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Canine herpes virus-1 (CHV1) causes a fatal hemorrhagic disease in neonatal puppies and is associated with reproductive problems in female dogs. This serologic study was conducted to assess the seroprevalence of CHV1 infection in Norway. Blood samples were collected from clinically healthy dogs (n = 436) one yr of age and older of both genders, supplied by four small animal clinics (A, B, C and D) in different parts of the country. The immunoperoxidase monolayer assay was used for testing of CHV1 antibodies. Serum titers were recorded as the reciprocal value of the highest dilution producing specific cell staining. Titers equal to or above 80 were considered positive for exposure to CHV1. In total, 80.0% of the dogs had titers ≥80 and were classified as positive. Mean age for seronegative dogs was 4.7 yrs (95% CI 4.1-5.4) and for seropositive dogs 5.0 yrs (95% CI 4.7-5.4). Of the dogs, 32.8% displayed a weakly positive titer of 80, whereas 41.5 and 5.7% fell into the moderately (titer 160 and 320) and strongly (titer ≥640) positive categories, respectively. No association was demonstrated when comparing CHV1 antibody titers to gender or reproductive parameters like previous matings, pregnancies, births or number of puppies born. Age, visit in foreign countries and clinic explained together 78% of the variation in antibody titer categories. The percentage of positive samples differed significantly between the four clinics (A 98%, B 58.5%, C 74.6%, D 89.5%). A reasonable explanation for this finding has not been established. No information about an ongoing outbreak of CHV1 infection was available. In conclusion, this study strongly indicates that CHV1 infection is endemic in the dog population of Norway. There are significant differences in seroprevalence between geographic regions in the country.

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Porcine reproductive and respiratory syndrome (PRRS) is characterized by reproductive failure in sows and respiratory problems in growing pigs. The disease is present in most countries throughout the world but was not diagnosed in Sweden until the summer of 2007 when it was first detected through the national PRRS surveillance program. The immediate mobilization of veterinary authorities, field veterinarians and the pig industry was a prerequisite for preventing the spread of the disease. Within 10 days seven herds were verified as infected and the measures taken included stamping out, cleaning, disinfection and a vacancy period of 3 weeks before the herds were repopulated. To evaluate the effectiveness of these measures, a national sero-surveillance was carried out during the autumn of 2007. Approximately 90% of the pig production was covered by this screening and all samples tested were negative with regard to antibodies to PRRS virus.

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Field canine coronaviruses (CCVs) identified during a series of outbreaks of gastroenteritis in Swedish dogs were subjected to genetic analysis involving the open reading frame 1b (ORF1b) and the membrane (M) and spike (S) protein genes. Four field viruses originating from the Stockholm region presented identical sequences and segregated separately from other CCVs characterized so far and from GOT/05, the variant recovered in Western Sweden. A recombinant origin of the fifth virus identified in the Stockholm region is suggested. In addition, the five viruses originating from the same geographical area displayed atypical 5' S gene sequences.

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A combination of immunohistochemical techniques, a panel of monoclonal antibodies, and computer-assisted morphometric analysis was used to examine the response of the ileal Peyer's patch of fetal lambs 7 days after treatment with ferritin per os. Consistent with previous studies in fetal lambs that have reported the ileal Peyer's patch to be indifferent to antigen, the present study did not find any significant changes in the size of the predominantly B-cell dome/follicle compartment or the predominantly T-cell interfollicular area, nor were differences identified in the distribution of IgM-positive (+), CD4+, and CD8+ cells in these two compartments. However, both compartments showed a significant increase (p < 0.05) in the percentage of area occupied by MHC II+ cells and a significant decrease (p < 0.05) in the percentage of area occupied by CD44+ and B5+ cells. These changes show that the ileal Peyer's patch of fetal lambs is not indifferent to antigen and may represent the transition of a purely primary lymphoid organ to an organ that has both primary and secondary lymphoid functions.

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Porcine lungs were macroscopically and microscopically examined at slaughter, with special regard to different stages of lesions similar to those caused by Mycoplasma hyopneumoniae. There was good conformity between the macroscopical and microscopical findings. In an extended abattoir survey, lesions were found in 4210 out of 4508 lungs examined. The majority of lungs with pleuritic lesions (274 out of 369) revealed by the extended examination were registered by the official procedure. No correlation between pleuritis and time for seroconversion, or with the levels of antibodies to Actinobacillus pleuropneumoniae, was found. Among lungs affected with pneumonic lesions (n = 3841), lesions similar to those caused by Mycoplasma hyopneumoniae were predominant (n = 3769). Only 15% of these lesions were revealed by official registration at slaughter. This figure is explained by the fact that only 35% of the infections were still active at the time of slaughter and that only ongoing lesions exceeding a certain magnitude were recorded according to the official regulations. By following the development of antibodies to Mycoplasma hyopneumoniae through the fattening period, the duration of the active infection was estimated to be approximately 12 weeks. Consequently, infections with Mycoplasma hyopneumoniae gained during the early fattening period will, in general, escape detection at slaughter.

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In five experiments 29 goats were infected experimentally by five different routes with a strain of Mycoplasma mycoides subspecies mycoides, LC type, isolated from a contagious caprine pleuropneumonia-like outbreak on a farm in northern Sweden. All the goats were colonised except those inoculated subcutaneously with small doses. In its pattern of pathogenicity this strain was similar to other experimentally tested strains except that peroral infection in kids produced no clinical signs. A 'contact' goat was also colonised but the clinical signs seen in it were probably due to a concomitant infection with Pasteurella haemolytica.

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Ten aborted foals, diagnosed as infected with Equine Herpes Virus 1 (EHV-1) on histopathological criteria, were examined for the presence of EHV-1 using immunohistology as the investigative instrument. The primary reagent was an antiserum specific for viral envelope glycoproteins. Immunohistology localised EHV-1 to areas of liver necrosis and to the cytoplasm of infected Kupffer cells and hepatocytes. Cytoplasmic immunolabelling was also prominent in reticular cells of the red pulp of the spleen and in intact and degenerated bronchiolar epithelium. Cytoplasmic immunolabelling was seen in morphologically unchanged cells and in cells containing intranuclear inclusion bodies. Three aborted foetuses with no histological signs of EHV-1 infection were negative when immunostained for EHV-1. Detection by electron microscopy of EHV-1 virions confirmed the EHV-1 specificity of the immunolabelling procedure.

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Intracutaneous injection of a crude supernatant fraction from homogenised Salmonella typhimurium SVA 44 (O 4, 5, 12) or S dublin SVA 47 (O 9, 12) elicited highly significant (P less than 0.005) double skin-fold thickness increases in calves spontaneously infected with salmonella and verified as excretors. The use of isolated structurally defined outer membrane components from salmonella bacteria established that the delayed skin reactions could be elicited by either the lipopolysaccharide which contains O-antigenic polysaccharide chains homologous to the infecting strain, or an outer membrane protein fraction (porin). The porin preparation gave rise to skin reactions regardless of which salmonella serotype the calf was infected with. Histological examination of biopsy material indicated a delayed skin reaction. No such reactions were seen in biopsies from control calves. The use of lipopolysaccharide permitted a salmonella serogroup specific skin test although the endotoxic side effects were marked in doses above 50 micrograms. Purified O-antigen specific polysaccharides devoid of lipid A from S typhimurium (O 4, 12) or S enteritidis (O 9, 12) failed however to elicit skin reactions. Infected calves had humoral antibody titres against the O antigen of the infecting strain which were significantly (P less than 0.005) higher than those found in control calves.

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Intracutaneous injection of a crude supernatant fraction from homogenised Salmonella typhimurium (O antigens 4, 5, 12) or S dublin (O antigens 9, 12) in 250 cattle or calves from salmonella infected herds elicited in 27 per cent and 42 per cent, respectively, a local dermal reaction. Both the time course and histological examinations of biopsy materials indicated a delayed type of hypersensitivity reaction. No local dermal reactions were seen in any of 250 heads of cattle or calves from control herds. The immunological characterisation of the S typhimurium and S dublin crude extracts revealed that they contained O antigens (ie, lipopolysaccharides) and outer membrane proteins, porins. A Yersinia enterocolitica serotype O3 extract did not evoke skin reactions in any of 70 tested animals. Fifteen calves infected with S typhimurium and five with S dublin exhibited increased ELISA titres against the O antigenically homologous lipopolysaccharides.

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