G. Manarolla

Molecular biological characterization of avian poxvirus strains isolated from different avian species

Fifteen strains of Avipoxvirus from different avian species were isolated and molecular biologically characterized. Most strains did not produce evident pocks on the chorioallantoic membranes of commercial and specific-pathogen free embryonated chicken eggs where, on the contrary, microscopic signs of viral growth were always detected. Polymerase chain reaction of highly conserved P4b gene was positive for all cases confirming to be a reliable diagnostic method for Avipoxvirus. Sequencing of these amplicons confirmed most strains clustered either with Fowlpox virus or with Canarypox virus whereas a possible new clade could be hypothesized for one strain from Japanese quail. Classification of Avipoxvirus strains by amplification of the newly identified locus fpv140 revealed major limitations as only five samples were positive. These results underline the importance to undertake similar studies on higher numbers of Avipoxvirus isolates and on wider genomic regions of this large viral group.

Avian mycobacteriosis in companion birds: 20-year survey.

The causative agents of avian mycobacteriosis in pet birds are rarely identified. The aim of this study is to add information about the etiology of avian mycobacteriosis. The identification of mycobacterium species in 27 cases of avian mycobacteriosis in pet birds was investigated by polymerase chain reaction (PCR) and sequencing of a rRNA hypervariable region. Avian mycobacteriosis appeared to be an infrequent diagnosis. Interestingly, a few cases of avian mycobacteriosis were recorded in very young birds. The most commonly affected species were the canary (Serinus canarius), the Eurasian goldfinch (Carduelis carduelis) and the red siskin (Spinus cucullatus). All but one bird were infected with Mycobacterium genavense. Mycobacterium avium was identified only in one case.

Genetic analysis of small ruminant lentiviruses following lactogenic transmission

Lactogenic transmission plays an important role in the biology of lentiviruses such as HIV and SIV or the small ruminant lentiviruses (SRLV). In this work we analyzed the characteristics of viruses that goats, naturally infected with two strains of SRLV, transmitted to their kids. The spectrum of viral genotypes transmitted was broader and the efficiency of transmission greater compared to their human and simian counterparts. The newly described A10 subgroup of SRLV was more efficiently transmitted than the B1 genotype. The analysis of a particular stretch of the envelope glycoprotein encompassing a potential neutralizing epitope revealed that, as in SIV, the transmitted viruses were positively charged in this region, but, in contrast to SIV, they tended to lack a glycosylation site that might protect against antibody neutralization. We conclude that the physiology of the ruminant neonatal intestine, which permits the adsorption of infected maternal cells, shaped the evolution of these particular lentiviruses that represent a valid model of lactogenic lentivirus transmission.

Adenoviral gizzard erosions in Italian chicken flocks

TYPE 1 avian adenoviruses belong to the genus Aviadenovirus within the adenovirus family. Five species of fowl adenovirus (fAdV) (designated by the letters A to E) are recognised within the Aviadenovirus genus based largely on molecular criteria, in particular restriction enzyme fragmentation

Epornitic of avian pox in common buzzards (Buteo buteo): virus isolation and molecular biological characterization

Six common buzzards from a bird rescue centre showed wart-like lesions on their toes. The lesions consisted of multiple crusty and proliferative nodules surrounded by skin swelling. Histologically, epithelial cell hypertrophy and hyperplasia with ballooning degeneration and large intracytoplasmic inclusion bodies consistent with avipoxvirus infection were seen. The virus was isolated in embryonated chicken eggs. Positive chorioallantoic membranes and samples of skin lesions were submitted for polymerase chain reaction. Molecular characterization based on the 4b core protein indicates a 100% homology of the isolated poxvirus with avian poxviruses belonging to subclade A2. However, analysis of fpv139 locus does not reveal similarities of the isolate with other avian poxviruses.

Mycobacterium genavense and Avian Polyomavirus co-infection in a European Goldfinch ( Carduelis carduelis )

Systemic mycobacteriosis associated with avian polyomavirus infection was diagnosed histologically in an 8-year-old, captive European goldfinch with a history of nervous signs. Severe mycobacterial lesions were observed in the central nervous system, lungs, cervical air sacs and adrenal glands, without involvement of the gastrointestinal tract. In addition to mycobacteriosis, intranuclear inclusions, typical of polyomavirus, were identified in the adrenal glands. Polymerase chain reaction assays were used to identify Mycobacterium genavense and finch polyomavirus as the causative agents. The absence of involvement of the gastrointestinal tract and the severity of the lesions in the respiratory tract suggested that inhalation may have been the primary route of infection with M. genavense.

Short communication: Epidemiology and genotyping of Candida rugosa strains responsible for persistent intramammary infections in dairy cows

The present study was undertaken during an outbreak of clinical and subclinical mastitis in 14 dairy cows caused by Candida rugosa, in which high somatic cell counts were seen and cases did not respond to antibiotic treatment. Intramammary infection cured spontaneously in 10 cows, whereas 4 cows were culled as a result of persistent infections. Repeated sampling of these cows and biomolecular analysis of the isolates showed that the infections were caused by the same genotype, even over a period of 2 lactations. Random amplification of the genome of C. rugosa milk isolates gave 3 different DNA banding patterns (genotypes G1, G2, and G3). Viable cells of C. rugosa were also isolated from various environmental sources and were present in high concentrations in total mixed ration samples, which could be considered the primary source of diffusion of viable yeast cells in the environment, as demonstrated by genotyping. The proven capacity of these microorganisms to survive in the environment of the cow, such as the total mixed ration, bedding, water, and cow skin, and to cause persistent intramammary infections highlights the importance of mycotic spread in dairy herds.

Rhabdomyosarcoma of the pectoral muscles of a free-living European robin (Erithacus rubecula)

An adult free-living European robin (Erithacus rubecula) with a large, firm, subcutaneous mass on the pectoral muscle was examined. The bird was unable to fly and died spontaneously. Necropsy revealed a yellowish, bilobate mass almost completely replacing the pectoral muscles with extensive osteolysis of the keel bone. Histopathology revealed a poorly demarcated, highly cellular sarcomatous tumour with metastases to the lungs, pulmonary blood vessels and heart. Immunohistochemistry was negative for neuron-specific enolase, S-100 protein and the p-27 major capsid protein of avian leukosis viruses. The homogeneously positive immunolabelling for vimentin and scattered positivity for myoglobin and desmin suggested a diagnosis of rhabdomyosarcoma. A retrospective examination of the records for 194 birds of the thrush family, including 64 robins submitted over a 20-year period, showed no diagnoses of neoplasia.

Morphological and Immunohistochemical Observations on Leiomyoma of the Ventral Ligament of the Oviduct of the Hen

Leiomyomas of the ventral ligament (LVLs) of the oviduct from 2-year-old spent layers were examined. These tumours can be present either as single large masses or as multiple smaller nodules. The most common site of origin of the tumours was the centre of the free margin of the ventral ligament, but some small tumours were observed at the insertion of this ligament into the magnum of the oviduct. Most samples were highly vascular and some blood vessels within the tumours had vacuolation of the smooth muscle cells. These findings suggest that the proliferative processes leading to LVLs may include transformation of the blood vessels of the ventral ligament. Immunohistochemically, the tumour cells expressed vimentin, α-smooth muscle actin, desmin and heavy-caldesmon. These avian leiomyomas have been proposed as a model for similar tumours in other species.

Multinucleated giant cells with an osteoclast phenotype derived from caprine peripheral blood mononuclear cells

Formation of multinucleated giant cells (MGCs) by macrophage fusion is a typical cytopathic effect of lentiviral replication in caprine monocytes and MGC formation from cultured caprine peripheral blood mononuclear cells (PBMCs) has been considered to be diagnostic for small ruminant lentivirus (SRLV) infection. In this study, formation of MGCs was observed after 7-14 days when PBMCs were cultured from healthy goats free from SRLV infection. These MGCs expressed tartrate-resistant acid phosphatase, calcitonin receptor, integrin αVβ3, cathepsin K and matrix metalloproteinase 9 and were able to resorb bone in vitro in the absence of RANKL and macrophage colony stimulating factor, consistent with an osteoclast phenotype.