The economic impact of infectious bovine keratoconjunctivitis (IBK) warrants continued investigation of the mechanisms by which Moraxella bovis survives on and colonizes the corneal surface. Virulent strains of M bovis produce hemolysin and exhibit different plasmid profiles than nonvirulent strains. Interactions among host, environment, vector, season, and concurrent infection influence the prevalence of IBK. Mycoplasma sp. or infectious bovine rhinotracheitis virus may enhance or hasten the disease process. The manifestations of IBK may range from mild conjunctivitis to severe ulceration, corneal perforation, and blindness. Treatment of IBK is dictated by economic considerations, intended animal use, and feasibility of administration. Antibiotic therapy is aimed at achieving drug concentrations in tears to meet or exceed the minimum inhibitory concentration for prolonged periods. At present, IBK is not a preventable disease. Affected animals must be separated from the herd and vector control vigorously instituted. Carrier animals must be identified and removed from the herd. Vaccination trials have been unsuccessful because of pili antigen crossreactivity, variable strains, and uncontrolled environmental factors. Recent investigations have determined that M bovis may utilize host iron sources via iron-repressible outer membrane proteins and siderophores for growth. Elucidation of normal defense mechanisms of the bovine eye may lead to new strategies to enhance the immune response against M bovis.Key words: Bovine pinkeye; IBK.he first reports of infectious bovine keratoconjunctivitis EpizoologyAlthough M bovis is the pathogen most commonly isolated from IBK, various factors are involved with the pathogenesis of this disease. The environment, season, concurrent pathogens, M bovis strain, and host immune system play integral roles in the occurrence and clinical severity of IBK. IBK is a highly contagious disease that spreads rapidly within a herd.6 The yearly and seasonal prevalence of the disease in different geographic regions varies greatly.l0." The isolation rate of M bovis infection gradually increases during the spring (21.4%) and summer (29.3%) months to reach a maximum in the fall at 45%.12 Peak IBK prevalence is preceded by the highest values of ultraviolet (UV) radiation.I3J4 IBK can occur during any time of the year, but outbreaks are more common during summer months. Nonetheless, heavy snowfall and UV radiation have been individually associated with outbreaks of IBK.M. bovis is spread by direct contact, nasal and ocular discharges, and by mechanical vectors. The most important vector is considered to be the face fly (Musca a~turnnalis).~~ The house fly (Musca dornestica) and barn fly (Stomoxys calcitrans) may also transport the organism. In addition to physically irritating the eye, insects may harbor the organism on their legs for up to 3 days.Is A positive correlation exists between the number of flies per animal and M bovis infection,I8 and disease prevalence is reduced by rigorous fly control pr...

The three different pore-forming RTX-toxins of Actinobacillus pleuropneumoniae are reviewed, and new and uniform designations for these toxins and their genes are proposed. The designation ApxI (for &tinobacillus pZeuropneumoniae RTX-toxin I) is proposed for the RTX-toxin produced by the reference strains for serotypes 1, 5a, 5b, 9,lO and 11, which was previously named haemolysin I (HlyI) or cytolysin I (ClyI). This protein is strongly haemolytic and shows strong cytotoxic activity towards pig alveolar macrophages and neutrophils; it has an apparent molecular mass in the range 105 to 110 kDa. The genes of the apxZ operon will have the designations apxZC, apxZA, apxZB, and apxZD for the activator, the structural gene and the two secretion genes respectively. The designation ApxII is proposed for the RTX-toxin which is produced by all serotype reference strains except serotype 10 and which was previously named App, HlyII, ClyII or Cyt. This protein is weakly haemolytic and moderately cytotoxic and has an apparent molecular m a s between 103 and 105 kDa. The genes of the apxZZ operon will have the designations apxZZC for the activator gene and apxZZA for the structural toxin gene. In the apxZZ operon, no genes for secretion proteins have been found. Secretion of ApxII seems to occur via the products of the secretion genes apxZB and apxZD of the apxZ operon. The designation ApxIII is proposed for the nonhaemolytic RTX-toxin of the reference strains for serotypes 2, 3, 4, 6 and 8, which was previously named cytolysin 111 (ClyIII), pleurotoxin (Ptx), or macrophage toxin (Mat). This protein is strongly cytotoxic and has an apparent molecular mass of 120 kDa. The genes of the apxZZZ operon have the designations apxZZZC, apxZZZA, apxZZZB and apxZZZD for the activator gene, the structural gene and the two secretion genes respectively.

Infrared thermography can be adjusted to account for ambient temperature and used to detect changes in MBST and radiant heat production attributable to a febrile response in pigs.

Abstract. Idiopathic cutaneous and renal glomerular vasculopathy (CRGV) (Alabama rot) is a potentially fatal disease of unknown etiology that affects the skin and kidneys of racing-and training-age Greyhounds. Ultrastructural examinations were performed on two healthy control Greyhounds and 1 2 Greyhounds diagnosed with CRGV based on the presence of characteristic, well-demarcated cutaneous ulcers of the extremities (1 2/ 12), thrombocytopenia (<200,000 plateletddl) (1 2/12), and acute renal insufficiency (BUN > 40 mg/dl, serum creatinine > 2.0 mg/dl) (7/ 12). Early glomerular ultrastructural changes included endothelial swelling, detachment, and necrosis; membranous whorl formation; and platelet adhesion and aggregation. Some capillaries were occluded with aggregated platelets, cellular fragments, and fibrin. Later changes included narrowing of capillary lumina and thickening of glomerular capillary walls by subendothelial accumulation of flocculent, amorphous, variable electron-dense material and occasionally erythrocytes, cellular processes, and fibrin. Glomerular endothelial cells were increased in number and plump, with villouslike cytoplasmic projections. Mesangial cell cytoplasmic processes occasionally were interposed between the endothelium and the basement membrane. No etiologic agents or electron-dense deposits typical of immune complexes were observed. Although the specific etiology was not determined, the ultrastructural changes suggest that glomerular endothelial damage is an important early event in the pathogenesis of CRGV.

Both of the vaccines provided significant protection against a severe challenge with serovar 1 A pleuropneumoniae. Neither vaccine was effective against a serovar 15 A pleuropneumoniae challenge. There was evidence that the Porcilis APP vaccine did provide some protection against the serovar 15 challenge because the ADG, after challenge of pigs given this vaccine, was greater than the control pigs.