Gastrointestinal spindle cell tumor of the rumen with metastasis to the liver in a goat.

Many neoplasms have been reported in goats; however, neoplasia of the rumen is rarely reported. A 9-y-old castrated male pygmy goat was presented with a history of respiratory stertor, fever, and anorexia. A respiratory diagnostic work-up including skull and thorax radiographs and endoscopy revealed minor enlargement of the arytenoids but no other abnormal findings. After a month of little improvement on symptomatic treatment and worsening general health, the goat was euthanized. On autopsy, the forestomachs, liver, spleen, diaphragm, and the ventral and lateral aspects of the cranial third of the walls of the peritoneal cavity were adhered to one another by fibrinous and fibrous adhesions. Numerous firm, white, up to 2 cm diameter nodules were found throughout the liver. A large sessile mass extended from the rumen wall into the lumen. The rumen mass was a gastrointestinal stromal tumor with metastasis to the liver.

A nine-base nucleotide sequence in the porcine circovirus type 2 (PCV2) nucleocapsid gene determines viral replication and virulence.

Porcine circovirus type 2 (PCV2) was retrospectively identified by serology in swine populations as an asymptomatic infection at least 25 years prior to the first reported case of PCV2-associated postweaning multisystemic wasting syndrome (PMWS). To investigate the sudden emergence of PMWS, viral sequences were amplified from frozen archived (1970-1971) porcine tissues and the complete genome of archival PCV2 was determined. The ORF1 gene product (viral DNA replicase) was homologous to contemporary PCV2 ORF1. In ORF2 (viral nucleocapsid gene) archival PCV2, a consistent linear nine-base sequence difference at base positions 1331 through 1339 was observed. The deduced amino acid sequence from these base changes alters the nucleocapsid conformation within the second immunogenic epitope from a hydrophobic (contemporary PCV2) to a hydrophilic (archival PCV2) configuration. To test the hypothesis that archival PCV2 was avirulent, cloned engineered archival and contemporary PCV2 genomes were constructed wherein the ORF1 gene was identical in each clone and the ORF2 gene (nucleocapsid protein) was sequence-identical in both clones except for the nine-base difference (bases 1331-1339), corresponding to archival and contemporary PCV2 viruses respectively. Clones were transfected into porcine kidney (PK) 15 cells and, after sequence confirmation, further passed in PK15 and 3D4/2 porcine alveolar macrophage cell cultures. Virulence trials in gnotobiotic piglets were conducted with cloned PCV2s. The data show that archival PCV2 is avirulent when compared to contemporary PCV2 and supports the hypothesis that the emergence of virulent contemporary PCV2 was a result of mutational events within this critical epitope after 1971.

Mast cell tumors in a llama (Lama glama).

A 9-year-old female llama (Lama glama) that served as a blood donor at The Ohio State University Veterinary Teaching Hospital developed multiple small, raised, firm, non-haired cutaneous masses on the right hip, left cheek, and right and left shoulders. Cytological evaluation of fine-needle aspirates from the cutaneous mass from the left shoulder and right hip comprised many well-differentiated, highly granulated mast cells with moderate numbers of eosinophils. Occasional mast cells exhibited erythrophagocytosis and contained a small amount of hemosiderin or several variably sized vacuoles. A cytologic diagnosis of mast cell tumor with evidence of prior hemorrhage was made, and the masses were surgically removed. Microscopically, each mass consisted of sheets of neoplastic round cells that formed nonencapsulated nodules in the dermis and infiltrated into the adjacent dermal collagen. Eosinophils were scattered among the mast cells at the periphery of the nodules. Neoplastic mast cells, but not eosinophils, exhibited positive membrane KIT expression and cytoplasmic vimentin staining. A final diagnosis of mast cell tumor was made based on cytology, histology, and immunohistochemistry.

Evaluation of Mycoplasma hyopneumoniae bacterins for porcine torque teno virus DNAs.

OBJECTIVE: To determine whether commercial Mycoplasma hyopneumoniae bacterins sold for use in swine contain porcine torque teno virus (TTV). SAMPLE POPULATION: 22 commercially available M hyopneumoniae bacterins. PROCEDURES: Direct and nested PCR assays for genogroup-specific TTV DNAs were performed on serials of M hyopneumoniae bacterins by use of published and custom-designed primer pairs at 3 laboratories in North America and Europe. RESULTS: Of the 22 bacterins tested by use of direct and nested PCR assays, 7 of 9 from the United States, 2 of 5 from Canada, and 4 of 8 from Europe contained genogroup 1- and genogroup 2-TTV DNAs. In some bacterins, the TTV DNAs were readily detected by use of direct PCR assays. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these data indicated that many of the commercially available M hyopneumoniae bacterins were contaminated with TTV DNA. It is possible that some of these bacterins could inadvertently transmit porcine TTV infection to TTV-naïve swine.

Evaluation of induction of porcine dermatitis and nephropathy syndrome in gnotobiotic pigs with negative results for porcine circovirus type 2.

OBJECTIVE: To determine whether porcine dermatitis and nephropathy syndrome (PDNS) could be experimentally induced in gnotobiotic swine. SAMPLE POPULATION: Plasma samples from 27 sows and 20 conventional weaned piglets were obtained, and 30 gnotobiotic pigs were used in experiments. PROCEDURES: 3 experiments were conducted. Groups of 3-day-old gnotobiotic pigs were inoculated with pooled plasma samples obtained from healthy feeder pigs in a herd that was in the initial phases of an outbreak of respiratory disease; gross and histologic lesions of PDNS were detected in the inoculated pigs. In a second experiment, 2- and 3-day-old gnotobiotic pigs were inoculated with porcine reproductive respiratory syndrome virus (PRRSV) and with PRRSV-negative tissue homogenate containing genogroup 1 torque teno virus (g1-TTV). Lesions of PDNS were detected. RESULTS: Pigs inoculated with pooled plasma or the combination of tissue-culture-origin PRRSV and g1-TTV tissue homogenate developed systemic hemostatic defects, bilaterally symmetric cutaneous hemorrhages, generalized edema, icterus, bilaterally symmetric renal cortical hemorrhage, dermal vasculitis with hemorrhage, and interstitial pneumonia consistent with a clinical and pathologic diagnosis of PDNS. The PRRSV RNAs and g1-TTV DNAs were detected in plasma; all pigs seroconverted to PRRSV, and all had negative results for porcine circovirus type 2 when tested by use of PCR assays. CONCLUSIONS AND CLINICAL RELEVANCE: These data suggested that PDNS is a manifestation of disseminated intravascular coagulation in swine. For the experimental conditions reported here, combined infection with g1-TTV and PRRSV was implicated in the genesis of these lesions.

A novel method for the detection of porcine circovirus type 2 replicative double stranded viral DNA and nonreplicative single stranded viral DNA in tissue sections.

Porcine circovirus type 2 (PCV2), an economically important pathogen of swine, is the necessary cause of post weaning multisystemic wasting disease (PMWS); PCV2 infection is associated with porcine dermatitis and nephritis syndrome (PDNS). Current immunohistochemical (IHC) methodologies identify PCV2 antigens but are not capable of differentiating replicating virus from nonreplicating virion particles in tissue sections. In this paper, a combination of IHC using commercial monoclonal antibodies specific for single stranded (ss) and double stranded (ds) DNA and PCV2 specific in situ hybridization (ISH) was used to show the specificity of the former for PCV2 DNA in tissue sections from PCV2-infected gnotobiotic pigs. Cold-ethanol-fixed tissue sections were superior to formalin-fixed tissues for detection of PCV2 DNA, presumably due to the lack of protein cross-linking in the latter. These data demonstrate that conventional IHC detects PCV2 DNA forms in experimentally infected PCV2-positive gnotobiotic porcine tissue sections that are minimally compromised by either formalin fixation or the hybridization conditions needed for ISH.