Rational discovery of novel immunodiagnostic and vaccine candidate antigens to control bovine tuberculosis (bTB) requires knowledge of disease immunopathogenesis. However, there remains a paucity of information on the Mycobacterium bovis-host immune interactions during the natural infection. Analysis of 247 naturally PPD+ M. bovis-infected cattle revealed that 92% (n = 228) of these animals were found to display no clinical signs, but presented severe as well as disseminated bTB-lesions at post-mortem examination. Moreover, dissemination of bTB-lesions positively correlated with both pathology severity score (Spearman r = 0.48; p<0.0001) and viable tissue bacterial loads (Spearman r = 0.58; p = 0.0001). Additionally, granuloma encapsulation negatively correlated with M. bovis growth as well as pathology severity, suggesting that encapsulation is an effective mechanism to control bacterial proliferation during natural infection. Moreover, multinucleated giant cell numbers were found to negatively correlate with bacterial counts (Spearman r = 0.25; p = 0.03) in lung granulomas. In contrast, neutrophil numbers in the granuloma were associated with increased M. bovis proliferation (Spearman r = 0.27; p = 0.021). Together, our findings suggest that encapsulation and multinucleated giant cells control M. bovis viability, whereas neutrophils may serve as a cellular biomarker of bacterial proliferation during natural infection. These data integrate host granuloma responses with mycobacterial dissemination and could provide useful immunopathological-based biomarkers of disease severity in natural infection with M. bovis, an important cattle pathogen.

Outbreaks of tick-borne disease cases in Santa Catarina, Brazil are known, but the presence of the pathogen DNA has never been determined. In this study, the first survey of Anaplasma marginale, Babesia bigemina, and Babesia bovis DNA on blood samples of 33 cattle from an outbreak in Ponte Alta Municipality, Santa Catarina, Brazil, has been carried out. A multiplex PCR detected 54.5% of animals were co-infected with 2 or 3 parasites, while 24.2% were infected with only 1 species. The most prevalent agent was B. bigemina (63.6%) followed by A. marginale (60.6%). This is the first report of tick-borne disease pathogens obtained by DNA analysis in Southern Brazil.

Mycoplasma synoviae and avian reovirus (ARV) are associated with several disease syndromes in poultry and cause notable global economic losses in the poultry industry. Rapid and efficient diagnostics for these avian pathogens are important not only for disease control but also for prevention of clinical disease progression. However, current diagnostic methods used for surveillance of these diseases in poultry flocks are laborious and time-consuming, and they have low sensitivity. The multiplex PCR (mPCR) developed in this study has been proven to be both sensitive and specific for simultaneous M. synoviae and ARV detection and identification in clinical samples. To evaluate the mPCR assay, the diagnostic test was applied to different clinical samples from natural and experimental M. synoviae and ARV-infected poultry. Results were compared with serologic, single PCR, and immunofluorescence analyses. Tibiotarsal articulation could be the best target for simultaneous detection of M. synoviae and ARV infection. The detection limit by visualization of mPCR-amplified products was 100 pg for both pathogens. Overall, the mPCR developed and standardized in this research is a useful tool for diagnosis and screening and for surveillance and control of M. synoviae and ARV infection in poultry flocks.

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Infectious arthritis or tenosynovitis in broiler and breeder chickens results in major loss of productivity because of reduced growth and downgrading at processing plants. The most common causative agents of avian infectious arthritis are the bacterium Mycoplasma synoviae and avian reoviruses (ARVs) (family Reoviridae, genus Orthoreovirus). In this study, we evaluated the occurrence of these two pathogens in arthritis or tenosynovitis lesions of broilers and breeder flocks in southern Brazil using molecular detection. Tissue sections from tibiotarsal joints with visible lesions from 719 broilers and 505 breeders were analysed using pathogen-specific polymerase chain reaction (PCR) assays. In breeders, 41.2% (n = 296) of lesions were positive for M. synoviae, 26.4% (n = 190) were positive for ARV, while co-infection was present in 12.2% (n = 88) of the samples. In broilers, 20.8% (n = 105) of lesions were positive for M. synoviae, 11.9% (n = 60) for ARV and 7.7% (n = 39) of these cases were positive for both pathogens. Post-mortem examination revealed lesions with varying degrees of gross pathological severity. Histopathological examination showed intense, diffuse lymphohistiocytic inflammatory infiltrates with heterophil accumulation, primarily in the synovial capsule and digital flexor tendon, in all samples. Improved strategies for early detection and control of these major avian pathogens are highly desirable for preventing the spread of infection and reducing economic losses in the poultry industry.

Pesq. Vet. Bras. 32(8):687-691, agosto 2012 687 RESUMO.-A artrite infecciosa em frangos de corte representa um problema sanitário e econômico de grande impacto, provocando perdas de produtividade e nos processos de produção e industrialização. Os principais agentes etiológicos associados aos casos de artrites e tenossinovites infecciosas em aves são Mycoplasma synoviae (MS) e Orthoreovirus aviario (ARV). Esse trabalho propôs investigar as alterações anatomohistopatológicas causadas pela infecção experimental concomitante por Mycoplasma synoviae e Orthoreovirus aviario em frangos de corte e conϐirmar a presença dos agentes através das técnicas de PCR e imunoϐluorescência indireta (RIFI Infectious arthritis in broiler represents an economic and health problem resulting in severe losses due to retarded growth and down grading at slaughterhouse. The most common agents associated with cases of infectious arthritis in poultry are Mycoplasma synoviae and Avian orthoreovirus. This study proposed to investigate the histopathological changes caused by mixed infection with Mycoplasma synoviae and Avian orthoreovirus in broilers and conϐirm the presence of the agents through PCR and immunoϐluorescence assay (IFA). We used 16 broiler chickens, housed in bed, with supply of food and water ad libitum. Ten-day-old broilers were infected with Mycoplasma synoviae and Avian orthoreovirus. Clinically, they showed lethargy and swelling of the hock joint. After 30 days, we proceeded to their euthanasia and necropsy. Histological lesions were observed due to the mixed infection with Mycoplasma synoviae and Avian orthoreovirus in different tissues. The histopathology of the joints was characterized by inϐiltration of heterophil leucocytes in the synovial membrane and the digital ϐlexor tendon. The inϐlammatory process was also found in trachea, lungs, air sac, liver, spleen, pericardium and proventriculus. The use of IFA was necessary to verify the presence of both agents in the hock joints, identifying the antigens of Mycoplasma synoviae and Avian orthoreovirus. The presence of M. synoviae was detected by PCR in trachea, lung, air sacs, synovial membrane and synovial ϐluid. Avian orthoreovirus was detected with PCR in liver, spleen, synovial membrane and digital ϐlexor tendon. In conclusion, this investigation suggests that a synergistic relationship exists between Mycoplasma synoviae and Avian orthoreovirus.

Serrano artisanal cheese is a traditional raw milk dairy product from southern Brazil. For safe consumption of raw milk products, ripening is a critical period for reducing populations of pathogenic and spoilage microorganism and, then, the knowledge on inactivation kinetics of microorganisms is necessary to guarantee food safety and quality. In the present work, inactivation kinetics of foodborne bacterial pathogens required by Brazilian regulations in serrano artisanal cheeses were statistically evaluated during ripening. The Salmonella spp., Listeria monocytogenes, coagulase-positive strain of Staphylococcus aureus and fecal coliforms were analyzed for up to 60 days. Experimental data were fitted using first-order model, Weibull and log-linear + shoulder models. Results showed no presence of Salmonella spp. and L. monogyatogenes in the cheeses through the studied period. The first-order and Weibull models presented good performance to represent coagulase-positive strain of S. aureus and fecal coliforms during ripening, although Weibull distribution showed better outcomes to experimental data. Log-linear+shoulder equation was discarded to describe the reduction of microorganism counts for physical criteria. Kinetics showed an initial resistance of fecal coliforms to be inactivated, unlike to coagulase-positive strain of S. aureus population. Modeling analysis allowed estimating serrano artisanal cheese ripening period to be longer than 33 days for achieving a safe product according to the Brazilian Regulatory Standards.

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