Main Causes of Death in Piglets from Different Brazilian Nursery Farms Based on Clinical, Microbiological, and Pathological Aspects.

Necropsies can reveal herd problems or comorbidities that can lead to management corrections, improvements in animal performance, and better decision making. Furthermore, the pattern and causes of mortality might differ when different systems are evaluated. The present study was conducted to establish the main causes of death in nursery pigs from different systems in Brazil, as well as the clinical, microbiological, and pathological aspects of these mortalities. Eighteen nurseries were analyzed (a total of 120,243 housed piglets), and 557 necropsies were performed. Streptococcus suis infection was the most prevalent cause of death (21.2%), followed by bacterial polyserositis (16.7%), chronic atrophic enteritis (13.5%), salmonellosis (8.8%), pneumonia (8.6%), and colibacillosis (6.1%). The increase in mortality rate in individual nurseries and, consequently, in the diagnoses was commonly associated with disease outbreaks. Infectious diseases constituted the largest portion of the diagnoses, making a great opportunity for improving production rates in herds. Moreover, the extensive range of observed diagnoses highlights the importance of conducting preliminary diagnostic investigations based on necropsy to determine the causes of death. This approach allows for the direction of complementary tests, which can diagnose agents with greater specificity. As a result, this allows for the implementation of more effective prevention and control strategies.

MicroRNAs as serum biomarker for Senecio brasiliensis poisoning in cattle.

Senecio spp. is one of the most frequent plant-related poisonings in cattle. Its ingestion generates the disease seneciosis, characterized by hepatic damages. Liver biopsies and serum markers dosage are tools used in diagnosis; however, many breeding cattle are undiagnosed. MicroRNAs are non-coding RNA, stable in biological fluids. Their difference in expression levels may indicate the presence of the poisoning. We analyzed the miRNA profiling to identify potential diagnostic biomarkers for Senecio brasiliensis poisoning. The expression of miR-21, miR-885, miR-122, miR-181b, miR-30a, miR-378, and let-7 f were evaluated in the serum of exposed cattle. At least one histological change was found in liver and lower quantity of albumin and high AST and ALP were also detected. MiRNAs miR-30a, miR-378, miR-21, miR-885, and miR-122 presented significantly higher expression in intoxicated animals than in healthy animals. Furthermore, miR-122, miR-885, and, especially, miR-21 signatures demonstrated high sensitivity and specificity, with potential application for detecting poisoning.

Evaluation of buffered Trypanosoma evansi antigen and rapid serum agglutination test (BA/Te) for the detection of anti-T. evansi antibodies in horses in Brazil.

Surra is an infectious disease caused by Trypanosoma evansi, which affects a large number of domestic and wild animal species. Infection control is based on rapid diagnosis followed by treatment of sick animals. This study aimed to evaluate a buffered T. evansi antigen and rapid serum agglutination test (BA/Te) for the detection of anti-T. evansi antibodies in serum samples of horses. For this purpose, 445 serum samples from horses were evaluated and the results compared with the diagnosis by CATT/T. evansi. Our data show a sensitivity of 92%, specificity of 91% and a degree of agreement kappa (κ) of 0.82 (95% CI: 0.771-0.877, P < 0.01) between BA/Te and CATT/T. evansi. Antigen specificity was also evaluated against reactive serum for other infectious agents circulating in equine herds. In conclusion, our findings show that BA/Te has the potential to be a practical and quick screening method for the detection of anti-T. evansi antibodies in horses.

First outbreak of autochthonous "surra" in horses in Santa Catarina State, Brazil: Parasitological, hematological and biochemical characteristics.

This study reports the first autochthonous "surra" outbreak in horses in the State of Santa Catarina, southern Brazil. Six horses with clinical suspicion of trypanosomosis had the natural infection by T. evansi confirmed by PCR and rapid serum agglutination test. Clinical, parasitological, and hematology evaluations were performed at initial observation (T0) and 90 days after (T1). At T0, all animals that tested positive for T. evansi in PCR presented with severe clinical signs and out of normal range hematological hematological (hematocrit, leukocytes, platelets, hemoglobin) and serum biochemical parameters (alanine aminotransferase (ALT), creatinine phosphokinase (CPK), lactate dehydrogenase (LDH), creatinine, bilirubin, and glucose). At T1, the progressive clinical recovery of animals, normalization of hemato-biochemical parameters, and negative PCR results for T. evansi were observed. It was not possible to identify the vector/mechanism of transmission through which animals were infected; therefore, the implementation of surveillance and control measures is essential to prevent the spread of this disease in horse herds, as well as to other animal species.

Molecular detection of Mycoplasma synoviae and avian reovirus infection in arthritis and tenosynovitis lesions of broiler and breeder chickens in Santa Catarina State, Brazil.

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.

First evaluation of an outbreak of bovine babesiosis and anaplasmosis in Southern Brazil using multiplex PCR.

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.

Asymptomatic cattle naturally infected with Mycobacterium bovis present exacerbated tissue pathology and bacterial dissemination.

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.

Rapid detection of Mycoplasma synoviae and avian reovirus in clinical samples of poultry using multiplex PCR.

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.

Características clínicas e anatomo-histopatologicas da infecção experimental mista por Orthoreovirus aviario e Mycoplasma synoviae em frangos de corte / Clinical and histologic lesions of mixed infection with Avian orthoreovirus and Mycoplasma synoviae in broilers

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 confirmar a presença dos agentes através das técnicas de PCR e imuno-luorescência indireta (RIFI). Para tal foram utilizados 16 frangos de corte, alojados em cama, com fornecimento de ração e água ad libitum. A infecção experimental foi realizada utilizando amostras atenuadas de MS e de ARV. Clinicamente as aves inoculadas apresentaram apatia e edemaciação da região da articulação tíbiotársica. Após 30 dias procedeu-se a eutanásia e a necropsia das aves. Na análise histopatológica constatou-se o efeito da infecção mista com MS e ARV sobre os diferentes órgãos/tecidos. Todos os animais apresentaram quadro de artrite e tenossinovite caracterizado pela presença de infiltrado inflamatório linfohistiocitário difuso, com acúmulo de heterófilos na cápsula articular/membrana sinovial e tendão flexor digital. Além disso, foi possível observar infiltrado inflamatório na traquéia, nos pulmões e sacos aéreos, no fígado, baço, pericárdio e proventrículo. A utilização da RIFI foi necessária para visualizar a presença de ambos os agentes nas articulações, identificando a presença de antígenos do ARV e do MS. A técnica de PCR constatou positividade do MS na traquéia, pulmões/sacos aéreos, cápsula articular/membrana sinovial e liquido sinovial. Já para o ARV a PCR foi positiva em amostras de fígado, baço, cápsula articular/membrana sinovial e tendão flexor digital. Com base nas lesões observadas e nos dados da literatura, sugere-se a ação concomitante por MS e ARV nos diferentes tecidos.

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 confirm the presence of the agents through PCR and immunofluorescence 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 infiltration of heterophil leucocytes in the synovial membrane and the digital flexor tendon. The inflammatory 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 fluid. Avian orthoreovirus was detected with PCR in liver, spleen, synovial membrane and digital flexor tendon. In conclusion, this investigation suggests that a synergistic relationship exists between Mycoplasma synoviae and Avian orthoreovirus.

Agentes bacterianos enteropatogênicos em suínos de diferentes faixas etárias e perfil de resistência a antimicrobianos de cepas de Escherichia coli e Salmonella spp / Enteropathogenic bacterial agents in pigs of different age groups and profile of resistance in strains of Escherichia coli and Salmonella spp. to antimicrobial agents

As enterites infecciosas bacterianas provocam severas perdas para a indústria suína em todo o mundo. Os objetivos deste trabalho foram determinar os agentes bacterianos, associados com a ocorrência de diarréia em suínos, em diferentes faixas etárias, no Estado de Santa Catarina, Brasil, e verificar o perfil de resistência das cepas de Escherichia coli e Salmonella spp, frente aos principais antimicrobianos utilizados em granjas de suínos. Os principais gêneros/espécies bacterianos diagnosticados foram Escherichia coli, Clostridium spp, Salmonella spp Brachyspira hyodysenteriae, Brachyspira pilosicoli e Lawsonia intracellularis. Os fatores de virulência de E. coli mais prevalentes na fase de maternidade foram F5 / (K99) 20 por cento, F6 / (987P) 16,3 por cento, F42 6,8 por cento e F41 5,7 por cento, já nas fases de creche e terminação, predominaram cepas com fimbrias F4 (K88) 11,2 por cento e 5,4 por cento, respectivamente. Para E. coli os maiores índices de resistência foram encontrados para oxitetraciclina (94 por cento) e tetraciclina (89,5 por cento) e os menores índices de resistência para neomicina (55 por cento), ceftiofur (57,4 por cento). Quanto às amostras de Salmonella spp, estas apresentaram maior resistência à oxitetraciclina (77 por cento), e à tetraciclina (42,1 por cento) e menor à gentamicina (3,5 por cento) e amoxicilina (4,8 por cento).

Infectious bacterial enteritis causes severe losses to the swine industry worldwide. The objective of this study was to determine the epidemiology of bacterial agents that are associated with the occurrence of diarrhea in pigs at different age groups, and to verify the profile of resistance of strains of Escherichia coli and Salmonella spp to the main antimicrobial agents. The main bacterial species diagnosed were Escherichia coli, Clostridium spp, Salmonella spp, Brachyspira hyodysenteriae, Brachyspira pilosicoli and Lawsonia intracellularis. The E. coli virulence factors of higher prevalence in preweaning piglets were F5 / (K99) 20 percent, F6 / (987P) 16.3 percent, F42 6.8 percent and F41 5.7 percent, whereas at the nursery and with finishing pigs, the prevalent strain was the fimbria F4 (K88) 11.2 percent e 5.4 percent, respectively. E. coli and Salmonella spp were highly resistant to oxytetracycline (94 percent) and tetracycline (90 percent), with the former having a low resistance to neomycin (55 percent) and ceftiofur (57 percent), and the latter to gentamicin (3.5 percent) and amoxicillin (4.8 percent).