Training Convolutional Neural Networks to Score Pneumonia in Slaughtered Pigs

The slaughterhouse can act as a valid checkpoint to estimate the prevalence and the economic impact of diseases in farm animals. At present, scoring lesions is a challenging and time-consuming activity, which is carried out by veterinarians serving the slaughter chain. Over recent years, artificial intelligence(AI) has gained traction in many fields of research, including livestock production. In particular, AI-based methods appear able to solve highly repetitive tasks and to consistently analyze large amounts of data, such as those collected by veterinarians during postmortem inspection in high-throughput slaughterhouses. The present study aims to develop an AI-based method capable of recognizing and quantifying enzootic pneumonia-like lesions on digital images captured from slaughtered pigs under routine abattoir conditions. Overall, the data indicate that the AI-based method proposed herein could properly identify and score enzootic pneumonia-like lesions without interfering with the slaughter chain routine. According to European legislation, the application of such a method avoids the handling of carcasses and organs, decreasing the risk of microbial contamination, and could provide further alternatives in the field of food hygiene.

Nicotinamide Adenine Dinucleotide-Dependent Flavin Oxidoreductase of Mycoplasma hyopneumoniae Functions as a Potential Novel Virulence Factor and Not Only as a Metabolic Enzyme

Mycoplasma hyopneumoniae (Mhp) is the main pathogen that causes enzootic pneumonia, a disease that has a significant impact on the pig industry worldwide. The pathogenesis of enzootic pneumonia, especially possible virulence factors of Mhp, has still not been fully elucidated. The transcriptomic and proteomic analyses of different Mhp strains reported in the literature have revealed differences in virulence, and differences in RNA transcription levels between high- and low-virulence strains initially indicated that nicotinamide adenine dinucleotide (NADH)-dependent flavin oxidoreductase (NFOR) was related to Mhp pathogenicity. Prokaryotic expression and purification of the NFOR protein from Mhp were performed, a rabbit-derived polyclonal antibody against NFOR was prepared, and multiple sequence alignment and evolutionary analyses of Mhp NFOR were performed. For the first time, it was found that the NFOR protein was conserved among all Mhp strains, and NFOR was localized to the cell surface and could adhere to immortalized porcine bronchial epithelial cells (hTERT-PBECs). Adhesion to hTERT-PBECs could be specifically inhibited by an anti-NFOR polyclonal antibody, and the rates of adhesion to both high- and low-virulence strains, 168 and 168L, significantly decreased by more than 40%. Moreover, Mhp NFOR not only recognized and interacted with host fibronectin and plasminogen but also induced cellular oxidative stress and apoptosis in hTERT-PBECs. The release of lactate dehydrogenase by hTERT-PBECs incubated with Mhp NFOR was significantly positively correlated with the virulence of Mhp. Overall, in addition to being a metabolic enzyme related to oxidative stress, NFOR may also function as a potential novel virulence factor of Mhp, thus contributing to the pathogenesis of Mhp; these findings provide new ideas and theoretical support for studying the pathogenic mechanisms of other mycoplasmas.

Mycoplasma hyopneumoniae as a causative agent of porcine enzootic pneumonia

Mycoplasma hyopneumoniae is a very important pathogen which causes enzootic pneumonia (EP) affecting pig herds worldwide. M. hyopneumoniae establishes itself in the respiratory system causing pathological changes, and resultant pneumonic lesions can be detected at slaughter via lung examination, appearing as red to pink lesions which resolve over time, leaving scar tissue on the lobes. Mycoplasma spp. infection can be complicated by coinfections with other pathogens such as swine influenza virus (SIV) and porcine circovirus (PCV2). These coinfections result in worsening of clinical symptoms and lung lesions, therefore increasing the impact on performance of the affected animals. Therefore, it is important that focus is placed on improving overall respiratory health and managing overall herd health, rather than just solely focusing on M. hyopneumoniae. Management practices should be implemented to control the disease, which commonly involve vaccination to reduce the impacts of the disease. Effective vaccination is important, and can be ensured by correct vaccine handling, storage and administration. The vaccine used can also play a part in the success of the vaccination programme so this should also be assessed, which can be done via lung examination and noting of clinical signs and performance parameters. When vaccination is successful, the level of lung lesions should be reduced, performance improved and consistency between batches, demonstrating that respiratory health is more stable.

Estimation of the prevalence of respiratory diseases in pigs in north-eastern Poland: Survey of pulmonary lesions in pigs at a slaughterhouse

A total of 29 520 animals, from 164 batches of pigs belonging to an identical number of herds, were involved in the study. The considered population of pigs were limited to the region of north-eastern Poland involving six voivodeships. From each herd, samples of blood were collected to evaluate the antibody titres to Mycoplasma hyopneumoniae, porcine reproductive and respiratory syndrome virus, Aujeszky’s disease virus and swine influenza virus. At an abattoir, the lung lesions of each batch were scored and the enzootic pneumonia-like lesion average value was calculated. Lesions, indicative of enzootic pneumonia, were found in 57.8% of the lungs. For all lungs, the enzootic pneumonia-like lesion average value was 1.74, ranging from 0.42 to 3.56 among the 164 batches. In the examined pig population, 57.8% were considered suffering from swine respiratory disease, the majority of the affected pigs came from the Podlaskie (21.7%) and Greater Poland (17.25%) voivodeships. In the most affected voivodeships, 88.37% and 85.16% of the farms were considered as disease-susceptible for Greater Poland and Podlaskie, respectively. The findings indicate that, in pigs in north-eastern Poland, the major pathogens causing pneumonia-like lesions are Mycoplasma hyopneumoniae (68.9%) and porcine reproductive and respiratory syndrome virus (44%).

Morphological and Biochemical Parameters of Pigs’ Blood with Enzootic Pneumonia

One of the most common diseases of pigs in large pig enterprises is enzootic pneumonia. The main etiological agent causing enzootic pneumonia is Mycoplasma hyopneumoniae. Mycoplasmas have minimal virulence, but they increase the susceptibility of pigs to secondary infections. In association with other microorganisms, Mycoplasma hyopneumoniae enhances its pathogenic effect, which makes the course of the disease more severe, often leading to the death of animals. Blood tests were performed to study the changes in morphological and biochemical parameters during the development of infection caused by Mycoplasma hyopneumoniae. Experimental groups of animals were formed, consisting of healthy as well as infected and ill pigs of different ages (2, 3, and 4 months), in which the pathogen M. hyopneumoniae was detected by polymerase chain reaction. The following hematological changes were revealed in the piglets suffering from respiratory mycoplasmosis: erythropenia, leukopenia, increased blood sedimentation rate (BSR), hypoproteinemia, hypoalbuminemia, increased activity of alanine aminotransferase and alkaline phosphatase, increased urea, and hyperglycemia. Keywords: pigs breeding; pneumonia; biochemical parameters; morphological parameters

Evaluation of the Frequency of Swine Enzootic Pneumonia in one Farm Based on Slaughterhouse, Clinical and Laboratory Monitoring

Background: Swine enzootic pneumonia (SEP), caused by the bacterium Mycoplasma hyopneumoniae, is one of the main respiratory diseases of pigs. The purpose of this study was to evaluate the frequency of SEP in one farm with an independent production system, low level of technification and high losses in the meat packing plant, based on slaughterhouse, clinical and laboratory monitoring.Materials, Methods & Results: This study consisted of three monitoring steps, divided into three periods: P1, P2 and P3. In the first step of the study, slaughterhouse reports were analyzed and slaughtering was monitored at one meatpacking plant in Santa Maria, RS, Brazil. The second step of the study started by drawing up a profile of the farm that supplied the pigs to the aforementioned slaughterhouse, after which clinical monitoring was performed on three occasions. The third step of the study (laboratory monitoring) involved collecting lung fragments containing suspected SEP lesions from the meatpacking plant and subjecting them analysis. The average measured enzootic pneumonia (EP) in P3 was 38.54% (P < 0.05) higher than in P1 and 29.79 higher than in P2. The mean frequency of pulmonary emphysema (PE) in P3 was 59.13% (P < 0.05) higher than in P1 and 48.04% higher than in P2. The mean number of lung adhesions (LA) did not differ statistically (P > 0.05) between P1, P2 and P3. As for the mean frequency of pulmonary hepatization (PH), P3 was 48.80% higher (P < 0.05) than P1 and 41.78% higher than P2. With regard to the mean frequency of craniodorsal lung lesions (CLL), P3 was 48.26% higher (P < 0.05) than P1 and 40.77% higher than P2. The mean frequency of disseminated lesions (DL) and the pneumonia severity index (PSI) showed no statistical difference (P > 0.05) between the three evaluated periods. On the other hand, in the finishing period (FP), the frequency of coughing and sneezing was 37.56% (P < 0.05) higher in P1 than in P3. The frequency of coughing and sneezing evaluated in the nursery phase (CF) did not differ (P > 0.05) between periods. The samples sent to the laboratory MicroVet tested positive for M. hyopneumoniae, Influenza virus and Pasteurella multocida capsular type A. In the samples sent to the laboratory LABAC, the mean PCRmo (PCR for identification of mollicutes) did not differ (P > 0.05) in the analyzed periods, although the presence of DNA from bacteria of the class Mollicutes was confirmed in the fragments. In addition, the mean results of PCRmy (PCR for identification of M. hyopneumoniae) also did not differ (P > 0.05), although they revealed positivity for M. hyopneumoniae. Discussion: In relationship to the mean frequency of PE in each analyzed period, our study revealed an increase in the number of pulmonary lesions at slaughter during the periods under analysis. This finding is in agreement with those of other authors, who explain that pneumonias is one of the main health problems for swine producers. Some lesions are identified more frequently in routine inspections in meatpacking plants, including pulmonary emphysema, lung adhesions and pneumonia caused by M. hyopneumoniae. In our study, we found that the clinical signs of respiratory distress decline between the periods under evaluation, but during slaughter, the lesions suggestive of SEP continued to show an upward trend, mainly because they were chronic. Other authors state that several control measures should be adopted to ensure good zootechnical indices, including vaccination, strategic medication and the reduction of risk factors, thereby minimizing the level of M. hyopneumoniae infection in the herd.

Frequency of M. hyopneumoniae, M. hyorhinis and M. hyosynoviae in nasal and lung samples from pigs with symptoms of porcine enzootic pneumonia

M. hyopneumoniae, M. hyorhinis y M. hyopsynoviae son especies genéticamente relacionadas del género Mycoplasma que afectan la producción porcina. El objetivo de este trabajo fue el aislamiento e identificación por PCR de M. hyopneumoniae, M. hyorhinis y M. hyosynoviae a partir de hisopos nasales y muestras de pulmón de cerdos de diferentes regiones mexicanas para determinar la frecuencia de estas especies y evaluar la PCR como herramienta diagnóstica para NEP. Se incluyeron cerdos de 4 a 8 semanas con diagnóstico clínico de NEP. Se obtuvieron muestras de pulmón e hisopos nasales para el aislamiento de Mycoplasma en medio Friis líquido y se identificaron mediante la PCR especie-específica basada en la subunidad 16S rRNA. El aislamiento se logró en 37.11 % (36/97) muestras. Las tres especies de Mycoplasma se identificaron en muestras de pulmón e hisopos nasales. La co-infección por Mycoplasma se identificó en el 27.77 % (10/36). Los géneros bacterianos asociados a las infecciones por Mycoplasma fueron E. coli, Bordetella, Enterobacter, SCN, Corynebacterium, Pasteurella, Streptococcus, Shigella y Kebsiella. La infección mixta estuvo presente en 26 hisopos nasales (45.61 %) y ausente en pulmones. Se concluyó que la frecuencia de Mycoplasma en las fincas de producción fue mayor a la esperada (40.27 %). También se identificaron otras especies de Mycoplasma involucradas en el desarrollo de la NEP. Por lo tanto, la vigilancia asistida por el aislamiento y las técnicas moleculares pueden ser de gran ayuda para la eliminación de Mycoplasma de las explotaciones porcinas y para los proveedores de pie de cría.

Evaluation of the clinical efficacy of a water soluble formulation of tylvalosin in the control of enzootic pneumonia associated with Mycoplasma hyopneumoniae and Pasteurella multocida in pigs

Background The efficacy of a water soluble formulation of tylvalosin (Aivlosin® 625 mg/g granules) was evaluated in the treatment and metaphylaxis of Enzootic Pneumonia (EP) in pigs. In all four trials, pigs in the tylvalosin group were administered 10 mg tylvalosin/kg bodyweight in drinking water daily for 5 consecutive days (TVN). In a single-challenge study, pigs were inoculated with lung homogenate containing Mycoplasma hyopneumoniae. In a dual challenge study, pigs were sequentially inoculated with pure culture of M. hyopneumoniae and Pasteurella multocida. Efficacy was evaluated based on reduction of lung lesions compared to unmedicated control pigs (CTL). In two field studies at European commercial farms with confirmed outbreaks of EP, treatment efficacy in clinically affected fatteners was evaluated based on improved clinical conditions compared to pigs treated with tylosin at 10 mg/kg by injection for 3 consecutive days (TYL). In these field trials, healthy in contact pigs were enrolled for metaphylaxis efficacy evaluation based on reduction in incidence of new clinical cases of respiratory disease compared to unmedicated pigs (CTL). Results In the M. hyopneumoniae-only challenge study, pigs in TVN group had lower lung lesion scores than CTL (6.52 vs. 14.97; p < 0.001). In the dual challenge study with M. hyopneumoniae and P. multocida, pigs in TVN group had lower lung lesion scores than CTL (3.32 vs. 8.37; p < 0.01) and the recovery of both challenge bacteria from the lungs was lower in TVN compared with CTL group (p < 0.01). In field outbreaks of EP, multicentre analysis showed that 13 days after the start of medication, treatment success for TVN pigs was significantly better than for TYL pigs (80.0% vs 48.7% p = 0.03) and metaphylactic administration of TVN significantly reduced the incidence of new clinical cases (2.1% vs. 7.8%; p < 0.01) compared with unmedicated controls. Conclusions Tylvalosin at 10 mg/kg daily for 5 days in drinking water was safe and effective in the treatment and metaphylaxis of EP in pigs associated with infections of M. hyopneumoniae either alone or in combination with P. multocida under both experimental challenge and field natural infection conditions.

ENTRIKIM THERAPEUTIC EFFICACY IN PIGS WITH ENZOOTIC PNEUMONIA

The number of T-lymphocytes in the subacute course decreases to 28.9±1.4% and in the chronic course it increased to 69.1±1.2%. However, against the background of lymphopenia, the absolute value of lymphocytes also decreased to 0.70±0.038·109 /l in the acute form of the disease. In chronic pneumonia, the number of lymphocytes was at the level of 0.44±0.04·109 /l. The T-x/T-c ratio also changed, depending on the form of enzootic pneumonia. With subacute – 1.7, and with chronic – 2.28. The entrikim treatment of piglets with a subacute course carried out for 7 days and a blood test 5 days after the implementation of sanitation showed that the number of Tlymphocytes increased twofold to 1.40±0.04·109 /l, while the Tx/Tc ratio was 2, 28, which corresponds to the physiological norm. After the treatment of piglets with a chronic course, all analyzed parameters characterizing the state of T-cell immunity testified to its normal functioning. A decrease in the total number of T-lymphocytes, individual EAK populations, indicate a depressive state of lymphopoiesis. A decrease in the number of T-lymphocytes to 0.44±0.04·109 /l in chronic course up to indicates a deep suppression of cellular immunity. In the subacute form of the disease, the number of B-lymphocytes decreased to 14.07±1.92%, but increased to 32.64±0.3% in the chronic course. But against the background of lymphopenia in subacute form, the absolute value of lymphocytes decreased to 0.36±0.04·109 /l, and in chronic lymphopenia to 0.20±0.06·109 /l. In the subacute form of the disease, the content of Ig A (1.49±0.03 mg/ml) and Ig G (1.39±0.02 mg/ml) does not differ from healthy animals, but a low level of Ig M (11.0±0.12 mg/ml) indicates a negative effect of mycoplasmas on humoral immunity. In chronic course, there is a sharp decrease (by 30%) Ig A to 1.49±0.03 and vice versa, a sharp increase by 30% in the Ig G content (11.8±011 mg/ml). After treatment of piglets with a subacute course of the disease, the number of B-lymphocytes increased by 2 times, and after treatment with m with a chronic course of the disease, by 3.5 times to 0.70±0.04·109 /L. The use of entrikim has a positive effect on humoral immunity, as the amount of Ig G increases by 45%. The therapeutic efficacy of entrikim increases due to the synergistic interaction of enrofloxacin, trimethoprim and tilmicosin phosphate. The therapeutic efficacy of entrikim in the subacute course was 90.7%, and in the chronic one – 74.4%.