Study on inactivation of porcine epidemic diarrhoea virus, porcine sapelovirus 1 and adenovirus in the production and storage of laboratory spray-dried porcine plasma.

AIM: Evaluation of the thermal and physical conditions for inactivation of adenovirus (AdV), porcine sapelovirus 1 (PSV1) and the economically important viruses porcine epidemic diarrhoea virus (PEDV) and porcine circovirus 2 (PCV2) in the production of spray-dried porcine plasma (SDPP). METHODS AND RESULTS: Citrate-treated porcine plasma of pH 7·5, 9·8 and 10·2 (8·5% dry-matter) was spiked with PEDV, PSV1, PCV2 and AdV and incubated at 3°C for maximum 24 h, and at 44 or 48°C for maximum 10 min (Experiment 1). Spiked citrate-treated concentrated plasma of pH 7·5 and 9·8 (24% dry-matter) was spray dried in a laboratory scale apparatus (Experiment 2). Aliquots of SDPP were stored over a period of 0-10 weeks at 11 and 20°C (Experiment 3). Reverse transcription(RT)-quantitative PCR detected no notable reduction in viral genomes in treated plasma and SDPP samples. No infectious PSV1 was re-isolated from plasma and SDPP samples in cell culture. At pH 10·2 and 3°C, infectivity of PEDV in plasma was reduced with a reduction factor of 4·2 log 10 (LRF) at 10 h contact time, whereas heating to 44°C for at least 1 min at alkali pH was needed to achieve a LRF of 4·2 for AdV. Spray drying at an outlet temperature of 80°C reduced AdV infectivity effectively (LRF = 5·2) and PEDV infectivity for 95% (LRF = 1·4). After storage at 20°C for 2 weeks no infectious PEDV was re-isolated from SDPP anymore (LRF ≥4·0). Due to growth of antibiotic-resistant bacteria from plasma in cell cultures used for PCV2 isolation, no data regarding inactivation of PCV2 were obtained. CONCLUSIONS: Five percent of PEDV stayed infectious after our spray drying conditions. Spray drying in combination with storage for ≥2 weeks at 20°C eliminated infectivity of PEDV effectively. SIGNIFICANCE AND IMPACT OF THE STUDY: The conditions for inactivation of virus in plasma and SDPP determined are important for producers to inactivate PEDV during production of SDPP.

[Early detection of COPD in occupational medicine in the Alpes-Maritimes]. / Détection précoce de la BPCO en milieu professionnel dans les Alpes-Maritimes.

INTRODUCTION: This study evaluated a standardized procedure aiming at early detection of COPD in a consecutive population of employees visiting occupational medicine. METHODS: A total of 2818 employees were included by 22 occupational physicians in 5 centers. Respiratory symptoms, smoking status, occupational exposures and socioprofessional categories were collected. Subjects with at least one symptom and/or risk factor underwent spirometry. RESULTS: In this population aged 39±12 years, 2603 patients were free of known asthma or COPD. The presence of at least one symptom was observed in 23.6 % of employees and was significantly associated with smoking status, occupational exposure to organic dust, gas fumes and vapors, and agriculture (P<0.0001). Airflow obstruction (FEV1/FVC < 0.70) was detected in 1.7 % of 1605 employees who underwent spirometry. With the inclusion of known COPD subjects (n=22), the prevalence reached 2.38 %. COPD was significantly associated with smoking intensity. Information on subsequent diagnosis was obtained in only two cases. The quality of spirometry was inadequate in 30 % of cases. Thirty-three percent of detected COPD subjects did not report any respiratory symptoms. CONCLUSION: The strategy used in this study (specific questionnaire plus spirometry) allowed detection of a few cases of previously undiagnosed COPD. Occupational physicians need specific training in spirometry and a better follow-up of care pathways is required to obtain diagnostic confirmation.