Seroprevalence and risk factors associated with Chlamydophila spp. infection in ewes in the northeast of Algeria

A cross-sectional study was carried out to estimate prevalence of Chlamydophila spp. antibodies and to investigate risk factors associated with chlamydial infection in 552 ewes between March 2011 and January 2012 in the province of Constantine. Anti-Chlamydophila antibodies were detected using an indirect enzyme-linked immunosorbent assay kit in 24.5 % of examined sera. Of the herds, 70.4 % had at least one seropositive animal. A pretested structured questionnaire was administered in order to collect information on individual animal health and herd management practices. Chi-square analysis and multivariable logistic regression model were used to identify risk factors related to Chlamydophila seropositivity. Univariable analysis revealed 17 variables with p?<?0.25 that were offered to the multivariable logistic regression model which in turn identified 12–23 months age group (OR?=?5.903, 95 % CI (OR)?=?1.690; 20.618) and not using disinfectants (OR?=?2.099, 95 % CI (OR)?=?1.314; 8.065) as risk factors for Chlamydophila spp. seropositivity. Moreover, occurrence of stillbirth problem (OR?=?3.682, 95 % CI (OR)?=?1.825; 7.430) and 5–10 % mortality rate in young lambs (OR?=?2.584, 95 % CI (OR)?=?1.058; 6.310) were significantly associated with seropositivity to Chlamydophila spp. On the other hand, availability of veterinary service was identified as a protective factor (OR?=?0.161, 95 % CI (OR)?=?0.051; 0.511).     

Stabling is associated with airway inflammation in young Arabian horses

We examined the effect of stabling on upper and lower airway inflammation in 14 yearling Arabian horses that had been at pasture since birth. Horses were divided into 2 groups of 7. One group was stabled for 3 months and the other remained at pasture. The groups were then switched over for another 3 months. The nasopharynx, guttural pouches and trachea were examined endoscopically and bronchoalveolar lavage performed every month. An upper airway inflammation score was devised based on the magnitude of pharyngeal lymphoid hyperplasia and guttural pouch inflammation. During stabling this score remained constant, whereas it decreased during the 3 months at pasture. Stabling was also associated with a higher number and percentage of neutrophils in bronchoalveolar lavage fluid and with a smaller percentage of lymphocytes. There was no correlation between upper airway inflammation score and bronchoalveolar lavage cytology. During a nasal occlusion test, dorsal displacement of the soft palate occurred more times in stabled than in pastured horses, but this was heavily biased by the results from one animal. We conclude that stabling is associated with inflammation of both the upper and lower airway of young horses.     

Experimental infection of calves with respiratory syncytial virus.

Three bovine isolates and one human isolate of RS virus were given intranasally to gnotobiotic, colostrum-deprived and conventional calves. All isolates produced a biphasic pyrexia associated with a serous nasal discharge. Virus was recovered from nasal secretions 4-10 days after inoculation from nasal, tracheal and bronchial mucosae and lung of animals killed 7-13 days after inoculation. Infection did not produce any macroscopic lesions, but histologically there was a focal degenerative rhinitis and a catarrhal bronchiolitis with the occasional formation of syncytia in bronchioles and alveoli.     

Observations on outbreaks of respiratory disease in calves associated with parainfluenza type 3 virus and respiratory syncytial virus infection.

In four outbreaks of indoor calf pneumonia, dyspnoea was a prominent clinical finding. At necropsy it was associated with pneumonia involving the cranial lobes of the lung and severe pulmonary emphysema. Histological examination of lung tissue revealed bronchiolitis and alveolitis with alveolar epithelial cell hyperplasia and multinucleate syncytium formation. Intraalveolar haemorrhage, intra-alveolar oedema and hyaline membrane formation were also noted. In all cases parainfluenza type 3 (PI3) virus was isolated from the lungs. In each of the four outbreaks there was evidence of PI3 virus and respiratory syncitial virus (RSV) infection.     

Pulmonary inflammation associated with aspirated meconium and epithelial cells in calves.

"Meconium aspiration syndrome" is a condition resulting in respiratory distress and the occasional death of newborn human beings. A retrospective study was conducted on 52 calves that were submitted for postmortem examination to the Atlantic Veterinary College, Charlottetown, Prince Edward Island, Canada. These calves died of infectious and noninfectious diseases within the first 2 weeks of life due to a variety of causes. The most common cause of death was infectious enteric disease. Histologic examination of lungs revealed that 42.5% of calves had evidence of meconium, squamous cells, or keratin in the lung. There was considerable variation in the magnitude of histologic changes in lungs containing aspirated material. Typically, affected lungs had only a few inconspicuous pieces of meconium, keratin, and squamous cells within bronchoalveolar spaces. Sporadically, the entire lumen of airways was obliterated by aspirated material. Lungs with aspirated material had a mild but diffuse alveolitis characterized by exudation of a few neutrophils, macrophages, and occasional multinucleated giant cells. Obstruction of small airways and focal atelectasis were also observed. Similar lesions have been reported in human meconium aspiration syndrome. It is concluded that histologic changes similar to those of human meconium aspiration syndrome occur commonly in calves that die within 2 weeks of birth. Further studies involving healthy age-matched calves are required to evaluate the clinicopathologic significance of meconium aspiration in this species.     

Use of volumetric capnography to identify pulmonary dysfunction in horses with and without clinically apparent recurrent airway obstruction

OBJECTIVE: To investigate whether volumetric capnography indices could be used to differentiate between horses without recurrent airway obstruction (RAO) and horses with RAO that were in clinical remission or that had clinically apparent RAO. ANIMALS: 70 adult Swiss Warmblood horses (20 used for pleasure riding and 50 used for dressage or show jumping). PROCEDURE: Horses were allocated to 4 groups on the basis of history, clinical signs, results of endoscopy, and cytologic findings (group 1, 21 healthy horses; group 2, 22 horses with RAO that were in remission; group 3, 16 horses with mild RAO; group 4, 11 horses with exacerbated RAO). Expiratory volume and CO2 curves were recorded by use of a computerized ultrasonic spirometer. Volumetric capnograms were plotted, and derived indices were calculated. RESULTS: Dead-space volume (VD) was calculated by use of the Bohr equation (VD(Bohr)) and for physiologic VD (VD(phys)). Ratios for VD(Bohr) to expiratory tidal volume (VT) and VD(phys) to V(T) as well as an index of effective CO2 elimination were significantly different among groups of horses. Age and use of the horses also significantly affected volumetric capnography indices. CONCLUSIONS AND CLINICAL RELEVANCE: Ratios of VD(Bohr) to VT and VD(phys) to VT as well as an index of effective CO2 elimination were sufficiently sensitive measures to distinguish between healthy horses and horses with RAO in remission. To optimize the ability of volumetric capnography indices to differentiate among horses in heterogeneous populations, it is important to account for effects of age and specific use of the horses.     

Coughing,mucus accumulation,airway obstruction,and airway inflammation in control horses and horses affected with recurrent airway obstruction

OBJECTIVE: To investigate relationships between cough frequency and mucus accumulation, airway obstruction, and airway inflammation and to determine effects of dexamethasone on coughing and mucus score. ANIMALS: 13 horses with recurrent airway obstruction (RAO) and 6 control horses. PROCEDURE: 6 RAO-affected and 6 control horses were stabled for 3 days. Coughing was counted for 4 hours before and on each day horses were stabled. Before and on day 3 of stabling, tracheal mucus accumulation was scored, airway obstruction was assessed via maximal change in pleural pressure (deltaPpl(max)), and airway inflammation was evaluated by use of cytologic examination of bronchoalveolar lavage fluid (BALF). Effects of dexamethasone (0.1 mg/kg, IV, q 24 h for 7 days) were determined in 12 RAO-affected horses. RESULTS: To assess frequency, coughing had to be counted for 1 hour. In RAO-affected horses, stabling was associated with increases in cough frequency, mucus score, and deltaPpl(max). Control horses coughed transiently when first stabled. In RAO-affected horses, coughing was correlated with deltaPpl(max), mucus score, and airway inflammation and was a sensitive and specific indicator of deltaPpl(max) > 6 cm H2O, mucus score > 1.0, and > 100 neutrophils/microL and > 20% neutrophils in BALF Dexamethasone reduced cough frequency, mucus score, and deltaPpl(max), but BALF neutrophil count remained increased. CONCLUSIONS AND CLINICAL RELEVANCE: Because of its sporadic nature, coughing cannot be assessed accurately by counting during brief periods. In RAO-affected horses, coughing is an indicator of airway inflammation and obstruction. Corticosteroid treatment reduces cough frequency concurrently with reductions in deltaPpl(max) and mucus accumulation in RAO-affected horses.     

Cardiovascular effects of acute pulmonary obstruction in horses with recurrent airway obstruction

BACKGROUND: Recurrent airway obstruction (RAO) is common in horses. Although pulmonary artery (PA) pressure increases during RAO, cardiac function in horses with RAO has received limited attention. HYPOTHESIS: The purpose of this study was to noninvasively determine the cardiovascular effects of acute pulmonary obstruction (APO) in horses with RAO and their reversibility. ANIMALS: Five geldings with RAO, inducible by exposure to moldy hay, were studied. METHODS: Pulmonary mechanics, echocardiography, serum troponin I concentrations, arterial blood gases, and hematocrit were obtained before and after 7 days of APO. Heart rate, PA diameter and flow characteristics, right and left ventricular luminal dimensions and wall thicknesses, global cardiac performance, and evidence of myocardial damage were evaluated. Pulmonary mechanics and echocardiography were reevaluated during remission. RRESULTS: Severe, transient APO did not induce chronic cor pulmonale in horses, because cardiac anatomy and function were normal between episodes. An acute episode of APO produced anatomical and functional cardiac changes in both the right and left heart (including increased PA diameter, abnormal septal motion, and decreased left ventricular diameter and estimated stroke volume), possibly because of the development of pulmonary hypertension, without apparent myocardial damage. The decrease in stroke volume was offset by the increase in heart rate. CONCLUSIONS AND CLINICAL IMPORTANCE: With APO of 7 days' duration, cardiovascular abnormalities and the functional airway changes that produce them are reversible when the offending allergens are removed.     

An investigation into the role of Chlamydophila spp. in bovine upper respiratory tract disease

An outbreak of upper respiratory tract disease was investigated in a group of 17 housed home-bred calves on a mixed dairy, beef and sheep farm in Devon. Conjunctival swabs were collected and tested for Chlamydophila spp. DNA using a PCR test that detects Chlamydophila abortus and Chlamydophila psittaci. Six of the calves tested gave a positive result. Further epidemiological observations and laboratory testing indicated that the adult dairy cows, from which the affected calves originated, were the most likely source of infection.     

Prevalence and risk factors for Cryptosporidium spp. infection in young calves

A cross-sectional study was designed to investigate the prevalence and risk factors for Cryptosporidium infection in young calves. Forty-one farms in a discrete, densely farmed 100 km2 area of North West England were visited over a 3-week period and 215 faecal samples were collected from young calves. Farms were not selected on the basis of existing scour problems. At the time of sampling, several investigator-observed variables were recorded at the pen, animal and stool levels. Samples were screened and 60/215 were confirmed as positive by PCR of the 18S rRNA gene. Risk factors for infection were explored using multilevel multivariable logistic regression with farm as a random effect. Age was significant in the final model, with a higher risk of infection in calves aged 8-21 days, when compared to those aged 0-7 days. The depth of the bedding was also significant in the final model, with calves housed in bedding 11-15 cm deep being at lower risk of infection than those on beds 0-5 cm deep. Consistency of the faeces was highly correlated with age and colour of the faeces and was not significantly associated with infection when these variables, and clustering at farm-level, were accounted for. This is interesting as Cryptosporidium is considered to be a primary enteropathogen. The results suggest that intervention strategies should be targeted at calves under 21 days old. These animals represent a significant reservoir of infection on the farm and may also pose a risk to public health, assuming that the species and genotypes shed are zoonotic pathogens.     

Myelitis associated with protozoal infection in newborn calves

Four newborn calves from different herds were examined because of recumbency and inability to rise. Abnormal physical findings were confined to the nervous and/or musculoskeletal systems. Because of poor prognosis, all calves were euthanatized and necropsied. The histopathologic findings were multifocal lymphocytic myelitis, meningitis, and encephalitis associated with protozoal cysts.     

Mycoplasma bovis infection in gnotobiotic calves and combined infection with respiratory syncytial virus

Mycoplasma bovis was inoculated alone or in combination with respiratory syncytial virus into the respiratory tracts of 12 gnotobiotic calves. Clinical signs ranged from transient pyrexia to protracted fever accompanied by severe lower respiratory signs and in one case, arthritis. Pulmonary lesions included foci of coagulative necrosis surrounded by mononuclear cells and suppurative bronchiolitis with varying degrees of lympho-reticular hyperplasia. No enhancement of lesions occurred in the combined infections of M. bovis and respiratory syncytial virus. M. bovis was identified by immunoperoxidase labelling in lesions of necrosis, especially at interfaces between the lesion and mononuclear cells and in bronchiolar exudates. Organisms were also located in necrotic lesions of joint capsules, in tonsillar crypts, and in liver.     

Investigation of Chlamydophila spp. in dairy cows with reproductive disorders

Background

Reports worldwide indicate high prevalence of Chlamydophila spp. infection in cattle. To assess the prevalence in Sweden, 525 cows in 70 dairy herds with reproductive disorders was investigated.

Methods

To detect antibodies two commercially available kits were used. Moreover, 107 specimens, including vaginal swabs, organ tissues and milk were analysed by Polymerase Chain Reaction (PCR).

Results

Two (0.4%) cows were seropositive in the Pourquier Cp. abortus ELISA. The seroprevalence with the Chekit ELISA was 28% with no difference between cases and controls. Five specimens were positive in real-time PCR and further analysed by nested PCR. Cp. pecorum was confirmed by partial omp1 DNA sequencing of the nested PCR product of vaginal swabs from control cows.

Conclusion

The results suggest that Cp. abortus infection is absent or rare in Swedish cows whereas Cp. pecorum is probably more spread. They also suggest that Chlamydophila spp. are not related to reproduction disorders in Swedish cattle.     

Pulmonary function changes and clinical findings associated with chronic respiratory disease in calves.

Thirteen field cases of chronic respiratory disease in crossbred calves aged between 1 and 8 months were subjected to a standardized examination in which clinical criteria were scored and weighted to allow quantification. Predicted values for pulmonary function variables were generated using regression equations previously established in normal calves which related measured pulmonary function variables to thoracic perimeter. Subsequent pulmonary function testing of each calf was undertaken and values obtained compared with predicted values and correlated with clinical scores. Diagnosis was confirmed at post-mortem examination. Calves with chronic respiratory disease had significantly reduced inspiratory and expiratory times, tidal volume, dynamic compliance and PaO2, significantly increased respiratory frequency, airway resistance and PaCO2 and more negative transpulmonary pressure values when compared to predicted pulmonary function values for the same calves. PaO2 and PaCO2 were the only variables correlated with clinical scores, suggesting their value in the assessment of severe cases of calf respiratory disease.     

Hydrops fetalis associated with pulmonary hypoplasia in Dexter calves

The occurrence of severe fetal dystocia due to hydrops fetalis associated with pulmonary aplasia in two male and pulmonary hypoplasia in one female Australian Dexter fetuses from two herds is described. Obstetrical intervention by caesarean section was required for delivery of the fetuses, with mortalities in one dam and the 3 calves. Clinical, pathological and genetic features are tabulated to assist in distinguishing pulmonary hypoplasia-associated hydrops fetalis from the more prevalent disorder of chondrodysplasia in Dexter cattle. Anasarca and complete absence or presence of only rudimentary lung tissue in a large thoracic cavity clearly distinguishes this entity from the lesions of Dexter chondrodysplasia that include severe micromelia and abundant lung tissue in a small thoracic cavity with shortened spine and rib cage. Pedigree information suggested that Dexter hydrops may be transmitted in an autosomal recessive manner.     

Study on diarrhea in young calves. 2. Pathomorphological studies in clinically healthy calves and in calves with diarrhea

Pathological-anatomical and histological investigations were performed in 49 calves aged from 1 to 18 days, 26 of them being affected by diarrhoea, 23 being without clinical signs. In both the groups above all rhinitis, gastritis and typhlocolitis could be observed, thus the affection could be characterized as rhinogastrocolitis. Significant differences only existed between diarrhoea affected and clinical incospicuous calves concerning the macroscopic signs of the colon, periportal infiltrates of the liver and thymus in involution. The peak of inflammatory reaction is in general reached at the 7. to 10. day of life. In concordance with bacteriological findings the results refer to an affection not due to coli infection. Virus etiology may not be excluded and has to be examined in further studies.     

Effect of infection with bovine respiratory syncytial virus on pulmonary clearance of an inhaled antigen in calves

OBJECTIVE: To evaluate the effect of infection with bovine respiratory syncytial virus (BRSV) on clearance of inhaled antigens from the lungs of calves. ANIMALS: Eleven 6- to 8-week-old Holstein bull calves. PROCEDURES: Aerosolized (99m)technetium ((99m)Tc)-labeled diethylene triamine pentacetate (DTPA; 3 calves), commonly used to measure integrity of the pulmonary epithelium, and (99m)Tc-labeled ovalbumin (OA; 8 calves), commonly used as a prototype allergen, were used to evaluate pulmonary clearance before, during, and after experimentally induced infection with BRSV or sham inoculation with BRSV. Uptake in plasma (6 calves) and lung-efferent lymph (1 calf) was examined. RESULTS: Clearance of (99m)Tc-DTPA was significantly increased during BRSV infection; clearance of (99m)Tc-OA was decreased on day 7 after inoculation. Clearance time was correlated with severity of clinical disease, and amounts of (99m)Tc-OA in plasma and lymph were inversely correlated with clearance time. Minimum amounts of (99m)Tc-OA were detected at time points when pulmonary clearance of (99m)Tc-OA was most delayed. CONCLUSIONS AND CLINICAL RELEVANCE: BRSV caused infection of the respiratory tract with peak signs of clinical disease at 7 or 8 days after inoculation. Concurrently, there was a diminished ability to move inhaled protein antigen out of the lungs. Prolonged exposure to inhaled antigens during BRSV infection may enhance antigen presentation with consequent allergic sensitization and development of chronic inflammatory lung disease. IMPACT FOR HUMAN MEDICINE: Infection of humans with respiratory syncytial virus early after birth is associated with subsequent development of allergic asthma. Results for BRSV infection in these calves suggested a supportive mechanism for this scenario.