Comparison of two heavy metal chelators for treatment of lead toxicosis in cockatiels

OBJECTIVE: To compare efficacy and safety of meso-2,3-dimercaptosuccinic acid (DMSA) and Ca EDTA for treatment of experimentally induced lead toxicosis in cockatiels (Nymphicus hollandicus). ANIMALS: 137 (69 females, 68 males) healthy cockatiels between 6 months and 8 years old. PROCEDURE: Lead toxicosis was induced by placing lead shot in the gastrointestinal tract. Treatment with Ca EDTA (40 mg/kg of body weight, IM, q 12 h), DMSA (40 or 80 mg/kg, PO, q 12 h), and sodium sulfate salts (SSS; 0.5 mg/kg, PO, q 48 h) was initiated 4 days after induction of lead toxicosis. Blood lead concentrations were determined, using atomic absorption spectrophotometry. Number of birds surviving and blood lead concentrations were compared among groups. RESULTS: In Phase II of the study, administration of DMSA and Ca EDTA significantly decreased blood lead concentrations when used alone or in combination in birds with lead toxicosis. Addition of SSS did not result in further decreases in lead concentrations. Eight of 12 (66.7%) birds without lead toxicosis given 80 mg of DMSA/kg did not survive to the end of the study. Lesions related to treatment with chelating agents were not detected during necropsy. CONCLUSIONS AND CLINICAL RELEVANCE: DMSA and Ca EDTA are effective chelating agents in cockatiels. Because DMSA is administered orally, it may be easier than other chelating agents for bird owners to administer at home. However, the narrow margin of safety of DMSA indicates that this agent should be used with caution.     

Administration of doxycycline in drinking water for treatment of spiral bacterial infection in cockatiels

OBJECTIVE: To determine efficacy of providing drinking water medicated with doxycycline for treatment of spiral bacterial infection in cockatiels. DESIGN: Randomized controlled clinical trial. Animals-18 cockatiels (Nymphicus hollandicus) naturally infected with spiral bacteria. PROCEDURES: Spiral bacterial infection was diagnosed by means of cytologic examination of swab specimens from the choana and oropharynx. Eleven birds (treatment group) were given drinking water to which doxycycline hyclate had been added at a concentration of 400 mg/L for 30 days; the remaining 7 birds (control group) were given unmedicated water. After completion of the study, 6 control birds were treated with drinking water medicated with doxycycline for 21 days. RESULTS: Daily mean plasma doxycycline concentration for birds in the treatment group ranged from 2.26 to 2.86 Mg/mL (overall range, 0.83 to 4.34 Mg/mL). All treated birds were negative for spiral bacteria after treatment for 21 days and remained negative when examined 160 days after treatment ended. Control birds remained positive for spiral bacteria. Control birds treated with doxycycline after completion of the study were negative for spiral bacteria after treatment for 21 days and 30 days after treatment ended. No clinically important adverse effects were associated with treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that providing drinking water to which doxycycline had been added at a concentration of 400 mg/L was effective in eliminating spiral bacterial infections in cockatiels.     

Flow cytometric analysis of nuclear DNA for sex identification in three psittacine species

OBJECTIVE: To evaluate flow cytometric analysis for sex identification in 3 psittacine species, establish reference values for blood cell DNA content for each species, and determine effects of sample storage on DNA content. ANIMALS: 36 orange-winged Amazon parrots, 41 budgerigars, and 39 cockatiels. PROCEDURE: Blood samples were stained and analyzed by use of flow cytometry to measure cellular DNA content. Samples were analyzed immediately after collection and after being stored at 4 C for 48 and 72 hours. RESULTS: Mean DNA content (picograms per cell) was 3.248 for Amazon parrots, 2.702 for budgerigars, and 2.946 for cockatiels; DNA concentrations in samples analyzed immediately overlapped in a male and a female Amazon parrot and among 19 cockatiels. For budgerigars, DNA overlap between sexes was not detected in samples analyzed immediately or after storage for 72 hours. Sex was identified correctly in 94.4% of Amazon parrots, 100% of budgerigars, and 51.3% of cockatiels. For both sexes, DNA content in samples analyzed immediately was significantly different from that of stored samples. CONCLUSIONS AND CLINICAL RELEVANCE: Flow cytometric analysis was accurate for sex identification of Amazon parrots and budgerigars. Sample storage at 4 C for 48 or 72 hours caused variability in DNA content.     

Pharmacokinetics of ceftiofur sodium in exotic and domestic avian species

The pharmacokinetics of ceftiofur sodium were determined in domestic chicks, turkey poults, adult cockatiels ( Nymphicus hollandicus ), and adult orange-winged Amazon parrots ( Amazona amazonica ) after subcutaneous (chicks and turkey poults) and intramuscular (i.m.) dosing (cockatiels and Amazon parrots). Turkey poult data were best fit to a single exponential model with disappearance half-lives ( t _1/2) of 8.6, 7.4 and 5.6 h after doses of 0.12, 0.24 and 0.48 mg ceftiofur free acid equivalents (CFAE)/poult, respectively. Data from chicks were best fit to a biexponential model with primary and secondary half-lives of 2.2 and 7.5, 3.7 and 6.8, and 3.8 and 5.3 h after doses of 0.04, 0.08 and 0.16 mg CFAE/chick, respectively. Cockatiel and Amazon parrot data were best fit to a biexponential model with primary and secondary half-lives of 0.28 and 2.5, and 0.93 and 7.9 h, respectively, after doses of 10 mg CFAE/kg body weight. The maximum concentration ( C _max) and area under the concentration time curve ( AUC ) in chicks and poults were dose-proportional. The C _max for cockatiels was 5.2 μg/mL and for Amazon parrots was 11 μg/mL. Clearance in cockatiels and Amazon parrots were 11.3 and 3.8 mL/min/kg, respectively, and reflected the much greater AUC seen in Amazon parrots. Clearance values of ceftiofur were similar in chicks and Amazon parrots, slightly greater in turkey poults and greatest in cockatiels. These results indicate that pharmacokinetic differences must be considered when establishing dosage regimens for different avian species.     

Ophthalmic diagnostic tests and ocular findings in healthy adult cockatiels (Nymphicus hollandicus)

Cockatiels (Nymphicus hollandicus) are a common companion psittacine for which little ophthalmic data has been gathered. The goal of this study was to establish normal ocular parameters in healthy cockatiels and evaluate whether intraocular pressure (IOP) varies by restraint method. Twenty-five cockatiels free of ophthalmic disease underwent complete ophthalmic examination including slit-lamp biomicroscopy, indirect ophthalmoscopy, and measurement of palpebral fissure diameter, tear production by absorbent paper point tear test (PPTT) and rebound tonometry. IOP measurements were obtained with birds held in two different body positions (vertical and dorsal recumbency). Cockatiel eyes are atapetal, anangiotic, and possess robust filoplumes, brown irises, pleated pecten, and circular pupil. There was no significant difference for horizontal palpebral fissure diameter, vertical palpebral fissure diameter, PPTT or IOP when comparing dorsal to vertical recumbency. For all eyes (50 eyes from 25 cockatiels), the mean (range) of horizontal palpebral fissures was 5.45 (5.0–6.0) mm, PPTT was 9.39 (6–14) mm/15s, and IOP (both recumbencies) was 13 (8.0–24.0) mm Hg. Described data can be used to improve diagnosis and management of ocular alterations in this species.     

Small intestinal cryptosporidiosis in cockatiels associated with Cryptosporidium baileyi-like oocysts

Four of six cockatiels died within a week after being purchased from a commercial breeder. A fifth bird was euthanatized and necropsied during this time, and tissues were collected for microscopic examination. The small intestine had moderate numbers of Cryptosporidium sp. parasites present. A few large, basophilic intranuclear inclusions were present in renal ductular epithelium. Cryptosporidium sp. oocysts were found in the feces of the surviving bird. Thirty oocysts were 7.2 by 5.5 microns. The shape index was 1.31. Morphological examinations of the fecal oocysts indicated that the Cryptosporidium species infecting the cockatiels was similar to C. baileyi, a parasite that is not usually associated with small-intestinal infections.     

Investigation of Japanese quail (Coturnix japonica) as a pharmacokinetic model for cockatiels (Nymphicus hollandicus) and Poicephalus parrots via comparison of the pharmacokinetics of a single intravenous injection of oxytetracycline hydrochloride

The purpose of this study was to determine whether Japanese quail (Coturnix japonica) would serve as a pharmacokinetic animal model for two small companion parrots: cockatiels (Nymphicus hollandicus) and Poicephalus parrots. Oxytetracycline (OTC) was the pharmacologic agent chosen for this study as it is eliminated primarily by renal glomerular filtration and undergoes minimal metabolism. A single intravenous injection of 20 mg/kg oxytetracycline hydrochloride was administered to the three study groups and blood samples were obtained at 5, 10, 15, and 30 min post-OTC injection as well as 1, 2, 4, 8, 12 and 24 h post-OTC injection. Quantification of plasma OTC was accomplished using a standardized microbial inhibition assay. Naïve-pooled data (NPD) analysis of the plasma concentration–time profile of OTC best fit a two-compartment open model for all three avian species. Noncompartmental analysis of the mean data yielded the following parameters for quail, cockatiels and Poicephalus parrots respectively: λ_z = 3.14, 4.57, 3.71 h; AUC = 38.9, 42.7, 49.6 μg·h/mL; and Cl = 514, 468, 403 mL/h/kg. Based on the similarity of these pharmacokinetic parameters, it appears that quail could be used as a model species to predict the appropriate OTC dosing regimen for small psittacine birds. A bootstrap procedure was also applied to these sparse data sets for both compartmental and noncompartmental analysis. The bootstrap procedure allowed for the calculation of variability of parameters; however, the estimates of the parameters were very similar to those calculated using the NPD and the data mean values.     

Eyelid malformation in four cockatiels

Four unrelated cockatiels had various degrees of maldevelopment of the eyelids. Only 1 eye of the 8 was normal. The condition had features compatible with ankyloblepharon or cryptophthalmos. Attempts were made to surgically establish an artificial palpebral fissure. Despite extensive surgical intervention and postoperative topical administration of corticosteroids, the skin over the orbit reverted to the preoperative state in all birds. Anecdotal information along with our findings suggest that this condition, although uncommon, is widespread in the cockatiel population in the United States.     

TECHNETIUM-99M AND IODINE-131 THYROID SCINTIGRAPHY IN NORMAL AND RADIOTHYROIDECTOMIZED COCKATIELS (NYMPHICUS HOLLANDICUS)

Thyroid scintigraphy using sodium ^99mTechnetium pertechnetate (⁹⁹TcO₄-) was performed in normal and radiothyroidectomized cockatiels ( Nymphicus hollandicus ). ¹³¹I scintigraphy was performed in the course of ablating the thyroid glands. The thyroid glands in normal birds were clearly visualized, but were not individually resolvable. Thyroid glands were not visualized in thyroid-ablated birds. With ^99mTcO₄ scans, thyroid (or other region of interest)/body count density ratios were used for comparisons of normal and thyroid-ablated birds. Normal ^99mTcO₄- thyroid/body ratios (mean +/− SD) for the dorsal and lateral views were 1.83 +/− 0.31 and 1.70 +/− 0.34 respectively. Pertechnetate thyroid/body count density ratios decreased (to 0.93 -/−0.14 and 0.88 +/− 0.12 for dorsal and lateral views respectively) after thyroid ablation, while crop/body ratios increased. ^99mTcO₄- thyroid scintigraphy, therefore, was capable of detecting hypofunctional thyroid abnormalities in ¹³¹I radiothyroidectomized cockatiels.     

Iohexol-based measurement of intestinal permeability in birds

Background: Iohexol has been successfully used as a marker to assess intestinal permeability in humans and various other mammals. The objective of this study was to evaluate the use of oral iohexol as an intestinal permeability marker in four anatomically and nutritionally diverse bird species. Methods: Three dosages (1 ml/kg, 2 ml/kg, 4 ml/kg) of iohexol (755 mg/ml) were administered orally to each six clinically healthy pigeons and chickens at two-week intervals. Iohexol plasma concentration was determined 45, 90 and 180 minutes after administration. A comparative study was performed by administering iohexol twice to each six clinically healthy cockatiels and falcons, and determining iohexol plasma concentration at 45 or 90 minutes after administration. Results: The recommended iohexol dosage for permeability testing in birds was determined to be 1 ml/kg. Median plasma iohexol concentrations were 27.77 µg/ml in pigeons, 12.97 µg/ml in chickens, 14.24 µg/ml in cockatiels, and 47.81 µg/ml in falcons, 45 minutes after this dosage was administered. At 90 minutes after administration, median plasma iohexol concentrations were 40.68 µg/ml in pigeons, 21.59 µg/ml in chickens, 32.03 µg/ml in cockatiels, and 55.96 µg/ml in falcons. Conclusions and clinical relevance: Oral iohexol was a safe and feasible marker for intestinal permeability assessment in birds. Further investigations are warranted to establish species-specific reference intervals in larger numbers of healthy birds, and to examine the use of iohexol as a permeability marker in birds with disorders associated with altered intestinal permeability.     

Zoonotic diseases in psittacine birds: apparent increased occurrence of chlamydiosis (psittacosis), salmonellosis, and giardiasis.

Between September 1977 and November 1978, chlamydiosis (psittacoisis) was diagnosed in 52 of 128 parrots, 5 of 12 cockatiels, 2 of 5 cockatoos, 3 of 6 macaws, 1 of 22 conures, 2 of 18 lovebirds, and 6 of 76 parakeets; 2 lories and 1 lorikeet were chlamydiosis negative. Two cases of human chlamydiosis were associated with two submissions of parrots subsequently found to have active infection. Twenty parrots (including 13 that were chlamydiosis positive), 2 cockatiels, 1 macaw, 1 lorie, and 1 parakeet yielded salmonella organisms, of which 16 were identified as Salmonella typhimurium, 8 as untypeable monophasic salmonellae of serogroup B, and 1 as S arizonae. Three S typhimurium from parrots that had been treated with chlortetracycline for chlamydiosis were resistant to tetracyclines, streptomycin, and sulfonamides; another isolate was found to be resistant to chloramphenicol only. Severe giardiasis was diagnosed in parakeets originating from six aviaries.     

Retropharyngeal lymph node infection in horses: 46 cases (1977–1992)

SUMMARY A retrospective study of 46 horses with retropharyngeal lymph node (RPLN) infection presented to the Rural Veterinary Centre between 1977 and 1992 was undertaken. Horses aged less than one year were most commonly represented (46%). Thirty-nine percent of cases had been exposed to horses with confirmed or suspected strangles (Streptococcus equi subsp equi infection) within the previous 8 weeks. Most frequent signs were unilateral or bilateral swelling of the throat region (65%), respiratory stertor/dyspnoea (35%), purulent nasal discharge (20%), inappetence and signs of depression (15%), and dysphagia (9%). All horses had a soft tissue density in the retropharyngeal region on radiographs. Rhinopharyngoscopy, ultrasonography, haematology as well as cytological and microbial analysis of material aspirated from the soft tissue swelling facilitated diagnosis in some horses. Fifteen horses (33%) were treated with procaine penicillin intramuscularly for 4 to 7 days followed by oral trimethoprim-sulphadimidine for 7 to 14 days. Non-steroidal anti-inflammatory drugs were administered to 6 horses. Four required tracheostomy for severe respiratory distress. The 15 horses treated medically responded to treatment and were discharged from hospital. Three horses (6%) with mild signs received no treatment and recovered uneventfully. Twenty-eight horses (61%) underwent general anaesthesia and surgical drainage of a RPLN abscess. Nineteen received procaine penicillin G for 4 to 7 days. Four of the nine horses that did not receive antibiotic treatment after surgery required further surgical drainage 10 days to 7 weeks after the initial surgery . Limited follow-up information was available for 37 horses. Thirty-two horses were considered to have made complete recovery, 3 horses had died through misadventure and 2 had been euthanased because of chronic ill-thrift .     

Trauma-induced aneurysmal bone cysts in two psittacine species (Cacatua alba and Nymphicus hollandicus).

An umbrella cockatoo (Cacatua alba) and two cockatiels (Nymphicus hollandicus) were presented with rapidly enlarging masses of the head or wing joints. Historic trauma to these areas was confirmed in two cases. All birds were >2 yr of age, and two were female. Cytologic examination of fluid aspirated from masses in two cases was described as serosanguineous cytologically but failed to reveal inflammation, neoplasia, or microorganisms. Radiographic evaluation of these masses included proliferation and lysis of bone, suggestive of a neoplastic process. Histopathologic examination of surgically excised tissues revealed proliferative new bone and an absence of neoplastic tissue in all cases, consistent with aneurysmal bone cyst formation. Despite the guarded prognosis reported for other companion animals, these case results suggest a good prognosis for aneurysmal bone cyst in psittaciformes. Complete surgical excision and histopathologic examination is recommended for definitive diagnoses of aneurysmal bone cyst. Postoperative bandaging and rational antibiotic use are indicated to prevent excessive motion and secondary infection of affected sites, respectively.     

Use of refractometry for determination of psittacine plasma protein concentration

Background: Previous studies have demonstrated both poor and good correlation of total protein concentrations in various avian species using refractometry and biuret methodologies. Objectives: The purpose of the current study was to compare these 2 techniques of total protein determination using plasma samples from several psittacine species and to determine the effect of cholesterol and other solutes on refractometry results. Methods: Total protein concentration in heparinized plasma samples without visible lipemia was analyzed by refractometry and an automated biuret method on a dry reagent analyzer (Ortho 250). Cholesterol, glucose, and uric acid concentrations were measured using the same analyzer. Results were compared using Deming regression analysis, Bland–Altman bias plots, and Spearman's rank correlation. Results: Correlation coefficients (r) for total protein results by refractometry and biuret methods were 0.49 in African grey parrots (n=28), 0.77 in Amazon parrots (20), 0.57 in cockatiels (20), 0.73 in cockatoos (36), 0.86 in conures (20), and 0.93 in macaws (38) (P≤.01). Cholesterol concentration, but not glucose or uric acid concentrations, was significantly correlated with total protein concentration obtained by refractometry in Amazon parrots, conures, and macaws (n=25 each, P<.05), and trended towards significance in African grey parrots and cockatoos (P=.06). Conclusions: Refractometry can be used to accurately measure total protein concentration in nonlipemic plasma samples from some psittacine species. Method and species‐specific reference intervals should be used in the interpretation of total protein values.     

An outbreak of the polyomavirus infection in budgerigars and cockatiels in Slovakia, including a genome analysis of an avian polyomavirus isolate

In winter 2003-04, large numbers of budgerigars (Mellopsitacus undulatus) and cockatiels (Nymphicus hollandicus) fell ill and died in a large parrot-breeding aviary in Slovakia. In budgerigars, the disease outbreak occurred at the age of 2-3 weeks; cockatiels died within their first 7 days of life. In budgerigars, symptoms of the disease included delayed growth, tremor, darkish discoloration of skin, quill bleeding, and feathering defects. cockatiels often died without any symptoms and with a full crop; feathering defects occurred sporadically. Electron microscopy with negative staining of aqueous lysates of the affected skin and of bleeding quills showed isolated or clustered polyomavirus particles 45-50 nm in size. Long filamentous forms of the virus were also found in virion clusters of skin lysates from the budgerigars. In ultrathin sections through the pathologically altered skin tissue of budgerigars, virus particles were present in both nuclei and cytoplasm of epidermal cells, often in crystalline form. In infected cells, enlarged nuclei showed an extensive chromatin margination. On the DNA level, presence of a polyomavirus infection was conclusively proved by the polymerase chain reaction using avian polyomavirus (APV)-specific primers. A sequence analysis of the gene encoding viral protein (VP)1 and of the combined region for VP2 and VP3 proteins revealed a previously undescribed synonymous mutation in this isolate. This report extended the knowledge of the area of APV occurrence and of the spectrum of hosts in the context of genomic and morphologic variability of APV isolates.     

The potential use of plasma glutamate dehydrogenase activity for the evaluation of hepatic disease in the cockatiel (Nymphicus hollandicus)

A reference interval for plasma glutamate dehydrogenase (GD) (E.C. 1.4.1.3) activity, of 0-8 IU/L, was established for the cockatiel (Nymphicus hollandicus). An automated modification of a commercial manual assay was used. This enzyme is considered liver specific in humans and numerous domestic animals, due to its organ distribution. A similar distribution was found in cockatiels in this study. Maximal enzyme activity was recovered from liver and kidney homogenate supernatants. Minimal activity was detected in skeletal muscle preparations. These results suggest a potential use for plasma GD activity in the evaluation of hepatocelluar injury/necrosis in cockatiels.     

Spermatozoa Characteristics in Six Psittacine Species Using Light Microscopy

Even though breeding of companion birds has increased continuously for years, the fecundity assessment of birds has hardly been acknowledged. Knowledge of the structure of spermatozoa is crucial for evaluation of the basic reproductive biology of any species as well as for phylogenetic research and cladistic analyses of internal relationships. Spermatozoa of six different psittacine species (Nymphicus hollandicus, Myiopsitta monachus, Agapornis roseicollis, Melopsittacus undulatus, Tanygnathus lucionensis, Guarouba guarouba) were examined using light microscopy. Head length (nucleus including acrosome), head width, midpiece length and tail length were measured and documented. Significant differences were obvious among almost all of the species for almost all four parameters. However, in all the six species a significant moderate correlation between spermatozoa midpiece lengths and tail lengths (r = 0.535, p ≤ 0.01), spermatozoa head lengths and midpiece lengths (r = 0.508, p ≤ 0.01) as well as tail lengths (r = 0.472, p ≤ 0.01) was found. The present results confirm that spermatozoa of cockatiels have shorter heads and midpieces than the other psittacines examined in this study. Spermatozoa characteristics in the monk parakeet, blue‐naped parrrot and golden conure are previously unreleased and documented for the first time.     

Rectal atresia in a newborn donkey

A case of a type I rectal atresia (also known as membranous rectal atresia) in a newborn donkey is reported. Clinical examination, survey radiographs and barium enema radiographs suggested rectal atresia. An exploratory laparotomy was performed; however, surgical correction of the defect was not possible due to the narrow pelvic cavity. Euthanasia was performed. At necropsy, it was possible to observe a fibrous cord connecting the small colon to a residual rectal ampulla, which opened to a normal anus. The radiographic and anatomical characteristics enabled the classification of the defect as type I rectal atresia, which is a rare congenital anomaly that is difficult to correct through surgery. This report contributes to the study of rectal atresia in newborn equids, alerts for the occurrence in donkeys and is, to our knowledge, the first to be reported in this species in Brazil.     

Surgical treatment and histopathology of different forms of olecranon and presternal bursitis in cattle and buffalo

Thirty seven cases of bursitis presented to our Veterinary Teaching Hospital from 2001 to 2005. There were 10 adult female buffalos with olecranon bursitis (one had bilateral bursitis) and 26 calves (7 cattle and 19 buffalos, 16 males and 10 females) with presternal bursitis. There were 10 out of 11 cases of olecranon bursitis and 21 out of 26 cases of presternal bursitis with different forms (cystic, proliferative and fibrous) that were removed surgically. The remaining 6 cases, cystic bursitis (olecranon = 1, presternal = 5), were treated by aspiration of their contents and injection of 4% iodine tincture intrabursally. Only 2 cases recovered, 3 cases progressed to fibrosis and required further surgical treatment 2 to 3 weeks later, and 1 case continued to have a cystic lesion. Histopathological examination of tissue specimens from different forms of bursitis revealed that the acquired bursae were generally lined with synovial-like membrane formed from 2-3 cellular layers that covered the connective tissue capsule. The connective tissue capsule differed from one type to another and consisted of fibrous tissues containing numerous small blood vessels, blood capillaries, lymphatics and nerves. There was also evidence for inflammation within the capsule represented by congestion of blood vessels and the presence of perivascular inflammatory cells, mostly mononuclear. In conclusion, surgical treatment was successful and effective for treatment of olecranon and presternal bursitis particularly for the chronic proliferative and fibrous form in cattle and buffalo. The histological structure of the acquired bursae was relatively similar consisting of a synovial-like membrane and a connective tissue capsule with varying degrees of the inflammatory process.