In the United States of America, Aujeszky's disease (pseudorabies) has been eradicated from all domestic swine. Some re-emergence of infection occurred as vaccine use diminished. Sporadic outbreaks have also occurred because of the reservoir of infection in feral swine that have spread across the southern two-thirds of the country and Hawaii. In order to be able to understand the origins of re-emerging virus, sequence analysis of variable genes in pseudorabies virus (PRV) has been used to differentiate strains. Most PRV from feral swine can be distinguished from virus circulating in domestic pigs during the national epizootic. However, several feral swine isolates of PRV from south central states are closely related or identical in sequence to strains from domestic pigs. Extensive study by PCR for the presence of virus in the oral cavity of feral pigs disclosed that the viral DNA is distributed widely in tonsils salivary glands, taste buds and even mucosa in the vicinity of tusks. Clearly the virus in feral swine has multiple mechanisms of transmission to insure persistent infection and the threat of re-emergence in domestic swine continues.

Pressure ulcers are a significant healthcare concern, especially for elderly populations. Our work served to ameliorate the chronicity of these ulcers by addressing ischemia-reperfusion injury mediated by neutrophils and the concomitant loss of vasculature in these wounds. To this end, chitosan scaffolds loaded with basic fibroblast growth factor (bFGF) contained in gelatin microparticles were developed and tested for clinical relevance in an aged mouse model. Pressure ulcers were induced in aged mice, and efficacy of treatment was assessed. On days 3 and 7, both chitosan and chitosan-bFGF scaffolds significantly accelerated wound closure compared to gauze control. By day 10, all wounds achieved similar closure. Delivery and angiogenic function of bFGF was verified through ELISA and histology. Elevated neutrophil levels were observed in chitosan and chitosan-bFGF groups. Since neutrophil elastase contributes to the proteolytic environments of pressure ulcers, the effect of chitosan on elastase was assessed. In vitro, chitosan inhibited elastase activity. In vivo, elastase protein levels in wounds were reduced with chitosan-bFGF scaffolds by day 10. These results suggest that chitosan is an effective material for growth factor delivery and can help to heal chronic ulcers. Collectively, our data show that chitosan-bFGF scaffolds are effective in accelerating wound closure of pressure ulcers in aged animals.

Objective: Description of acute respiratory failure in a cat due to profound hypokalemia associated with primary hyperaldosteronism.Case summry: A cat was presented with weakness and paraparesis that deteriorated rapidly into acute ventilatory failure. The serum potassium concentration declined despite intravenous fluid therapy. Positive pressure ventilation was required to support ventilatory function. A functional adrenocortical adenoma was found at necropsy in conjunction with a serum aldosterone concentration of greater than 3329 pmol/L.New or unique information provided: Respiratory failure secondary to profound hypokalemia is a rare, although recognized, condition. There are few reports that focus on this aspect of respiratory failure in the veterinary literature and primary hyperaldosteronism has not been reported as a cause of respiratory failure in cats.

An outbreak of tracheitis, sinusitis, and conjunctivitis, originating in recently imported birds, caused high morbidity and mortality in a flock of finches in Central Illinois. Although several species were present, Gouldian finches (Erythrura [Chloebia] gouldiae) were most commonly and severely affected. Birds submitted for necropsy displayed microscopic lesions characteristic of herpesviral infection, including epithelial cytomegaly and karyomegaly with basophilic, intranuclear inclusion bodies in the nasopharynx, sinuses, trachea, parabronchi, conjunctiva, and occasionally the lacrimal gland or proximal proventricular glands. Viral particles consistent with herpesvirus were visualized within affected epithelial cells with electron microscopy. Based on a partial sequence of the viral DNA polymerase gene, this virus was found to be identical to a herpesvirus previously implicated in a similar outbreak in Canada and is most likely an alphaherpesvirus.

Tissue stages similar to those of Sarcocystis neurona, the causative agent of equine protozoal myeloencephalitis, were identified in skeletal muscles of a dog. The dog, a 6-year-old Labrador retriever, was seropositive for Toxoplasma gondii infection and euthanized due to a history of polymyositis and progressive muscular atrophy. Histologically, 30, variably sized, microscopic, intracellular sarcocysts were observed in 60 sections of skeletal muscles taken from the neck, fore limbs and hind limbs. The cysts were only observed in inflamed skeletal muscles, but were mostly in myocytes at the periphery of areas infiltrated with leukocytes. Ultrastructurally, the cyst wall had villar protrusions consistent with sarcocysts. Immunohistochemistry with monoclonal S. neurona antibodies demonstrated positive labeling of zoites in merozoites or schizonts in the skeletal muscle interstitium, but no labeling of the sarcocysts. Initial PCR analysis with primers amplifying a genetic sequence encoding Apicomplexan 18s rRNA, and subsequent PCR analysis with differentiating primers indicated that the genetic sequences had 100% identity with sequences reported for S. neurona.

ABSTRACT Pasteurella multocida subsp. multocida is a commensal and opportunistic pathogen of food animals, wildlife, and pets and a zoonotic cause of human infection arising from contacts with these animals. Here, an investigation of multiple serotype A strains demonstrated the occurrence of membrane sialyltransferase. Although P. multocida lacks the genes for the two earliest steps in de novo sialic acid synthesis, adding sialic acid to the growth medium resulted in uptake, activation, and subsequent transfer of sialic acid to a membrane acceptor resembling lipooligosaccharide. Two candidate-activating enzymes with homology to Escherichia coli cytidine 5′-monophospho- N -acetylneuraminate synthetase were overproduced as histidine-tagged polypeptides. The synthetase encoded by pm0187 was at least 37 times more active than the pm1710 gene product, suggesting pm0187 encodes the primary sialic acid cytidylyltransferase in P. multocida . A sialate aldolase (pm1715) mutant unable to initiate dissimilation of internalized sialic acid was not attenuated in the CD-1 mouse model of systemic pasteurellosis, indicating that the nutritional function of sialate catabolism is not required for systemic disease. In contrast, the attenuation of a sialate uptake-deficient mutant supports the essential role in pathogenesis of a sialylation mechanism that is dependent on an environmental (host) supply of sialic acid. The combined results provide the first direct evidence of sialylation by a precursor scavenging mechanism in pasteurellae and of a potential tripartite ATP-independent periplasmic sialate transporter in any species.

An 11-year-old cat was evaluated because of dyspnea. Since 11 months of age, the cat had hyperextensibility of the skin consistent with cutaneous asthenia. Radiographic examination revealed a diaphragmatic hernia with intestinal loops in the thorax. Electron microscopic examination of skin specimens revealed collagen fibers of highly variable diameter, consistent with cutaneous asthenia. The diaphragmatic hernia was surgically repaired and healed well. Four weeks later, a left-sided perineal hernia was repaired surgically, and 4 months later, a right-sided perineal hernia was repaired surgically and colopexy and cystopexy were performed. All surgical procedures were successful and tissues healed well. Dermatosparaxis is a rare hereditary disorder that commonly results in cutaneous fragility and hyperextensibility in affected animals. The diagnosis depends on clinical findings and light and electron microscopic changes in affected tissues. Surgical repair can be performed successfully in an affected cat, and healing of incisions can occur without complications.

Papillomavirus was identified in pigmented epidermal plaques (PEP) from three dogs: a miniature schnauzer with hyperadrenocorticism and hypoglobulinemia, an American Staffordshire terrier with hypoglobulinemia, and a Pomeranian with unconfirmed hypothyroidism. Squamous cell carcinoma (SCC) arose within several plaques in the Pomeranian. Clinical improvement coincided in the first two cases with treatment of the concurrent disease and the administration of low-dose oral interferon-alpha. This is the first report of PEP in an American Staffordshire terrier and a Pomeranian. The potential for malignant transformation of PEP to SCC emphasizes the need for recognition and clinical management of PEP.

Although host adapted to pigs, Salmonella enterica serovar Choleraesuis (S. choleraesuis) can induce a virulent foodborne salmonellosis in humans. To directly investigate virulence factors of S. choleraesuis, we extended the functional genomics approach of signature-tagged mutagenesis to S. choleraesuis and pigs. When a test pool of 45 randomly signature-tagged null mutants was inoculated orally and intraperitoneally in pigs, one of the mutants that failed to colonize by either route was tagged in hilA. In the broad host range serovar S. typhimurium, hilA regulates invasion genes in the first pathogenicity island and is required for enteric but not systemic infections in mice experimentally infected with S. typhimurium. The pool of tagged S. choleraesuis null mutants was a complex mix inoculated in pigs. When pigs were challenged with an equal mixture of the hilA mutant and wild type bacteria, the hilA mutant was at a competitive disadvantaged (attenuated) in pigs inoculated orally but not in intraperitoneally inoculated pigs. Our data support that hilA in S. choleraesuis infections of pigs has a role in enteric but not systemic infections similar to that of S. typhimurium in the murine model of human typhoid fever. The role of hilA may be conserved across Salmonella serovars and host species.

Haemophilus parasuis, which causes polyserositis, polysynovitis, meningitis, septicemia, and pneumonia in pigs, has emerged as an increasing problem in modern swine production systems. Co-factors for and the pathogenesis of H. parasuis disease are not defined. One of the potential virulence factors of H. parasuis is its neuraminidase (sialidase). While purifying the H. parasuis neuraminidase from the membrane fraction, we developed a protocol to renature enzymatic activity after enzyme preparations were resolved electrophorectically in denaturing polyacrylamide gels. The H. parasuis neuraminidase co-resolved with recombinant neuraminidase of Vibrio cholera; thus its apparent molecular mass is 82 kilodalton (kDa). The H. parasuis neuraminidase was associated with the membrane fraction and the purification protocol removed over 99% of the H. parasuis cell protein while retaining over 90% of the neuraminidase activity. Purified protein will provide another avenue to clone the neuraminidase gene that has been refractory to cloning and the protocol will be a means to purify recombinant protein.

Objectives: To evaluate the impact of endemic infection with porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), transmissible gastroenteritis virus-porcine respiratory coronavirus (TGEV-PRCV), pseudorabies virus (PRV), Mycoplasma hyopneumoniae, and Actinobacillus pleuropneumoniae (APP) on the reproductive performance of sows. Methods: Seventeen groups of 30 to 60 sows and gilts in seven herds were monitored over a 2-year period by serological testing for the pathogens listed above. Litter size, number of stillborn (including mummies), average weaning weight, preweaning deaths, and interfarrowing interval were recorded for the sows that were tested. Multiple linear regression analyses were performed to evaluate the association of the measures of reproductive performance with serological test results. Results: Infection with PRRSV was consistently associated with poorer reproductive performance. Sows that had antibodies to PRRSV had, on average, 0.1 to 0.9 more stillborn piglets per litter than did seronegative animals. The average interfarrowing interval was 3 to 10 days longer for PRRSV-seropositive sows. A consistent correlation between reproductive performance and serological results could not be found for SIV, TGEV-PRCV, PRV, M hyopneu-moniae, or APP. Implications: Even in herds where no clinical signs of the disease are present, reproductive performance may be substantially inferior in sows with high levels of antibody against PRRSV.

In the third season (2002) of the West Nile virus epidemic in the United States, two canids (wolf and dog) were diagnosed with West Nile virus encephalitis and myocarditis with similarities to known affected species (humans, horses, and birds). The West Nile virus infections were confirmed by immunohistochemistry and polymerase chain reaction.

In today's intensive pork production systems, herd health is a major factor determining the profitability of the business. Among the economically most important diseases in the Midwest are porcine reproductive and respiratory syndrome, pseudorabies, transmissible gastroenteritis, swine influenza and pneumonia caused by Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae. Several studies have evaluated the financial impact of acute outbreaks of these diseases in swine operations (Miller & Kliebenstein, 1985, Mullan et a. 1994, Poulson et al., 1993, Rougoor et al., 1996). However, the predominant problem in many swine operations is a subclinical infection of the herd rather than acute outbreaks of diseases. Infected pigs are not obviously sick or die, but perform poorly. The economic consequences of subclinical infection can be slow growth, decreased feed efficiency, low fertility, increased numbers of abortions and stillbirths, and smaller litter sizes (Baysinger et al., 1997). For farms operating on an 'all in, all out' basis, the difference in weight gain between infected and non-infected pigs can be an additional problem, because finishing pigs do not reach market weight at the same time.

PURPOSE:Existing animal models of visceral pain in the mouse are of limited practical usefulness since they are labor intensive or not visceral specific. Recently a rat model of cyclophosphamide (CP) cystitis was developed that requires only intraperitoneal injection and features inflammation confined to the bladder. We adapted this model for use in multiple mouse strains to investigate the genetic basis of variability in visceral nociception.MATERIALS AND METHODS:Outbred CD-1 mice and 12 inbred mouse strains were tested for behavioral changes induced by CP (0 to 300 mg/kg intraperitoneally).RESULTS:We noted that despite the absence of postural changes or abdominal crises in CD-1 mice, CP produced dose dependent decreases in voluntary locomotor activity unaccompanied by ataxia measured on the rotarod test; referred hyperalgesia of the tail base region but not of the hind paw, which was inhibited in dose dependent fashion by morphine (0 to 20 mg/kg); and bladder inflammation corresponding to these behavioral indices. Furthermore, the extent of hypolocomotion was genotype dependent across 12 inbred strains.CONCLUSIONS:The simple and automatable nature of CP cystitis using hypolocomotion as a dependent measure renders it an attractive model in which to investigate the genetic and physiological bases of visceral pain. Comparison of strain sensitivity to CP induced hypolocomotion with other nociceptive assays suggests that genes specific to visceral nociception may exist.

Coplanar polychlorinated biphenyls (PCBs) cause adverse effects in developing and adult animals. Less is known about the effects of nonplanar ortho-substituted PCBs. We investigated the effects of 2 nonplanar PCB congeners, 95 (2,3,6-2',5'-penta CB) or 101 (2,4,5-2',5'-penta CB), and estradiol on selected endocrine parameters. In Study 1, weanling female Sprague-Dawley (S-D) rats were given a single dose of PCB 95 ip at 4, 8, 16, and 32 mg/kg/day for 2 consecutive days and killed 24 h after the last dose. PCB 95 exposure caused a dose-dependent (p < 0.001) decrease in serum thyroxine (T4) levels. Serum thyroid stimulating hormone (TSH) concentrations did not change, but prolactin (PRL) levels increased in a nonlinear (with dose) manner. No significant changes were seen in thyroid gland morphology and pituitary lactotroph number. In Study 2, progression or regression of effects was assessed by lengthening the time and a second congener was tested. Weanling female S-D rats received a single dose of PCB 95 or PCB 101 ip at 16 and 32 mg/kg/day for 2 days and were killed 48 h after the last dose. PCB 95 and PCB 101 both decreased serum T4 (p < 0.001) and hypothalamic dopamine (DA; p < 0.05) levels. No changes were seen in serum triiodothyronine (T3), TSH, and PRL concentrations. Morphological analysis of the thyroid gland showed a decrease (p < 0.05) in colloid area in rats treated with PCB 95 or 101. However, the epithelial cell height increased only in PCB 95 treated rats. Thyroid epithelial cell proliferation increased (p < 0.05) following exposure to estradiol and PCB 95. The results suggest that the HPT axis appears to be a target of ortho-substituted PCBs. PCB 95 was more effective than PCB 101 in causing these changes.

While new swine production technologies are making inroads into controlling many swine pathogens, Haemophilus parasuis-induced disease has unexpectedly emerged as an increasing problem (Nicolet, 1992; Boeckman, 1995; Radle, 1996; Zimmerman et al., 1997; Rapp-Gabrielson, 1999; Dee, 2000). Innovative new strategies of disease control are needed to meet the challenges associated with new production technologies for high health herds, including segregated early weaning and all-in all-out pig flow in production facilities.