health Grant has yielded promising advances in the diagnosis and study of Macrorhabdus ornithogaster in budgerigars. The aim of this project was to investigate improved diagnostic and treatment options for the fungal pathogen Macrorhabdus ornithogaster (MO) in budgerigars.

Outcome/Results:

Through this project, investigators were able to successfully develop and validate an MO quantitative PCR (qPCR) assay - an easy, reliable, non-invasive test to diagnose this fungus antemortem. In addition, they were able to culture MO using a modified protocol. Even though they were unable to sustain this culture long enough to test for the best antifungal drugs, they found alternative ways to grow the fungus, which can be used to improve culture maintenance for antifungal testing. Finally, investigators found a lower than expected number of MO-positive birds in the Brookfield Zoo budgerigar aviary, which could be due to intermittent shedding of this pathogen. Birds with lower body weights were more likely to be MO qPCR positive, so body weight could serve as an indicator for identifying suspect cases. They did not observe a decline (response to treatment) based on the amount of MO DNA from budgerigars treated with in-water antifungals compared to controls; however, the results do support that this pathogen is intermittently shed. 

Describe how this project advanced the field of avian medicine:

This study offers several important advancements for avian veterinarians managing Macrorhabdus ornithogaster (MO) infections. The development of a validated TaqMan qPCR assay represents a major diagnostic breakthrough. It allows for sensitive, specific, and non-invasive detection and quantification of MO in fecal samples—critical for early identification and monitoring of infection, especially in asymptomatic or intermittently shedding birds.

Explain how the results can be used in practice:

This tool provides clinicians with a reliable antemortem diagnostic method that can be used in both clinical and zoo settings, improving diagnostic accuracy over traditional microscopy. The finding that MO-positive birds had significantly lower body weights than negative ones suggests that body weight could be a useful screening metric. Clinicians may use weight monitoring alongside qPCR to identify birds that warrant further testing, even when clinical signs are mild or absent.

Summary submitted by:

Jennifer Langan, DVM, DACZM, DECZM (Zoo Health Management)

 AAV 2022 Avian Health Grant Recipient

Pictured: Markus Drag, M.S.
AAV 2022 Avian Health Grant Recipient

Project Title:

Development and implementation of ultra-sensitive diagnostics for pathogens in zoo-housed and domestic birds

Nothing is published yet; however, the investigators did present 2 conference abstracts and several oral conference presentations on the subject in 2023. They are planning to submit the first manuscript in 2024 to a high impact journal as soon as the validation is finished.

Principal Investigator:

Markus Drag, M.S., Department of Conservation, Copenhagen Zoo in collaboration with the section for Veterinary Clinical Microbiology, Department of Veterinary and Animal Sciences, University of Copenhagen

Principal Investigator Institution:

Copenhagen Zoo, Frederiksberg, Denmark

About the Project:

Main points about the project/summary:

To create a new diagnostic test for very early detection (before clinical symptoms) and monitoring of aspergillosis in birds in both zoological gardens, nature reserves, and agriculture.

The investigators have created an in vivo experimental aspergillosis model in domestic chickens, which was approved and licensed by the Danish Animal Inspectorate and provided them with valuable samples, and they have analyzed the data with various advanced tools and methods to identify the best markers. The funding from the Association of Avian Veterinarians has been essential for running the animal model experiment and the respective sample analyses (eg, lab reagents, sequencing costs).

During the research process, many challenges have been encountered. When doing omics-based analyses, such as genomics, it is always convenient to have reference genomes or other data available; however, not much is known about many of the avian species so they are really treading on new ground. Luckily, more is known about chickens, and that is why they've selected them as the model organism. They are also an economically important species, so there is added benefit using them as a model.

Outcome/Results: 

The initial results are promising! With their new method, they can distinguish between infected and healthy chickens before any other diagnostic test using just 200 microliters of serum. Currently, the team is working on a large-scale validation of the research to establish the sensitivity and specificity of the assay using pathogens other than Aspergillus.

Describe how this project advanced the field of avian medicine:

Even though diagnostics for Aspergillus currently exist, these tests are primarily based on direct antibody/immune assays against the pathogen. This new test takes another approach by assessing the amount of cell death of certain cell types/tissues, which will change subtly when the pathogen establishes in the host tissue. To the best of the investigator's knowledge, this type of test is not currently used in avian medicine.

Explain how the results can be used in practice:

If the validation is successful, the investigators hope to rapidly adapt the diagnostic test to species other than chickens. Parrots and sea birds are especially impacted by Aspergillus, and by using routine monitoring it should be possible to detect early infection and institute appropriate changes to the environment to remove any possible source of Aspergillus and initiate treatment protocols.

Summary submitted by:

Alba Palomo Lara (Veterinary Student)             

 AAV 2019 Avian Health Grant Recipient

Pictured: Dr. Dana Franzen-Klein,
AAV 2019 Avian Health Grant Recipient

Project Title:

Reference Ranges for Blood Lactate Levels in Captive Raptors

Publication in progress

Principal Investigator:

Dana Franzen-Klein DVM, MS

Principal Investigator Institution:

Medical Director at The Raptor Center at the University of Minnesota, St. Paul, MN

Additional Investigator(s):

Dr. Kyra Knutson, DVM, DACZM - Avian, Exotics & Zoological Medicine Veterinarian at Oradell Animal Hospital

About the Project:

Main points about the project/summary:

To know if blood lactate levels can be used to assess prognosis and response to treatment in avian species, first we had to know if point-of-care lactate meters are accurate in various avian species; then we obtained the normal resting blood lactate value in the species of interest. Therefore, the main points were:

• Assess the utility of a point-of-care lactate meter (Lactate Plus, Nova® biomedical)
• Determine normal reference ranges for three raptor species: bald eagles (Haliaeetus leucocephalus), great horned owls (Bubo virginianus), and red-tailed hawks (Buteo jamaicensis)

Outcome/Results: 

• The Lactate Plus meter produced consistent results, with the precision testing coefficient of variation measuring below 6%. However, the linearity testing with the Lactate Plus meter produced inconsistent results and is being further assessed.
• Blood lactate levels were measured in 50 bald eagles, 37 great horned owls, and 41 red-tailed hawks.
• Preliminary data analysis provided the following mean blood lactate ± one standard deviation values by species: bald eagle 11.0 ± 3.8 mmol/L, great horned owl 7.3 ± 3.2 mmol/L, red-tailed hawk 8.1 ± 2.9 mmol/L.
• These resting blood lactate levels are significantly higher than those seen in humans (2 mmol/L is normal) and some mammalian species (dogs <4 mmol/L). They are also different than some of the reported resting values in other avian species.

Describe how this project advanced the field of avian medicine:

This project provides a building block for future research into the clinical utility of this point-of-care/patient side diagnostic in avian species, because it obtained a good sample size to characterize normal lactate values in three raptor species.

Explain how the results can be used in practice:

How the results may be used in practice still needs to be determined. This was a starting project to determine the normal values for these three species. From there, we would see if it could be applied to assess response to treatment or determine prognosis as it is used in companion animal medicine.

Summary submitted by:

Alba Palomo Lara (Veterinary Student)             

 AAV 2018 Wild Bird Health Grant Recipient

Pictured: Dr. Ellen Bronson,
AAV 2018 Wild Bird Health Grant Recipient

Project Title:

Pharmacokinetics of Primaquine Phosphate after a Single Oral Administration to African Penguins (Spheniscus demersus)

Journal of Zoo and Wildlife Medicine 2021 Apr;52(1):75-80. DOI: 10.1638/2020-0172

Principal Investigator:

Jessica H. Carag, DVM, MS

Principal Investigator Institution:

Maryland Zoo, Baltimore, Maryland

Additional Investigator(s):

Samantha J. Sander, DVM, DACZM, Jen Kottyan, BS, Jess Phillips, BS, Jenny Brubaker, BS, RVT, Crisanta Cruz-Espindola, MS, Dawn Boothe, DVM, MS, PhD, DACVIM, DACVCP, Ellen Bronson, DVM (Dr med vet), DACZM

About the Project:

What made you decide to do a research study about avian malaria infections, specifically in penguins?

• The Maryland Zoo has the largest breeding colony of African penguins in North America.
• They are closely monitored for avian malaria, and veterinarians at the zoo have been studying this since the 1960s.
• There had been no study done investigating anti-malarial drugs on any avian species.

What are some of the main points about the project?

• The most common drug used to prevent malaria in humans is primaquine. Avian species can contract avian malaria, so the study was done to see if the same drug could be safely used in African penguins.
• The first problem that was encountered was that avian species have a higher metabolism than humans. Initial observation: when 4 African penguins were given the drug either once or twice a week, it was noted that the blood concentrations of the drug did not reach optimal levels for the penguin to be considered protected against malaria.
• During the research study, 15 penguins were given 26.3mg of primaquine once a week to control avian malaria to see if the penguins could build an immunity against the disease.

Outcome/Results: 

• Penguins reached appropriate blood concentrations at 24 hours using the 26.3mg dose of the drug once a week to control avian malaria.
• Currently, there are no guidelines on the "best dose" of primaquine for African penguins. More research is currently being pursued.
  

Describe how this project advanced the field of avian medicine:

• First study – no one had done it before, so it was very rewarding.
• AZA African Penguin Survivability (Penguins in Human Care – Malaria is a big effect in the community) – Dr. Bronson is one of the advisors for this program.
• More research is currently being done.
• If a penguin comes in contact with malaria, primaquine is taken for prevention. Maryland Zoo monitors new penguins weekly for the first two summers by taking blood smears (20 minutes per bird). If at least one avian malaria parasite is observed on the blood smear, then the bird is treated for 10 days with primaquine and chloroquine. African penguins do appear to develop immunity over time (Maryland Zoo has been helping the penguins overcome the infection) – each penguin is monitored for any side effects when given the drugs.
  

Explain how the results can be used in practice:

Treatment protocols have changed in zoos and aquariums.

What is next?

A second study is currently being done to answer the question on how avian species can build a natural immunity to avian malaria.

Summary submitted by:

Ashley Long (1st year vet student at St. George's University)             

Project Title:

Superficial Chronic Ulcerative Dermatitis (SCUD) in Psittacine Birds: Review of 11 Cases (2008-2016)

Journal of Avian Medicine and Surgery 32(1):25–33, 2018

Principal Investigator:

Tariq Abou-Zahr, BVSc, MRCVS

Principal Investigator Institution:

Vets Now Referrals (Abou-Zahr, Carrasco, Forbes, Dutton, Froehlich, De Bellis), Unit 10-14 Berkshire House, Shrivenham Road, Swindon, SN1 2NR, United Kingdom; Universite´ de Lie`ge (Shimizu), Faculte´ de Me´decine Ve´te´rinaire, Quartier Valle´e 2, Avenue de Cureghem 3 B44, 4000, Lie`ge, Belgium

Additional investigator(s):

Daniel Calvo Carrasco, AP, LV, Cert AVP(ZM), MRCVS, Naomi Shimizu, DVM, MRCVS, Neil A. Forbes, BVetMed, Dipl ECZM (Avian), FRCVS, Thomas A. G. Dutton, BVM&S, Cert AVP(ZM), MRCVS, Fiona Froehlich, Mag Med Vet, GP Cert(ExAP), MRCVS, and Filippo De Bellis, DVM, CertVD, Dipl ECVD, MRCVS

About the Project:

This is a case series of 11 psittacines that were diagnosed with superficial chronic ulcerative dermatitis (SCUD) over an 8-year period at a private practice. In this study, SCUD refers to lesions on the skin surface without deep pyoderma or neoplasia and lasting at least 1 month. The SCUD lesions from the birds were sampled for aerobic and anaerobic bacterial culture and fungal culture under anesthesia after minor debridement of necrotic superficial tissue; debridement was repeated if needed. Handmade collars with foam piping were made for each bird with a flat disk if the foam piping was inadequate. 

Birds received the following treatments: twice daily 1 of 3 topical ointments (mupirocin, silver sufadiazine, germicidal barrier ointment); analgesia (meloxicam 0.5 mg/kg PO BID), 1 of 3 oral antibiotics (amoxicillin clavulanate 125 mg/kg PO BID, trimethoprim-sulfamethoxazole 30 mg/kg PO BID, or enrofloxacin 15 mg/kg PO BID); and gonadotropin-releasing hormone agonist implant (in 4/11 birds). Birds were re-examined every 1-4 weeks. Treatment continued until all lesions resolved. Antibiotics were continued 7 days after healing. Antibiotics were changed in 4/11 cases.

This case series reports the signalment, incidence of recurrence, most common microbial species cultured, and average time to complete resolution of dermatitis of the 11 cases. 

Outcome/Results:

Of the 11 cases, 6 were African grey parrots (Psittacus erithacus), 1 peach-faced love bird (Agapornis roseicollis), 1 galah (Eolophus roseicapilla), 1 Goffin’s cockatoo, 1 Moluccan cockatoo (Cacatua moluccensis), and 1 Senegal parrot (Poicephalus senegalus). Six were confirmed to be male, 4 female, and 1 undetermined via DNA sexing. All 11 birds were hand-reared, kept indoors, strongly imprinted on owners and without avian companions, and 10/11 showed regurgitation or courtship behavior towards owners. Concurrent feather-damaging behavior was observed in 7/11 cases. Three birds (18%) had previous lesions and 1 was euthanized for recurrent signs.  Fungal cultures were negative in all cases. Bacterial cultures were positive in 9/11 cases: Enterobacter cloacae, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Acinetobacter baumanii. In 9/11 cases, a single anatomic site was affected (most commonly  the axillae). In 2/11 cases, more than one lesion was found. One case involved additional treatments with a hydrocolloid dressing sutured in place. Lesions required 1-21 months to resolve, with a median of 2 months.

Describe how this project advanced the field of avian medicine:

This study showed the most common psittacines affected by SCUD, some common predisposing husbandry factors, the most common bacteria involved in the dermatitis, and most common sites affected. 

Explain how the results can be used in practice:

This paper outlines a protocol for working up and treating SCUD with evidence-based medicine. 

Summary submitted by:

Kaleigh Eichel

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