Actinobacillus Infections: Infections with bacteria of the genus ACTINOBACILLUS.Actinobacillus: A genus of PASTEURELLACEAE described as gram-negative, nonsporeforming, nonmotile, facultative anaerobes. Most members are found both as pathogens and commensal organisms in the respiratory, alimentary, and genital tracts of animals.Actinobacillus pleuropneumoniae: A species of gram-negative, facultatively anaerobic coccobacillus-shaped bacteria that has been isolated from pneumonic lesions and blood. It produces pneumonia with accompanying fibrinous pleuritis in swine.Aggregatibacter actinomycetemcomitans: A species of Gram-negative, facultatively anaerobic spherical or rod-shaped bacteria indigenous to dental surfaces. It is associated with PERIODONTITIS; BACTERIAL ENDOCARDITIS; and ACTINOMYCOSIS.Actinobacillus suis: A species of gram-negative bacteria in the genus ACTINOBACILLUS. It is mainly a pathogen of PIGS, but also can infect HORSES.Pleuropneumonia: Inflammation of the lung parenchyma that is associated with PLEURISY, inflammation of the PLEURA.Actinobacillus equuli: A genus of gram-negative bacteria in the genus ACTINOBACILLUS, which is pathogenic for HORSES and PIGS.Swine Diseases: Diseases of domestic swine and of the wild boar of the genus Sus.Haemophilus: A genus of PASTEURELLACEAE that consists of several species occurring in animals and humans. Its organisms are described as gram-negative, facultatively anaerobic, coccobacillus or rod-shaped, and nonmotile.Aggressive Periodontitis: Inflammation and loss of PERIODONTIUM that is characterized by rapid attachment loss and bone destruction in the presence of little local factors such as DENTAL PLAQUE and DENTAL CALCULUS. This highly destructive form of periodontitis often occurs in young people and was called early-onset periodontitis, but this disease also appears in old people.Periodontitis: Inflammation and loss of connective tissues supporting or surrounding the teeth. This may involve any part of the PERIODONTIUM. Periodontitis is currently classified by disease progression (CHRONIC PERIODONTITIS; AGGRESSIVE PERIODONTITIS) instead of age of onset. (From 1999 International Workshop for a Classification of Periodontal Diseases and Conditions, American Academy of Periodontology)Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Aggregatibacter: A genus of PASTEURELLACEAE. Members are nonmotile, Gram-negative, facultatively anaerobic rods or coccobacilli. Its members are X factor (HEMIN) independent and variably dependent on V factor (NAD).Exotoxins: Toxins produced, especially by bacterial or fungal cells, and released into the culture medium or environment.Pasteurellaceae: A family of coccoid to rod-shaped nonsporeforming, gram-negative, nonmotile, facultatively anaerobic bacteria that includes the genera ACTINOBACILLUS; HAEMOPHILUS; MANNHEIMIA; and PASTEURELLA.Pasteurella: The oldest recognized genus of the family PASTEURELLACEAE. It consists of several species. Its organisms occur most frequently as coccobacillus or rod-shaped and are gram-negative, nonmotile, facultative anaerobes. Species of this genus are found in both animals and humans.Cytotoxins: Substances that are toxic to cells; they may be involved in immunity or may be contained in venoms. These are distinguished from CYTOSTATIC AGENTS in degree of effect. Some of them are used as CYTOTOXIC ANTIBIOTICS. The mechanism of action of many of these are as ALKYLATING AGENTS or MITOSIS MODULATORS.Serotyping: Process of determining and distinguishing species of bacteria or viruses based on antigens they share.Actinobacillosis: A disease characterized by suppurative and granulomatous lesions in the respiratory tract, upper alimentary tract, skin, kidneys, joints, and other tissues. Actinobacillus lignieresii infects cattle and sheep while A. equuli infects horses and pigs.Hemolysin Proteins: Proteins from BACTERIA and FUNGI that are soluble enough to be secreted to target ERYTHROCYTES and insert into the membrane to form beta-barrel pores. Biosynthesis may be regulated by HEMOLYSIN FACTORS.Actinobacillus seminis: A species of gram-negative bacteria in the genus ACTINOBACILLUS, which causes EPIDIDYMITIS in SHEEP.Bacterial Toxins: Toxic substances formed in or elaborated by bacteria; they are usually proteins with high molecular weight and antigenicity; some are used as antibiotics and some to skin test for the presence of or susceptibility to certain diseases.Periodontal Diseases: Pathological processes involving the PERIODONTIUM including the gum (GINGIVA), the alveolar bone (ALVEOLAR PROCESS), the DENTAL CEMENTUM, and the PERIODONTAL LIGAMENT.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Gingiva: Oral tissue surrounding and attached to TEETH.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Bacterial Proteins: Proteins found in any species of bacterium.Transferrin-Binding Proteins: A class of carrier proteins that bind to TRANSFERRIN. Many strains of pathogenic bacteria utilize transferrin-binding proteins to acquire their supply of iron from serum.Dental Plaque: A film that attaches to teeth, often causing DENTAL CARIES and GINGIVITIS. It is composed of MUCINS, secreted from salivary glands, and microorganisms.Genes, Bacterial: The functional hereditary units of BACTERIA.Electronic Mail: Messages between computer users via COMPUTER COMMUNICATION NETWORKS. This feature duplicates most of the features of paper mail, such as forwarding, multiple copies, and attachments of images and other file types, but with a speed advantage. The term also refers to an individual message sent in this way.Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.C-Reactive Protein: A plasma protein that circulates in increased amounts during inflammation and after tissue damage.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Seminal Vesicles: A saclike, glandular diverticulum on each ductus deferens in male vertebrates. It is united with the excretory duct and serves for temporary storage of semen. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Library Administration: Planning, organizing, staffing, direction, and control of libraries.Chronic Periodontitis: Chronic inflammation and loss of PERIODONTIUM that is associated with the amount of DENTAL PLAQUE or DENTAL CALCULUS present. Chronic periodontitis occurs mostly in adults and was called adult periodontitis, but this disease can appear in young people.Porphyromonas gingivalis: A species of gram-negative, anaerobic, rod-shaped bacteria originally classified within the BACTEROIDES genus. This bacterium produces a cell-bound, oxygen-sensitive collagenase and is isolated from the human mouth.Gingivitis: Inflammation of gum tissue (GINGIVA) without loss of connective tissue.Biohazard Release: Uncontrolled release of biological material from its containment. This either threatens to, or does, cause exposure to a biological hazard. Such an incident may occur accidentally or deliberately.Blastocystis hominis: A species of parasitic protozoa found in the intestines of humans and other primates. It was classified as a yeast in 1912. Over the years, questions arose about this designation. In 1967, many physiological and morphological B. hominis characteristics were reported that fit a protozoan classification. Since that time, other papers have corroborated this work and the organism is now recognized as a protozoan parasite of humans causing intestinal disease with potentially disabling symptoms.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Typhoid-Paratyphoid Vaccines: Vaccines used to prevent TYPHOID FEVER and/or PARATYPHOID FEVER which are caused by various species of SALMONELLA. Attenuated, subunit, and inactivated forms of the vaccines exist.Vaccines: Suspensions of killed or attenuated microorganisms (bacteria, viruses, fungi, protozoa), antigenic proteins, synthetic constructs, or other bio-molecular derivatives, administered for the prevention, amelioration, or treatment of infectious and other diseases.Typhoid Fever: An acute systemic febrile infection caused by SALMONELLA TYPHI, a serotype of SALMONELLA ENTERICA.Drug Delivery Systems: Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.Poliovirus Vaccine, Oral: A live vaccine containing attenuated poliovirus, types I, II, and III, grown in monkey kidney cell tissue culture, used for routine immunization of children against polio. This vaccine induces long-lasting intestinal and humoral immunity. Killed vaccine induces only humoral immunity. Oral poliovirus vaccine should not be administered to immunocompromised individuals or their household contacts. (Dorland, 28th ed)Vaccines, Inactivated: Vaccines in which the infectious microbial nucleic acid components have been destroyed by chemical or physical treatment (e.g., formalin, beta-propiolactone, gamma radiation) without affecting the antigenicity or immunogenicity of the viral coat or bacterial outer membrane proteins.Peritonitis: INFLAMMATION of the PERITONEUM lining the ABDOMINAL CAVITY as the result of infectious, autoimmune, or chemical processes. Primary peritonitis is due to infection of the PERITONEAL CAVITY via hematogenous or lymphatic spread and without intra-abdominal source. Secondary peritonitis arises from the ABDOMINAL CAVITY itself through RUPTURE or ABSCESS of intra-abdominal organs.Pemphigoid, Benign Mucous Membrane: A chronic blistering disease with predilection for mucous membranes and less frequently the skin, and with a tendency to scarring. It is sometimes called ocular pemphigoid because of conjunctival mucous membrane involvement.Appetite: Natural recurring desire for food. Alterations may be induced by APPETITE DEPRESSANTS or APPETITE STIMULANTS.Abdominal Pain: Sensation of discomfort, distress, or agony in the abdominal region.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Age of Onset: The age, developmental stage, or period of life at which a disease or the initial symptoms or manifestations of a disease appear in an individual.

Pulmonary lesions in guinea pigs experimentally infected with Actinobacillus pleuropneumoniae (A.p.) serovar 1. (1/272)

Pathological studies were carried out on the lungs of guinea pigs intratracheally inoculated with 4.6 x 10(6-8) colony forming units (CFU)/head of Actinobacillus pleuropneumoniae serovar 1. All animals in the highest dose group died within 24 hr post inoculation (hpi) and showed pulmonary lesions being hemorrhagic in nature while all animals in the lowest dose group were killed as scheduled at 11 days post inoculation (dpi) and showed only hyperplasia of peribronchial lymphoid tissues. In the middle dose group, two died within 24 hpi, two died at 9 dpi, and the remaining one was killed at 11 dpi. Two guinea pigs which died at 9 dpi showed fibrinonecrotic pleuropneumonia which is the most characteristic acute pulmonary lesion in swine, and has not yet been reproduced in laboratory animals up to the present time. This suggests that guinea pigs may be a useful laboratory animal for studying the pathogenesis of Actinobacillus pleuropneumoniae infection in swine.  (+info)

Vaccination and protection of pigs against pleuropneumonia with a vaccine strain of Actinobacillus pleuropneumoniae produced by site-specific mutagenesis of the ApxII operon. (2/272)

The production of toxin (Apx)-neutralizing antibodies during infection plays a major role in the induction of protective immunity to Actinobacillus pleuropneumoniae reinfection. In the present study, the gene encoding the ApxII-activating protein, apxIIC, was insertionally inactivated on the chromosome of a serovar 7 strain, HS93. Expression of the structural toxin, ApxIIA, and of the two genes required for its secretion, apxIB and apxID, still occurs in this strain. The resulting mutant strain, HS93C- Ampr, was found to secrete the unactivated toxin. Pigs vaccinated with live HS93C- Ampr via the intranasal route were protected against a cross-serovar challenge with a virulent serovar 1 strain of A. pleuropneumoniae. This is the first reported vaccine strain of A. pleuropneumoniae which can be delivered live to pigs and offers cross-serovar protection against porcine pleuropneumonia.  (+info)

Actinobacillus pleuropneumoniae osteomyelitis in pigs demonstrated by fluorescent in situ hybridization. (3/272)

Necrotizing osteomyelitis and fibrinopurulent arthritis with isolation of Actinobacillus pleuropneumoniae serotype 2 is reported in two pigs from a herd with lameness and mild coughing problems among 8 to 12-week-old pigs. Application of fluorescent in situ hybridization targeting 16S ribosomal RNA of A. pleuropneumoniae in formalin-fixed tissue was performed to verify the association of A. pleuropneumoniae with the bone and joint lesions. By in situ hybridization A. pleuropneumoniae was demonstrated as multiple microcolonies or single cells dispersed in focal fibrinonecrotizing pleuropneumonia, in joints with arthritis, and in bone necroses including lysis of growth plate and suppurative inflammation in the adjacent trabecular metaphysis, thus demonstrating that well-known infections manifest new, unusual lesions.  (+info)

Agents of the "suis-ide diseases" of swine: Actinobacillus suis, Haemophilus parasuis, and Streptococcus suis. (4/272)

In recent years, Actinobacillus suis, Haemophilus parasuis, and Streptococcus suis have emerged as important pathogens of swine, particularly in high health status herds. Their association with a wide range of serious clinical conditions and has given rise to the moniker "suis-ide diseases." These organisms are early colonizers and, for that reason, are difficult to control by management procedures such as segregated early weaning. Vaccination, serodiagnostic testing, and even serotyping are complicated by the presence of multiple serotypes, cross-reactive antigens, and the absence of clear markers for virulence. In this review, we discuss our current understanding of the pathogenesis, epidemiology, and management of the causative agents of the "suis-ide diseases" of swine.  (+info)

Phenotypic variation in Actinobacillus actinomycetemcomitans during laboratory growth: implications for virulence. (5/272)

This study examined alteration of specific virulence traits associated with phenotypic changes seen when a low-passage disease-associated and well maintained parent strain of Actinobacillus actinomycetemcomitans was compared to a laboratory-grown spontaneous variant/mutant. Clinical isolates of A. actinomycetemcomitans recovered from periodontitis patients typically grow as rough, adherent colonies on primary culture but undergo transformation to smooth, non-adherent colonies following repeated passage in vitro. The relationship of these phenotypic changes to the virulence of the organism or to the processes that underlie this transformation are not understood. A fresh clinical isolate, designated strain CU1000, was obtained from the first molar site of a patient with classical signs of localized juvenile periodontitis and used as the parent strain to study virulence-related phenotypes. Following several passages of CU1000 on selective agar, a spontaneous variant that demonstrated smooth, opaque, non-adherent colonies was isolated and designated strain CU1060. This study compared the properties of these two strains with respect to colony morphology, autoaggregation, surface appendages, adherence to saliva-coated hydroxyapatite (SHA), LPS chemotype and activity, induction of fibroblast proteinase activity and antigenic properties. CU1000 demonstrated rough, raised, star-positive colonies which upon electron microscopic examination revealed the presence of large, flexible, bundled fibrils. In addition, CU1000 showed adherence to SHA, several unique protein antigens and elevated endotoxin and fibroblast proteinase activity. CU1060, on the other hand, showed minimal adherence to SHA and fewer reactive proteins compared to the fresh clinical isolates. This strain formed smooth, opaque colonies on agar, showed minimal fibril formation and limited endotoxin and fibroblast-proteinase-inducing activity. These findings demonstrate that clinical isolates of A. actinomycetemcomitans undergo significant virulence-reducing phenotypic alterations during in vitro passage and support the need to study this organism in its clinical form.  (+info)

Detection of antibodies against Actinobacillus pleuropneumoniae serotypes 1, 2, 5 and 7 using the immunohistochemical staining. (6/272)

Whole cells of Actinobacillus pleuropneumoniae (A. pleuropneumoniae) serotype 1, 2, 5 or 7 attached to fibrins were fixed in 10% neutral buffered formalin and embedded in paraffin. The sections on a slide glass were stained by the avidin-biotin complex immunoperoxidase (ABC) method. Test sera were applied to sections as primary antibodies. The serum antibodies against A.pleuropneumoniae (serotypes 1, 2, 5 and 7) were measured by the ABC method and complement fixation (CF) test. There was good correlation between the ABC and CF tests. The present results indicate that the immunohistochemical staining is as useful as the CF test for the detection and quantification of antibody in swine sera.  (+info)

Characterization of apxIVA, a new RTX determinant of Actinobacillus pleuropneumoniae. (7/272)

A fourth type of RTX determinant was identified in Actinobacillus pleuropneumoniae and was designated apxIVA. When expressed in Escherichia coli, recombinant ApxIVA showed a weak haemolytic activity and co-haemolytic synergy with the sphingomyelinase (beta-toxin) of Staphylococcus aureus. These activities required the presence of an additional gene, ORF1, that is located immediately upstream of apxIVA. The apxIVA gene product could not be detected in A. pleuropneumoniae cultures grown under various conditions in vitro; however, pigs experimentally infected with A. pleuropneumoniae serotypes 1, 5 and 7 started to produce antibodies that reacted with recombinant ApxIVA 14 d post-infection, indicating that apxIVA is expressed in vivo. In addition, sera from pigs naturally and experimentally infected with any of the serotypes all reacted with recombinant ApxIVA. The apxIVA gene from the serotype 1 A. pleuropneumoniae type strain Shope 4074T encodes a protein with a predicted molecular mass of 202 kDa which has typical features of RTX proteins including hydrophobic domains in the N-terminal half and 24 glycine-rich nonapeptides in the C-terminal half that bind Ca2+. The glycine-rich nonapeptides are arranged in a modular structure and there is some variability in the number of modules in the ApxIVA proteins of different serotypes of A. pleuropneumoniae. The deduced amino acid sequences of the ApxIVA proteins have significant similarity with the Neisseria meningitidis iron-regulated RTX proteins FrpA and FrpC, and to a much lesser extent with other RTX proteins. The apxIVA gene could be detected in all A. pleuropneumoniae serotypes and seems to be species-specific. Although the precise role of this new RTX determinant in pathogenesis of porcine pleuropneumonia needs to be determined, apxIVA is the first in vivo induced toxin gene that has been described in A. pleuropneumoniae.  (+info)

Genomic relatedness among Actinobacillus pleuropneumoniae field strains of sterotypes 1 and 5 isolated from healthy and diseased pigs. (8/272)

Forty-four Actinobacillus pleuropneumoniae isolates recovered from both healthy and diseased pigs were characterized by random amplified polymorphic DNA analysis (RAPD), pulsed field gel electrophoresis (PFGE) and apx toxin gene typing. Nine RAPD types and 14 PFGE patterns were identified. No common RAPD or PFGE patterns were found between strains of serotype 1 and those of serotype 5. The RAPD analysis indicated that the 15 serotype 1 strains isolated from diseased pigs were assigned to 4 RAPD types, with 66% of strains characterized by the same RAPD type. By contrast, the 5 strains of serotype 1 isolated from healthy carriers were dispersed in 4 RAPD types. These data suggest that the diversity of strains isolated from healthy pigs could be higher than that of strains recovered from diseased pigs. In addition, all serotype 5 strains exhibited a unique RAPD type. Unlike RAPD, PFGE analysis allowed discrimination among isolates of serotype 1 and among those of serotype 5. All but 3 isolates showed the same apx genotype as their respective serotype reference strain. These data indicate that RAPD analysis is a valuable rapid tool for routine subtyping of strains of serotype 1. For strains of serotype 5, a combination of several typing methods, such as PFGE and apx gene typing, is needed to provide useful information on the molecular epidemiology of swine pleuropneumonia.  (+info)

  • Several studies have shown a greater prevalence of HLA-B27 antigen in WD patients (26% versus 8% in European and American populations, respectively) ( 16 , 22 ), but no causal association between HLA-B27 presence and infection susceptibility has been demonstrated. (
  • In these cases, the clinical expression of M. hyo depends on many factors such as pig susceptibility, the M. hyo bacterial load and strain virulence as well as the presence of exacerbating bacterial and viral co-infections, he says. (
  • Our objective was to detect genes that may be involved in conferring heritable differences in susceptibility to common infections in intensive pig production. (
  • A clinical palpation and semen smear examination of 647 rams submitted to the Regional Veterinary Laboratory during 1967 revealed that 42 (6,5%) of these animals had clinical epididymitis or orchitis, 6 (0,9%) showed other types of genital lesions and 98 (15,1%) suffered from subclinical genital infection. (
  • A. seminis was isolated from 5 out of 6 of these rams with clinical lesions and 10 out of 15 of those which showed evidence of subclinical infection. (
  • To evaluate lung lesions at slaughter after three-dose vaccination with a subunit Actinobacillus pleuropneumoniae vaccine containing ApxI, ApxII, ApxIII, and an outer membrane protein. (
  • Actinobacillus pleuropneumoniae -related lesions and ADG did not differ between control and treatment groups. (
  • Clinical observation should be followed by necropsy to look for gross lesions characteristic of M. hyo infection - or other pathogens. (
  • Often the lesions of arthritis are chronic in the cases presented to the diagnostic laboratory, therefore a specific cause remains "undetermined" but most of these are a sequel to a previous bacterial infection (Figure 3). (
  • CVPC quantification by means of lung lesion scoring is frequently used to estimate the incidence and severity of lung lesions associated to M . hyopneumoniae infections, at experimental, herd and abattoir levels [ 4 - 6 ]. (
  • Immunopathological events are considered to play an important role in both M . hyopneumoniae infection pattern and development of the associated lung lesions [ 3 ]. (
  • Actinobacillus seminis is frequently isolated from the lesions that produces clinical signs and reproductive discrepancies in ram wherein transmission implicit through direct contact between mucous membrane from all orifices during pre-mating period owing to boost up homosexual activity in which ewe considered as the intermediate carriers upholding ewe to lamb transmission. (
  • Gastric acidity is a major barrier to colonization and infection of the gastrointestinal tract by microorganisms and is a first line of defense against microbial pathogens that infect their host via the oral route. (
  • Following infection of 12 pigs, clinical signs of pneumonia developed within 20 h, whereafter the animals received a single dose of either danofloxacin (2.5 mg/kg) or tiamulin (10 mg/kg). (
  • The present model provides a valuable tool in the evaluation of antibiotic treatments, offering the advantage of clinical and pathological examinations combined with the use of biochemical infection markers. (
  • Infection is usually acquired in calfhood but generally no clinical signs are seen until animals are at least four years old. (
  • Lack of response commonly results from clinical factors such as diabetes, steroid use, HIV infection or age. (
  • Duration of efficacy of ceftiofur crystalline free acid sterile suspension against clinical disease in grower pigs challenged with Actinobacillus pleuropneumoniae. (
  • To evaluate the duration of efficacy of a single dose of ceftiofur crystalline free acid sterile suspension (CCFA-SS) against clinical disease in grower pigs inoculated intratracheally with Actinobacillus pleuropneumoniae . (
  • Clinical signs of M. hyo infection tend to be seen late during the grower or finisher period. (
  • M. hyo-associated clinical disease is generally self-limiting unless pigs are immunologically naïve or they have complicating infections or abnormal environmental stresses. (
  • The bacteriology section publishes research findings which focus on clinical, macro pathological, cell and molecular biological aspects of bacterial infections. (
  • During the chronic stage of infection pigs lacked clinical signs and lung alterations were characterized by reparation and remodelling processes such as tissue sequestration and fibroblastic pleuritis with a high-grade accumulation of small PR-39-positive cells resembling polymorphonuclear neutrophils. (
  • On 4 stud farms where Elberg Rev. 1 vaccine was meticulously applied and the complete absence of Brucella ovis infection was established, of a total of 327 rams examined, 10 (3,6%) were found to be clinically and 72 (22,0%) subclinically affected. (
  • Mesenteric lymphangitis and sepsis due to RTX toxin-producing Actinobacillus spp in 2 foals with hypothyroidism-dysmaturity syndrome. (
  • Evaluar las lesiones pulmonares en el rastro después de una vacunación con tres dosis de una vacuna de Actinobacillus pleuropneumoniae de subunidades conteniendo ApxI, ApxII, ApxIII, y una proteína de membrana externa. (