Survey of desert bighorn sheep in California for exposure to selected infectious diseases

From February 1983 to June 1985, 188 desert bighorn sheep (Ovis canadensis nelsoni, = 161 and Oc cremnobates, = 27) from 18 herds in 17 mountain ranges and one captive herd were caught, marked, and had blood, fecal, and nasal mucus samples collected. Nasal swab specimens were cultured bacteriologically and virologically specifically for parainfluenza-3 (PI-3) virus. Bacterial flora differed from herd to herd. Pathogenic pneumophilic bacteria (eg, Pasteurella sp) seldom were found. Parainfluenza-3 virus was isolated from 6 bighorn sheep in 3 herds. Fecal specimens were examined for parasite ova and low numbers of lungworm (Protostrongylus sp) larvae were found in feces from 2 herds. Sera were evaluated for antibodies against respiratory syncytial virus, ovine progressive pneumonia, infectious bovine rhinotracheitis, PI-3, bovine viral diarrhea, brucellosis, leptospirosis, contagious ecthyma, bluetongue, and epizootic hemorrhagic disease. Blood clots were cultured virologically for bluetongue and epizootic hemorrhagic disease. Serologic evidence of bluetongue and/or epizootic hemorrhagic disease was found in 9 herds, and bluetongue virus (serotypes 10,11,13 and 17) was isolated from 3 herds. Antibody titers against PI-3 and respiratory syncytial virus were found in 9 and 13 herds, respectively. Evidence of bovine viral diarrhea infection was found in 6 herds, whereas infectious bovine rhinotracheitis was found in only 1 herd. Antibody titers against contagious ecthyma were found in 9 of 18 herds in California, and active lesions were seen occasionally. Evidence of ovine progressive pneumonia, leptospirosis, or brucellosis was not found.     

Development of pneumonia in desert bighorn sheep after exposure to a flock of exotic wild and domestic sheep

From 1986 to 1989, 5 desert bighorn sheep (3 Ovis canadensis mexicana and 2 O c nelsoni), ranging in age from 2 to 3 years, were exposed to a flock of exotic wild and domestic sheep to potentially achieve naturally acquired pneumonia. Pasteurella multocida was isolated from nasal samples from 4 of 6 sheep randomly sampled from the flock. Bighorn sheep were exposed individually and each exposure period was a trial. Treatment before and after exposure varied and included combinations of alpha interferon, antibiotics, anti-inflammatory drugs, and vaccines. Treatments were chosen on the basis of recommendations of others for treating pneumonia in desert bighorn sheep as well as our own experience in sheep and cattle. Regardless of treatment used, bighorn sheep in trials 1 to 4 developed signs of pneumonia within 10 to 14 days of exposure. Bighorn sheep in trials 1 to 3 died within 11 to 17 days of initial exposure. In trial 4, the bighorn sheep was isolated from the carrier sheep for treatment of pneumonia on day 14 and died on day 30. Pasteurella multocida was isolated from lung tissue in 3 of the 4 bighorn sheep. On the basis of results of trials 1 to 4, a more in depth clinical study was conducted in trial 5. Nasal and blood specimens were collected prior to and during trial 5 for bacteriologic culturing and serologic testing for bovine viral diarrhea virus, infectious bovine rhinotracheitis, parainfluenza-3 virus, and respiratory syncytial virus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fatal Pasteurella haemolytica pneumonia in bighorn sheep after direct contact with clinically normal domestic sheep

Six Rocky Mountain bighorn sheep were raised in captivity from birth (n = 5) or taken from the wild as a lamb (n = 1). After the bighorn sheep were in captivity for over a year, 6 clinically normal domestic sheep were placed on the 2 ha of pasture on which the bighorn sheep were kept. Nasal swab specimens were obtained from all sheep at the time the domestic sheep were introduced. Pasteurella haemolytica was isolated from swab specimens obtained from 4 of 6 domestic sheep, but not from specimens obtained from the bighorn sheep. All 6 bighorn sheep died of acute hemorrhagic pneumonia after exposure to domestic sheep. Death in the bighorn sheep occurred on days 4, 27, 27, 29, 36, or 71 after initial exposure to domestic sheep. Pasteurella haemolytica was isolated from respiratory tract tissue specimens of all bighorn sheep at the time of death. None of the domestic sheep were clinically ill during the study. At the end of the study, 3 of 6 domestic sheep were euthanatized, and at necropsy, P haemolytica was isolated from 2 of them. The most common serotypes in bighorn and domestic sheep were P haemolytica T-3 and A-2. Other serotypes isolated included P haemolytica A-1, A-9, and A-11 in bighorn sheep and A-1 in domestic sheep. On the basis of results of this study and of other reports, domestic sheep and bighorn sheep should not be managed in proximity to each other because of the potential fatal consequences in bighorn sheep.     

Ultrastructural pathology of the upper respiratory tract of rabbits experimentally infected with Pasteurella multocida A:3.

Twenty-four 8 to 9 week-old Pasteurella multocida -free rabbits were divided into three equal groups, the first group was pretreated with hydrocortisone and inoculated intranasally with pasteurella multocida serotype A:3. The second group was inoculated intranasally with P. multocida without hydrocortisone treatment. The third group was inoculated with phosphate buffered saline only and used as a control group. Pasteurella multocida was isolated from the nasal cavity of all infected rabbits in group 1 and 2 and from the trachea of seven rabbits in group 1 and five rabbits in group 2. This study was conducted to observe the ultrastructural changes of the upper respiratory tract of hydrocortisone treated and non-treated rabbits infected with P. multocida serotype A:3. The ultrastructural changes detected in infected rabbits were ciliary destruction and deciliation of the ciliated epithelial cells, cellular swelling, goblet cell hyperplasia and endothelial cell damage. Pasteurella multocida was observed attached to the degenerated cilia, microvilli and mucus. Pasteurella multocida infection was associated with inflammatory responses, which may have caused tissue damage. It is possible that hydrocortisone modulates the severity of infection as an immune suppressor and an inhibitor of goblet cell secretion.     

Effects of intranasal inoculation with Bordetella bronchiseptica, porcine reproductive and respiratory syndrome virus, or a combination of both organisms on subsequent infection with Pasteurella multocida in pigs

OBJECTIVE: To determine effects of intranasal inoculation with porcine reproductive and respiratory syndrome virus (PRRSV) or Bordetella bronchiseptica on challenge with nontoxigenic Pasteurella multocida in pigs. ANIMALS: Seventy 3-week-old pigs. PROCEDURE: In experiment 1, pigs were not inoculated (n= 10) or were inoculated with PRRSV (10), P. multocida (10), or PRRSV followed by challenge with P. multocida (10). In experiment 2, pigs were not inoculated (n = 10) or were inoculated with B. bronchiseptica (10) or PRRSV and B. bronchiseptica (10); all pigs were challenged with P. multocida. Five pigs from each group were necropsied 14 and 21 days after initial inoculations. RESULTS: Pasteurella multocida was not isolated from tissue specimens of pigs challenged with P. multocida alone or after inoculation with PRRSV. However, in pigs challenged after inoculation with B. bronchiseptica, P. multocida was isolated from specimens of the nasal cavity and tonsil of the soft palate. Number of bacteria isolated increased in pigs challenged after coinoculation with PRRSV and B. bronchiseptica, and all 3 agents were isolated from pneumonic lesions in these pigs. CONCLUSIONS AND CLINICAL RELEVANCE: Infection of pigs with B. bronchiseptica but not PRRSV prior to challenge with P. multocida resulted in colonization of the upper respiratory tract and tonsil of the soft palate with P. multocida. Coinfection with PRRSV and B. bronchiseptica predisposed pigs to infection of the upper respiratory tract and lung with P. multocida. Porcine reproductive and respiratory syndrome virus and B. bronchiseptica may interact to adversely affect respiratory tract defense mechanisms, leaving pigs especially vulnerable to infection with secondary agents such as P. multocida.     

Pasteurellaceae isolated from tonsillar samples of commercially-reared American bison (Bison bison).

As commercial producers of American bison (Bison bison) become more numerous, concerns relative to bison health management increase. Since loss due to respiratory disease associated with Pasteurella and related Pasteurellaceae is a major concern for cattle producers, a study was conducted to determine what types of Pasteurellaceae are carried by bison to evaluate the potential of pneumonic pasteurellosis in bison herds where management practices are comparable to those used for cattle. Tonsillar biopsies, collected in May (n = 29) and August (n = 25) 1997 from 24- to 30-month-old bison bulls, at the time of slaughter were cultured for Pasteurellaceae. Pasteurella spp. were isolated from all the samples collected in May. These included isolates identified as P. haemolytica, trehalosi, testudinis, and multocida subsp. multocida a and multocida b. Actinobacillus spp. and Haemophilus somnus were also isolated from some samples. Pasteurella spp., haemolytica, trehalosi, and multocida subsp. multocida a, multocida b and septica, plus 2 nonspeciated indole-positive biotypes, U2 and U16, were isolated from the second group of tonsil samples. Most of these organisms, including P. haemolytica, P. multocida subsp., and H. somnus are associated with disease in domestic livestock and should be regarded as potential pathogens for bison, particularly in animals which become stressed by management practices commonly used with cattle such as herding, crowding, and shipping.     

Bacterial Identity and Characteristics in Healthy and Unhealthy Respiratory Tracts of Sheep and Calves

Barbour, E.K., Nabbut, N.H., Hamadeh, S.K. and Al-Nakhli, H.M., 1997. Bacterial identity and characteristics in healthy and unhealthy respiratory tracts of sheep and calves. Veterinary Research Communications, 21 (6), 421-430The aim of this study was to compare different bacteriological aspects of the respiratory systems of healthy (H) versus unhealthy (UH) animals with respiratory signs. The prevalence of different bacterial species was determined in the upper and lower respiratory tract of H and UH Najdi sheep, Somali sheep and Holstein calves. The characteristics of Pasteurella spp. isolates, and the biotype of Pasteurella haemolytica were identified in H and UH animals. Eighteen out of 28 (64.3%) of the identified bacterial species in the upper respiratory tract were more prevalent in the nasal cavities of UH Najdi and Somali sheep and Holstein calves with respiratory signs than in apparently healthy animals; four of the most prevalent bacteria in the upper respiratory system of UH sheep were Moraxella spp., Pseudomonas pseudomallei, Erysipelothrix spp., and Pasteurella multocida, while three of the most prevalent bacteria in UH calves were Pasturella haemolytica, Actinomyces spp., and Pseudomonas aeruginosa. The prevalence of six different bacterial species was greater in the lungs of UH animals, namely Actinomyces pyogenes, Erysipelothrix spp., P. haemolytica, Pasteurella ureae, Staphylococcus aureus, and Staphylococcus epidermidis, which could be risk factors in the complexity of the prevalent respiratory diseases of the animals surveyed.Of the biochemical, cytological and colonial characteristics studied in the identified P. haemolytica and P. multocida, two characters were significantly different (p < 0.05) in organisms isolated from UH as compared to those from H animals. These were the higher loss of haemolytic power by the strains of P. haemolytica and the decreased fermentation of trehalose by all the strains of P. multocida recovered from healthy animals.The only biotype of P. haemolytica isolated from H animals was biotype A, while both biotypes A (88.0% of the isolates) and T (12.0% of the isolates) were recovered from UH animals.     

Domestic sheep (Ovis aries) Pasteurellaceae isolates from diagnostic submissions to the Caine Veterinary Teaching Center (1990-2004)

A retrospective study of Pasteurellaceae isolated from domestic sheep (Ovis aries) was conducted. The aim was to identify Pasteurellaceae present in animals that were clinically healthy and others with evidence of respiratory disease. The bacteria had been isolated from samples submitted to the University of Idaho Caine Veterinary Teaching Center as part of disease diagnostic testing. The 844 isolates identified mainly three species of Pasteurellaceae: Mannheimia haemolytica, Pasteurella multocida, and Pasteurella (Bibersteinia) trehalosi. A total of 114 biovariants were identified among these three species. Individual biovariants were identified 1-180 times. Two of those (M. haemolytica 1 and P. (B.) trehalosi 2) constituted 36% of the isolates, and were the only biovariants sufficiently numerous to account for >7% of the total isolates. Samples were primarily submitted from sheep with signs of respiratory disease. Eighty percent of biovariants were identified most often in animals with signs of respiratory disease, but 26% of biovariants were isolated from both sheep with respiratory disease and apparently healthy sheep. P. multocida constituted 4.7% of isolates, and were exclusively associated with animals with respiratory disease. The ability of isolates to produce beta-hemolysis on culture media was not associated with animals with respiratory disease (odds ratio 0.77, 95% CI 0.50-1.19). The inference of this study is limited due to the retrospective study design. However, it is the first study that provides an extensive baseline list of biovariants associated with respiratory disease in domestic sheep.     

Hemorrhagic septicemia in fallow deer (Dama dama) caused by Pasteurella multocida multocida.

Four outbreaks of hemorrhagic septicemia caused by Pasteurella multocida multocida occurred in a population of 1,800 fallow deer (Dama dama) during 1992-1996. A total of 340 fallow deer were submitted for postmortem examination. Pasteurellosis was diagnosed in 273 of 312 deer suspected of having septicemia. Pasteurella multocida was isolated from 257 animals, and the diagnosis was based on typical pathologic changes alone in the other 16 animals. Pasteurella multocida was isolated in pure culture from 219 of 248 samples of cerebrospinal fluid. Eighteen animals were observed moribund with severe depression, foamy nasal discharge, and respiratory distress, and 257 were found dead. Major clinical signs and pathologic changes included extensive swelling of the head and the neck and peracute or acute septic pneumonia, petechial and ecchymotic hemorrhages on serous membranes, and severely hemorrhagic adrenal glands and abomasum. Rhinitis and necrotic pharyngeal mucosae were common. Histologically, the most advanced lesions were in the nasal mucosa and pharynx. The swelling of the head and the neck arose from a diffuse cellulitis in the subcutaneous and intermuscular tissues. The earliest lesions in the lungs included large numbers of bacteria in the pulmonary capillaries, but various degrees of fibrinous exudation to the alveoli and infiltration with heterophils usually were observed.     

Isolation of adenovirus from lambs with upper respiratory syndrome.

The role of viruses in the etiology of recurrent upper respiratory disease in newly weaned lambs was studied during 1984-1985 at the North Dakota Sheep Experiment Station. Serum samples collected from lambs at weaning, from lambs with signs of respiratory disease, and 3 weeks following the onset of clinical signs were tested for antibodies to ovine adenovirus (OAV), respiratory syncytial virus (RSV), and parainfluenza type-3 virus (PI-3). Virus isolation studies were performed on nasal secretions samples taken at the same time. Parainfluenza type-3 was isolated from 1 of 275 lambs tested, and there was 2.5% overall 4-fold increase in antibody titer to PI-3 during the 2-year study. An adenovirus with a different restriction endonuclease digestion pattern from that previously reported adenovirus strains in the United States was isolated from 13 of 275 nasal secretions collected from lambs at the time of weaning. There was a 17.6% overall 4-fold increase in seroconversion to the adenovirus isolated from the lambs with clinical disease.     

Haemophilus somnus (Histophilus somni) in bighorn sheep.

Respiratory disease and poor lamb recruitment have been identified as limiting factors for bighorn-sheep populations. Haemophilus somnus (recently reclassified as Histophilus somni) is associated with respiratory disease in American bison, domestic sheep, and cattle. It is also harbored in their reproductive tracts and has been associated with reproductive failure in domestic sheep and cattle. Therefore, reproductive tract and lung samples from bighorn sheep were evaluated for the presence of this organism. Organisms identified as H. somnus were isolated from 6 of 62 vaginal but none of 12 preputial swab samples. Antigen specific to H. somnus was detected by immunohistochemical study in 4 of 12 formalin-fixed lung tissue samples of bighorn sheep that died with evidence of pneumonia. Notably, H. somnus was found in alveolar debris in areas of inflammation. The 6 vaginal isolates and 2 H. somnus isolates previously cultured from pneumonic lungs of bighorn sheep were compared with 3 representative isolates from domestic sheep and 2 from cattle. The profiles of major outer membrane proteins and antigens for all of the isolates were predominantly similar, although differences that may be associated with the host-parasite relationship and virulence were detected. The DNA restriction fragment length profiles of the bighorn-sheep isolates had similarities not shared with the other isolates, suggesting distinct phylogenetic lines. All of the isolates had similar antimicrobial profiles, but the isolates from the bighorn sheep produced less pigment than those from the domestic livestock, and growth of the former was not enhanced by CO2. Wildlife biologists and diagnosticians should be aware of the potential of these organisms to cause disease in bighorn sheep and of growth characteristics that may hinder laboratory detection.     

Antimicrobial susceptibility patterns of respiratory tract pathogens from sheep and goats

OBJECTIVE: To determine the antimicrobial susceptibility of common respiratory tract pathogens from sheep and goats. DESIGN: Cross-sectional study. SAMPLE POPULATION: 41 respiratory tract isolates from sheep and 36 isolates from goats. PROCEDURES: Disk diffusion assay was used to determine antimicrobial susceptibility of isolates to amoxicillin-clavulanic acid, ceftiofur, ciprofloxacin, florfenicol, and tetracycline. Minimum inhibitory concentrations of florfenicol for these isolates were determined by use of the microbroth dilution technique. RESULTS: The most common isolates were Pasteurella multocida (n = 28) and Mannheimia haemolytica (39). All isolates were susceptible to amoxicillin-clavulanic acid, ceftiofur, ciprofloxacin, and florfenicol. Five percent (4/77) of isolates were resistant to tetracycline. CONCLUSIONS AND CLINICAL RELEVANCE: Susceptibility of respiratory tract pathogens isolated from sheep and goats to commonly used antimicrobial drugs in this study was high. Treatment of these species for bacterial respiratory tract disease is likely not complicated by antimicrobial resistance.     

Characterization of Pasteurella multocida isolated from rabbits in Canada.

In a survey for the somatic and capsular serotypes of Pasteurella multocida present in domestic rabbits in Canada, but mainly in Ontario, samples were obtained from research facilities, commercial rabbitries and from abattoir and necropsy specimens. Sources of isolates were upper respiratory tract infections, localized bronchopneumonias , acute fibrinous pneumonias, abscesses and otitis media. Of 59 isolates obtained, 47.0% were type 12:A, 30.5% 3:D and 12.0% were 3:A. Less common types were 12(4):A, 12:D, 4(12):A and 3:untypable. Somatic group 3 was most commonly isolated from acute pneumonic disease, while serogroup 12:A was most commonly found in upper respiratory tract infections and in localized chronic bronchopneumonia. Two serotypes of P. multocida were isolated from four pneumonic lungs collected from abattoir specimens. Most isolates were susceptible to the commonly used antibiotics.     

Pasteurella species isolated from the bovine respiratory tract and their antimicrobial sensitivity patterns

Pasteurella haemolytica biotype A, serotype 1 (P haemolytica A1) was the most commonly isolated Pasteurella species from 80 calves examined at necropsy from 40 outbreaks of respiratory disease, the majority of which were pathologically confirmed as bovine pneumonic pasteurellosis (transit fever; shipping fever). Similarly, nasopharyngeal swabs from in-contact and apparently healthy calves indicated the widespread presence of P haemolytica A1. Pasteurella multocida and other serotypes of P haemolytica A1 were found including six isolations of P haemolytica T10, a fairly common pathogen in sheep. Approximately two-thirds of the isolates were tested for their antimicrobial sensitivity patterns and the degree of sensitivity for P haemolytica A1, the most frequently isolated serotype, was chloramphenicol (100 per cent), sulphamethoxazole trimethoprim (98 per cent), oxytetracycline (80 per cent), ampicillin (85 per cent), penicillin (82 per cent), streptomycin (3 per cent) and lincomycin (1 per cent).     

Toxigenic Pasteurella multocida in rabbits with naturally occurring atrophic rhinitis

In a commercial rabbitry nasal swabs were taken from 36 animals with enzootic upper respiratory disease resembling porcine atrophic rhinitis. 35 Pasteurella multocida strains were isolated from 17 rabbits. Among 30 strains tested for dermonecrotic toxin production 3, derived from 3 animals, were positive in the guinea pig skin test. 15 Bordetella bronchiseptica strains were recovered from 14 rabbits. No toxigenic strains were found among 6 isolates tested using the same method.     

Prevalence of Pasteurella multocida and other respiratory pathogens in the nasal tract of Scottish calves

The prevalence of Pasteurella multocida, a cause of bovine respiratory disease, was studied in a random sample of beef suckler and dairy farms throughout Scotland, by means of a cross-sectional survey. A total of 637 calves from 68 farms from six geographical regions of Scotland were sampled between February and June 2008. Deep nasal swabs were taken, and samples that were culture-positive for P multocida were confirmed by PCR. Prevalence of P multocida was 17 per cent (105 of 616 calves); 47 per cent of farms had at least one positive animal. A higher prevalence was detected in dairy calves than beef calves (P=0.04). It was found that P multocida was associated with Mycoplasma-like organisms (P=0.06) and bovine parainfluenza type 3 virus (BPI-3) (P=0.04), detected by culture and quantitative PCR of nasal swabs, respectively. Detection of P multocida was not associated with bovine respiratory syncytial virus (BRSV), bovine herpesvirus type 1 (BoHV-1) or bovine viral diarrhoea virus (BVDV). Mycoplasma-like organisms, BPI-3, BRSV, BoHV-1 and BVDV were detected in 58, 17, four, 0 and eight calves, on 25, five, two, 0 and five of the 68 farms, respectively.     

Pasteurella multocida and Bordetella bronchiseptica in atrophic rhinitis and pneumonia in swine.

A total of 163 pigs from nine farrow-to-finish herds representing various levels of atrophic rhinitis (AR) were selected for postslaughter examination of AR and pneumonia. Nasal swabs and lungs were cultured for detection of Bordetella bronchiseptica and Pasteurella multocida. Seventy-three pigs were examined at eight weeks of age and 90 contemporaries at six months of age. Mean AR scores were 1.21 and 1.11 for the eight week and six month old pigs, respectively (0 = normal, 3 = severe). In individual pigs increasing AR score was related to increasing pneumonia score in eight week old pigs but not in six month old hogs. In eight week old pigs, B. bronchiseptica and P. multocida were isolated more frequently from pigs with higher AR scores. From nasal swabs of six month old hogs, Bordetella was almost never recovered while Pasteurella was frequently isolated score. Toxigenic type DP. multocida was isolated from nasal cultures of only seven (4%) pigs and from lung cultures of only one pig. Pasteurella was never isolated from lungs of the eight week old pigs and Bordetella never from the six month old hogs. The isolation rate of P. multocida, predominantly type A, from lungs of six month old pigs increased from 11% in grossly normal lungs to 86% in lungs with severe pneumonia. Pigs from one herd free from lesions of AR and pneumonia were also examined; type AP. multocida was isolated from nasal cultures of one of six eight week old pigs. Somatic antigens of P. multocida were determined for 94 nasal and 20 lung isolates. Somatic serovar 3 was found in 93% of the nasal isolates and in all lung isolates.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pasteurella multocida-associated sinusitis in khaki Campbell ducks (Anas platyrhynchos)

Pasteurella multocida group B, serotype 3, was isolated from sinusitis-affected khaki Campbell ducks. To study the role of P. multocida in sinusitis, commercial khaki Campbell ducks were experimentally infected with P. multocida alone or combined with Escherichia coli. In Expt. 1, experimental ducks were infected with P. multocida intranasally or ocularly. A comparison was done by intranasal inoculation with pooled nasal discharge from the affected ducks or phosphate-buffered saline. The ducks intranasally inoculated with the nasal discharge or P. multocida showed sinusitis. In Expt. 2, E. coli alone or a combination of P. multocida and E. coli was intranasally inoculated into experimental ducks. The ducks intranasally inoculated with the combination of P. multocida and E. coli had sinusitis, the same as found in the field but less severe than that of the field cases. Pasteurella multocida was already present in litter/floor of duck farms. We concluded that P. multocida played a role in induction of sinusitis. However, the sinusitis in ducks may be initiated by poor management, especially in the brooding period of ducks.     

Ultrastructural pathology of nasal and tracheal mucosa of rabbits experimentally infected with Pasteurella multocida serotype D:1

Sixteen 8- to 9-week-old Pasteurella multocida-free New Zealand White rabbits were divided into two equal groups. The first group was inoculated intranasally with P multocida serotype D:1 strain and the second group that was inoculated with phosphate-buffered saline (PBS) only was used as a control group. Pasteurella multocida was isolated from the nasal cavity of all infected rabbits in group 1 and from tracheal swabs of seven rabbits in this group. Four rabbits in group 1 died with clinical signs of septicaemia, two rabbits had mucopurulent nasal discharge and pneumonic lesions and the other two did not show any clinical signs or gross lesions. The ultrastructural changes detected were deciliation or clumping of cilia of ciliated epithelium, cellular swelling, vacuolation and sloughing. The subepithelial capillaries showed congestion, intravascular fibrin deposition, platelets aggregation and endothelial injury. Pasteurella multocida was observed attached to the injured endothelial cells. Heterophils, mast cells, vacuolated monocytes and macrophages infiltrated the lamina propria and between the degenerated epithelial cells.     

PRRSV感染猪体内多杀性巴氏杆菌的分离与血清型鉴定

应用常规方法和PCR技术,对来自安徽肥西、庐江、肥东、定远、桐城5个地区猪场检测为猪繁殖与呼吸综合征病毒(PRRSV)阳性的肺脏进行多杀性巴氏杆菌(Pm)的分离及其血清型鉴定。结果显示,49份病料中分离鉴定出7株Pm,且均属于A型,分离率为14.3%,高于其他细菌(副猪嗜血杆菌、猪链球菌)的检出率。表明猪繁殖与呼吸综合征(PRRS)患猪继发或混合感染Pm的比率较高,而且A型Pm是安徽省感染猪群中的主要血清型。