Occurrence and spread of influenza A(H1N1)pdm09 virus infection in Norwegian pig herds based on active serosurveillance from 2010 to 2014.

The incursion of influenza A(H1N1)pdm09 virus was detected by Norway's active serosurveillance of its pig population in 2009. Since then, surveillance data from 2010 to 2014 revealed that 54% of 5643 herd tests involving 1567 pig herds and 28% of 23 036 blood samples screened positive for antibodies against influenza A virus. Positive herds were confirmed to have influenza A(H1N1)pdm09 virus infection by haemagglutination inhibition test. In 50% of positive herd tests, ⩾60% of the sampled pigs in each herd had antibodies against influenza A(H1N1)pdm09 virus. This within-herd animal seroprevalence did not vary for type of production, herd size or year of test. The overall running mean of national herd seroprevalence, and annual herd incidence risks fluctuated narrowly around the means of 45% and 32%, respectively, with the highest levels recorded in the three densest pig-producing counties. The probability of a herd being seropositive varied in the five production classes, which were sow pools, multiplier herds, conventional sow herds, nucleus herds, and fattening herds in descending order of likelihood. Large herds were more likely to be seropositive. Seropositive herds were highly likely to be seropositive the following year. The study shows that influenza A(H1N1)pdm09 virus is established in the Norwegian pig population with recurrent and new herd infections every year with the national herd seroprevalence in 2014 hovering at around 43% (95% confidence interval 40-46%).

Pandemic influenza A(H1N1)v: human to pig transmission in Norway?

In Norway there is an ongoing outbreak in pigs of infections with pandemic influenza A(H1N1)v virus. The first herd was confirmed positive on 10 October 2009. As of 26 October, a total of 23 herds have been diagnosed as positive. The majority of the herds seem to have been infected by humans. Sequence analysis of pig viruses from the index farm shows that they are identical or virtually identical to human viruses from the same geographical region.

Peyer's patches in experimental Salmonella dublin infection in calves. Microvascular and epithelial changes contributing to atrophy of lymphoid follicles.

Six calves were infected per os with Salmonella dublin and killed nine hours to seven days later. Early changes included occlusion of capillaries with a hyaline material, particularly in the ileal Peyer's patch (PP). Central areas of the follicles contained hemorrhages and edema. In later stages the follicle-associated epithelium (FAE) of both the jejunal and ileal PP was fused with the adjacent epithelium and the follicles were collapsed. As judged from 5'nucleotidase histochemistry, follicles were depleted of lymphocytes whereas reticular cells were retained. Carbonic anhydrase (CA) histochemistry showed a decreased reaction in the ileal FAE and a reduced amount of CA reactive material in the follicles of the ileal PP, indicating loss of FAE differentiation and function. Hyaline material and fibrinous thrombi were seen occluding the blood capillaries and the lymphatics, respectively. The villi were atrophied and covered with thick fibrin deposits. Using antifibrinogen antibodies, immunoperoxidase stained fibrin in the lymphatics and the lumenal deposits but not the hyaline material in the capillaries. Reaction for CA indicated that this hyaline material originated from erythrocytes. Factors contributing to the follicle atrophy may include anoxia due to stasis in the microcirculation with the formation of erythrocyte thrombi, and reduced lymphopoiesis due to a decrease in the stimulating factors provided by the FAE.

Control of Yersinia enterocolitica in pigs at herd level.

A higher herd prevalence of antibodies (ELISA) to Yersinia enterocolitica O:3 was found in conventional slaughter production (86.0% seropositive herds) than in conventional farrow-to-finish herds (53.1% seropositive herds). The herd prevalence of antibodies to Y. enterocolitica in multiplying herds (56.1%) was similar to the level in the conventional farrow-to-finish herds. An epidemiological study in conventional pig herds demonstrated that farrow-to-finish production (odds ratio, OR = 0.15) was an important protective factor. Using under-pressure ventilation (OR = 0.33) and manual feeding of slaughter pigs (OR = 0.44) also lowered the herd prevalence. The most expressed risk factor was using an own farm vehicle for transport of slaughter pigs to abattoirs (OR = 12.92). Separation between clean and unclean section in herds (OR = 2.67), daily observations of a cat with kittens on the farm (OR = 2.41) and using straw bedding for slaughter pigs (OR = 2.25) were other factors that increased the risk. In conclusion, the epidemiological data suggest that it is possible to reduce the herd prevalence of Yersinia enterocolitica O:3 by minimising contact between infected herds and non-infected herds. Further, attempts to reduce the prevalence at the top levels of the breeding pyramids may be beneficial for the industry as a whole. The meat industry may use serological tests as a tool to lower the prevalence in the pig population by limiting the contact between seropositive and seronegative herds. However, because of the high prevalence of Y. enterocolitica in pig herds, a strict slaughter hygiene will remain an important means to reduce carcass contamination with Y. enterocolitica O:3 as well as other pathogenic micro-organisms.

An abattoir survey of pneumonia and pleuritis in slaughter weight swine from 9 selected herds. I. Prevalence and morphological description of gross lung lesions.

The prevalence and pathomorphology of gross lung lesions were studied in 855 slaughter weight pigs from 9 selected herds in south-eastern Norway. Pneumonic or pleuritic lesions were found in 84% of the lungs, ranging from 37% in the least affected herd to 97% in the one most affected. Bronchopneumonia indicative of a primary Mycoplasma hyopneumoniae infection was found in 70% of the lungs, ranging from 9% to 82% in the individual herds. The amount of bronchopneumonic lesions in individual lungs ranged from 0 to 69%, with an average of 7.8%. Pleuropneumonia indicative of Actinobacillus (Haemophilus) pleuropneumoniae infection was found in 29% of the lungs ranging from 0 in the least affected herd to 58% in the most affected. Diffuse pleuritis was found in 41% of the lungs and the prevalence ranged from 4% to 63%.

An abattoir survey of pneumonia and pleuritis in slaughter weight swine from 9 selected herds. III. Serological findings and their relationship to pathomorphological and microbiological findings.

Blood samples from 777 pigs, originating from 9 different herds, were collected at slaughter and examined for antibodies to Mycoplasma hyopneumoniae and Actinobacillus (Haemophilus) pleuropneumoniae by the indirect hemagglutination assay (IHA) and the complement fixation (CF) test, respectively. Results were compared to pathological and microbiological findings. Antibodies to M. hyopneumoniae in positive titers of 1/80 or higher were found in 62% of the samples. The relationship between positive IHA titers to M. hyopneumoniae and gross findings indicative of enzootic pneumonia of pigs (EPP), histological findings indicative of EPP, the isolation of M. hyopneumoniae and the demonstration of M. hyopneumoniae by indirect immunofluorescent testing ranged from 64% to 68%. No correlation was noted between positive IHA titers and the isolation of Mycoplasma flocculare. Positive antibody titers to A. pleuropneumoniae of 1/10 or higher were detected in 5% to 85% of the samples from individual herds. Positive titers to A. pleuropneumoniae serotype 2 were found in 71% to 79% of the sampled animals from herds with high frequencies of pneumonic lesions indicative of pleuropneumonia. In herds with low frequencies of pleuropneumonia, positive titers were recorded in from 0 to 4% of the tested pigs. However, no statistical association was found between pleuropneumonia and positive titers to A. pleuropneumoniae serotype 2 in individual animals. Twenty-one per cent of samples with positive CF titers to A. pleuropneumoniae showed antibodies to more than one serotype.

An abattoir survey of pneumonia and pleuritis in slaughter weight swine from 9 selected herds. II. Enzootic pneumonia of pigs: microbiological findings and their relationship to pathomorphology.

Lungs from 191 slaughter pigs with gross lesions indicative of enzootic pneumonia of pigs (EPP) and 80 grossly normal lungs, all originating from 9 different herds, were subjected to microbiological and pathological examinations. The microbiological studies included both bacterial and mycoplasmal culture and also testing for Mycoplasma hyopneumoniae antigen in tissue by indirect immunofluorescent technique. M. hyopneumoniae, Pasteurella multocida and Mycoplasma hyorhinis were detected in 83%, 43% and 37% of the pneumonic lungs, respectively. Mycoplasma flocculare was the most frequently isolated organism in the non-pneumonic lungs. The greatest amounts of macroscopic pneumonia (25.2%) were recorded in lungs with all the three agents M. hyopneumoniae, P. multocida and M. hyorhinis present. The amounts of pneumonia in lungs with M. hyopneumoniae alone and in concurrence with P. multocida, were 9.3% and 15.6%, respectively. M. hyorhinis was also, in this study, associated with higher frequency of diffuse pleuritis. These findings indicate that M. hyorhinis might be involved in the pathogenesis of pneumonia in slaughter pigs. Ninety-six per cent of the isolates of P. multocida from pneumonic lungs could be characterized as type A. In the herds which had the most severe pneumonia problems, toxin production was detected in 83% of the P. multocida strains while only 28% were toxigenic in herds with subclinical to moderate pneumonia problems.

An abattoir survey of pneumonia and pleuritis in slaughter weight swine from 9 selected herds. IV. Bacteriological findings in chronic pneumonic lesions.

A total of 855 pig lungs were collected at slaughter and evaluated macroscopically. Bacteriological examinations were carried out on tissue samples from chronic pleuropneumonic lesions (n = 196) and from chronic bronchopneumonic lesions with suppuration (n = 14). Samples from normal lung tissue (n = 22) were also included. Pasteurella multocida was isolated from 54%, Actinobacillus (Haemophilus) pleuropneumoniae from 11%, and Streptococcus spp. from 14% of the pneumonic lesions, respectively. From normal lung tissue P. multocida was isolated from 3 (14%) of the samples, A. pleuropneumoniae was not recovered and streptococci were isolated from only 1 (5%) of these samples. The above mentioned bacterial species were recovered either in pure cultures or mixed with various other microbes. A total of 109 P. multocida strains were further characterized by capsular serotyping and testing for production of dermonecrotic toxin. Ninety-nine (91%) of the strains were capsular type A 10 (9%) were type D. Out of the type A and the type D strains 94% and 90% were toxigenic, respectively. Most of the A. pleuropneumoniae strains were serotype 2. Strains of serotypes 1 and 7 were also identified. The majority of the streptococci were identified as either Streptococcus suis or Streptococcus dysgalactiae. Actinomyces pyogenes was isolated from 14% of the lesions and anaerobic bacteria from 18%, respectively. The significance of the various bacterial species in relation to the development of chronic pneumonic lesions is discussed. Special attention is paid to P. multocida, and it is concluded that this bacterial species is probably of importance for the development of both types of chronic pneumonias.

Hereditary multifocal renal cystadenocarcinomas and nodular dermatofibrosis in 51 German shepherd dogs.

The clinical findings in German shepherd dogs with hereditary multifocal renal cystadenocarcinomas and nodular dermatofibrosis are presented. Between 1978 and 1996, 51 cases were examined. Eight cases were detected after being offered a clinical examination because the disease was present in a parent. The remaining 43 dogs were diagnosed after an unsolicited visit to a clinic because of a specific problem. Skin lesions were the main reason (37 per cent) the owners presented their dog for examination. The mean age at diagnosis of renal cystadenocarcinomas and nodular dermatofibrosis was 8.2 years. The male-to-female ratio was 1.1, while the corresponding figure for a reference population was 1.25. Enlarged and abnormally shaped kidneys were palpated in 60 per cent of the dogs and were detected by radiography in 86 per cent of cases. The renal lesions, including metastases, were the main reason for euthanasia and death. The mean age at death was 9.3 years, and the mean age at the first detection of nodular dermatofibrosis was 6.4 years.

Effects on peritoneal proteolysis and hemodynamics by high doses of methyl-prednisolone in experimental acute pancreatitis.

Acute pancreatitis was induced in 15 anesthetized pigs by injection of Na-taurocholate into the pancreatic duct. Seven animals were pretreated with methyl-prednisolone sodium succinate 30 mg/kg intravenously. Using chromogenic peptide substrate assays, values of trypsin (TRY), plasma prekallikrein (PKK), plasma kallikrein (KK) and functional plasma kallikrein inhibition capacity (KKI) were studied in the peritoneal exudate. Cardiac output (CO) and arterial pressure (AP) were regularly monitored before and during a six hour observation period. In acute untreated pancreatitis a 40% reduction of PKK levels was found paralleled by an increased KK activity and a reduction of KKI capacity. High TRY levels were found in several animals. The mortality rate was 63%. The pretreated animals all survived. CO and AP were significantly less reduced than in the untreated animals. Components of the plasma kallikrein-kinin system and TRY in the exudate remained mainly unchanged. Methyl-prednisolone given as pretreatment significantly improves hemodynamic parameters and increases the survival rate. Methyl-prednisolone suppresses generation of trypsin activity and activation of the plasma kallikrein-kinin system in the peritoneal exudate which may be of significant importance to the outcome.

Experiences after Twenty Months with Pandemic Influenza A (H1N1) 2009 Infection in the Naïve Norwegian Pig Population.

Pandemic (H1N1) 2009 influenza A virus was detected in Norwegian pigs in October 2009. Until then, Norway was regarded free of swine influenza. Intensified screening revealed 91 positive herds within three months. The virus was rapidly transmitted to the susceptible population, including closed breeding herds with high biosecurity. Humans were important for the introduction as well as spread of the virus to pigs. Mild or no clinical signs were observed in infected pigs. Surveillance of SIV in 2010 revealed that 41% of all the Norwegian pig herds had antibodies to pandemic (H1N1) 2009 virus. Furthermore, this surveillance indicated that pigs born in positive herds after the active phase did not seroconvert, suggesting no ongoing infection in the herds. However, results from surveillance in 2011 show a continuing spread of the infection in many herds, either caused by new introduction or by virus circulation since 2009.

Adult respiratory distress syndrome (ARDS). Incidence, clinical findings, pathomorphology and pathogenesis. A review.

Acute and progressive respiratory distress ("shock lung") is a well known and feared complication in human patients with a variety of underlying disorders, even though the lungs are not involved primarily. In spite of the fact that dogs, and other animals, very often have been used in experimental models studying this syndrome, "shock lungs" have not received much attention in veterinary medicine. With the improved and more intensive treatment of severely diseased animals during the last years, especially pet animals, it is reasonable to assume that the lungs will be more important as an end organ also in veterinary practice. Animals in shock, particularly if complicated with sepsis, are prone to develop progressive respiratory distress. This paper reviews the current knowledge about the clinical picture, pathology and pathogenesis of acute respiratory disease, with main emphasize on the pathogenetic mechanism.

Hereditary multifocal renal cystadenocarcinomas and nodular dermatofibrosis in the German shepherd dog: macroscopic and histopathologic changes.

A syndrome characterized by bilateral, multifocal renal cystadenocarcinomas and nodular dermatofibrosis was found in 43 German shepherd dogs. Affected kidneys varied in weight from normal to 2950 g. The cut surface revealed multiple solid and cystic tumors that varied in size from barely visible to 27 cm in diameter. Metastases were found in ten of the 23 dogs examined since 1979. All 23 dogs had numerous firm nodules in the skin and subcutis, and ten of 11 bitches had multiple uterine leiomyomas. Histological examination of the renal cortex showed multifocal hyperplastic to highly malignant epithelial proliferations. Skin lesions consisted of dense collagen fibers, and the uterine tumors consisted of interlacing bundles of smooth muscle cells. Pedigree analysis strongly indicates that the syndrome is hereditary, probably in an autosomal dominant pattern. This seems to be the first description of such a syndrome in domestic animals. Comparable syndromes in man are discussed.

Computed tomography of hereditary multifocal renal cystadenocarcinomas in German shepherd dogs.

The purpose of the study was to characterize the renal lesions of hereditary renal cystadenocarcinomas in the German shepherd dog using computed tomography (CT). Fourteen dogs with renal cystadenocarcinomas and nodular dermatofibrosis, and two unaffected dogs were studied. There were nine dogs with spontaneous disease and seven dogs from a test mating. The characteristic renal CT findings of renal cystadenocarcinomas were bilateral multiple cysts and tumor masses of various sizes. The earliest changes were detected between 4 and 5 years of age and the smallest cysts measured 2-3 mm in diameter. Abdominal CT examination gives a wide field view and excellent anatomic images of the kidneys. It is easy to differentiate between cysts and solid tumors. CT examination is useful for the early detection of renal cystadenocarcinomas and for screening suspected carrier dogs before breeding.

Respiratory failure caused by intratracheal saline: additive effect of xanthine oxidase.

Administration of physiological saline or drugs together with saline into the airways is becoming common clinical practice. However, there are few studies on possible side effects. We have studied the effects of saline, saline plus xanthine oxidase, and saline plus xanthine oxidase plus superoxidase dismutase on lung-thorax compliance and on arterial blood gases in anesthetized, paralyzed guinea pigs, ventilated for 2.5 h. Saline bolus (2-3 ml isotonic saline/kg body weight) into the airways reduced the compliance within 20 min to a mean of 39% of the pretreatment levels, and necessitated as increase in the respirator pressure. Saline plus xanthine oxidase decreased the compliance to 16% of the pretreatment levels. The xanthine oxidase-induced (but not saline-induced) decrease in lung compliance was relieved by superoxide dismutase. According to the present results xanthine oxidase induces a lung injury possible by production of free oxygen radicals. Superoxide dismutase can be valuable in prevention of free oxygen radical-mediated lung damage. Saline alone can be harmful when applied to the airways. This should be considered in clinical trials and in clinical practice.

Sodium taurocholate-induced acute pancreatitis in pigs. Pathomorphological studies of the pancreas in untreated animals and animals pretreated with high doses of corticosteroids or protease inhibitors.

Acute pancreatitis was induced in anesthetized pigs by injection of Na-taurocholate into the pancreatic duct. The pigs were allocated to 4 groups. One group remained untreated while the other groups received either C1-inhibitor, aprotinin or methyl-prednisolone intravenously as pretreatment. Extensive necroses of the pancreatic parenchyma, peripancreatic oedema and accumulation of large amounts of fluid in the abdominal cavity developed within a few hours in all experimental groups. Pretreatment significantly improved hemodynamics and increased the survival rate at 6 hours. It is concluded that the most essential effect of the pretreatments were reduction of proteolytic activities which are secondary to the pancreatic lesions.

The revised amino acid sequence of serum amyloid A (SAA) protein in mink.

The revised amino acid sequence of mink protein SAA was shown to be composed of 111 amino acid residues. The protein has an insertion of eight amino acid residues compared with that reported earlier. Microheterogeneities were observed in positions 6, 10, 24, 27, 67 and 71. The amino acid sequence is in accordance with the SAA mink cDNA sequences, except for the phenylalanine in position 6. The data indicate a third SAA gene in mink.