Exploring the Genetic Diversity of Mycoplasma hyopneumoniae in Pigs with Pneumonia and Pleurisy at Slaughter.

Mycoplasma (M.) hyopneumoniae is the key pathogen of the porcine respiratory disease complex (PRDC) and contributes to pleurisy in pigs. Due to its limited metabolism and laborious cultivation, molecular tools are useful for diagnosis. This study investigated the genetic diversity of M. hyopneumoniae in slaughter pigs with pneumonia and pleurisy, and it assessed co-infections by Pasteurella multocida type A (PM), Actinobacillus pleuropneumoniae (APP), and swine influenza virus A (sIVA). Lungs (n = 70) with different pleurisy scores and lesions compatible with M. hyopneumoniae infection were collected for convenience. Macroscopic and microscopic evaluations were performed. M. hyopneumoniae was detected using qPCR, and MLST was used for genetic characterization. Co-infections with PM and APP were also evaluated by qPCR, while the immunohistochemistry assessed sIVA infection. All lungs were positive for M. hyopneumoniae. Histopathology confirmed M. hyopneumoniae-associated lesions. MLST characterization was possible in 25 lungs and revealed 10 distinct allelic profiles, with none matching known sequence types in the public database. Co-infections were detected in 40% of the samples with APP and 32% with PM, with 12% showing both pathogens and 52% of the samples presenting microscopic lesions compatible with sIVA infection. The diverse genetic profiles found underscore the need for research on isolation and potential pathogenic variations.

Shedding reduction and immunity modulation in piglets with an inactivated Mycoplasma hyopneumoniae vaccine encapsulated in nanostructured SBA-15 silica.

Mycoplasma (M.) hyopneumoniae is a primary etiological agent of porcine enzootic pneumonia (PEP), a disease that causes significant economic losses to pig farming worldwide. Current commercial M. hyopneumoniae vaccines induce partial protection, decline in preventing transmission of this pathogen or inducing complete immunity, evidencing the need for improving vaccines against PEP. In our study, we aimed to test the effectiveness of the SBA-15 ordered mesoporous silica nanostructured particles as an immune adjuvant of a vaccine composed of M. hyopneumoniae strain 232 proteins encapsulated in SBA-15 and administered by intramuscular route in piglets to evaluate the immune responses and immune-protection against challenge. Forty-eight 24-day-old M. hyopneumoniae-free piglets were divided into four experimental groups with different protocols, encompassing a commercial vaccine against M. hyopneumoniae, SBA-15 vaccine, SBA-15 adjuvant without antigens and a non-immunized group. All piglets were challenged with the virulent strain 232 of M. hyopneumoniae. Piglets that received the SBA-15 and commercial vaccine presented marked immune responses characterized by anti-M. hyopneumoniae IgA and IgG antibodies in serum, anti-M. hyopneumoniae IgA antibodies in nasal mucosa and showed an upregulation of IL-17 and IL-4 cytokines and downregulation of IFN-γ in lungs 35 days post-infection. Piglets immunized with SBA-15 vaccine presented a reduction of bacterial shedding compared to piglets immunized with a commercial bacterin. In addition, piglets from SBA-15 adjuvant suspension group presented increased IL-17 gene expression in the lungs without involvement of Th1 and Th2 responses after challenge. These results indicated that SBA-15 vaccine induced both humoral and cell-mediated responses in the upper respiratory tract and lungs, first site of replication and provided protection against M. hyopneumoniae infection with a homologous strain with reduction of lung lesions and bacterial shedding. Finally, these results enhance the potential use of new technologies such as nanostructured particles applied in vaccines for the pig farming industry.

Prevalence and Risk Factors of Leptospira spp. Infection in Backyard Pigs in the State of Paraná, Brazil.

Leptospirosis is a zoonotic disease that poses a significant threat to human and animal health worldwide. Among different animal species, pigs are known to play a crucial role in the transmission of the pathogenic Leptospira spp. This study aimed to investigate the prevalence of Leptospira spp. infection and associated risk factors in backyard pigs in the state of Paraná, Brazil. A set of 1393 blood samples were collected from pigs on 188 subsistence properties from 136 different municipalities of the Paraná state and tested using the microscopic agglutination test (MAT) to detect antibodies against 24 different Leptospira spp. serovars. The results revealed an overall seroprevalence of 15.87% (221/1393; 95% CI: 13.95-17.78%) for Leptospira spp. antibodies, with Icterohaemorrhagiae, Butembo, and Pomona being the most commonly detected in serovar levels. The lack of rodent control (OR 1.12, 95% CI: 0.63-1.98, p = 0.02) was the only variable associated with disease incidence and was identified as a significant risk factor for Leptospira spp. infection in this context. These findings highlight the urgent need to implement effective control measures, such as improved housing conditions, rodent control, and veterinary assistance, to prevent the spread of this zoonotic disease in backyard pigs in Paraná, Brazil.