BackgroundMycoplasma hyopneumoniae is the etiologic agent of enzootic pneumonia mainly occurring in fattening pigs. It is assumed that horizontal transmission of the pathogen during nursery and growing phase starts with few suckling pigs vertically infected by the sow. The aim of the present study was the exploration of the herd prevalence of M. hyopneumoniae infections in suckling pigs followed by an investigation of various herd specific factors for their potential of influencing the occurrence of this pathogen at the age of weaning.ResultsIn this cross-sectional study, 125 breeding herds were examined by taking nasal swabs from 20 suckling pigs in each herd. In total, 3.9% (98/2500) of all nasal swabs were tested positive for M. hyopneumoniae by real-time PCR. Piglets tested positive originated from 46 different herds resulting in an overall herd prevalence of 36.8% (46/125) for M. hyopneumoniae infection in pigs at the age of weaning. While the herds were epidemiologically characterized, the risk for demonstration of M. hyopneumoniae was significantly increased, when the number of purchased gilts per year was more than 120 (OR: 5.8), and when the number of farrowing pens per compartment was higher than 16 (OR: 3.3). In herds with a planned and segregated production, where groups of sows entered previously emptied farrowing units, the risk for demonstration of M. hyopneumoniae in piglets was higher in herds with two or four weeks between batches than in herds with one or three weeks between batches (OR: 2.7).ConclusionsIn this cross-sectional study, several risk factors could be identified enhancing the probability of breeding herds to raise suckling pigs already infected with M. hyopneumoniae at the time of weaning. Interestingly, some factors (farrowing rhythm, gilt acclimatisation issues) were overlapping with those also influencing the seroprevalences among sows or the transmission of the pathogen between older age groups. Taking the multifactorial character of enzootic pneumonia into account, the results of this study substantiate that a comprehensive herd specific prevention programme is a prerequisite to reduce transmission of and disease caused by M. hyopneumoniae.

BackgroundIn recent years, the occurrence and the relevance of Mycoplasma hyopneumoniae infections in suckling pigs has been examined in several studies. Whereas most of these studies were focused on sole prevalence estimation within different age groups, follow-up of infected piglets or assessment of pathological findings, none of the studies included a detailed analysis of individual and environmental risk factors. Therefore, the aim of the present study was to investigate the frequency of M. hyopneumoniae infections in suckling pigs of endemically infected herds and to identify individual risk factors potentially influencing the infection status of suckling pigs at the age of weaning.ResultsThe animal level prevalence of M. hyopneumoniae infections in suckling pigs examined in three conventional pig breeding herds was 3.6% (41/1127) at the time of weaning. A prevalence of 1.2% was found in the same pigs at the end of their nursery period. In a multivariable Poisson regression model it was found that incidence rate ratios (IRR) for suckling pigs are significantly lower than 1 when teeth grinding was conducted (IRR: 0.10). Moreover, high temperatures in the piglet nest during the first two weeks of life (occasionally >40°C) were associated with a decrease of the probability of an infection (IRR: 0.23-0.40). Contrary, the application of PCV2 vaccines to piglets was associated with an increased infection risk (IRR: 9.72).ConclusionsSince single infected piglets are supposed to act as initiators for the transmission of this pathogen in nursery and fattening pigs, the elimination of the risk factors described in this study should help to reduce the incidence rate of M. hyopneumoniae infections and thereby might contribute to a reduced probability of high prevalences in older pigs.

Objective: To describe the clinical characteristics and outcomes in a population of dogs with negative-pressure pulmonary edema (NPPE) and to identify the main causes of the disease. To evaluate any associations with morbidity and mortality.Design: Retrospective study.Setting: Three university teaching hospitals and two private referral centers.Animals: Thirty-five client-owned dogs presented with NPPE. Interventions: NoneMeasurements and Main Results: Data collected included patient characteristics, clinical history, clinicopathological abnormalities, radiographic features, treatments and outcome. Median age was 4 months (range 2-90) and median weight was 7.1 kg (range 1.7-37.2). There were many causes of NPPE including leash tugs, near hanging, accidental choking, anatomical obstruction to airflow and purposeful airway obstruction by people. The most common cause of NPPE was accidental choking (40% of cases). Dogs with an anatomical obstruction were older than 24 months. Hypoxemia with an increased alveolar-arterial gradient was common on presentation. The majority of thoracic radiographs (65.7%) showed an alveolar or interstitial pattern in the caudodorsal area as previously described in the literature. Oxygen therapy was administered to 33 (94.3%) dogs. Furosemide was administered to 18 (51.4%) dogs. Median length of hospitalization was 2 days (range 0-14). Twenty-eight (80%) dogs survived to discharge. Seven dogs were mechanically ventilated and only 2 of them (28.6%) 2 survived to discharge. Requirement for mechanical ventilation (p<0.001) was the only parameter associated with mortality.Conclusions: Most cases of NPPE occur in juvenile dogs. Different incidents associated with upper airway obstruction can produce an episode of NPPE.Choking on food or toys and near hanging have not been previously described in the veterinary literature as inciting causes of NPPE. The overall prognosis is good.