Epidemiological characteristics of pulmonary pneumocystosis and concurrent infections in pigs in Jeju Island, Korea

Epidemiological characteristics of swine pulmonary Pneumocystis (P.) carinii and concurrent infections were surveyed on Jeju Island, Korea, within a designated period in 172 pigs submitted from 54 farms to the Department of Veterinary Medicine, Jeju National University. The submitted cases were evaluated by histopathology, immunohistochemistry, PCR/RT-PCR, and bacteriology. P. carinii infection was confirmed in 39 (22.7%) of the 172 pigs. Histopathologically, the lungs had moderate to severe lymphohistioctyic interstitial pneumonia with variable numbers of fungal organisms within lesions. Furthermore, porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV-2) co-infection was a common phenomenon (12.8%, 20.5%, and 48.7% were positive for PRRS, PCV-2, or both, respectively, as determined by PCR/RT-PCR). Infection was much more concentrated during winter (December to March) and 53.8% of the infected pigs were 7- to 8-weeks old. In addition, three pigs showed co-infection with bacteria such as Pasteurella multocida and Streptococcus suis. The results of the present study suggest that the secondary P. carinii infection is common following primary viral infection in swine in Korea. They further suggest that co-infection of P. carinii might be enhanced by the virulence of primary pathogens or might have synergistic effects in the pigs with chronic wasting diseases.     

Role of Bibersteinia trehalosi, respiratory syncytial virus,and parainfluenza-3 virus in bighorn sheep pneumonia

Pneumonic bighorn sheep (BHS) have been found to be culture- and/or sero-positive for Bibersteinia trehalosi, respiratory syncytial virus (RSV), and parainfluenza-3 virus (PI-3). The objective of this study was to determine whether these pathogens can cause fatal pneumonia in BHS. In the first study, two groups of four BHS each were intra-tracheally administered with leukotoxin-positive (Group I) or leukotoxin-negative (Group II) B. trehalosi. All four animals in Group I developed severe pneumonia, and two of them died within 3 days. The other two animals showed severe pneumonic lesions on euthanasia and necropsy. Animals in Group II neither died nor showed gross pneumonic lesions on necropsy, suggesting that leukotoxin-positive, but not leukotoxin-negative, B. trehalosi can cause fatal pneumonia in BHS.     

Pulmonary inflammation due to exercise-induced pulmonary haemorrhage in Thoroughbred colts during race training

This study investigated the putative roles of inflammation and platelet-activating factor (PAF) in exercise-induced pulmonary haemorrhage (EIPH). Two-year-old Thoroughbred colts (n=37) were exercised on a racetrack for 5months before commencement of the study. Each colt was then exercised at 15-16m/s over 800-1000m and broncho-alveolar lavage fluid (BALF) was collected 24h later. The colts were subsequently divided into two groups on the basis of BALF analysis; an EIPH-positive group (presence of haemosiderophages, n=23) and an EIPH-negative group (absence of haemosiderophages, n=14). BALF from the EIPH-positive group had a significantly higher protein concentration (0.39±0.28 vs. 0.19±0.12mg/mL, P=0.031), higher PAF bioactivity (0.18±0.12 vs. 0.043±0.05 340:380nm ratio, P=0.042) and a higher lipid hydroperoxide concentration compared to the EIPH-negative group. There was also a lower nitrite concentration and reduced production of superoxide anion and hydrogen peroxide by alveolar macrophages in the EIPH-positive group. There was evidence of pulmonary inflammation and a decreased innate immune response of alveolar macrophages in EIPH-positive colts compared with the EIPH-negative group.     

Transient hypogammaglobulinaemia of the young in a Thoroughbred yearling

A 12-month-old Thoroughbred colt was presented for chronic recurrent respiratory disease characterised by persistent nasal discharge, intermittent pyrexia and coughing of several months' duration. These episodes were responsive to empirical antimicrobial therapy but returned once therapy was discontinued. History, physical examination and initial diagnostics were suggestive of bacterial pneumonia and possible underlying immunodeficiency. Serum immunoglobulin analysis and peripheral blood lymphocyte phenotyping revealed low serum IgG and IgM concentrations. In this 12-month-old colt, low serum IgG concentration was the most diagnostic parameter and supported a presumptive diagnosis of transient hypogammaglobulinaemia of the young. The colt responded favourably to repeated treatment with antimicrobials for bacterial pneumonia, and serial immunologic testing over the following months showed gradual increase in serum IgG and IgM concentrations, supporting the diagnosis of delayed development of humoral immunity in this patient.     

T cell rich,B cell lymphoma in the small colon of a yearling horse

A one‐year‐old, Thoroughbred colt presented for evaluation due to a one month history of fever of unknown origin and progressive weight loss. On initial presentation, the horse was febrile and showed signs localised to the respiratory tract. These included bilaterally increased bronchovesicular sounds and a moderate, diffuse interstitial pattern on thoracic radiographs. A transtracheal wash yielded mucopurulent debris, culture of which grew small numbers of Staphylococcus epidermidis and Aspergillus spp. The horse was discharged with a diagnosis of bronchointerstitial pneumonia and placed on antibiotic therapy. Ten days after initial presentation, he developed abdominal pain that was unresponsive to on‐farm treatment. The horse was febrile, displayed increased respiratory rate and effort, and showed moderate signs of abdominal pain. On rectal examination, a firm, 8–10 cm mass was palpated on midline. The colt was admitted to the hospital and scheduled for exploratory laparotomy, but died a short time later before surgery could be performed. This report describes the clinical, diagnostic and histopathological findings of a case of alimentary lymphoma in a yearling colt.     

Respiratory infections in housed sheep,with particular reference to mycoplasmas

A commercial housed flock with an annual occurrence of pneumonia was investigated. The organism most commonly isolated from the respiratory tract of lambs up to 6 months old was Mycoplasma ovipneumoniae. Mycoplasma arginini, Mycoplasma conjunctivae, Acholeplasma laidlawii, ureaplasmas and Pasteurella haemolytica biotype A were also isolated: viruses were not isolated, but infection with parainfluenza virus type 3 (P13) was indicated by serology. Colostrum derived antibodies to M. ovipneumoniae and M. arginini declined to minimum levels by 50 days. The development of active immunity to mycoplasmas and P13 virus was associated with an increased incidence of clinical respiratory disease. Histopathological examination of the lungs from 34 lambs showed that 15 had lesions of a proliferative exudative (P.E.) pneumonia, a further 11 showed lymphoid hyperplasia sometimes associated with interstitial thickening, and eight showed no significant pathological changes. Isolations of M. ovipneumoniae were highest from animals with P.E. pneumonia, while M. arginini did not appear to be associated with any specific lung changes. P. haemolytica biotype A was isolated from all cases of P.E. pneumonia. M. ovipneumoniae, M. arginini and P. haemolytica were also isolated from the lower respiratory tract of a proportion of 31 ewes examined post-mortem, but P.E. pneumonia was not observed in these animals.     

First molecular detection of Pneumocystis spp. in red foxes (Vulpes vulpes linnaeus, 1758) and raccoon dogs (Nyctereutes procyonoides gray, 1834)

Fungal organisms of the genus Pneumocystis may cause Pneumocystis pneumonia (PCP) in humans, but also domestic and wild mammals. Almost every animal species hosts its own genetically distinct Pneumocystis species, however information is sparse. In this study, 62 red foxes (Vulpes vulpes) and 37 raccoon dogs (Nyctereutes procyonoides) were collected in North-East Germany. The lung tissues of the animals were analysed by a new designed specific pan-Pneumocystis mtLSU rRNA gene PCR and sequencing. With this PCR, detection and discrimination of all known Pneumocystis spp. in a single step should be possible. This first detection of Pneumocystis spp. in 29/62 (46.8%) red foxes and 29/37 (78.4%) raccoon dogs indicated, that they harbour two dissimilar strains, as seen by specific single nucleotide position changes (SNPs). Nevertheless, five samples with contrary SNPs showed a probable inter-species transmission.     

Association of bovine respiratory syncytial virus with atypical interstitial pneumonia in feedlot cattle

Thirty-three cattle with fatal respiratory tract disease were examined for gross and histologic lesions and for the presence of viral and bacterial agents in the lungs. Fifteen cattle had lesions characteristic of atypical interstitial pneumonia (AIP), and 18 had other respiratory tract diseases, including infectious bovine rhinotracheitis, shipping fever pneumonia, bronchopneumonia, pulmonary abscess, and edema of the trachea. Gross necropsy findings in the cattle with AIP were uncollapsed and emphysematous lungs; histopathologic findings included interstitial edema, thickening of alveolar walls, hyaline membrane formation, and hyperplasia of type-II pneumonocytes. The infective agents found in the lungs of the 33 cattle included bovine respiratory syncytial virus, bovine herpesvirus type 1, Pasteurella sp, mycoplasmas, and Corynebacterium pyogenes. Bovine respiratory syncytial virus was detected by use of immunofluorescence and immunoperoxidase on lung tissue sections; bovine herpesvirus type 1 was detected by these techniques and by isolation of the virus. Bovine respiratory syncytial virus was significantly (P = 0.01) associated with lesions of AIP (11 of 15), compared with those of other respiratory tract diseases (5 of 18).     

Common variable immune deficiency in a Pomeranian with Pneumocystis carinii pneumonia

A Pomeranian dog, 1 year- and 8 month-old neutered female, was presented with persistent respiratory distress and recurrent generalized demodicosis. Physical examination revealed cyanosis, rough respiratory sounds, multifocal alopecia and dermal erosions on the dorsal side of the forelimbs, perineal area and skin around the eyes. A severe diffuse interstitial lung pattern was observed on thoracic radiographs. The blood examination revealed neutrophilia and hypoglobulinemia. Serum immunoglobulin concentrations of IgG and IgA were low. Histopathological examination revealed severe diffuse interstitial pneumonia with Pneumocystis carinii infection. Severe lymphoid depletion was observed in the spleen and other organs with lymphoid follicles consisted mainly of CD3-positive T cells and few cells of B-cell lineage. B-cell hypoplasia with subsequent antibody deficiency was suspected.     

Intestinal spirochetosis in a 21-month-old thoroughbred colt

A 21-month-old Thoroughbred colt showed continuous diarrhea and developmental retardation for 7 months, and was thereafter subjected to euthanasia for necropsy and laboratory examinations. At necropsy, the cecal and colonic mucosae were diffusely rough and hyperemic. Histopathologically, the mucosa and submucosa were edematous and were infiltrated by numerous lymphocytes and macrophages. Meanwhile, three morphological types of Brachyspira antigen-containing spirochetes were found to be numerous in the crypts and in the mucus layer over the epithelium in the cecal and colonic lesions. They were frequently observed in intercellular gaps and in the cytoplasm of degenerative epithelial cells, and in the lamina propria, particularly in cavities around blood vessels. These invasive intestinal spirochetes might be one of pathogens inducing colitis and diarrhea in horses.     

Cryptococcal Pneumonia and Meningitis in a Horse

Gross and microscopic evidence of Cryptococcus neoformans in the lungs and central nervous system of a mature Thoroughbred horse presenting with granulomatous pneumonia and meningitis has been described in this article.     

Detection of respiratory pathogens in porcine lung tissue and lavage fluid

The objective of this study was to compare the detection rate of bacterial agents in bronchoalveolar lavage fluid (BALF), taken without visual control, to that in affected lung tissue obtained from the same pig at necropsy. BALF and affected lung tissue were examined for Mycoplasma hyopneumoniae using PCR, and standard cultural methods were used for Actinobacillus pleuropneumoniae, Bordetella bronchiseptica, Haemophilus parasuis, Pasteurella multocida and Streptococcus suis. All pigs with a history of respiratory symptoms were submitted as live animals for routine diagnostic examination. In each animal the site of lavage, marked by injecting methylene blue, differed from the site of pneumonic lesions. M. hyopneumoniae was detected more frequently in lung tissue than in BALF in cases with moderate or severe lung lesions. The detection rates of M. hyopneumoniae were higher in the BALF of pigs with mild lesions. Cultural examination of BALF was at least as satisfactory as affected lung tissue for detecting B. bronchiseptica, H. parasuis and P. multocida.     

Antibiotics: Their application in veterinary practice

A 3-week-old Thoroughbred colt was presented for weakness and cyanosis. A pansystolic regurgitant murmur and other physical findings suggested that the foal developed pulmonary oedema as a consequence of congenital heart disease. A large atria1 septal defect, a high ventricular septal defect and dysplasia of the atrioventricular valves were visualised echocardiographically. A persistent common atrioventricular canal was observed at necropsy.     

An outbreak of fatal hemorrhagic pneumonia caused by Streptococcus equi subsp. zooepidemicus in shelter dogs

An outbreak of fatal hemorrhagic pneumonia with 70~90% morbidity and 50% mortality occurred in an animal shelter in Yangju, Gyeonggi Province, Korea. Clinically, the affected dogs showed severe respiratory distress within 48 h after arriving in the shelter. The dead were found mainly with nasal bleeding and hematemesis. At necropsy, hemothorax and hemorrhagic pneumonia along with severe pulmonary consolidation was observed, though histopathological analysis showed mainly hemorrhagic bronchopneumonia. Lymphoid depletion was inconsistently seen in the spleen, tonsil and bronchial lymph node. Gram-positive colonies were shown in blood vessels or parenchyma of cerebrum, lung, liver, spleen, and kidney. Also, Streptococcus (S.) equi subsp. zooepidemicus was isolated from the various organs in which the bacterium was microscopically and histologically detected. In addition, approximately 0.9 Kb specific amplicon, antiphagocytic factor H binding protein, was amplified in the bacterial isolates. In this study, we reported an outbreak of canine hemorrhagic bronchopneumonia caused by S. equi subsp. zooepidemicus in an animal shelter in Yangju, Korea.     

Common atrioventricular canal in a foal

A 3-week-old Thoroughbred colt was presented for weakness and cyanosis. A pansystolic regurgitant murmur and other physical findings suggested that the foal developed pulmonary oedema as a consequence of congenital heart disease. A large atrial septal defect, a high ventricular septal defect and dysplasia of the atrioventricular valves were visualised echocardiographically. A persistent common atrioventricular canal was observed at necropsy.     

Rhodococcus equi occipital bone osteomyelitis,septic arthritis and meningitis in a neurological foal

This case report describes a 3‐month‐old female Thoroughbred foal that presented following the acute onset of apparent respiratory distress, abnormal head carriage and severe neurological deficits referable to the brainstem or cranial cervical spinal cord. Ultrasonography revealed an abscessing pneumonia. Radiographs did not show evidence of bony pathology at the atlanto‐occipital region, an area consistent with the observed neurological deficits. With magnetic resonance imaging, atlantal and occipital osteomyelitis, atlanto‐occipital septic arthritis, and atlanto‐axial synovitis were diagnosed. Brainstem meningitis and extradural compression were also revealed. Culture of the right occipitoatlantal joint and cerebrospinal fluid yielded a pure culture of Rhodococcus equi. These findings and multifocal R. equi abscessation were confirmed at necropsy.     

Scedosporium prolificans infection associated with arthritis and osteomyelitis in a horse

Scedosporium prolificans was associated with arthritis and degenerative osteomyelitis in a 6-year-old Thoroughbred racehorse. The horse was suspected to have an inflammatory lesion of the interosseous tendon, but treatment had resulted in only a minimal response. Shortly after diagnostic arthrocentesis of the left metacarpophalangeal joint was performed, the joint became severely swollen, and radiography of the area revealed lysis of the distal end of the third metacarpal bone, the proximal sesamoid bones, and the proximal end of the proximal phalanx. The horse did not respond to treatment and was euthanatized. At necropsy, severe erosive arthritis and degenerative osteomyelitis of the left metacarpophalangeal joint were seen. Swab specimens of the ulcerated lesions of the articular cartilage were submitted for microbial culture, and Scedosporium prolificans was isolated. Scedosporium prolificans is a newly recognized opportunistic fungal pathogen of humans and animals. In humans, S prolificans typically causes focal locally invasive infections that primarily involve musculoskeletal tissues; most often, infection is a result of penetrating trauma or surgical incision. In immunocompromised patients, fatal disseminated infection can occur. The fungus is resistant to almost all currently available antimycotic agents.     

Corynebacterium equi Infections in Horses, 1958-1984: A Review of 131 Cases

Of 131 cases of Corynebacterium equi infection in horses submitted for necropsy to the Ontario Veterinary College or Veterinary Laboratory Services, OMAF, Guelph, Ontario from 1958 to 1984, 115 were diagnosed as suppurative pneumonia, and of these 55 had associated ulcerative enterocolitis. Only five animals had intestinal involvement without pulmonary lesions. The remaining 11 cases included arthritis/cellulitis, skin abscesses and submandibular lymphadenitis. While the lung, intestine and associated lymph nodes yielded C. equi most frequently, in 21% of cases C. equi was also cultured from parenchymatous organs (spleen, liver or kidney) or blood. Corynebacterium equi infection accounted for 10% of all foals submitted for postmortem examination and 45% of all foals with pneumonia. Affected foals were one to four months of age. Submissions occurred between the months of May and August with a peak during July. There was a significantly greater prevalence of C. equi infection in Standardbreds when compared with other breeds. Of foals in this study, 36% were from farms which had had other horses succumb to this disease. Of the foals with pulmonary involvement, 21% did not have fever or clinical signs referable to the respiratory or gastrointestinal systems, findings which indicated that a large percentage of cases were subclinical.     

Differences in phagocytosis susceptibility in Haemophilus parasuis strains

Haemophilus parasuis is a colonizer of the upper respiratory tract of healthy pigs, but virulent strains can cause a systemic infection characterized by fibrinous polyserositis, commonly known as Glässer’s disease. The variability in virulence that is observed among H. parasuis strains is not completely understood, since the virulence mechanisms of H. parasuis are largely unknown. In the course of infection, H. parasuis has to survive the host pulmonary defences, which include alveolar macrophages, to produce disease. Using strains from different clinical backgrounds, we were able to detect clear differences in susceptibility to phagocytosis. Strains isolated from the nose of healthy animals were efficiently phagocytosed by porcine alveolar macrophages (PAM), while strains isolated from systemic lesions were resistant to this interaction. Phagocytosis of susceptible strains proceeded through mechanisms independent of a specific receptor, which involved actin filaments and microtubules. In all the systemic strains tested in this study, we observed a distinct capsule after interaction with PAM, indicating a role of this surface structure in phagocytosis resistance. However, additional mechanisms of resistance to phagocytosis should be explored, since we detected different effects of microtubule inhibition among systemic strains.     

Cricopharyngeal-laryngeal dysplasia in a horse with sudden clinical onset idiopathic laryngeal hemiparesis

A 7-year-old Thoroughbred racehorse developed loud exercise-related respiratory noises and exercise intolerance over a short period. Examination showed congenital cricopharyngeal-laryngeal dysplasia (rostral displacement of the palatopharyngeal arch) and also left sided idiopathic laryngeal hemiparesis, the latter appearing to be of recent clinical onset. The animal developed colic some months after laryngeal surgery and a nephrosplenic entrapment was surgically corrected. Aerophagia and regurgitation worsened after surgery and, after developing inhalation pneumonia, the animal was destroyed. Post-mortem examination confirmed the presence of idiopathic laryngeal hemiparesis and of cricopharyngeal-laryngeal dysplasia which had some previously undescribed laryngeal muscle abnormalities.