Associations between Pleurisy and the Main Bacterial Pathogens of the Porcine Respiratory Diseases Complex (PRDC).

Porcine Respiratory Diseases Complex (PRDC) is a multifactorial disease that involves several bacterial pathogens, including Mycoplasma hyopneumoniae (M. hyopneumoniae), Actinobacillus pleuropneumoniae (A. pleuropneumoniae), Pasteurella multocida (P. multocida), Glaesserella parasuis (G. parasuis), and Streptococcus suis (S. suis). In pigs, the infection may cause lesions such pleurisy, which can lead to carcass condemnation. Hence, 1015 carcasses were selected from three different commercial pig farms, where the respiratory conditions were evaluated using slaughterhouse pleurisy evaluation system (SPES) and classified into five groups. In total, 106 pleural and lung fragments were collected for qPCR testing to identify the five abovementioned pathogens. A moderate correlation between the severity of the lesions and the presence of P. multocida (R = 0.38) and A. pleuropneumoniae (R = 0.28) was observed. Concerning the lung samples, the severity of the lesions was moderately correlated with the presence of P. multocida (R = 0.43) and M. hyopneumoniae (R = 0.35). Moreover, there was a strong correlation between the presence of P. multocida and M.hyopneumoniae in the pleura (R = 0.82). Finally, this approach may be a useful tool to identify and quantify causative agents of PRDC using qPCR, providing a comprehensive evaluation of its relevance, strength, and potential application in the field as a surveillance tool for veterinarians.

Use of organic acids to reduce Salmonella Typhimurium excretion in swine / Uso de ácidos orgânicos para reduzir a excreção de Salmonella Typhimurium em suínos

The use of antimicrobials as growth promoters and disease prevention is being constantly reduced in several animal production systems, including in the swine industry. Therefore, this study aimed to evaluate the effectiveness of using acidifiers to control Salmonella Typhimurium in 65-day-old pigs by detecting the pathogen in organs at euthanasia. For this, 24 piglets were divided into two experimental groups consisting of 12 piglets each. An untreated control group (G1) and a treatment group (G2) received a liquid organic acidifier in the drinking water for 10 days (D-5 to D5). Five days after the start of treatment (D0), all piglets were challenged with 106 CFU of Salmonella Typhimurium and assessed for 12 days (D12). Every three days (D3, D6, D9, and D12), three animals from each experimental group were euthanized and then submitted for necropsy. Samples from the intestines (ileum, cecum, mesenteric lymph nodes, and ileocolic lymph nodes), liver, spleen, and lungs were collected to isolate Salmonella. The results show that, numerically, Salmonellaisolation in the organs of G2 was lower than in G1 and that the number of positive cecum samples in G1 (66.7%; 8/12) was statistically different from the number of positive models in G2 (16.7%; 2/12), with a reduction of 28.6% of the total cecum positive samples in the treated group compared to the control. Therefore, it was observed that the liquid organic acidifier product could reduce the colonization of organs by Salmonella Typhimurium.(AU)

O uso de antimicrobianos como promotores de crescimento e prevenção de doenças vem sendo constantemente reduzido em diversos sistemas de produção animal, inclusive na suinocultura. Portanto, o objetivo do presente estudo foi avaliar a eficácia do uso de acidificantes no controle de Salmonella Typhimurium em suínos de 65 dias de idade, detectando o patógeno em órgãos após a eutanásia. Para isso, 24 leitões foram divididos em dois grupos experimentais constituídos por 12 leitões cada. Um grupo controle não tratado (G1) e um grupo de tratamento (G2) que recebeu um acidificante orgânico líquido na água de beber por 10 dias (D-5 a D5). Cinco dias após o início do tratamento (D0), todos os animais foram inoculados oralmente com 106 UFC de Salmonella Typhimurium e avaliados por 12 dias (D12). A cada três dias (D3, D6, D9 e D12), três leitões de cada grupo experimental foram eutanasiados e posteriormente submetidos à necropsia. Amostras de intestino (íleo, ceco, linfonodos mesentéricos e linfonodos ileocólicos), fígado, baço e pulmões foram coletadas para o isolamento de Salmonella. Os resultados mostram que, numericamente, o isolamento de Salmonella nos órgãos do G2 foi inferior ao G1, e que o número de amostras positivas de ceco no G1 (66,7%; 8/12) foi estatisticamente diferente do número de amostras positivas no G2 (16,7%; 2/12), com redução de 28,6% do total de amostras positivas de ceco no grupo tratado em relação ao controle. Portanto, observou-se que o ácido orgânico líquido foi capaz de reduzir a colonização de órgãos por Salmonella Typhimurium.(AU)

Use of organic acids to reduce Salmonella Typhimurium excretion in swine / Uso de ácidos orgânicos para reduzir a excreção de Salmonella Typhimurium em suínos

The use of antimicrobials as growth promoters and disease prevention is being constantly reduced in several animal production systems, including in the swine industry. Therefore, this study aimed to evaluate the effectiveness of using acidifiers to control Salmonella Typhimurium in 65-day-old pigs by detecting the pathogen in organs at euthanasia. For this, 24 piglets were divided into two experimental groups consisting of 12 piglets each. An untreated control group (G1) and a treatment group (G2) received a liquid organic acidifier in the drinking water for 10 days (D-5 to D5). Five days after the start of treatment (D0), all piglets were challenged with 106 CFU of Salmonella Typhimurium and assessed for 12 days (D12). Every three days (D3, D6, D9, and D12), three animals from each experimental group were euthanized and then submitted for necropsy. Samples from the intestines (ileum, cecum, mesenteric lymph nodes, and ileocolic lymph nodes), liver, spleen, and lungs were collected to isolate Salmonella. The results show that, numerically, Salmonella isolation in the organs of G2 was lower than in G1 and that the number of positive cecum samples in G1 (66.7%; 8/12) was statistically different from the number of positive models in G2 (16.7%; 2/12), with a reduction of 28.6% of the total cecum positive samples in the treated group compared to the control. Therefore, it was observed that the liquid organic acidifier product could reduce the colonization of organs by Salmonella Typhimurium. (AU)

Salmonella Bacterin Vaccination Decreases Shedding and Colonization of Salmonella Typhimurium in Pigs.

Since the occurrence of swine salmonellosis has increased over time and control strategies other than biosecurity are highly recommended, the present study aimed to evaluate the efficacy of vaccination with Salmonella Choleraesuis and Salmonella Typhimurium bacterins in pigs. Two experimental groups were formed: G1, animals immunized with two doses of a commercial vaccine (n = 20); G2, control group (n = 20). After vaccination, all pigs were orally challenged (D0) with 108 CFU of Salmonella Typhimurium and evaluated for 40 days. Every 10 days after D0, five piglets from each experimental group were euthanized and submitted to the necroscopic examination, when organ samples were collected. Blood samples and rectal swabs were collected before the first dose of the vaccine (D-42), before the second dose (D-21), before the challenge (D0), and thereafter, every three days until D39. Blood count, serum IgG measurement by ELISA, and the excretion of Salmonella Typhimurium in feces were evaluated. While the results from blood count and serum IgG concentration did not differ, the detection and excretion of Salmonella between G1 and G2 differed (p < 0.05). Therefore, it was observed that this vaccine partially protected the animals against experimental infection with Salmonella Typhimurium, reducing the excretion of bacteria in feces.

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.

Anti-influenza A virus antibodies in Tayassuidae from commercial rearing farms in Brazil / Detecção de anticorpos contra vírus influenza A em Tayassuidae de criações comerciais no Brasil

ABSTRACT: Family Tayassuidae in the suborder Suina include two species of peccaries in Brazil: the white-lipped peccary (Tayassu pecari) and the collared peccary (Pecari tajacu). These animals share common pathogens with domestic swine (Sus scrofa); however, their role as potential carrier remains unclear. This study focused on detecting the prevalence of influenza A antibodies in Tayassu pecari and Pecari tajacu from commercial rearing farms from two states in Brazil. A set of 50 blood samples from Pecari tajacu and 55 from Tayassu pecari were analyzed using a commercial indirect ELISA in order to investigate anti influenza A antibodies. Pecari tajacu samples presented 22% (11/50) of seropositivity for the virus. Serological surveillance is an important tool to identify the presence and the spread of the influenza virus in feral pigs.

RESUMO: A família Tayassuidae pertencente a subordem Suina e compreende duas espécies presentes no Brasil: Queixada (Tayassu pecari) e o Caititu (Pecari tajacu). Ambas as espécies compartilham patógenos com o suíno doméstico (Sus scrofa), entretanto o papel destes animais como carreadores destas infecções permanece indefinido. O presente estudo teve como objetivo detectar a ocorrência de anticorpos contra vírus influenza A em amostras de soro de rebanhos comerciais de queixada e caititu, provenientes de dois estados do Brasil. Um total de 50 amostras de soro de Pecari tajacu e 55 amostras de Tayassu pecari foram testadas por meio de ELISA, sendo que 22% (11/50) das amostras de Pecari tajacu foram soropositivas para o agente. Estudos de vigilância sorológica são importantes para identificar a presença e a disseminação do vírus influenza em suínos selvagens.

Congenital tremor in piglets: Is bovine viral diarrhea virus an etiological cause?

Congenital tremor in pigs involves several etiologies, including pestivirus, which may cause neurological injuries in different animal species. To evaluate whether bovine viral diarrhea virus (BVDV), an important pestivirus, is one of the etiological agents of congenital tremor in swine, gilts and the fetuses were challenged at 45 days of gestation with BVDV-2. Four pregnant gilts were inoculated oronasally, four gilts underwent fetal intrauterine inoculation, and two gilts constituted the control group. Antibody titers were determined by virus neutralization (VN), and viral RNA was detected by RT-PCR. Blood samples were collected from all gilts and piglets born to obtain whole blood and serum for analysis. One third of the neonates were euthanized at three days old, and samples of the encephalon, brain stem and spinal cord were collected for anatomopathological evaluation and viral RNA detection. The piglets that remained alive were clinically evaluated every day, and blood sampling was performed regularly for 35 days. The piglets from gilts in both inoculation treatment groups showed no clinical neurological signs and were born with no viral RNA in their blood and organs. Piglets born from oronasally inoculated gilts did not present antibodies against BVDV-2 at birth, although they were acquired by passive maternal transfer. In contrast, intrauterine-inoculated piglets were born with high antibody titers (80 to 640) against the agent, which remained high until the end of the experimental period. Microscopically, no noticeable changes were observed. Macroscopically, 29.5% of the total piglets euthanized, from both inoculation groups, were born with a low cerebellar:brain ratio. Nevertheless, some piglets had a high cerebellar:brain ratio, indicating the need for standardizing this value. Thus, it was concluded that BVDV is not an etiological agent for congenital swine tremor.

Bovine viral diarrhea virus infections in pigs: why is this situation important for Brazilian herds? / A infecção pelo vírus da diarreia viral bovina em suínos: por que essa situação é importante para os rebanhos brasileiros?

Swine can be infected by the bovine viral diarrhea virus (BVDV) under natural conditions. For this reason, further information and divulgation are needed regarding the pathogenicity of this virus in swine. This infection is practically unknown in the realm of pig farming, and, as it shares some similarities with the classical swine fever virus (CSFV), its diagnosis becomes a challenge for official sanitary programs. Studies have shown the absence of clinical signs in piglets and reproductive problems in sows due to BVDV infections. There is little research on the prevalence, risk factors, preventive measures and control of BVDV in pigs around the world. And in Brazil, the data is practically non-existent. At the time of diagnosis, comparing the most efficient laboratory tests such as virus neutralization, ELISA, RT-PCR, and immunofluorescence so as to minimize the risk of cross serological reactions when dealing with a persistent or transient infection, can be an important tool. Moreover, the practical implications for CSFV eradication programs are a main reason for the development of further research against this infection. Therefore, this paper aims to review various aspects of BVDV infection in pigs, and how this information can be important for Brazilian herds.(AU)

O suíno pode ser infectado pelo vírus da diarreia viral bovina (BVDV) em condições naturais, por isso são necessárias maiores informações e mais divulgação sobre a ação deste vírus nos suínos. Esta infecção é praticamente desconhecida na suinocultura e, devido a algumas semelhanças com vírus da peste suína clássica (VPSC), torna-se um desafio para os programas sanitários oficiais. Estudos revelam a ausência de sinais clínicos em leitões ao mesmo tempo em que evidenciam problemas reprodutivos em porcas devido à infecção do BVDV. Poucas são as pesquisas sobre a prevalência, fatores de riscos, medidas de prevenção e controle do BVDV em suínos no mundo e, no Brasil, os dados são praticamente inexistentes. No diagnóstico, comparar os exames laboratoriais mais eficientes como a virusneutralização, ELISA, RT-PCR e imunofluorescência, diante de uma infecção persistente ou transitória, e assim minimizar o risco de reações sorológicas cruzadas pode ser uma ferramenta fundamental. Ademais, as implicações práticas em programas de erradicação da PSC são um grande motivo para o desenvolvimento de mais pesquisas frente a esta infecção. Portanto, este trabalho pretende revisar diversos aspectos da infecção do BVDV em suínos evidenciando o quanto essa situação pode ser importante para os rebanhos brasileiros.(AU)

A cross-sectional study to estimate the frequency of anti-bovine viral diarrhea virus-1 antibodies in domestic pigs of Mossoró region in the state of Rio Grande do Norte, Brazil / Estudo transversal para estimar a frequência de anticorpos anti-vírus da diarreia viral bovina-1 em suínos domésticos da região de Mossoró, no estado do Rio Grande do Norte, Brasil

ABSTRACT: This study investigated the occurrence of antibodies for BVDV-1 in swine herds located in the region of Mossoró city of the state of Rio Grande do Norte, Brazil. A sample size of 412 animals was estimated assuming unknown prevalence (set at 50%). Virus neutralization assay was used to the detect the presence of antibodies for BVDV-1 and the results found were analysed using multivariable logistic regression model. The obtained prevalence was 4% at animal level and 45% at the animal and herd level. The titers were highly variable between animals and within farms. The multivariable logistic regression analysis showed an association between being housed outside and exposure to BVDV-1 (OR=0.24, 95% CI:0.06, 0.96, P=0.04). Highly correlated data and low prevalence of antibodies at the animal level resulted in insufficient power to detect significant differences with other selected risk factors. In conclusion, the prevalence is within the range reported for other countries.

RESUMO: Este estudo investigou a ocorrência de anticorpos contra o BVDV-1 em rebanhos suínos localizados na região da cidade de Mossoró do Estado do Rio Grande do Norte, Brasil. Um tamanho de amostra de 412 animais foi estimado assumindo uma prevalência desconhecida (fixada em 50%). O teste de virusneutralização foi utilizado para detectar a presença de anticorpos ao BVDV-1 e os resultados obtidos foram analisados usando o modelo de regressão logística multivariada. A prevalência obtida foi de 4% em nível animal e de 45% dos rebanhos. Os títulos foram muito variáveis entre os animais e dentro de fazendas. A análise de regressão logística multivariada apontou associação entre animais criados soltos e a exposição ao BVDV-1 (OR=0,24; 95% IC: 0,06; 0,96; P=0.04). A alta correlação entre os dados junto com a baixa prevalência de anticorpos a nível animal pode ter sido insuficiente para que as diferenças reais fossem detectadas. Em conclusão, a prevalência está dentro do intervalo referido em outros países.

Virulence factors of Escherichia coli in relation to the importance of vaccination in pigs / Fatores de virulência da Escherichia coli associados à importância da vacinação nos suínos

ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) is the major cause of diarrhea in newborn and weaned pigs. Bacteria adhesion to the host cell is considered a specific phenomenon among fimbrial and non-fimbrial adhesins with their respective receptors on enterocytes. Enteric disorders are related with the fimbriae F4 (K88), F5 (K99), F6 (987P), F41, and F18. In addition to ETEC, another category of E. coli , porcine pathogenic E. coli (PEPEC),can cause diarrhea in pigs; it produces the porcine attaching and effacing-associated (Paa) adhesin in, which is capable to cause a typical lesion known as an attaching and effacing (A/E) lesion. Immunization of sows with adhesin is important to stimulate the production of antibodies and their subsequent transfer to piglets through colostrum. The aim of this paper is to illustrate the main impacts of enteric diseases caused by E. coli in swine production and to highlight the importance of continuing research on this bacterium to improve disease prevention through vaccination.

RESUMO: Escherichia coli ( E. coli ) enterotoxigênica (ETEC) é considerada importante causa de diarreia em suínos neonatos e desmamados. A adesão da bactéria à célula do hospedeiro é considerada um fenômeno específico entre as adesinas fimbriais e não fimbriais com seus respectivos receptores nos enterócitos. Os distúrbios entéricos estão relacionados com as fímbrias F4 (K88), F5 (K99), F6 (987P), F41 e F18. Além da ETEC, outra categoria de E. coli pode causar diarreia nos suínos, denominada de PEPEC (porcine pathogenic E. coli ), a qual produz a adesina Paa (Porcine attaching adherence), capaz de provocar uma lesão típica denominada A/E (attaching and effacing). A imunização das matrizes com adesinas é importante para estimular a produção de anticorpos e a consequente transferência através do colostro aos leitões. O objetivo deste trabalho foi mostrar os principais impactos das doenças entéricas causadas por Escherichia coli na produção de suínos, e mostrar a importância de atualizar o estudo dessa bactéria para prevenir a doença através da vacinação.

Estratégia para erradicação de focos da Doença de Aujeszky em suínos no Estado de São Paulo / Strategy for eradication of outbreaks of Aujeszky's Disease in pigs in the São Paulo state

Este trabalho teve como objetivo a avaliação de duas estratégias para erradicação de focos da doença de Aujeszky (DA) em suínos criados comercialmente no estado de São Paulo. Foram identificados dois focos da enfermidade, no município de Cerqueira César, um apresentando somente animais sororreagentes (Foco 1) e outro, casos clínicos da doença (Foco 2). Foram avaliadas duas estratégias de erradicação, uma por eliminação dos sororreagentes e outra por despovoamento gradual, com acompanhamento durante 12 meses. A erradicação por eliminação dos sororreagentes foi aplicada no Foco 1 e compreendeu na identificação por exame sorológico, isolamento e abate dos positivos; vacinação dos negativos e reposição no plantel com animais provenientes de propriedade livre. No início dos trabalhos, 68% do plantel era positivo e ao final 51%. No Foco 2 utilizou-se o despovoamento gradual, onde todos os animais foram enviados ao abate sanitário, realizado vazio sanitário nas instalações, seguido pelo repovoamento com animais livres. Esta última estratégia, nas condições desse trabalho, mostrou-se a mais eficaz, pois erradicou a DA.

This study aimed to evaluate strategies for eradication of Aujeszky Disease (AD) virus infection after outbreaks in swine production systems in Sao Paulo state. Two outbreaks were identified in Cerqueira César county. The first outbreak coursed with seropositive pigs (outbreak 1), and the other with pigs presenting clinical signs (outbreak 2). In order to eradicate the infection, two sanitary strategies were tested: (1) eradication of animals with positive serology and (2) by gradual depopulation, with a follow up of 12 months. The serology eradication was used in outbreak 1, and included the identification, isolation and slaughter of positive animals; followed by vaccination of negative animals and replacement with pigs from farms free of the disease. At the beginning, 68% of pigs were positive, and at the end it declined to 51%. In outbreak 2, gradual depopulation was used, and all animals were sent to sanitary slaughter, until facilities were completely empty. Afterwards, animals free of the disease were used for repopulation. It was seen that the last strategy was more effective because eradicated the infection.