Streptomyces cyaneus dermatitis in a dog.

BACKGROUND: A nearly 4-year-old neutered male Australian Terrier was referred for a nodular pyogranulomatous mass of the right axilla. It had been poorly responsive to antibiotic therapy. CASE REPORT: Based on filamentous Gram-positive organisms identified in earlier biopsy material, infection by an Actinomyces sp. was suspected and the dog showed clinical improvement on a trial of potentiated sulfonamides. Recurrence 5 months later prompted euthanasia, with Streptomyces cyaneus being cultured and confirmed by genetic sequencing of part of the 16 s ribosomal RNA gene. CONCLUSION: Invasive Streptomyces spp. infections are uncommon in humans and animals, and isolations are sometimes considered to be contaminants, but the demonstration of the organism within the lesion in this instance indicates that the isolation of a Streptomyces sp. from veterinary cases should not always be considered as contamination, because this genus is clearly pathogenic.

The pathology of 'scale drop syndrome' in Asian seabass, Lates calcarifer Bloch, a first description.

This is the first pathological description of 'scale drop syndrome' (SDS) in Asian seabass, Lates calcarifer Bloch. Cumulative mortality was estimated at 40-50%. The vasculitis in all major organs including the skin and associated tissue necrosis was distinctive. The dermis overlying scale beds was often necrotic and associated with scale loss. Necrosis of splenic ellipsoids, renal glomeruli and choroid rete glands of eye were further hallmarks of a disease with systemic vascular involvement. The brain was not spared vascular damage, and the resulting multifocal encephalomalacia probably accounts for the spiral swimming behaviour in some affected fish. Other lesions included accentuated hepatic lobulation and gastric gland necrosis. Nuclear chromatin margination and karyolysis in hepatocytes, renal tubular epithelium and gastric and intestinal epithelium suggest specific targeting of cells. Basophilic cytoplasmic inclusions were present in spleen, kidney, liver, heart and choroid rete, but they were not prominent. Using transmission electron microscopy, two morphological forms of virions were observed: single- and double-enveloped hexagonal virions. Based on size and morphology, these virions resemble iridovirus or herpesvirus. The cause of SDS is unknown, but the pathological changes, especially the vasculitis, suggest an infectious aetiology, possibly viral.

The molecular characterization of an Eimeria and Cryptosporidium detected in Asian seabass (Lates calcarifer) cultured in Vietnam.

An intestinal Eimeria was previously reported as a significant pathogen of Asian seabass (Lates calcarifer) in nurseries in Vietnam. In the present study, both Eimeria and Cryptosporidium were detected by sequence analyses of fragments of the 18S rRNA gene amplified from these Vietnamese L. calcarifer tissues. Based on these analyses, the Eimeria from the Vietnamese L. calcarifer formed clades with the Eimeria detected in L. calcarifer tissues from Australia, but clustered separately from other known Eimeria and Goussia species. The Cryptosporidium detected in L. calcarifer from Vietnam clustered closest with C. parvum and C. hominis. In situ hybridization using DIG-labeled DNA probes generated from 18S PCR products on the Vietnamese L. calcarifer wax block tissues showed that this method could not be used to distinguish between Eimeria and Cryptosporidium, due to the conserved nature of the 18S locus. A previously published study on the morphology of parasite developmental stages and oocysts in the Vietnamese L. calcarifer tissues showed only an intestinal Eimeria infection. The Cryptosporidium could be present at very low levels undetectable by microscopy in intestines, or being ubiquitous, was a possible contaminant from feed or water. While molecular analysis is a very useful tool in the study of disease and identification of aetiological agents, this study reiterates the importance of demonstrating organisms in situ in tissues.

An intestinal Eimeria infection in juvenile Asian seabass (Lates calcarifer) cultured in Vietnam--a first report.

This is the first report of an intestinal Eimeria infection in Asian seabass (Lates calcarifer) at the histopathological and ultrastructural levels. The Eimeria infection was often associated with severe pathology and significant mortality in the absence of other pathogens. This showed that it is an important disease of juvenile L. calcarifer in small scale nurseries in Vietnam. Heavy infection and high prevalence levels of the Eimeria infection are suspected to be linked to the low daily water exchange rates practised in these nurseries. Although systemic iridovirus infection was concurrently observed in some of the fish examined, it was not as consistently present in diseased fish as the Eimeria infection.

Cutaneous asthenia in a Warmblood foal.

A 6-week-old Warmblood colt foal was presented for investigation of multiple haematoma formation in various locations, poor wound healing and abnormal scar formation. Based on the history and clinical presentation of hyperextensible skin with prolonged skin tenting, the foal was diagnosed with cutaneous asthenia and euthanased because of the poor prognosis. Histopathological and electron microscopic findings were inconclusive. This is the first case report of cutaneous asthenia in a Warmblood horse in Australia. Cutaneous asthenia is reviewed with particular reference to hereditary equine regional dermal asthenia and its similarities and differences to the case presented.

Detection of Minchinia occulta in samples of pearl oysters Pinctada maxima infected by Haplosporidium hinei.

OBJECTIVE: To determine if juvenile pearl oysters (Pinctada maxima) infected with Haplosporidium hinei are also infected with another haplosporidian parasite, Minchinia occulta. DESIGN: Archived samples of pearl oysters infected with H. hinei were examined using polymerase chain reaction (PCR) assays and in situ hybridisation (ISH) to analyse and identify haplosporidians. A 144-bp and 220-bp region of Minchinia DNA were targeted by PCR and amplified DNA from formalin-fixed H. hinei-infected pearl oyster samples was sequenced. A 25-bp oligonucleotide probe targeting a variable section of the parasite's small subunit rRNA gene was used in ISH. RESULTS: The results of DNA-based diagnostic assays supported each other. The sequences obtained by PCR were found to be almost identical to M. occulta from rock oysters and the ISH assay demonstrated infection with M. occulta in affected pearl oysters. ISH indicated a prevalence of infection of 26.7% in one of the previous outbreaks. CONCLUSION: Pearl oyster spat are susceptible to infection by a Minchinia parasite, most likely M. occulta, which was recently identified in rock oysters within the pearl-producing zones of Western Australia and is associated with mortalities of up to 80% in this species. The occurrence of haplosporidian co-infections in pearl oysters suggests the immunocompetence of juvenile oysters may be an important factor in preventing infection and therefore preventing mortalities such as those occurring in the recent outbreaks of pearl oyster oedema disease.

Remission of histiocytic ulcerative colitis in Boxer dogs correlates with eradication of invasive intramucosal Escherichia coli.

BACKGROUND: Historically, histiocytic ulcerative (HUC) (or granulomatous) colitis of Boxer dogs was considered an idiopathic immune-mediated disease with a poor prognosis. Recent reports of dramatic responses to enrofloxacin and the discovery of invasive Escherichia coli within the colonic mucosa of affected Boxer dogs support an infectious etiology. HYPOTHESIS: Invasive E. coli is associated with colonic inflammation in Boxer dogs with HUC, and eradication of intramucosal E. coli correlates with clinical and histologic remission. ANIMALS: Seven Boxer dogs with HUC. METHODS: Prospective case series. Colonic biopsies were obtained at initial evaluation in 7 dogs, and in 5 dogs after treatment with enrofloxacin. Biopsies were evaluated by standardized histopathology, and fluorescence in situ hybridization (FISH) with probes to eubacteria and E. coli. RESULTS: Intramucosal E. coli was present in colonic biopsies of 7/7 Boxers with HUC. Clinical response was noted in all dogs within 2 weeks of enrofloxacin (7 + or - 3.06 mg/kg q24 h, for 9.5 + or - 3.98 weeks) and was sustained in 6 dogs (median disease-free interval to date of 47 months, range 17-62). FISH was negative for E. coli in 4/5 dogs after enrofloxacin. E. coli resistant to enrofloxacin were present in the FISH-positive dog that relapsed. CONCLUSIONS AND CLINICAL RELEVANCE: The correlation between clinical remission and the eradication of mucosally invasive E. coli during treatment with enrofloxacin supports the causal involvement of E. coli in the development of HUC in susceptible Boxer dogs. A poor response to enrofloxacin treatment might be due to colonization with enrofloxacin-resistant E. coli.

Spore ornamentation of Minchinia occulta n. sp. (Haplosporidia) in rock oysters Saccostrea cuccullata (Born, 1778).

A Minchinia sp. (Haplosporidia: Haplosporidiidae) parasite was identified infecting rock oysters and morphologically described by Hine and Thorne (2002) using light microscopy and transmission electron microscopy (TEM). The parasite was associated with up to 80% mortality in the host species and it is suspected that the parasite would be a major impediment to the development of a tropical rock oyster aquaculture industry in northern Western Australia. However, attempts to identify the parasite following the development of a specific probe for Haplosporidium nelsoni were unsuccessful. The SSU region of the parasite's rRNA gene was later characterized in our laboratory and an in situ hybridization assay for the parasite was developed. This study names the parasite as Minchinia occulta n sp. and morphologically describes the parasite using histology, scanning electron microscopy and transmission electron microscopy. The non-spore stages were unusual in that they consisted primarily of uninucleate stages reminiscent of Bonamia spp. The parasite's spores were ovoid to circular shaped and measured 4.5 microm-5.0 microm x 3.5-4.1 microm in size. The nucleus of the sporoplasm measured 1.5-2.3 microm and was centrally located. The spores were covered in a branching network of microtubule-like structures that may degrade as the spore matures.

Acute necrotising pulmonary vasculitis and pulmonary hypertension in a juvenile dog.

A five-month-old female Jack Russell terrier was presented for investigation of acute lethargy, anorexia, coughing, respiratory distress and weakness. Examination findings included cyanosis, a grade 3 of 6 systolic heart murmur and prolonged capillary refill time. Radiography and echocardiography revealed severe pulmonary hypertension, cor pulmonale and right-sided heart failure. Indirect measurement of the systolic pulmonary artery pressure estimated pressures over 100 mmHg. Despite treatment the patient died. Post-mortem examination did not identify a congenital cardiovascular anomaly. Histopathology confirmed acute necrotising pulmonary arteritis and immunohistochemistry failed to identify any immune complex or complement deposition.

Spore ornamentation of Haplosporidium hinei n. sp. (Haplosporidia) in pearl oysters Pinctada maxima (Jameson, 1901).

An infection of pearl oysters, Pinctada maxima, attributed to a Haplosporidium sp. by Hine and Thorne (1998) has been detected on 3 occasions and is considered to represent a serious concern to the pearling industry in Australia. The spore ornamentation of the parasite was determined by scanning electron microscopy and transmission electron microscopy. Spores of the parasite were pleomorphic, or elongated 3.5-4 microm x 2.5-3.0 microm in size. Two filaments were wound around the spore and originated from 2 'knob-like' posterior thickenings. Both filaments passed up one side of the spore together until just below the operculum whereupon each split and passed obliquely under the lip of the opercula lid. Each filament wrapped around the spore 4 times. The posterior thickenings seem to appear late in the development of the spore and were composed of spore wall material. A second set of branching tubular filaments composed of a different material was observed on the spore body although not on mature spores possessing a 'knob-like' posterior thickening. The ornamentation on the spores of the pearl oyster parasite was unique amongst described haplosporidian species where spore ornamentation is known. The parasite is named in this manuscript as Haplosporidium hinei n. sp.

Cutaneous papillomatosis and carcinomatosis in the Western barred bandicoot (Perameles bougainville).

A progressive wart-like syndrome in both captive and wild populations of the Western barred bandicoot (WBB) is hindering conservation efforts to prevent the extinction of this endangered marsupial. In this study, 42 WBBs exhibiting the papillomatosis and carcinomatosis syndrome were examined. The disease was characterized by multicentric proliferative lesions involving cutaneous and mucosal surfaces, which were seen clinically to increase in size with time. Grossly and histologically the smaller skin lesions resembled papillomas, whereas the larger lesions were most commonly observed to be squamous cell carcinomas. Large amphophilic intranuclear inclusion bodies were observed in hyperplastic conjunctival lesions of 8 WBBs under light microscopy. Conjunctival lesions from 2 WBBs examined using transmission electron microscopy contained a crystalline array of spherical electron-dense particles of 45-nm diameter, within the nucleus of conjunctival epithelial cells, consistent with a papillomavirus or polyomavirus. Conjunctival samples from 3 bandicoots that contained intranuclear inclusion bodies also demonstrated a positive immunohistochemical reaction after indirect immunohistochemistry for papillomavirus structural antigens. Ultrastructural and/or immunohistochemical evidence of an etiologic agent was not identified in the nonconjunctival lesions examined. Here we describe the gross, histopathologic, ultrastructural, and immunohistochemical findings of a papillomatosis and carcinomatosis syndrome recently identified in the WBB.

Gall bladder torsion and rupture in a dog.

A 6-year-old desexed female German Shepherd dog was referred to the Murdoch University Veterinary Hospital for assessment and management of acute onset vomiting, diarrhoea, polydipsia and lethargy of 2 days duration. Surgical, microbiological and histological findings were consistent with necrotising cholecystitis secondary to gall bladder torsion, resulting in gall bladder rupture and secondary non-septic bile peritonitis. A chronic peritoneopleural perforation resulting from an abdominal cavity foreign body and congenital peritoneopericardial hernia were also present. The dog made a full recovery following cholecystectomy, foreign body removal, repair of the peritoneopleural perforation and peritoneopericardial herniorrhaphy. This is the first recorded case of gall bladder torsion in the dog.

Klossiella quimrensis (Apicomplexa: Klossiellidae) causes renal coccidiosis in western barred bandicoots Perameles bougainville (Marsupialia: Peramelidae) in Western Australia.

Previous studies have described a range of Klossiella species parasitic in marsupial hosts. Klossiella quimrensis is the etiologic agent of renal coccidiosis in the peramelid marsupial hosts Isoodon obesulus and Perameles gunnii in Eastern Australia, but there is no previous report of klossiellosis in Western Australian peramelids. This study describes klossiellosis diagnosed by histology of renal tissue sections collected during necropsy of 20 Perameles bougainville between 2000 and 2005. Sporonts, sporoblasts, and macrogametes were identified within parasitophorous vacuoles of epithelial cells located near the renal corticomedullary junction. The prevalence of renal coccidiosis in P. bougainville diagnosed by renal histology is estimated at 30%. Only a single unsporulated sporocyst was detected by examination of cystocentesis-collected urine, indicating that microscopic evaluation of urine samples is an insensitive diagnostic test for detection of K. quimrensis in P. bougainville. This infection in P. bougainville is indirectly associated with mild multifocal interstitial lymphohistiocytic nephritis and is likely to be only minimally pathogenic in otherwise healthy individuals. Our study also extends the host and geographic range of K. quimrensis to include P. bougainville and Western Australia.

A new eimeria species parasitic in western barred bandicoots, Perameles bougainville (Marsupialia: Peramelidae), in western Australia.

Feces from western barred bandicoots, Perameles bougainville, examined during routine monitoring of captive breeding colonies and wild populations were frequently found to contain oocysts. Fecal oocysts from 1 individual housed at Kanyana Wildlife Rehabilitation Centre were allowed to sporulate in 2% potassium dichromate (K2Cr2O7) at room temperature. Sporulated oocysts are subspheroidal 18.8 X 17.9 (16.9-21.0 x 16.0-19.9) microm, with length/width (L/W) ratio of 1.05 (1.00-1.15), lack a micropyle and oocyst residuum, but they usually have a polar granule within a smooth trilaminate oocyst wall 1.0 (0.7-1.3) microm thick. Sporocysts are ovoid, 9.1 x 7.0 (8.1-10.8 x 6.1-8.6) microm, with L/W ratio of 1.32 (1.04-1.51), have a Stieda body, sporocyst residuum, and 2 comma-shaped sporozoites, each containing 2 spheroidal refractile bodies. Sporulation takes 2-5 days at room temperature. This is the first formal description of an Eimeria species parasitic in the order Peramelemorphia.

Paraspiralatus sakeri n. g., n. sp. (Nematoda: Spiruroidea, Spirocercidae) from saker falcons, Falco cherrug in Saudi Arabia and the first report of larvae from the subcutaneous tissues of houbara bustards, Chlamydotis undulata macqueeni in Pakistan.

A new nematode genus and species, Paraspiralatus sakeri, is described from the stomach of a wild-caught, female saker falcon in Saudi Arabia. This spirurid differs from the nearest genus and species Spiralatus baeri Chabaud, Brygoo & Durette, 1963 in the shape of the pseudolabia, shape of the buccal capsule and absence of a large cephalic vesicle. In addition, third stage spirurid larvae were recovered for the first time from subcutaneous tissues of two houbara bustards. These had died in the Rahim Yar Khan Rehabilitation Center (Houbara Foundation International, Lahore, Pakistan) in Pakistan and were examined at the National Avian Research Center in the United Arab Emirates. The morphology of the larvae and host pathology are described. Comparative studies with the adult spirurids from the saker falcon showed each to have similar cephalic and pharyngeal morphological features to the adults described indicating they are probably the same species. Spirurid nematodes of the suborder Spirurina normally have an arthropod intermediate host. In view of the host, the site from which the larvae were recovered and the fact that this is a rare occurrence, the houbara bustard is considered to be a paratenic host.

Use of trilostane for the treatment of pituitary-dependent hyperadrenocorticism in a cat.

Hyperadrenocorticism occurs much less frequently in cats than in dogs and, at present, is more difficult to manage successfully. This report documents the use of the steroid synthesis inhibitor trilostane for the treatment of hyperadrenocorticism in a domestic shorthaired cat with pituitary-dependent disease. Although trilostane was able to alleviate the severity of the clinical signs and was well tolerated, the cat subsequently died of renal failure secondary to a fungal infection of the urinary tract.

Absence of canine oral papillomavirus DNA following prophylactic L1 particle-mediated immunotherapeutic delivery vaccination.

In the canine oral papillomavirus (COPV) model, following wart regression, COPV DNA was detected by PCR at the challenge site. However, following particle-mediated immunotherapeutic delivery (PMID) of COPV L1 and subsequent challenge, no COPV DNA could be detected. These data support PMID of COPV L1 as a protective vaccine and suggest that PMID of L1 may induce virus clearance.

Detection of viral DNA and E4 protein in basal keratinocytes of experimental canine oral papillomavirus lesions.

We studied experimental canine oral papillomavirus (COPV) infection by in situ hybridization and immunohistochemistry of weekly biopsies. After 4 weeks, viral DNA in rete ridges suggested a keratinocyte stem cell target. Abundant viral DNA was seen in E4-positive cells only. E4 was predominantly cytoplasmic but also nuclear, being concentrated in the nucleoli during wart formation. Infected cells spread laterally along the basal layer and into the parabasal layers, accompanied by E7 transcription and increased mitoses. Most of the lower epithelium was positive for viral DNA, but, in mature warts, higher levels of E4 expression and genome amplification occurred in only sporadic superficial cells. L1 expression was late and in only a subset of E4-positive cells. During regression, viral DNA was less abundant in deep epithelial layers, suggesting downregulation of replication prior to replacement of infected cells from beneath. Detection of viral DNA in post-regression tissue indicated latent infection.

Intra-epithelial vaccination with COPV L1 DNA by particle-mediated DNA delivery protects against mucosal challenge with infectious COPV in beagle dogs.

Protection against viral challenge with canine oral papillomavirus (COPV) was achieved by immunisation via particle-mediated DNA delivery (PMDD) of a plasmid encoding the COPV L1 gene to cutaneous and oral mucosal sites in beagle dogs. The initial dose of approximately 9 microg of DNA was followed by two booster doses at 6 week intervals. A similar approach was used to vaccinate a control group of animals with plasmid DNA encoding the Hepatitis B virus S gene. Following challenge at the oral mucosa with COPV all animals vaccinated with the COPV L1 gene were protected against disease. However five of six animals in the control group developed COPV induced papillomas at the oral mucosa. Both cell-mediated lymphoproliferative and humoral antibody responses to the DNA vaccine were observed. Our data indicate that PMDD of plasmid DNA can protect against mucosal challenge with papillomavirus.

Regression of canine oral papillomas is associated with infiltration of CD4+ and CD8+ lymphocytes.

Canine oral papillomavirus (COPV) infection is used in vaccine development against mucosal papillomaviruses. The predictable, spontaneous regression of the papillomas makes this an attractive system for analysis of cellular immunity. Immunohistochemical analysis of the timing and phenotype of immune cell infiltration revealed a marked influx of leukocytes during wart regression, including abundant CD4+ and CD8+ cells, with CD4+ cells being most numerous. Comparison of these findings, and those of immunohistochemistry using TCRalphabeta-, TCRgammadelta-, CD1a-, CD1c-, CD11a-, CD11b-, CD11c-, CD18-, CD21-, and CD49d-specific monoclonal antibodies, with previously published work in the human, ox, and rabbit models revealed important differences between these systems. Unlike bovine papillomavirus lesions, those of COPV do not have a significant gamma/delta T-cell infiltrate. Furthermore, COPV lesions had numerous CD4+ cells, unlike cottontail rabbit papillomavirus lesions. The lymphocyte infiltrate in the dog resembled that in human papillomavirus lesions, indicating that COPV is an appropriate model for human papillomavirus immunity.