Cerebral and Ocular Ochroconiasis in 2 Elegant Crested Tinamou (Eudromia elegans) Chicks.

Two elegant crested tinamou chicks (Eudromia elegans), aged 27 and 50 days, respectively, died following acute onset of weakness and neurologic disease. Microscopically, the cerebral hemispheres of both chicks and the optic lobes of 1 chick contained multifocal granulomatous and heterophilic inflammation and necrosis with intralesional pigmented, thin-walled, fungal hyphae. In 1 chick, hyphae extended along the optic nerve into the globe and were associated with severe granulomatous and heterophilic inflammation of the choroid, retina, pecten, and vitreous. In both chicks, polymerase chain reaction amplification of the fungal 28S large subunit ribosomal RNA was positive with 99% sequence identity to Ochroconis gallopava. While a well-characterized fungal infection of domestic poultry, ochroconiasis has rarely been reported in exotic avian species, and this is the first histologic characterization of ocular ochroconiasis in any avian species.

A novel herpesvirus in 3 species of pheasants: mountain peacock pheasant (Polyplectron inopinatum), Malayan peacock pheasant (Polyplectron malacense), and Congo peafowl (Afropavo congensis).

The mountain peacock pheasant (Polyplectron inopinatum), the Malayan peacock pheasant (Polyplectron malacense), and the Congo peafowl (Afropavo congensis) are all listed as vulnerable to extinction under the International Union for Conservation of Nature Red List of Threatened Species. Here the authors report fatal infection with a novel herpesvirus in all 3 species of birds. DNA was extracted from the livers of birds with hepatocellular necrosis and intranuclear eosinophilic inclusions consistent with herpesvirus infection. Based on degenerate herpesvirus primers and polymerase chain reaction, 220- and 519-base pair products of the herpes DNA polymerase and DNA terminase genes, respectively, were amplified. Sequence analysis revealed that all birds were likely infected with the same virus. At the nucleotide level, the pheasant herpesvirus had 92% identity with gallid herpesvirus 3 and 77.7% identity with gallid herpesvirus 2. At the amino acid level, the herpes virus had 93.8% identity with gallid herpesvirus 3 and 89.4% identity with gallid herpesvirus 2. These findings indicate that the closest relative to this novel herpesvirus is gallid herpesvirus 3, a nonpathogenic virus used widely in a vaccine against Marek's disease. In situ hybridization using probes specific to the peacock pheasant herpesvirus DNA polymerase revealed strong intranuclear staining in the necrotic liver lesions of an infected Malayan peacock pheasant but no staining in normal liver from an uninfected bird. The phasianid herpesvirus reported here is a novel member of the genus Mardivirus of the subfamily Alphaherpesvirinae and is distinct from other galliform herpesviruses.

Molecular characterization of isosporoid coccidia (Isospora and Atoxoplasma spp.) in passerine birds.

Prevalence and disease caused by isosporoid coccidia in passerine birds are well recognized, but confusion about the life cycles of the parasites has led to taxonomic inconsistencies. In this study, we characterized segments of the chromosomal small and large-subunit ribosomal RNA (rRNA) genes of coccidial parasites from 23 species of passerine birds, as well as heat shock protein 70, apicoplast rRNA, and chromosomal 5.8s rRNA genes from a subgroup of these animals, and we correlated genetic data with morphologic findings for different parasite developmental stages, host phylogeny, and overall taxonomic relations within the phylum Apicomplexa. Our findings indicate that isosporoid coccidia of passerine birds are monophyletic but exhibit substantial diversity, with most avian species having one or several unique parasite lineages that underwent synchronous speciation with their hosts, interrupted by sporadic episodes of lateral transmission across species and families. Molecular analyses support a homoxenous life cycle, with sexual forms occurring chiefly in the intestines and asexual merozoites present systemically. Rarely, extraintestinal sexual stages can occur. The passerine coccidia are genetically most closely related to species of Eimeria rather than Isospora. We suggest that these parasites, whether identified from blood merozoite stages or fecal oocysts, be provisionally grouped as a homogeneous clade of individual species in a single taxon and formally named when reliable criteria allowing reclassification of related genera in the suborder Eimeriina are clarified.

Persistent atrial standstill in a cat.

A domestic shorthaired cat was presented with a 1-month history of cardiomegaly and recurrent chylothorax. The heart rate was 130 beats/min and no P waves were present on a surface electrocardiogram. Thoracic radiographs and an echocardiogram demonstrated severe biatrial dilatation, pleural effusion and restrictive pleural disease. Permanent atrial standstill was suspected. Pleurocentesis was performed and therapy was started with enalapril, frusemide and aspirin. Intracardiac electrograms revealed no atrial activity, and atrial pacing failed to elicit atrial or ventricular depolarisations. The patient was euthanased. Necropsy showed severe atrial wall thinning with marked cardiocyte loss. Persistent atrial standstill is a rare disease in the cat. Clinical signs may have been due to loss of atrial function, ventricular diastolic dysfunction, bradycardia, neurohormonal activation and reduced atrial natriuretic peptide plasma concentrations.

Histologic features of mammary carcinomas in zoo felids treated with melengestrol acetate (MGA) contraceptives.

Melengestrol acetate (MGA), a potent synthetic progestin, has been used as a contraceptive in zoo felids since 1975. Mammary gland carcinomas have been linked to MGA treatment in zoo felids, but the histologic features of these tumors and steroid receptor expression have not been described. Zoo felid mammary tumors were requested from participating zoos from 1986 through 1998, and 31 mammary carcinomas from 28 MGA-treated and 3 untreated felids were received. The carcinomas were evaluated on the basis of histologic pattern, tumor grade, and occurrence of metastasis; then features of the tumors were compared to determine if carcinomas in MGA-treated felids differed from those that occur spontaneously. Estrogen- and progesterone-receptor expression was evaluated in 17 of the 31 carcinomas. Of the 31 tumors, 22 (70.9%) had multiple histologic patterns, 29 (93.5%) were high grade, and 28 (90.3%) had metastasized. Within tumors, the tubulopapillary pattern was most common (87.1%, n = 27); solid (61.3%, n = 19), cribriform (38.7%, n = 12), and comedone (25.8%, n = 8) patterns were less common; and the mucinous (3.2%, n = 1) pattern was rare. Both MGA-treated and untreated zoo felids had similar patterns and grades of mammary gland cancer as well as prevalence of metastasis. These results indicate that mammary carcinomas in zoo felids are high grade with a predominant tubulopapillary pattern and aggressive behavior. Five of 17 carcinomas expressed progesterone receptors, and 1 of 17 expressed estrogen receptors. Although more zoo felids with cancer had been exposed to MGA in this study, mammary carcinomas were similar in appearance and behavior in untreated and MGA-treated zoo felids. The association of MGA with the development of malignant mammary gland tumors should be considered when using this contraceptive in zoo felids.

Polycystic kidney and liver disease in two related West Highland White Terrier litters.

Polycystic kidney and liver disease was present in four of six female and three of five male offspring born in two matings between the same pair of West Highland White Terriers. Clinical signs were apparent and serum biochemistry analysis consistent with liver failure was evident by 5 weeks of age. Affected pups were euthanatized because of their disease. Renal cysts were confirmed to be of collecting duct origin by Dolichos bifluros agglutinin lectin histochemistry, and hepatic cysts were of biliary origin. The clinically unaffected parents were related through multiple common ancestors, and there were no reports of similar disease in related dogs. An autosomal recessive mode of inheritance is therefore suggested. This is the first report of polycystic kidney and liver disease in the West Highland White Terrier. The features of the disease in these pups are similar to those of autosomal recessive polycystic kidney disease (ARPKD) in humans. The West Highland White Terrier may therefore be a potential animal model for ARPKD.