Identification, Biochemical Characterization, and In Vivo Detection of a Zn-Metalloprotease with Collagenase Activity from Mannheimia haemolytica A2.

Respiratory diseases in ruminants are a main cause of economic losses to farmers worldwide. Approximately 25% of ruminants experience at least one episode of respiratory disease during the first year of life. Mannheimia haemolytica is the main etiological bacterial agent in the ruminant respiratory disease complex. M. haemolytica can secrete several virulence factors, such as leukotoxin, lipopolysaccharide, and proteases, that can be targeted to treat infections. At present, little information has been reported on the secretion of M. haemolytica A2 proteases and their host protein targets. Here, we obtained evidence that M. haemolytica A2 proteases promote the degradation of hemoglobin, holo-lactoferrin, albumin, and fibrinogen. Additionally, we performed biochemical characterization for a specific 110 kDa Zn-dependent metalloprotease (110-Mh metalloprotease). This metalloprotease was purified through ion exchange chromatography and characterized using denaturing and chaotropic agents and through zymography assays. Furthermore, mass spectrometry identification and 3D modeling were performed. Then, antibodies against the 110 kDa-Mh metalloprotease were produced, which achieved great inhibition of proteolytic activity. Finally, the antibodies were used to perform immunohistochemical tests on postmortem lung samples from sheep with suggestive histology data of pneumonic mannheimiosis. Taken together, our results strongly suggest that the 110-Mh metalloprotease participates as a virulence mechanism that promotes damage to host tissues.

Establishment of lung auscultation scoring method and responses of acute phase proteins and heat shock proteins in vaccinated and non-vaccinated goats.

Pneumonic pasteurellosis is an economically important infectious disease in the small ruminant industry which causes sudden death and loss for farmers. Nonetheless, this disease is still a common sight in sheep and goats in Malaysia, probably due to the unpopular usage of pasteurellosis vaccine or inappropriate vaccination practices. The aim of this study was designed to classify the severity of pneumonia via the establishment of auscultation scoring method and to quantify the acute phase proteins and heat shock proteins responses from vaccinated and non-vaccinated goats. Goat farms, consist of vaccinated and non-vaccinated farms, were selected in this study: where 15 clinically normal healthy goats and 9 pneumonic goats were selected from vaccinated farms whereas 15 clinically normal healthy goats and 31 pneumonic goats from non-vaccinated farms were selected for this study. Crackle lung sounds were not detected in both vaccinated and non-vaccinated normal goats. However, vaccinated pneumonic goats showed mild crackle lung sound while non-vaccinated pneumonic goats exhibited moderate crackle lung sound. There were significant increases (p < 0.05) in acute phase proteins and heat shock proteins concentrations for the non-vaccinated pneumonic goats group. In this study, conclusion can be made that the vaccinated goats exhibited very mild clinical responses of pneumonia and non-significant biomarker responses compared to the non-vaccinated goats. Thus, vaccination is an effective preventive measure to control pneumonic pasteurellosis and acute phase proteins and heat shock proteins can be considered as future biomarkers in screening and rapid diagnostic method for this particular disease.

Bacterial, PCR and clinico-pathological diagnosis of naturally occurring pneumonic pasturellosis (mannheimiosis) during subtropical climate in sheep.

Mannheimia haemolytica is causative agent of pneumonic pasteurellosis (mannheimiosis) that causes huge economic losses to livestock farmers. We investigated the microbial and clinico-pathological patterns associated with ovine pneumonic pasturellosis during an outbreak. Prior to death, infected sheep revealed clinical signs including dyspnoea, salivation, pyrexia and mucopurulent nasal discharge. Mortality was significantly (p < 0.05) high in young sheep as compared to adults. Necropsy findings revealed presence of froth in trachea, congestion and consolidation of lungs, pulmonary edema, severe pleural adhesions, pericarditis, hemorrhages on mucosa of jejunum and kidneys. Histopathological examination revealed circumscribed and centrally calcified necrotic areas punctuated with chronic inflammatory cells and interstitial pneumonia. Moreover, bronchial epithelial hyperplasia, edema, congestion, mononuclear cell infiltration, thick interlobular septae and peri-vascular cuffing were the striking changes in lungs. Furthermore, lungs showed severe fibrin depositions along with abundant amount of fibrin meshwork on pleura infiltrated with chronic inflammatory cells. Histologically, liver, kidneys and lymph nodes showed degenerative changes. Mannheimia haemolytica and Pasteurella multocida were differentially identified on the basis of culture characteristics and biochemical tests. M. haemolytica was further confirmed by using polymerase chain reaction. From the findings of current study, it is concluded that M. haemolytica is a major respiratory threat in small ruminants that causes severe pneumonic changes in infected animals.

One-step multiplex real time RT-PCR for the detection of bovine respiratory syncytial virus, bovine herpesvirus 1 and bovine parainfluenza virus 3.

BACKGROUND: Detection of respiratory viruses in veterinary species has traditionally relied on virus detection by isolation or immunofluorescence and/or detection of circulating antibody using ELISA or serum neutralising antibody tests. Multiplex real time PCR is increasingly used to diagnose respiratory viruses in humans and has proved to be superior to traditional methods. Bovine respiratory disease (BRD) is one of the most common causes of morbidity and mortality in housed cattle and virus infections can play a major role. We describe here a one step multiplex reverse transcriptase quantitative polymerase chain reaction (mRT-qPCR) to detect the viruses commonly implicated in BRD. RESULTS: A mRT-qPCR assay was developed and optimised for the simultaneous detection of bovine respiratory syncytial virus (BRSV), bovine herpes virus type 1 (BoHV-1) and bovine parainfluenza virus type 3 (BPI3 i & ii) nucleic acids in clinical samples from cattle. The assay targets the highly conserved glycoprotein B gene of BoHV-1, nucleocapsid gene of BRSV and nucleoprotein gene of BPI3. This mRT-qPCR assay was assessed for sensitivity, specificity and repeatability using in vitro transcribed RNA and recent field isolates. For clinical validation, 541 samples from clinically affected animals were tested and mRT-qPCR result compared to those obtained by conventional testing using virus isolation (VI) and/or indirect fluorescent antibody test (IFAT). CONCLUSIONS: The mRT-qPCR assay was rapid, highly repeatable, specific and had a sensitivity of 97% in detecting 102 copies of BRSV, BoHV-1 and BPI3 i & ii. This is the first mRT-qPCR developed to detect the three primary viral agents of BRD and the first multiplex designed using locked nucleic acid (LNA), minor groove binding (MGB) and TaqMan probes in one reaction mix. This test was more sensitive than both VI and IFAT and can replace the aforesaid methods for virus detection during outbreaks of BRD.

Conglutinin and immunoconglutinin titers in stressed calves in a feedlot.

OBJECTIVE: To determine whether increased conglutinin titers are evident in stressed calves that do not develop respiratory tract disease in feedlots, compared with respiratory tract disease, and to determine the increase in immunoconglutinin titers. ANIMALS: 101 mixed-breed beef calves. PROCEDURE: Calves were processed at 4 farms of origin and allowed to remain with their dams for another 100 days. Calves from each farm were brought to a centrally located order-buyer barn. In a feedlot, 101 calves were assigned to pens and observed daily for clinical signs of acute respiratory tract disease. When sick calves were detected, they were treated with antibiotics and isolated in a pen for 4 days. Conglutinin and immunoconglutinin titers were determined for all calves. RESULTS: During the 28-day study, 73 calves developed respiratory tract disease, whereas 28 calves remained healthy. Mean conglutinin titers differed significantly among calves from the 4 farms. Significant differences were not detected in conglutinin titers among calves on the basis of sex, morbidity, or vaccination status against Mannheimia haemolytica at each farm, the order-buyer barn, or the feedlot on days 8, 15, and 28 after arrival. Immunoconglutinin titers in calves differed significantly among farms and morbidity status. CONCLUSIONS AND CLINICAL RELEVANCE: Mean conglutinin titers in calves do not appear to be associated with the incidence of acute respiratory tract disease; however, increased immunoconglutinin titers appear to be associated with recovery of stressed calves from respiratory tract disease during the first 15 days after arrival in a feedlot.

Spontaneous pasteurellosis in captive Rocky Mountain bighorn sheep (Ovis canadensis canadensis): clinical, laboratory, and epizootiological observations.

We observed clinical signs, compared adrenal responses, and performed diagnostic tests on 12 captive Rocky Mountain bighorn sheep (Ovis canadensis canadensis) during a spontaneous outbreak of pasteurellosis. Cortisol in urine and feces was measured for bighorns sampled three times between 20 October and 1 November 1986. By 6 November, four of these had developed pneumonia, four showed only mild rhinitis, and four remained clinically normal. Bighorns that ultimately developed pneumonia showed elevated mean urinary (P = 0.003) and fecal (P = 0.046) cortisol excretion over the 12-day sampling period. Twenty-four hour mean urine cortisol: creatinine ratios ranged from 10 to 57 ng/mg dry matter for affected and 5 to 22 ng/mg for healthy individuals; 24 hr mean fecal cortisol concentrations ranged from 7.2 to 20 ng/g dry matter for affected and 3.6 to 9.1 ng/g dry matter for healthy individuals. Elevated cortisol excretion preceded clinical pneumonia in affected bighorns by less than or equal to 16 days. Beta-hemolytic Pasteurella haemolytica biotype T, serotype 3 or 4, was isolated from nasal and pharyngeal swabs from all eight bighorns with pneumonia or mild rhinitis. We detected no evidence of parainfluenza 3, bovine respiratory syncytial virus, or Chlamydia psittaci using fluorescent antibody and/or serologic tests. Although elevated cortisol excretion was associated with pneumonia, we also believe age, reproductive physiology, and/or prior recovery from clinical pasteurellosis may have influenced individual susceptibility to pneumonia during this epizootic.

Field study of undifferentiated respiratory disease in housed beef calves.

A severe outbreak of undifferentiated respiratory disease affecting 119 of 144 (82.6 per cent) two- to five-month-old housed beef calves was studied by monitoring their clinical signs and rectal temperatures daily or every second day for two months. New cases of respiratory disease, which were first identified three weeks after the calves were housed, occurred over a period of 29 days. The cause of the outbreak was not conclusively determined although 20 per cent of the calves sampled showed serological evidence of recent infection with bovine respiratory syncytial virus and parainfluenzavirus 3. Seventeen of 61 calves (27.9 per cent) which were treated with tilmicosin had to be treated again, compared with nine of 58 calves (15.5 per cent) which were treated with both tilmicosin and flunixin meglumine and did not need further treatment, but this difference was not statistically significant.

[Pasteurelloses]. / Les pasteurelloses.

According to the genetic relationships among Gram-negative bacilli the genus Pasteurella is included with the genus Haemophilus and the genus Acinobacillus within the family Pasteurellacae. Pasteurella multocida, the type species, is responsible for the majority of human Pasteurella infections. P. multocida is a member of the normal flora in the upper respiratory tract of many mammals or birds. It causes sporadic or epidemic diseases among different animal species, particularly pneumonia and atrophic rhinitis in swine in intensive breeding stations. The most common human infection with P. multocida is a local cellulitis following dog or cat bites and scratches. Serious local complications are sometimes responsible for prolonged disability. The respiratory tract is the second human source of P. multocida isolates. The frequency of recovery of P. multocida from oropharynx of apparently healthy pig breeders suggests that respiratory pasteurellosis could be an occupational disease. The mechanisms of virulence of P. multocida are unclear. Several factors are involved: capsules preventing phagocytosis, a dermonecrotic toxin causing experimental atrophic rhinitis, hyaluronidase, neuraminidase and proteases. Penicillin is considered to be the drug of choice for Pasteurella infection. Tetracyclin is efficient for bites but has no bactericidal effect. Oxacillin, first-generation cephalosporins, macrolides and aminoglycosides have poor activities. In the case of beta-lactamase producing strains a bactericidal effect could be achieved with fluoroquinolones or third generation cephalosporins.

PCR assay detects Mannheimia haemolytica in culture-negative pneumonic lung tissues of bighorn sheep (Ovis canadensis) from outbreaks in the western USA, 2009-2010.

Mannheimia haemolytica consistently causes severe bronchopneumonia and rapid death of bighorn sheep (Ovis canadensis) under experimental conditions. However, Bibersteinia trehalosi and Pasteurella multocida have been isolated from pneumonic bighorn lung tissues more frequently than M. haemolytica by culture-based methods. We hypothesized that assays more sensitive than culture would detect M. haemolytica in pneumonic lung tissues more accurately. Therefore, our first objective was to develop a PCR assay specific for M. haemolytica and use it to determine if this organism was present in the pneumonic lungs of bighorns during the 2009-2010 outbreaks in Montana, Nevada, and Washington, USA. Mannheimia haemolytica was detected by the species-specific PCR assay in 77% of archived pneumonic lung tissues that were negative by culture. Leukotoxin-negative M. haemolytica does not cause fatal pneumonia in bighorns. Therefore, our second objective was to determine if the leukotoxin gene was also present in the lung tissues as a means of determining the leukotoxicity of M. haemolytica that were present in the lungs. The leukotoxin-specific PCR assay detected leukotoxin gene in 91% of lung tissues that were negative for M. haemolytica by culture. Mycoplasma ovipneumoniae, an organism associated with bighorn pneumonia, was detected in 65% of pneumonic bighorn lung tissues by PCR or culture. A PCR assessment of distribution of these pathogens in the nasopharynx of healthy bighorns from populations that did not experience an all-age die-off in the past 20 yr revealed that M. ovipneumoniae was present in 31% of the animals whereas leukotoxin-positive M. haemolytica was present in only 4%. Taken together, these results indicate that culture-based methods are not reliable for detection of M. haemolytica and that leukotoxin-positive M. haemolytica was a predominant etiologic agent of the pneumonia outbreaks of 2009-2010.

Doenças de ovinos diagnosticadas no Laboratório de Anatomia Patológica Animal da Universidade Federal de Mato Grosso do Sul (1996-2010) / Sheep diseases diagnosed at the Laboratory of Animal Pathology, Federal University of Mato Grosso do Sul, Brazil (1996-2010)

Nas últimas décadas a pecuária ovina cresceu significativamente no Brasil. Concomitantemente, grupos de pesquisas e laboratórios de diagnósticos realizam estudos retrospectivos com a finalidade de fornecer subsídios técnico-científicos para os médicos veterinários. Desta forma, realizou-se um estudo de prevalência nos arquivos do Laboratório de Anatomia Patológica Animal (LAP) da Universidade Federal de Mato Grosso do Sul (UFMS) no período de Janeiro de 1996 a Dezembro de 2010. O Laboratório de Bacteriologia da UFMS e o Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul forneceram apoio diagnóstico nos casos de mannheimiose pulmonar e scrapie, respectivamente. Os laudos da espécie ovina foram revisados e agrupados em conclusivos e inconclusivos, dos quais foram excluídos os casos experimentais e de outros estados e países. Os casos conclusivos foram classificados de acordo com a etiologia da doença. Os exames da espécie ovina somaram 331 laudos (3,97 %) de um total de 8.333 casos diagnosticados no período. Destes, foram excluídos sessenta e quatro (19,3%) casos experimentais e materiais oriundos de outros estados ou países. Dos 267 casos remanescentes, 87 (32,6%) foram inconclusivos e 180 (67,4%) considerados conclusivos, sendo 60 (33,3%) doenças infecciosas e parasitárias; 45 (25%) intoxicações e toxi-infecções; 41 (22,8%) "lesões sem causa definida"; 22 (12,2%) doenças metabólicas e nutricionais; 10 (5,6%) foram classificadas como "outros distúrbios" e 2 (1,1%) neoplasmas. A hemoncose, intoxicação por Brachiaria spp., pleuropneumonias, broncopneumonias, pneumonias fibrinonecrosante ou fibrinossupurativa sem causa definida e a intoxicação por cobre foram as doenças mais prevalentes no período estudado. Dois casos de scrapie foram diagnosticados no período.

Sheep farming has increased significantly in Brazil during the last decades. Concurrently, research groups and diagnostic laboratories compile data and perform retrospective studies to provide important insight for professionals. A prevalence study from January 1996 to December 2010 was carried out in the archives of Laboratório de Anatomia Patológica Animal (LAP), Universidade Federal de Mato Grosso do Sul (UFMS). Laboratório de Bacteriologia, UFMS, and Setor de Patologia Veterinária at Universidade Federal do Rio Grande do Sul helped on the diagnostic of pulmonary mannheimiosis and scrapie respectively. The reports for sheep were reviewed and grouped into conclusive and inconclusive ones. The conclusive cases were classified according to the etiology of the disease. In the period, 331 exams (3.97%) were done. Sixty-four experimental cases and materials from other states or countries (19.3%) were excluded. Remaining cases (267), eighty-seven (32.6%) were inconclusive and 180 (67.4%) were considered conclusive reports, were classified according to the etiology: 60 (33.3%) infectious and parasitary diseases; 45 (25%) were poisonings and toxi-infections; 41 (22.8%) were summarized as "injuries without apparent cause"; 22 (12.2%) cases of metabolic and nutritional diseases; 10 (5.6%) were classified as "other disorders" and 2 (1.1%) case of neoplasms. Haemonchosis, fibrinonecrotic or fibrinopurulent pleuropneumonia, bronchopneumonia and pneumonia, poisonings by Brachiaria spp. and copper poisoning were the most prevalent diseases in sheep. Two cases of scrapie have been diagnosed in this period.

Hemoptysis as the sole presentation of Pasteurella multocida infection.

Pasteurella multocida has been implicated as the cause of a variety of respiratory conditions (eg, bronchitis, pneumonia, lung abscess, empyema), but hemoptysis has been noted only in conjunction with other lung conditions. We report a case in which hemoptysis was the sole manifestation of Pasteurella infection. The patient was a middle-aged man with severe obstructive lung disease and exposure to cats. Diagnosis was made by bronchoscopy and high-dose penicillin was required for resolution.

Pneumonic pasteurellosis associated with Pasteurella haemolytica in chipmunks (Tamias sibiricus).

A laboratory study was performed in order to identify the possible cause of death in chipmunks (Tamias sibiricus) imported from China with respiratory disease. Severe congestion, alveolar oedema and fibrinous pleuritis were observed. Biochemical analyses identified the causative organism as Pasteurella haemolytica. An in vitro susceptibility test using various antimicrobial agents revealed sensitivity to beta-lactams (ampicillin and amoxicillin) and streptomycin.