Extent Of Lung Lesions Research Articles

Relationship between imaging-derived parameters and circulating microRNAs to study the degree of lung involvement in hospitalized geriatric patients with COVID-19 pneumonia.

Chest computed tomography (CT) scan is useful to evaluate the type and extent of lung lesions in coronavirus disease 2019 (COVID-19) pneumonia. This study explored the association between radiological parameters and various circulating serum-derived markers, including microRNAs, in older patients with COVID-19 pneumonia. A retrospective analysis was designed to study geriatric patients (≥75 years) with COVID-19 pneumonia, who underwent chest CT scan on admission, and for whom clinical data and serum samples were obtained. To quantify the extent of lung involvement, CT-score, the percentage of healthy lung (HL%), the percentage of ground glass opacity (GGO%),and the percentage of lung consolidation were assessed using computer-aided tools. The association of these parameters with two circulating microRNAs, miR-483-5p and miR-320b, previously identified as biomarkers of mortality risk in COVID-19 geriatric patients, was tested. A total of 73 patients with COVID-19 pneumonia were evaluable (median age 85 years; interquartile range 82-90 years). Among chest CT-derived parameters, thepercentage of lung consolidation (HR 1.08, 95% CI 1.02-1.14), CT-score (HR 1.14, 95% CI 1.03-1.25), and HL% (HR 0.97, 95% CI 0.95-0.99) emerged as significant predictors of mortality, whereas non-significant trends toward increased mortality were observed in patients with higher GGO%. We also found a significant positive association between serum miR-483-5p and GGO% (correlation coefficient 0.28; P = 0.018) and a negative association with HL% (correlation coefficient -0.27; P = 0.023). Overall, the extent of lung consolidation can be confirmed as a prognostic parameter of COVID-19 pneumonia in older patients. Among various serum-derived markers, miR-483-5p can help in exploring the degree of lung involvement, due to its association with higher GGO% and lower HL%. Geriatr Gerontol Int 2024; ••: ••-••.

Montelukast Influence on Lung in Experimental Diabetes.

Background and Objectives: The influence of montelukast (MK), an antagonist of cysLT1 leukotriene receptors, on lung lesions caused by experimental diabetes was studied. Materials and Methods: The study was conducted on four groups of six adult male Wistar rats. Diabetes was produced by administration of streptozotocin 65 mg/kg ip. in a single dose. Before the administration of streptozotocin, after 72 h, and after 8 weeks, the serum values of glucose, SOD, MDA, and total antioxidant capacity (TAS) were determined. After 8 weeks, the animals were anesthetized and sacrificed, and the lungs were harvested and examined by optical microscopy. Pulmonary fibrosis, the extent of lung lesions, and the lung wet-weight/dry-weight ratio were evaluated. Results: The obtained results showed that MK significantly reduced pulmonary fibrosis (3.34 ± 0.41 in the STZ group vs. 1.73 ± 0.24 in the STZ+MK group p < 0.01) and lung lesion scores and also decreased the lung wet-weight/dry-weight (W/D) ratio. SOD and TAS values increased significantly when MK was administered to animals with diabetes (77.2 ± 11 U/mL in the STZ group vs. 95.7 ± 13.3 U/mL in the STZ+MK group, p < 0.05, and 25.52 ± 2.09 Trolox units in the STZ group vs. 33.29 ± 1.64 Trolox units in the STZ+MK group, respectively, p < 0.01), and MDA values decreased. MK administered alone did not significantly alter any of these parameters in normal animals. Conclusions: The obtained data showed that by blocking the action of peptide leukotrienes on cysLT1 receptors, montelukast significantly reduced the lung lesions caused by diabetes. The involvement of these leukotrienes in the pathogenesis of fibrosis and other lung diabetic lesions was also demonstrated.

Concordance between transbronchial lung cryobiopsy and surgical lung biopsy in patients with idiopathic multicentric Castleman disease: A report of four cases

BackgroundIdiopathic multicentric Castleman disease (iMCD) is a rare polyclonal lymphoproliferative disease often associated with pulmonary involvement. Recently, transbronchial lung cryobiopsy (TBLC) has been reported to be useful for the diagnosis of diffuse interstitial lung disease. However, there have been no reports of pathological assessment of TBLC for iMCD. MethodTo clarify the efficacy of TBLC in the diagnosis of iMCD, we retrospectively reviewed four iMCD patients who had undergone both TBLC and surgical lung biopsy (SLB). ResultsThe median age was 44 years; 2 males and 2 females. Two or three TBLC specimens were taken from each patient. All patients had no complications other than minimal bleeding. The size of the TBLC specimens was approximately 5–6 × 3–4 mm, and the alveolar region, and centrilobular and perilobular areas were adequately sampled. As with SLB, the extent of lung lesions and inflammatory cell infiltration could be sufficiently evaluated by TBLC. The presence of lymphoid follicles could also be assessed by TBLC; however, the germinal centers with lymphoid follicles were difficult to evaluate. The TBLC specimens could also be evaluated for immunostaining, especially IgG4 immunostaining, to rule out IgG4-related lung disease. Pulmonary pathological grading showed a high concordance rate between major pathological findings of TBLC and SLB. The pathologist's confidence level of TBLC for the diagnosis of iMCD was high in all cases. ConclusionsTBLC exhibits a high concordance rate with SLB in the pathological evaluation of iMCD, which may be useful for the diagnosis of iMCD.

Evaluation of Antiviral Activity of Ivermectin against Infectious Bovine Rhinotracheitis Virus in Rabbit Model.

Infectious bovine rhinotracheitis (IBR) caused by bovine herpes virus 1 (BoHV-1) can lead to enormous economic losses in the cattle industry. Vaccine immunization is preferentially used to decrease its transmission speed and resultant clinical signs, rather than to completely stop viral infection. Therefore, a drug effective in treating IBR is urgently needed. Our previous work demonstrated that ivermectin significantly inhibited viral replication in a cell infection model. This study aimed to investigate its antiviral effects in vivo by using a rabbit infection model. The viral inhibition assay was first used to confirm that ivermectin at low concentrations (6-25 nM) could reduce viral titers (TCID50) significantly (p < 0.001) at 24 h post-infection. In rabbits, ivermectin was administrated with one to three doses, based on the recommended anti-parasite treatment dosage (0.2 mg/kg bodyweight) through subcutaneous injection at different days post-infection in the treated IBRV infection groups, while non-treated infection group was used as the control. The infected rabbits showed hyperthermia and other clinical signs, but the number of high-fever rabbits in the ivermectin treatment groups was significantly lower than that in the non-treated infection group. Furthermore, in ivermectin treatment groups, the cumulative clinical scores correlated negatively with drug doses and positively with delay of administration time post-infection. The overall nasal shedding time in ivermectin-treated groups was two days shorter than the non-treated challenge group. At the same time point, the titer of neutralizing antibodies in the treatment group with triple doses was higher than the other two-dose groups, but the difference between the treatment groups decreased with the delay of drug administration. Correspondingly, the serious extent of lung lesions was negatively related to the dosage, but positively related to the delay of drug administration. The qPCR with tissue homogenates showed that the virus was present in both the lung tissues and trigeminals of the infected rabbits. In conclusion, ivermectin treatment had therapeutic effect by decreasing clinical signs and viral shedding, but could not stop virus proliferation in lung tissues and trigeminals.

Association between Enzootic Pneumonia-like Lung Lesions and Carcass Quality and Meat pH Value in Slaughter Pigs.

Although the prevalence of respiratory diseases in slaughter pigs ranges from 19% to 74% and continues to be an important concern for swine herds worldwide, only a few studies have investigated the relationship between respiratory disease and pork quality. The general aim of this study was to investigate associations between the prevalence and severity of enzootic pneumonia-like lesions in Polish slaughter pigs on different carcass and meat-quality characteristics at the animal and herd levels. The average prevalence of bronchopneumonic lungs with different degrees of lesions was 94.57%. The majority of lesions indicated the acute stage of enzootic pneumonia. Our results indicate a statistically significant interaction between the mean weight of carcasses depending on the extent of the lesions (p = 0.04) at the animal level. The correlation between meatiness and severity of lung lesions was r = -0.25 (p = 0.00). The correlation between the extent of lung lesions and pH45 value was r = -0.17 (p = 0.005) on the animal level and r = -0.63 (p = 0.017) at the herd level. This implies that lung lesions in slaughter pigs negatively influence not only animal health and welfare, but also carcass quality.

Comparative characteristics new cases of respiratory tuberculosis among HIV infected patients in consideration of detecting ways

The aim of the study: to compare clinical and X-rays characteristics respiratory tuberculosis identified by screening or uptake with complains among HIV infect-ed patients. Materials and methods. Research includ-ed all new cases of respiratory tuberculosis among HIV infected patients of Leningrad district from 2014 to 2016 years. Patients had been identified by two ways: uptake with complaints and screening. Statistical evalu-ation of groups by tuberculosis signs was carried out: du-ration of HIV infection, severity of immunosuppression, extent of lung lesions, cavitations, increased lymph nodes, positive sputum smears or positive sputum cultural for tuberculosis, clinical forms and mortality during the first year treatment. Results. There are 852 HIV/TB patients included in the research. According to these ways all patients separated in two groups: pa-tients with complaints contain 454 persons (53,3%) and patients detected by screening 398 persons (46,7%). Conclusion. Our research showed that there are no any significant difference between HIV/TB patients identi-fied by these ways (by screening or uptake with com-plains) when comparing on using these tuberculosis signs.

Usefulness of Hospital Admission Chest X-ray Score for Predicting Mortality and ICU Admission in COVID-19 Patients.

We aimed to investigate the performance of a chest X-ray (CXR) scoring scale of lung injury in prediction of death and ICU admission among patients with COVID-19 during the 2021 peak pandemic in HCM City, Vietnam. CXR and clinical data were collected from Vinmec Central Park-hospitalized patients from July to September 2021. Three radiologists independently assessed the day-one CXR score consisting of both severity and extent of lung lesions (maximum score = 24). Among 219 included patients, 28 died and 34 were admitted to the ICU. There was a high consensus for CXR scoring among radiologists (κ = 0.90; CI95%: 0.89–0.92). CXR score was the strongest predictor of mortality (tdAUC 0.85 CI95% 0.69–1) within the first 3 weeks after admission. A multivariate model confirmed a significant effect of an increased CXR score on mortality risk (HR = 1.33, CI95%: 1.10 to 1.62). At a threshold of 16 points, the CXR score allowed for predicting in-hospital mortality and ICU admission with good sensitivity (0.82 (CI95%: 0.78 to 0.87) and 0.86 (CI95%: 0.81 to 0.90)) and specificity (0.89 (CI95%: 0.88 to 0.90) and 0.87 (CI95%: 0.86 to 0.89)), respectively, and can be used to identify high-risk patients in needy countries such as Vietnam.

Automated quantification of COVID-19 pneumonia severity in chest CT using histogram-based multi-level thresholding segmentation

BackgroundChest computed tomography (CT) has proven its critical importance in detection, grading, and follow-up of lung affection in COVID-19 pneumonia. There is a close relationship between clinical severity and the extent of lung CT findings in this potentially fatal disease. The extent of lung lesions in CT is an important indicator of risk stratification in COVID-19 pneumonia patients. This study aims to explore automated histogram-based quantification of lung affection in COVID-19 pneumonia in volumetric computed tomography (CT) images in comparison to conventional semi-quantitative severity scoring. This retrospective study enrolled 153 patients with proven COVID-19 pneumonia. Based on the severity of clinical presentation, the patients were divided into three groups: mild, moderate and severe. Based upon the need for oxygenation support, two groups were identified as follows: common group that incorporated mild and moderate severity patients who did not need intubation, and severe illness group that included patients who were intubated. An automated multi-level thresholding histogram-based quantitative analysis technique was used for evaluation of lung affection in CT scans together with the conventional semi-quantitative severity scoring performed by two expert radiologists. The quantitative assessment included volumes, percentages and densities of ground-glass opacities (GGOs) and consolidation in both lungs. The results of the two evaluation methods were compared, and the quantification metrics were correlated.ResultsThe Spearman’s correlation coefficient between the semi-quantitative severity scoring and automated quantification methods was 0.934 (p < 0.0001).ConclusionsThe automated histogram-based quantification of COVID-19 pneumonia shows good correlation with conventional severity scoring. The quantitative imaging metrics show high correlation with the clinical severity of the disease.

Changes in the levels of some cytokines when using blood purification in COVID-19 patients

The use of high-adsorption membrane hemofiltration in COVID-19 positive patients to reduce the severity of a cytokine storm is clearly beneficial but at the same time, there are no certain procedures for its practical use.The objective:to study the change in the levels of IL-6 and IL-18 in response to prolonged (24-72 hours) high-adsorption membrane hemofiltration.Subjects and methods. We retrospectively analyzed the data on IL-6 and IL-18 levels and their changes in 69 patients who were COVID-19 positive and had different degrees of lung damage, they had received high-adsorption membrane hemofiltration during their stay at the intensive care unit. The extent of lung lesions was the following: 4 people had CT-2, 44 people had CT-3, and 21 patients had CT-4. 18 patients had an unfavorable outcome of the disease. High-adsorption membrane hemofiltration (Prismaflex) was used in the group of patients who had clinical signs of the rapid progression of the disease and also such laboratory findings as elevated values of C-reactive protein (above 100 mg/L), ferritin (more than 600 μg/L), and progression of lymphopenia. This intervention lasted for 24 hours at CT-2/3, and 48 hours at CT-4. The effluent dose was 30.0 ± 6.4 ml/kg/h. The levels of IL-6, IL-18, and procalcitonin were tested before and after the completion of the intervention, and the difference between their concentration before and after high-adsorption membrane hemofiltration was calculated. The potential association between received data (IL-6, IL-18, delta of IL-6, delta of IL-18) and degree of lung damage and outcomes was analyzed.Results.It was detected that the more the lungs were affected, the lower levels of IL-6 and IL-18 were and vice versa and this correlation was not associated with the use of tocilizumab (used in 44 people). The maximum decrease in the level of cytokines was observed in the group of patients with CT-2. There was a significant association between the delta of IL-6 (F = 6.69; p ≤ 0.05) and the outcome which was especially pronounced in people with a favorable outcome.Conclusion.As the inflammation progresses in the lungs, the levels of IL-6 and IL-18 decrease which may be a manifestation of the depletion of the cytokine storm. The use of prolonged high-adsorption membrane hemofiltration (24-48 h) allows reducing the level of cytokines. The delta value reflects a decrease in IL-6 concentration, it significantly correlates with the outcome which indicates the importance of using this method in a continuous mode.

Identification, Monitoring, and Prediction of Disease Severity in Patients with COVID-19 Pneumonia Based on Chest Computed Tomography Scans: A Retrospective Study.

Background and Aims Non-contrast chest computed tomography (CT) scans can accurately evaluate the type and extent of lung lesions. The aim of this study was to investigate the chest CT features associated with critical and non-critical patients with coronavirus disease 2019 (COVID-19). Methods A total of 1078 patients with COVID-19 pneumonia who underwent chest CT scans, including 169 critical cases and 909 non-critical cases, were enrolled in this retrospective study. The scans of all participants were reviewed and compared in two groups of study. In addition, the risk factors associated with disease in critical and non-critical patients were analyzed. Results Chest CT scans showed bilateral and multifocal involvement in most (86.4%) of the participants, with 97.6 and 84.3% reported in critical and non-critical patients, respectively. The incidences of pure consolidation (p=0.019), mixed ground-glass opacities (GGOs) and consolidation (p<0.001), pleural effusion (p<0.001), and intralesional traction bronchiectasis (p=0.007) were significantly higher in critical compared to non-critical patients. However, non-critical patients showed higher incidence of pure GGOs than the critical patients (p<0.001). Finally, the total opacity scores of the critical patients were significantly higher than those of non-critical patients (13.71±6.26 versus 4.86±3.52, p<0.001), with an area under the curve of 0.91 (0.88-0.94) for COVID-19 detection. Conclusions Our results revealed that the chest CT examination was an effective means of detecting pulmonary parenchymal abnormalities in the natural course of COVID-19. It can distinguish the critical patients from the non-critical patients (AUC=0.91), which is helpful for the judgment of clinical condition and has important clinical value for the diagnosis and follow-up of COVID-19 pneumonia.

Impacts of Mycoplasma loads and lung lesions on immune and hematological statuses of pigs in an eight-breed cross heterogeneous population.

Developments of pulmonary diseases, often accompanied by infections of bacteria, severely affect the meat production and welfare of pigs. This study investigated 307 pigs at age of 240 d from an eight-breed cross reared under standardized housing conditions for associations among the extent of lung lesions, bacteria load inferred from 16S rRNA sequencing of bronchoalveolar lavage fluid, as well as 57 immune cells and 25 hematological traits. We showed that the pigs under study suffered substantial and varied lung lesions, and the Mycoplasma is the most associated bacteria genera. At a false discovery rate of 0.05 (FDR < 0.05), the severity of lung lesions were significantly associated with greater CD8+ to CD3+ cell ratio, neutrophil-to-lymphocyte ratio (NLR), and standard deviation of red blood cell volume distribution width (RDW-SD), and lower CD4-CD8-/CD3+, CD3+CD4-CD8-/PBMCs (peripheral blood mononuclear cells) and CD14-CD16-/PBMCs cell ratios, mean corpuscular hemoglobin concentration, lymphocyte count, and lymphocyte count percentage, reflecting an status of inflammation, immune suppression, and hypoxia of the pigs accompanying the progression of the lung lesions. The Mycoplasma abundance showed positive correlations with neutrophil count, neutrophil count percentage, NLR, monocyte count, coefficient of variation in red blood cell volume distribution width , and RDW-SD, and negative correlations with mean corpuscular hemoglobin concentration, lymphocyte count, and lymphocyte count percentage; these correlations are largely consistent with those of lung lesions, supporting the comorbidity of lung lesions and Mycoplasma infection. We also observed nonlinear associations that sharp increases in neutrophil count and neutrophil count percentage occurred only when Mycoplasma abundance raised above the population-average level. The results provide helpful insights into the changes of host immune status in response to Mycoplasma relevant lung diseases in pigs.

High-resolution Chest CT Features and Clinical Characteristics of Patients Infected with COVID-19 in Jiangsu, China

BackgroundA pneumonia associated with the coronavirus disease 2019 (COVID-19) recently emerged in China. It was recognized as a global health hazard. Methods234 inpatients with COVID-19 were included. Detailed clinical data, chest HRCT basic performances and certain signs were recorded Ground-glass opacity (GGO), consolidation, fibrosis and air trapping were quantified. Both clinical types and CT stages were evaluated. ResultsMost patients (approximately 90%) were classified as common type and with epidemiologic history. Fever and cough were main symptoms. Chest CT showed abnormal attenuation in bilateral multiple lung lobes, distributed in the lower and/or periphery of the lungs (94.98%), with multiple shapes. GGO and vascular enhancement sign were most frequent seen, followed by interlobular septal thickening and air bronchus sign as well as consolidation, fibrosis and air trapping. There were significant differences in most of CT signs between different stage groups. The SpO2 and OI were decreased in stage IV, and the CT score of consolidation, fibrosis and air trapping was significantly lower in stage I (P<0.05). A weak relevance was between the fibrosis score and the value of PaO2 and SpO2 (P<0.05). ConclusionsClinical performances of patients with COVID-19, mostly with epidemiologic history and typical symptoms, were critical valuable in the diagnosis of the COVID-19. While chest HRCT provided the distribution, shape, attenuation and extent of lung lesions, as well as some typical CT signs of COVID-19 pneumonia.

Sex influences the association between haemostasis and the extent of lung lesions in tuberculosis

BackgroundWorldwide tuberculosis (TB) reports show a male bias in morbidity; however, the differences in pathogenesis between men and women with TB, as well as the mechanisms associated with such differences, are poorly investigated. We hypothesized that comparison of the degree of lung injury and clinical indices of well-matched men and women with newly diagnosed TB, and statistical analysis of the correlation between these indices and the extent of lung lesions, can provide insights into the mechanism of gender bias in TB.MethodsWe evaluated the acid-fast bacilli grading of sputum samples and compiled computed tomography (CT) data of the age-matched, newly diagnosed male and female TB patients without history of smoking or comorbidities. Inflammatory biomarker levels and routine haematological and coagulation-associated parameters were compared. Binary logistic regression analysis was used to define the association between the indices and lung lesions, and the influence of sex adjustment.ResultsWomen with TB have a longer delay in seeking healthcare than men after onset of the TB-associated symptoms. Men with TB have significantly more severe lung lesions (cavities and healing-associated features) and higher bacterial counts compared to women with TB. Scoring of the CT images before and after anti-TB treatment showed a faster response to therapy in women than in men. Coagulation- and platelet-associated indices were in models from multivariate regression analysis with groups of males or females with TB or in combination. In univariate regression analysis, lower lymphocyte counts were associated with both cavity and more bacterial counts, independent of sex, age and BMI. The association of international normalized ratios (INR), prothrombin times (PTs), mean platelet volumes (MPVs) and fibrinogen (FIB) level with lung lesions was mostly influenced by sex adjustment.ConclusionsSex influences the association between haemostasis and extent of TB lung lesions, which may be one mechanism involved in sex bias in TB pathogenesis.

Efficacy of a one-shot marbofloxacin treatment on acute pleuropneumonia after experimental aerosol inoculation of nursery pigs

BackgroundPorcine pleuropneumonia, caused by Actinobacillus pleuropneumoniae, is a bacterial respiratory disease of swine. Acute outbreaks of the disease are often accompanied by high mortality and economic losses. As severe cases of the disease frequently require parenteral antibiotic treatment of the animals, the efficacy of a single, high dose of marbofloxacin was compared to a three-time application of a dose of enrofloxacin under experimental conditions.MethodsA blinded, controlled, randomized and blocked dose confirmation study was conducted to test the efficacy and safety of a single dose of 8 mg/kg marbofloxacin (160 mg/ml, Forcyl® Swine, Vetoquinol SA, France) to treat acute porcine pleuropneumonia after experimental aerosol inoculation of pigs with A. pleuropneumoniae serotype 2. The results were compared to a three consecutive day treatment of 2.5 mg/kg enrofloxacin and a mock (saline) treatment. Criteria for the assessment of efficacy were severity of lung lesions, bacteriological cure and the course of clinical disease after treatment.Results:Thirty six nursery pigs were divided into three treatment groups: marbofloxacin (T1), enrofloxacin (T2) and mock (T3). Statistically significant superiority (p < 0.05) of marbofloxacin and enrofloxacin compared to the mock-treated group was demonstrated for all efficacy criteria. The need of rescue euthanasia due to severity of symptoms was significantly reduced in both treatment groups (T1: 1 pig; T2: 0 pigs; vs. T3: 8 pigs). On day 6 after treatment initiation, clinical cure was observed in 10 (T1), 10 (T2) but only 1 of the piglets in T3. Extent of lung lesions (mean of lung lesion score T1: 3.9, T2: 6.0, T3: 21.1) and bacteriological isolation from lung tissue (on day 6 after treatment initiation: T1 = 0 pigs; T2 = 1 pig; T3 = all pigs) were also significantly reduced within both treatment groups. There were no adverse events linked to the drug administration and no injection site reactions were observed.ConclusionsBoth applied antimicrobial treatments were proven safe and efficacious for the treatment of acute porcine pleuropneumonia. No statistically significant differences were detected between the antibiotic treatments.

Field study on the safety and efficacy of intradermal versus intramuscular vaccination against Mycoplasma hyopneumoniae

The present study compares the safety and efficacy of a needle-free, intradermal Mycoplasma hyopneumoniae vaccine to an intramuscular one. 420 piglets (21+3 days of age) were randomly assigned to two...

A Bovine Model of Respiratory Chlamydia psittaci Infection: Challenge Dose Titration

This study aimed to establish and evaluate a bovine respiratory model of experimentally induced acute C. psittaci infection. Calves are natural hosts and pathogenesis may resemble the situation in humans. Intrabronchial inoculation of C. psittaci strain DC15 was performed in calves aged 2–3 months via bronchoscope at four different challenge doses from 106 to 109 inclusion-forming units (ifu) per animal. Control groups received either UV-inactivated C. psittaci or cell culture medium. While 106 ifu/calf resulted in a mild respiratory infection only, the doses of 107 and 108 induced fever, tachypnea, dry cough, and tachycardia that became apparent 2–3 days post inoculation (dpi) and lasted for about one week. In calves exposed to 109 ifu C. psittaci, the respiratory disease was accompanied by severe systemic illness (apathy, tremor, markedly reduced appetite). At the time point of most pronounced clinical signs (3 dpi) the extent of lung lesions was below 10% of pulmonary tissue in calves inoculated with 106 and 107 ifu, about 15% in calves inoculated with 108 and more than 30% in calves inoculated with 109 ifu C. psittaci. Beside clinical signs and pathologic lesions, the bacterial load of lung tissue and markers of pulmonary inflammation (i.e., cell counts, concentration of proteins and eicosanoids in broncho-alveolar lavage fluid) were positively associated with ifu of viable C. psittaci. While any effect of endotoxin has been ruled out, all effects could be attributed to infection by the replicating bacteria. In conclusion, the calf represents a suitable model of respiratory chlamydial infection. Dose titration revealed that both clinically latent and clinically manifest infection can be reproduced experimentally by either 106 or 108 ifu/calf of C. psittaci DC15 while doses above 108 ifu C. psittaci cannot be recommended for further studies for ethical reasons. This defined model of different clinical expressions of chlamydial infection allows studying host-pathogen interactions.

Proinflammatory cytokine expression in prrsv infection: paracrine synthesis and correlation with the extent of lung lesions

Proinflammatory cytokine expression in prrsv infection: paracrine synthesis and correlation with the extent of lung lesions

The comparative pathogenicity of strains of eight serovars and untypable strains of Mannheimia haemolytica in experimental pneumonia of sheep

The experimental induction of pneumonic pasteurellosis in groups of conventionally reared lambs by 8 serovars (A1, A2, A6, A7, A8, A9, T10, and A11) and untypable (UT) strains of Mannheimia haemolytica (Mh) were examined and compared. The groups of lambs were inoculated intratracheally with 1.4 x 10(8) +/- 0.6 x 10(8) (mean +/- SD) colony-forming units of the Mh serovars or UT isolates in the 6-hour log phase of growth. The variables measured as indicators of disease severity were clinical score, percentage lung consolidation and microbiological re-isolation. The clinical parameters for each group were computed daily for 6 days post infection and the lambs which died were necropsied while the remaining lambs were killed on day 7 pi and the extent of lung consolidation was measured. Clinically, the mean scores for the M. haemolytica serovars were A1 (6.1), A2 (18.8), A6 (0.5), A7 (17.4) and A9 (8.5). The mean percent lung lesion scores for M. haemolytica serovars were A1 (12.5), A2 (66.3), A6 (5.0), A7 (51.3), A9 (33.8) and A11 (2.5). The percent mean pneumonic lung lesions recorded for groups inoculated with A2, A7 and A9 were significantly (P < 0.05) higher than the extent of lung lesions in the other groups. A statistically significant correlation was observed between clinical scores and the severity of the lung lesions (r = 0.96, P < 0.01). High titres of M. haemolytica were recovered from lung lesions, with 10 to 100 times the number of organisms inoculated being present in the lung lesions of lambs inoculated with serovars A2 and A7. These data indicate that although M. haemolytica serovars A1, A2, A6, A7, A9 and A11 are important primary lung pathogens of lambs, serovars A2, A7, and A9 are to be regarded as highly virulent strains that have a greater predilection than the other serovars for causing pneumonia in lambs.

No simple association between time elapsed from seroconversion until slaughter and the extent of lung lesions in Danish swine

The association between the extent of pathological lung lesions at slaughter and the time elapsed from seroconversion to slaughter was examined in a longitudinal study including 830 pigs from eight herds. Pigs from an age of 3 weeks were bled every fourth week, and the sera were analyzed for the presence of antibodies to Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae serotypes 2, 5, 6, 7 and 12. At slaughter, the extent of mycoplasma-like catharral pneumonia, chronic pleuritis (dorso-caudal and ventro-cranial), interlobular-scar retractions, acute pleuropneumonia and chronic pleuropneumonia was recorded. Poisson regression was used to model the relationship between time elapsed from seroconversion to slaughter (divided into 4-week intervals) and extent of lesions, including “age at slaughter” and “gender” as independent variables and “litter” as an explanatory random variable. Analysis was only performed on lesions which had a prevalence >20% in at least five of the herds (mycoplasma-like catharral pneumonia, ventro-cranial and dorso-caudal pleuritis). Only a few consistent statistical associations were revealed across herds. Pigs seroconverting to M. hyopneumoniae close to slaughter expressed the largest extent of mycoplasma-like catharral pneumonia, and early seroconversion to M. hyopneumoniae was related to large ventro-cranial pleuritic lesions. In these eight herds, recording of the extent of pathological lung lesions at slaughter at most yielded insight into the within-herd epidemiologic dynamics of M. hyopneumoniae — and not to any of the serotypes of A. pleuropneumoniae.

The Effect of Pasteurella haemolytica A2 Infection on Phagocytosis Efficiency of Caprine Broncho-Alveolar Macrophages

An experiment was designed to study the in vivo effect of Pasteurella haemolytica A2 infection on the phagocytosis activity of caprine broncho-alveolar macrophages and the extent of pneumonic lesions. Twelve healthy local Kacang goats, about 7 months of age, were divided into two groups of six. Goats in group 1 were inoculated intratracheally with 4 ml inoculum containing 2.8 x 10(9) colony-forming units (CFU)/ml of Staphylococcus aureus. Goats in group 2 were inoculated intratracheally with 4 ml of inoculum containing 9.5 x 10(8) CFU/ml of Pasteurella haemolytica A2 isolated earlier from pneumonic lungs of goat. At intervals of 3 and 7 days post-challenge five goats from each group were killed and the lungs were washed with sterile phosphate-buffered saline. Smears were prepared from the lung washing fluid and the number of macrophages with phagocytic activity was determined. At day 3 post-infection, goats of both groups showed a similar pattern of pneumonic lesion. The lung washing fluid of goats in group 2 was found to contain numerous neutrophils and macrophages. Goats in group 2 showed significantly (P < 0.05) higher extent of lung lesions than group 1. Similarly, the average extent of lung lesions was significantly (P < 0.05) more severe in group 2 at day 7 post-infection. The lung washing fluid contained mostly macrophages. The phagocytic activity following S. aureus infection was more efficient and significantly (P < 0.01) higher compared with infection by P. haemolytica A2. There were weak correlations between the extent of pneumonic lesion and the phagocytic activity. Thus, goats with poor phagocytic activity were likely to develop more extensive lung lesions.