Effect of parity segregation on Mycoplasma hyopneumoniae infection dynamics and pneumonic lesions in pigs

ABSTRACT: Gilts represent a group risk for Mycoplasma hyopneumoniae vertical transmission in swine herds. Therefore, parity segregation can be an alternative to control M. hyopneumoniae infections. The study evaluated the effect of parity segregation on M. hyopneumoniae infection dynamics and occurrence and severity of lung lesions at slaughter. For that, three multiple site herds were included in the study. Herd A consisted of the farm where gilts would have their first farrowing (parity order (PO) 1). After the first farrowing PO 1 sows were transferred to herd B (PO2-6). Herd C was a conventional herd with gilt replacement (PO1-6). Piglets born in each herd were raised in separated nursery and finishing units. Sows (n = 33 (A), 37 (B), 34 (C)) in all herds were sampled prior to farrowing and piglets (n = 54 (A), 71 (B), 66 (C)) were sampled longitudinally at 21, 63, 100, 140 days of age and at slaughter for M. hyopneumoniae detection by PCR and lung lesions scoring. M. hyopneumoniae prevalence in sows did not differ among herds. Prevalence of positive piglets was higher at weaning in the PO1 herd (A) (P < 0.05). However, prevalence of positive pigs from 100 days of age to slaughter age was higher in the PO2-6 herd (B) (P < 0.05). Lung lesion occurrence and severity were higher in herd B. The authors suggested that the lack of a proper gilt acclimation might have influenced the results, leading to sows being detected positive at farrowing, regardless of the parity.

Lungworms (Metastrongylus Spp.) Demonstrated in Domestic Pigs with Respiratory Disease - What was the True Relevance of that?

BackgroundAn outdoor pig herd was affected by severe respiratory disease in one out of three pastures. At necropsy, Mycoplasma hyopneumoniae and Pasteurella multocida were detected in the lungs, as well as the lung worm Metastrongylus apri. The life cycle of Metastrongylus spp. includes earth worms as an intermediate host, and since domesticated pigs mainly are reared indoors lungworms has not been diagnosed in domestic pigs in Sweden for decades, not even in pigs reared outdoors. Therefore, this disease outbreak was scrutinised from the view of validating the impact of Metastrongylus spp..ResultsAt the time of the disease outbreak, neither eggs of Metastrongylus spp. nor Ascaris suum were detected in faeces of pigs aged ten weeks. In contrast, five-months-old pigs at the pasture with respiratory disease shed large amounts of eggs from Ascaris suum, whereas Ascaris suum not was demonstrated in healthy pigs aged six months at another pasture. Low numbers of eggs from Metastrongylus spp. were seen in faecal samples from both these age categories.At slaughter, seven weeks later, ten normal weighted pigs in the preceding healthy batch were compared with ten normal weighted and five small pigs from the affected batch. Healing Mycoplasma-like pneumonic lesions were seen in all groups. Small pigs had more white spot liver lesions, and all small pigs shed eggs of Ascaris suum in faeces, compared to around 50% of the pigs in the normally sized groups. Metastrongylus spp. were demonstrated in 13 of the 25 pigs (52%), %), representing all groups included.ConclusionAs Metastrongylus spp. were demonstrated regardless of health status, and in another healthy outdoor herd, the impact of Metastrongylus spp. on the outbreak of respiratory disease was depreciated. Instead, Metastrongylus spp. was suggested to be common in outdoor production, although rarely diagnosed. The reason for this is because they will escape detection at routine inspection at slaughterhouses, and that they appeared to generally not induce clinical signs of respiratory disease. Instead, a possible association with a high burden of Ascaris suum was suggested to have preceded the severe outbreak with respiratory disease.

Pneumonia enzoótica em suínos: revisão

A Pneumonia Enzoótica Suína (PES) é uma doença endêmica em países com produção de suínos, podendo ser encontrada pelo mundo todo. Tem como agente etiológico a bactéria Mycoplasma hyopneumoniae é uma das principais doenças respiratória dos suínos. Desempenha um papel importante na saúde animal e de extrema importância na suinocultura, principalmente nas fases de crescimento e terminação, é considerada um fator de grandes prejuízos com a condenação das carcaças, aumento do uso de medicamentos e diminuição do desempenho produtivo, gerando significativas perdas econômicas à suinocultura mundial. Considerando a importância da infecção, o presente trabalho realizou uma revisão bibliográfica sobre os principais fatores que favorecem a infecção, objetivando compreender seus aspectos biológicos, patogênicos, de diagnóstico, tratamento e sua profilaxia. O conhecimento das formas de transmissão é imprescindível para compreender suas formas de disseminação, as técnicas diagnósticas apropriadas e a prevenção da enfermidade. Dessa forma, é de extrema importância à realização de pesquisas a fim de que sejam diminuídos os prejuízos econômicos, através da correção dos fatores de risco, medidas terapêuticas e imunoprofiláticas.

Oral vaccination of piglets against Mycoplasma hyopneumoniae using silica SBA-15 as an adjuvant effectively reduced consolidation lung lesions at slaughter

Mycoplasma (M.) hyopneumoniae is the main pathogen of porcine enzootic pneumonia (PEP). Its controlling is challenging, and requires alternative strategies. This study aimed to develop an oral vaccine against M. hyopneumoniae using a nanostructured mesoporous silica (SBA-15) as an adjuvant, and compare its effect with an intramuscular (IM) commercial vaccine (CV). Fifty 24 day-old M. hyopneumoniae-free piglets composed five equal groups for different immunization protocols, consisting of a CV and/or oral immunization (OI). Control piglets did not receive any form of immunization. All piglets were challenged with M. hyopneumoniae strain 232 on D49 by tracheal route. IgA antibody response in the respiratory tract, bacterial shedding and serum IgG were evaluated. The piglets were euthanized on 28 (D77) and 56 (D105) days post-infection. Lung lesions were macroscopically evaluated; lung fragments and bronchoalveolar fluid (BALF) were collected for estimation of bacterial loads by qPCR and/or histopathology examination. All immunization protocols induced reduction on Mycoplasma-like macroscopic lung lesions. IgA Ab responses anti-M. hyopneumoniae, the expression of IL-4 cytokine and a lower expression of IL-8 were induced by CV and OI vaccines, while IgG was induced only by CV. Oral immunization using silica as a carrier-adjuvant can be viable in controlling M. hyopneumoniae infection.

Genotype diversity of Mycoplasma Hyopneumoniae in Chinese swine herds based on multilocus sequence typing

Background Between 2018 and 2020, 989 clinical specimens from pigs showing clinical signs of a variety of swine diseases in 27 provinces in China were sampled and submitted for further testing. Nested PCR targeting the 16S rRNA gene of Mycoplasma hyopneumoniae and subsequent sequencing were used to analyse these specimens. Mycoplasma hyopneumoniae-positive samples were assayed by multilocus sequence typing (MLST). The aim of the study was to reveal the distribution of M. hyopneumoniae and determine the genotypes of M. hyopneumoniae in pig herds in China based on MLST. Results Among these 989 samples, 199 samples were M. hyopneumoniae-positive. The M. hyopneumoniae positivity rate was 7.2% (35/494) in 2018, 18.4% (38/207) in 2019, and 43.8% (126/288) in 2020. In total, 47 samples were successfully assayed by MLST. Sixteen new M. hyopneumoniae sequence types from 9 provinces were recorded in the present study. Conclusions This is the first report on sample positivity rates and molecular typing results for M. hyopneumoniae in swine herds in China. MLST has revealed high genotype diversity among M. hyopneumoniae from different provinces of China.