Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 2-phase study was conducted to evaluate the ability of the NEB-1 strain of porcine reproductive and respiratory syndrome virus (PRRSV) to potentiate common bacterial pathogens of swine. In phase I, 25 of 50 4-5-week-old specific-pathogen-free (SPF) pigs were exposed to NEB-1 PRRSV (day 0). Seven days after virus inoculation, 8 groups received 1 of 4 bacterial pathogens: Haemophilus parasuis, Streptococcus suis, Salmonella cholerasuis, and Pasteurella multocida. The ability of NEB-1 PRRSV to produce clinical disease, viremia, neutralizing antibody, gross and microscopic lesions and to potentiate bacterial pathogens was assessed. Response to NEB-1 PRRSV was similar among inoculated pigs; prolonged hyperthermia, lethargy, mild to moderate dyspnea, and cutaneous erythema were consistent clinical signs. No clinical differences were observed in groups after bacterial challenge. Virus was isolated from serum at weekly intervals through the end of the study, and all PRRSV-inoculated pigs had seroconverted by study termination. Two of 5 pigs died in non-PRRSV-inoculated groups challenged with H. parasuis and Streptococcus suis. Mortality in PRRSV-infected pigs was limited to 1 of 5 pigs from the Salmonella cholerasuis-challenged group. Gross lesions were seen in pigs dying after inoculation in H. parasuis- and Streptococcus suis-inoculated groups, in Salmonella cholerasuis- and P. multocida-challenged pigs, and in 1 non-PRRSV-inoculated control pig. Microscopic lesions consisted of mild to moderate proliferative interstitial pneumonia, nonsuppurative myocarditis, lymphoid hyperplasia, and nonsuppurative encephalitis in PRRSV-inoculated pigs. Findings in phase I indicated that NEB-1 PRRSV does not potentiate bacterial disease while inducing consistent clinical signs, viremia, seroconversion, and microscopic lesions.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Porcine reproductive and respiratory syndrome: NEB-1 PRRSV infection did not potentiate bacterial pathogens. 757 44

The clinical picture of myocarditis/myopericarditis is of importance in differential diagnosis, especially in younger patients with suspected myocardial infarction. Myocarditis/myopericarditis commonly presents with chest pain, and the diagnosis is usually established on clinical grounds. However, endomyocardial biopsy is necessary to confirm the diagnosis. We evaluated the characteristics of acute myocarditis over the years 1980-1998 in 54 patients of the Department of Medicine of the University Hospital, Zurich. Two to 6 patients per year were hospitalised with this diagnosis. In most cases the diagnosis was established by a combination of criteria, such as a preceding infection of the upper respiratory tract, thoracic pain, ST segment elevations in different precordial leads followed by T wave inversions, arrhythmias, elevation of cardiac enzymes, reversible hypokinesia by echocardiography and normal coronary arteries. At least 3 of 5 criteria were requested. In a first step we analysed retrospectively all patients with acute myocarditis/myopericarditis in the years 1980-1993. Among 30 cases of acute myocarditis/myopericarditis the following causes could be identified: one influenza B, one Toxoplasma gondii infection, 2 Epstein-Barr infections and one bacterial myocarditis with gram-negative rods. The aetiology of the other 25 cases remained unknown. The majority of myocarditis/myopericarditis healed without complications. One patient with Epstein-Barr myocarditis and one with Toxoplasma gondii infection died. Two patients developed dilated cardiomyopathy. In a second phase we analysed prospectively all cases with acute myocarditis/myopericarditis over the period 1994-1998: 24 patients with acute myocarditis/myopericarditis were hospitalised. At that time coronary angiography and endomyocardial biopsies were performed more frequently. We found 2 patients with giant cell myocarditis and 2 with Toxoplasma gondii infection and HIV, all of whom died. In addition, there were 2 patients with eosinophilic myocarditis, one with Lyme carditis, one with Epstein-Barr myocarditis, one with myopericarditis after Campylobacter enteritis and one histologically proven myocarditis after pneumonia with Haemophilus influenzae. The aetiology of the remaining 13 cases with myocarditis/myopericarditis could not be established. Three patients with probable viral myocarditis developed cardiogenic shock requiring intraaortic balloon pump, and fully recovered. The patient with Lyme carditis manifested with total atrioventricular block and was treated with a temporary pacemaker. One patient with lymphocytic myocarditis required heart transplantation because of terminal heart failure and one female patient with histologically proven diffuse lympho-monocytic myocarditis died of cardiogenic shock. All the other cases healed without complications. Serologies are of little diagnostic value and should be restricted to serologies with therapeutic implications. We believe that the apparent increase in myocarditis/myopericarditis in recent years is a result of better diagnostic tools, such as more specific cardiac enzyme tests, coronary angiography and endomyocardial biopsies. In most cases the therapy remains symptomatic. In elected, severe cases steroids and other immunosuppressive drugs are sometimes used.
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PMID:[Diagnosis and course of myocarditis: a survey in the medical clinics of Zurich University Hospital 1980 to 1998]. 1102 70

Haemophilus somnus causes pneumonia, reproductive failure, infectious myocarditis, thrombotic meningoencephalitis, and other diseases in cattle. Although vasculitis is commonly seen as a result of systemic H. somnus infections, the pathogenesis of vascular damage is poorly characterized. In this study, we demonstrated that H. somnus (pathogenic isolates 649, 2336, and 8025 and asymptomatic carrier isolates 127P and 129Pt) induce apoptosis of bovine endothelial cells in a time- and dose-dependent manner, as determined by Hoechst 33342 staining, terminal deoxynucleotidyl transferase-mediated dUTP-FITC nick end labeling, DNA fragmentation, and transmission electron microscopy. H. somnus induced endothelial cell apoptosis in as little as 1 h of incubation and did not require extracellular growth of the bacteria. Viable H. somnus organisms induced greater endothelial cell apoptosis than heat-killed organisms. Since viable H. somnus cells release membrane fibrils and blebs, which contain lipooligosaccharide (LOS) and immunoglobulin binding proteins, we examined culture filtrates for their ability to induce endothelial cell apoptosis. Culture filtrates induced similar levels of endothelial cell apoptosis, as did viable H. somnus organisms. Heat inactivation of H. somnus culture filtrates partially reduced the apoptotic effect on endothelial cells, which suggested the presence of both heat-labile and heat-stable factors. We found that H. somnus LOS, which is heat stable, induced endothelial cell apoptosis in a time- and dose-dependent manner and was inhibited by the addition of polymyxin B. These data demonstrate that H. somnus and its LOS induce endothelial cell apoptosis, which may play a role in producing vasculitis in vivo.
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PMID:Haemophilus somnus induces apoptosis in bovine endothelial cells in vitro. 1117 40

The purpose of this study was to determine the presence of Hemophilus somnus, Mycoplasma bovis, Mannheimia hemolytica, and bovine viral diarrhea virus (BVDV) in lesional tissues of feeder calves dying with myocarditis. Tissues from the heart and lungs of 92 calves dying with myocarditis in Alberta feedlots were immunohistochemically stained for the antigens of these agents. Tissues from 44 calves dying from noninfectious causes and 35 calves dying with pneumonia were tested as controls. Hemophilus somnus was found in cardiac lesions in the majority of myocarditis cases (70/92). Mycoplasma bovis was concurrently demonstrated in the hearts of 4/92 affected calves. No bacterial pathogens were found in heart tissues from the control groups of calves. Bovine viral diarrhea virus was demonstrated in the tissues of 4/92 myocarditis cases compared with those of 13/35 calves dying from pneumonia and 0/44 calves dying from noninfectious causes. The results demonstrate that H. somnus is the principle pathogen associated with myocarditis in feedlot calves and that the presence of BVDV is more common in these calves compared with calves dying of noninfectious causes. The findings also suggest that BVDV is an important pathogen in calves dying with gross postmortem lesions of pneumonia.
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PMID:Immunohistochemical study of Hemophilus somnus, Mycoplasma bovis, Mannheimia hemolytica, and bovine viral diarrhea virus in death losses due to myocarditis in feedlot cattle. 1507 95

Haemophilus somnus has long been associated with thrombotic meningoencephalomyelitis but has also been identified as the agent responsible for other clinical diseases including respiratory disease, reproductive problems, myocarditis, otitis, conjunctivitis, mastitis, and polyarthritis. Exposure to the bacteria is widespread and infection may occur via the respiratory tract from urogenital excretions and secretions.Diagnosis and treatment of hemophilosis may be easy or difficult depending on the manifestation presented, and special procedures must be taken to facilitate isolation of the organism. Satisfactory control measures are not available; vaccination is the only preventive measure demonstrating a beneficial effect.
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PMID:The Haemophilus somnus disease complex (Hemophilosis): A review. 1742 40

Hemophilosis was the most significant cause of mortality in fall-placed calves in a large feedlot in Saskatchewan, despite routine single immunization of calves with a commercial Haemophilus somnus bacterin on arrival. Common manifestations of fatal H. somnus infection were myocarditis and pleuritis; occasionally, thrombotic meningoencephalomyelitis (TME), peracute septicemia, and pneumonia were observed. Circumstantial evidence suggested that H. somnus may be a pathogen in polyarthritis. Death from pneumonia mainly occurred during the first five weeks in the feedlot. Death from myocarditis, pleuritis, TME, and septicemia, and euthanasia because of polyarthritis, occurred mainly after the third week in the feedlot.The median fatal disease onset (FDO) for pneumonia was day 12; for septicemia, day 17; for polyarthritis, day 18; for myocarditis and pleuritis, day 22; and for TME, day 29. Calves that died from myocarditis frequently were found dead in their "home" pen; however, 88% of these animals had been treated previously. Fifty-seven percent of the calves that died from pleuritis were never treated, and those that died from TME or septicemia were either never treated or died shortly after initial treatment.
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PMID:Epidemiological features of calf mortality due to hemophilosis in a large feedlot. 1742 5

Results of necropsy examinations of 297 bovine carcasses with naturally occurring disease caused by Haemophilus somnus infection, and necropsied at the Western College of Veterinary Medicine in the period from 1970 to 1990, were analyzed with reference to the ages of affected cattle, seasonal occurrence of disease, the relative frequency of encephalitis, pneumonia, and myocarditis, and interrelationships among these conditions. The cattle came from 177 separate herds in the province of Saskatchewan. There was a range in age from one week to 10 years, and a mean age of 38 weeks. The diseases had a marked seasonal fall and winter incidence. The data indicated a trend characterized by an increasing percentage of cattle with pneumonia and myocarditis and a decreasing percentage with encephalitis during the period.
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PMID:Haemophilus somnus infection: A retrospective analysis of cattle necropsied at the Western College of Veterinary Medicine from 1970 to 1990. 1742 13

Histophilus somni (Haemophilus somnus) is an obligate inhabitant of the mucosal surfaces of bovines and sheep and an opportunistic pathogen responsible for respiratory disease, meningoencephalitis, myocarditis, arthritis, and other systemic infections. The identification of an exopolysaccharide produced by H. somni prompted us to evaluate whether the bacterium was capable of forming a biofilm. After growth in polyvinyl chloride wells a biofilm was formed by all strains examined, although most isolates from systemic sites produced more biofilm than commensal isolates from the prepuce. Biofilms of pneumonia isolate strain 2336 and commensal isolate strain 129Pt were grown in flow cells, followed by analysis by confocal laser scanning microscopy and scanning electron microscopy. Both strains formed biofilms that went through stages of attachment, growth, maturation, and detachment. However, strain 2336 produced a mature biofilm that consisted of thick, homogenous mound-shaped microcolonies encased in an amorphous extracellular matrix with profound water channels. In contrast, strain 129Pt formed a biofilm of cell clusters that were tower-shaped or distinct filamentous structures intertwined with each other by strands of extracellular matrix. The biofilm of strain 2336 had a mass and thickness that was 5- to 10-fold greater than that of strain 129Pt and covered 75 to 82% of the surface area, whereas the biofilm of strain 129Pt covered 35 to 40% of the surface area. Since H. somni is an obligate inhabitant of the bovine and ovine host, the formation of a biofilm may be crucial to its persistence in vivo, and our in vitro evidence suggests that formation of a more robust biofilm may provide a selective advantage for strains that cause systemic disease.
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PMID:Characterization and comparison of biofilm development by pathogenic and commensal isolates of Histophilus somni. 1764 81

Histophilus somni (Haemophilus somnus) is one of the key bacterial pathogens involved in the multifactorial etiology of the Bovine Respiratory Disease Complex. This Gram negative pleomorphic rod also causes bovine septicemia, thrombotic meningencephalitis, myocarditis, arthritis, abortion and infertility, as well as disease in sheep, bison and bighorn sheep. Virulence factors include lipooligosaccharide, immunoglobulin binding proteins (as a surface fibrillar network), a major outer membrane protein (MOMP), other outer membrane proteins (OMPs) and exopolysaccharide. Histamine production, biofilm formation and quorum sensing may also contribute to pathogenesis. Antibodies are very important in protection as shown in passive protection studies. The lack of long-term survival of the organism in macrophages, unlike facultative intracellular bacteria, also suggests that antibodies should be critical in protection. Of the immunoglobulin classes, IgG2 antibodies are most implicated in protection and IgE antibodies in immunopathogenesis. The immunodominant antigen recognized by IgE is the MOMP and by IgG2 is a 40 kDa OMP. Pathogenetic synergy of bovine respiratory syncytial virus (BRSV) and H. somni in calves can be attributed, in part at least, to the higher IgE anti-MOMP antibody responses in dually infected calves. Other antigens are probably involved in stimulating host defense or immunopathology as well.
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PMID:Histophilus somni host-parasite relationships. 1821 58

Histophilus somni (Haemophilus somnus) is an important pathogen of cattle that is responsible for respiratory disease, septicemia, and systemic diseases such as thrombotic meningoencephalitis, myocarditis, and abortion. A variety of virulence factors have been identified in H. somni, including compositional and antigenic variation of the lipooligosaccharide (LOS). Phosphorylcholine (ChoP) has been identified as one of the components of H. somni LOS that undergoes antigenic variation. In this study, five genes (lic1ABCD(Hs) and glpQ) with homology to genes responsible for ChoP expression in Haemophilus influenzae LOS were identified in the H. somni genome. An H. somni open reading frame (ORF) with homology to H. influenzae lic1A (lic1A(Hi)) contained a variable number of tandem repeats (VNTR). However, whereas the tetranucleotide repeat 5'-CAAT-3' is present in lic1A(Hi), the VNTR in H. somni lic1A (lic1A(Hs)) consisted of 5'-AACC-3'. Due to the propensity of VNTR to vary during replication and cause the ORF to shift in and out of frame with the upstream start codon, the VNTR were deleted from lic1A(Hs) to maintain the gene constitutively on. This construct was cloned into Escherichia coli, and functional enzyme assays confirmed that lic1A(Hs) encoded a choline kinase, and that the VNTR were not required for expression of a functional gene product. Variation in the number of VNTR in lic1A(Hs) correlated with antigenic variation of ChoP expression in H. somni strain 124P. However, antigenic variation of ChoP expression in strain 738 predominately occurred through variable extension/truncation of the LOS outer core. These results indicated that the lic1(Hs) genes controlled expression of ChoP on the LOS, but that in H. somni there are two potential mechanisms that account for antigenic variation of ChoP.
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PMID:Molecular characterization of phosphorylcholine expression on the lipooligosaccharide of Histophilus somni. 1968 67


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