Dinâmica de infecção de Mycoplasma hyopneumoniae em leitoas de reposição

A infecção por Mycoplasma (M.) hyopneumoniae é responsável por perdas econômicas significativas na suinocultura, causando uma pneumonia crônica que normalmente afeta clinicamente suínos de crescimento e terminação. Considerando-se a importância das matrizes de menor ordem de parto na transmissão de M. hyopneumoniae e que uma grande quantidade de leitoas é introduzida nos planteis anualmente, este projeto teve como objetivo compreender aspectos pouco conhecidos da dinâmica de infecção de M. hyopneumoniae em leitoas de reposição. O primeiro estudo avaliou a dinâmica e persistência da infecção por M. hyopneumoniae em leitoas em condições naturais de campo. Quarenta e quatro leitoas foram selecionadas aos 20 dias de idade (ddi) e a detecção de M. hyopneumoniae por PCR foi avaliada mensalmente por suabe de laringe, resultando em um total de 12 coletas. Além disso, 220 leitões filhos dessas matrizes foram amostrados um dia antes do desmame para avaliação da transmissão vertical. Os resultados deste estudo demonstraram que o início da detecção ocorreu aos 110 ddi e um aumento significativo foi observado aos 140 ddi (p<0,05). Ao desmame, apenas 2,3% das fêmeas foi positiva e não foram detectados leitões desmamados positivos. Adicionalmente, 77,2% das leitoas foi detectada positiva por um a três meses, 4,6% por quatro a cinco meses e 18,2% nunca foi detectada positiva, indicando a presença de subpopulações de animais negativos em granjas positivas. Em um segundo estudo, avaliou-se a detecção de M. hyopneumoniae por PCR em leitoas de reposição interna e a variabilidade genética entre granjas foi avaliada por MLVA (Multiple Locus Variable-number tandem repeats Analysis). Um total de 298 leitoas provenientes de três multiplicadoras positivas foram selecionadas e coletadas uma vez para realização de ELISA e duas a três vezes para PCR em um estudo longitudinal. Ainda, a transmissão vertical foi avaliada em 425 leitões pré-desmame. Aos 150 ddi, 47 a 67,4% das leitoas foi detectada positiva por PCR, decréscimos foram observados até a última amostragem nas três granjas avaliadas (p<0,05), e nenhum leitão foi positivo pré-desmame. Ainda, 30,7% das leitoas não foi detectada positiva em nenhuma nas amostragens e os resultados de MLVA indicaram um ampla variabilidade genética de M. hyopneumoniae em leitoas aos 150 ddi. No terceiro estudo, 210 leitoas de reposição negativas para M. hyopneumoniae introduzidas em três granjas positivas foram selecionadas e avaliadas longitudinalmente por PCR e ELISA com o objetivo de comparar dois tipos de fluxo de aclimatação (all-in all-out ou fluxo contínuo). Ainda, a variabilidade genética foi analisada por MLVA. Observou-se um aumento significativo (p<0,05) nas prevalências de leitoas positivas para M. hyopneumoniae por PCR na segunda coleta e um decréscimo ao longo do tempo independentemente do tipo de fluxo de aclimatação utilizado. Os resultados de ELISA revelaram que as três granjas avaliadas tiveram um aumento significativo na prevalência de leitoas positivas da primeira para a segunda coleta (p<0,05), que se manteve alta até o fim do experimento. Ainda, baixa variabilidade genética de M. hyopneumoniae foi observada por MLVA. Um quarto estudo também foi conduzido com o objetivo de avaliar a absorção e detecção de M. hyopneumoniae utilizando-se suabes de nylon flocados e de ponta de rayon. Os resultados deste experimento indicaram uma maior absorção e uma maior detecção de M. hyopneumoniae por PCR (p<0,05) utilizando-se suabes de nylon flocados.Mycoplasma (M.) hyopneumoniae infection is responsible for important economic losses to pig production, causing a chronic pneumonia that usually affects growing and finishing pigs. Regarding the importance of low parity dams on M. hyopneumoniae transmission and that a high proportion of gilts is introduced in the farms every year, this project aimed to better understand unknown aspects about the infection dynamics of M. hyopneumoniae in replacement gilts. The first study assessed the dynamics and persistence of M. hyopneumoniae infection in gilts in natural conditions. Forty-four gilts were selected at 20 days of age (doa) and M. hyopneumoniae detection was evaluated using laryngeal swabs for PCR testing every month, resulting in 12 samplings. Additionally, 220 piglets born from the selected dams were sampled one day prior to weaning to evaluate vertical transmission. The results of this study showed that the first detection occurred at 110 doa and a significant increase was observed at 140 doa (p<0.05). A small proportion (2.3%) of positive gilts was detected one day prior to weaning and no piglets were detected positive at the same sampling moment. Moreover, 77.2% of the gilts was detected positive for one to three months, 4.6% for four to five months, and a lack of detection was observed in 18.2% of the gilts, indicating the presence of negative subpopulations in positive farms. A second study assessed the M. hyopneumoniae detection in self-replacement gilts longitudinally. A total of 298 gilts from three positive multiplier farms were selected and sampled once for ELISA testing and two or three times for PCR. Moreover, vertical transmission was evaluated in 425 piglets one day prior to weaning, and the genetic variability within farms was assessed in gilts by MLVA (Multiple Locus Variablenumber tandem repeats Analysis). The prevalence of positive gilts at 150 doa ranged from 47 to 67.4% within farms by PCR, decreases were observed up to the last sampling in all farms (p<0.05), and no positive piglets were detected prior to weaning. A lack of detection was observed in 30.7% of the gilts during the study, and high genetic variability was detected within farms. In the third study, 210 M. hyopneumoniae negative purchased gilts were introduced in three farms with two types of acclimation flow (all-in all-out or continuous flow). The gilts were selected for ELISA and PCR testing in a longitudinal study, which aimed to compare the infection dynamics regarding the type of flow. Also, genetic variability was assessed by MLVA. The results showed a significant increase (p<0.05) in the prevalence of M. hyopneumoniae positive gilts by PCR in the second sampling, and a decrease over time regardless the type of flow. The ELISA results revealed a significant increase in the prevalence of positive gilts in the three farms (p<0.05) from the first to the second sampling, which remained high up to the completion of the study. Moreover, limited genetic variability of M. hyopneumoniae was observed by MLVA testing. A fourth study was also performed, which aimed to assess the absorption and detection of M. hyopneumoniae using two types of swabs (nylon-flocked and rayon-bud). The results indicated a higher absorption and M. hyopneumoniae detection by PCR using nylon-flocked swabs (p<0.05)

Frequency of Methicillin-Resistant Staphylococcus aureus (MRSA) in Fattening Pigs in the State of Rio Grande do Sul, Brazil

Background: Staphylococcus (S.) aureus is an important nosocomial pathogen in humans and animals worldwide. The commonest class of antibiotics used to treat staphylococcal infections is the β-lactams. Frequently, S. aureus strains show high resistance to methicillin and other β-lactam antibiotics, called “Methicillin-resistant Staphylococcus aureus” (MRSA). Although MRSA has emerged at slower rate in domestic animals, it has frequently been found in the nasal cavity of healthy piglets and its transmission between pigs and swine handlers has already been studied. The aim of this work was to assess the presence of MRSA in finishing pigs in the state of Rio Grande do Sul, Brazil.Materials, Methods &amp; Results: A total of 350 nasal swabs were collected from 10 to 20 week old finishing pigs. Sampling was performed in five pig farms in northeast Rio Grande do Sul State, Brazil. Swabs were stored in tubes without transport medium and carried to the laboratory under refrigeration. The specimens were cultured in selective and differential Agar (Baird Parker) and then were incubated at 37ºC for 48 h. After isolation of typical colonies of S. aureus, they were inoculated in BHI (Brain Heart Infusion) broth at 37ºC for 24 h and tested for tube coagulase activity. Coagulase positive samples were selected for growth in Oxacillin Resistant Screening Agar (ORSA) supplemented with 2 mg/L of oxacillin. This media contains aniline blue to demonstrate mannitol fermentation. Oxacillin and 5.5% NaCl have the capacity to reduce the growth of non-staphylococcal bacteria, selecting for MRSA.  Blue colonies growth after 24 to 48 h of incubation at 37ºC indicate the presence of positive MRSA strains. Specimens with at least one colony growing in ORSA within 48 h were considered resistant. Linear regression was performed in order to identify the association between herd size and MRSA frequency (SAS 9.4, 2012). Growth of S. aureus occurred on 18.0% of the samples and differences among farms were found. However, after incubation in ORSA only 18 (5.1%) were MRSA positive, ranging from zero to 12.5% among farms.  Significant correlation between herd size and MRSA frequency (adjusted r² = 0.978; P = 0.001) was observed.Discussion: In a previous study in pig herds in Brazil examining swine nasal swabs, 22.5% was positive for S. aureus and none for MRSA. One of 5 farms tested in our work also had no positive animals and 4 of them showed low frequencies, ranging from 1.7% to 12.5% with an average of 5.1%. Our results were similar to those found in Asian countries, but were very different from European data. Some factors can be associated with MRSA frequency in pig farms, such as dust, air contamination, poor hygiene, age, herd size, replacement rate and number of sources. In the present work we found a strong positive correlation (r² adjusted = 0.978; P = 0.001) between herd size and MRSA frequency, such as detected by previous authors. It might occur due to a higher risk of bacterial introduction and higher pressure of infection, easing dissemination of MRSA. Herd size may be a crucial factor to explain the frequencies found, since farms had very similar facilities and handling practices. Although the average frequency has been low in this work when compared to other countries, MRSA was present in almost all farms. This bacteria is able to transmit mecA gene to S. aureus susceptible populations, increasing MRSA frequencies over time

Virulence Factors and Antimicrobial Resistance Profile of Escherichia coli Isolated from Nursery Piglets and Drinking Water

Background: One of the most frequent health problems in the swine industry is the post-weaning diarrhea in nursery pigs, which leads to significant losses due to weight loss, dehydration, cost of medication and mortality. Escherichia coli  (E. coli) is one of the main bacterial agents of the post-weaning diarrhea. To investigate the possibility of enterotoxigenic  E. coli (ETEC) transmission through drinking water to nursery piglets, the objective of this study was to isolate, characterize by virulence factors, and compare the antimicrobial resistance profiles of E. coli from drinking water samples in nurseries and from rectal swabs of their piglets presenting post-weaning colibacillosis.Materials, Methods & Results: Fifteen rectal swabs from diarrheic piglets in their first three weeks after weaning and one water sample were collected from each of ten nurseries located in Rio Grande do Sul State, south of Brazil. After enrichment with a commercial broth medium, water samples were cultured in blood agar, as well as the rectal swab samples, and the characteristic colonies were identified by standard biochemical analysis. Following isolation and identification of E. coli, the colonies from water samples and their corresponding piglets’ samples were characterized by multiplex PCR in order to determine specific ETEC fimbria and toxin genes. Finally, all E. coli isolates were submitted to antimicrobial susceptibility testing. Virulence factors and antimicrobial sensitivity could then be compared between water and piglets’ samples. The difference in the antimicrobial resistance frequency for each of the sample groups were compared using the multi comparison test. E. coli was isolated in four out of the ten water samples, although none of the water samples presented ETEC virulence factors. From 60 rectal swab samples (15 from each of the four positive farms with E. coli isolated from water samples), 21 E. coli were isolated and seven demonstrated characteristic ETEC virulence factors. The fimbriae exhibited in higher frequency were F18 (62.5%) and F4 (25%) and the toxins were STb (100%) and STaP (75%). E. coli isolated from water samples presented higher resistance to the antimicrobials apramycin, florfenicol, lincomycin, lincomycin+spectinomycin, oxytetracycline, and sulfamethoxazole+trimethoprim; it did not present resistance to colistin and fosfomycin. The seven ETEC from rectal swab samples presented a higher resistance to lincomycin, and lower resistance frequency to fosfomycin. The other 14 E. coli non-ETEC from rectal swab samples presented a higher resistance to florfenicol and no resistance to colistin.Discussion: Enterotoxigenic E. coli is an important agent causing post-weaning colibacillosis, although, differently from other studies, this experiment did not find the agent in most of the sampled animals. In contrast to other authors, ETEC was not found in water, as the development of its virulence factors may depend on conditions presented exclusively in the animal. By the results we can conclude that, although E. coli was isolated from the drinking water, it was not a significant mechanism for nursery piglets’ infection with ETEC in this experiment. The samples analyzed presented a wide range of resistance to different antimicrobials, including multi-resistance. In some cases, E. coli found in water presented different antimicrobial profile from the bacterium found in the rectal swab samples. Enterotoxigenic E. coli was susceptible to fosfomycin and its use may represent a prudent antimicrobial choice to the swine industry

EPIDERMITE EXSUDATIVA DOS SUÍNOS

A epidermite exsudativa (EE) é uma doença da pele causada pelo coco Gram-positivo Staphylococcus (S.) hyicus. Acomete suínos de diversas idades, sendo mais frequente em leitões de maternidade ou recém-desmamados. Para que a infecção se estabeleça e a doença se desenvolva é fundamental a ação de toxinas esfoliativas produzidas por cepas virulentas de S. hyicus, que são responsáveis por induzir as lesões da pele. O diagnóstico presuntivo da EE é realizado considerando variáveis como: a idade dos animais afetados, distribuição e progressão das lesões e sinais clínicos. O diagnóstico definitivo pode ser obtido pelo isolamento do S. hyicus. O controle da enfermidade depende da correção dos fatores predisponentes, incluindo o uso de terapia antimicrobiana que deve ser usada para animais nas fases iniciais da doença

Comparison of Phenotypic and Genotypic Identification Methods of Pasteurella multocida Serotypes Isolated from Pigs

Background: Pasteurella multocida serotypes A and D are commonly associated with pneumonia and pleuritis in pigs.  Different phenotypic techniques, such as hyaluronidase and acriflavine tests, and genotyping techniques, such as PCR, are used to distinguish between these serotypes. The objective of this study was to compare the capsular identification methods of type A and type D P. multocida isolated from pigs using both phenotypic (hyaluronidase and acriflavine tests) and genotypic (multiplex PCR) techniques.Materials, Methods & Results: A total of 44 lyophilized P. multocida isolates, obtained between 1981 and 1997 from pig farms at Rio Grande do Sul State, Brazil, were analyzed. The isolates were reactivated in Brain Heart Infusion (BHI) broth and cultured in BHI broth and blood agar supplemented with 5% sheep blood. Colony identity was further confirmed by evaluating colony morphology in blood agar and confirming the absence of growth on MacConkey agar. Bacteria in Tryptone Soy Agar (TSA) were used for the Triple Sugar Iron (TSI), Sulfide-Indole-Motility (SIM), and nitrate, glucose, lactose, sucrose and mannitol fermentation tests. For hyaluronidase test, P. multocida colonies were streaked transversally across the entire plate, approximately 3-5mm apart, in order to observe their lines of growth. Following this, a hyaluronidase producing strain of Staphylococcus aureus was heavily streaked at right angles to the P. multocida lines and the plates were incubated at 37°C for 24 h. Type A isolates were then identified as those with smaller colonies in the region adjacent to the Staphylococcus aureus streak (negative satellitism). For acriflavine test, the isolates were inoculated into tubes containing 2 mL of BHI, incubated at 37°C for 18-24 h, centrifuged (500 g for 15 min) and 1.5 mL of the supernatant was discarded. A 1:1000 solution of acriflavine neutral (0.5 mL) was then added to the residual broth containing bacteria and kept at room temperature. Solutions of acriflavine were freshly prepared each week and stored protected from light. Type D strains were identified by the appearance of a heavy flocculent precipitate within 5 min. DNA extraction by heat shock was performed prior to multiplex PCR for the detection of capsular genes hyaD-hyaC (capsular typing A) and dcbF (capsular typing D). Test of symmetry and a weighted kappa coefficient were used to evaluate correlations and to assess agreement of the  results between the identification methods, respectively. Phenotypic tests showed that two isolates were type D (4.55%), 40 were type A (90.9%) and two (4.55%) were untypable isolates (4.55%) while PCR showed that 38 isolates were type A (86.36%) and six were type D (13.64%). The correlation analysis between the phenotypic and genotypic tests showed that 90.9% of the strains were identified as belonging to the same serotype by both tests and the weighted kappa coefficient (K = 0.633) indicates a substantial agreement between the two tests.Discussion: There was a disagreement between the phenotypic and genotypic results in four of the isolates (9.09%). The phenotypically untypable isolates were classified as type D by multiplex PCR. Nonetheless, we conclude that PCR testing is a more reliable method to differentiate between P. multocida serotypes A and D

Eficácia de desinfetantes para inativar o vírus da influenza A H1N1 isolado de suínos

The aim of this study was to access the efficacy of four disinfectants to inactivate influenza A [H1N1] 0 hour and 72 hours after disinfectant dilution. A pandemic H1N1 influenza virus isolated from a pig with respiratory disease was used to obtain inoculums containing 6.4log10 EID50/mL; 5.4log10 EID50/mL; 4.4log10 EID50/mL and 3.4log10 EID50/mL. Suspension test was composed of 400μL of viral inoculum, 100μL of organic load and 500μL of each individually diluted disinfectant and incubated for ten minutes of contact time. After a neutralizing step, each mixture was filtered on a 0.22μm membrane and 0.2mL was inoculated in six 9-day-old embryo chicken egg through allantoic route. The allantoic fluid from eggs was harvest for RT-PCR and hemagglutination test. The experiment was repeated 72 hours after disinfectant dilution. On the first assessment with fresh disinfectant, influenza virus was inactivated by oxidizing compost disinfectant and phenolic disinfectant in all virus concentrations, the quaternary ammonium compound (QAC) and glutaraldehyde association inactivated the virus up to a concentration of 5.4log10 EID50/mL. QAC disinfectant did not eliminate virus viability. Seventy-two hours after disinfectants were diluted, oxidizing compost disinfectant and QAC and glutaraldehyde association disinfectant demonstrated the same result as the evaluation with fresh disinfectant solution. Phenolic disinfectant inactivated viral inoculum up to a concentration of 5.4log10 EID50/mL. QAC had no effect on inactivating 3.4log10 EID50/ mL of influenza virus. In conclusion, three of the four disinfectants tested were effective to inactivate pandemic H1N1 influenza virus in the presence of organic load. Test result performed 72hours after disinfectant dilution suggest a decrease in the effectiveness of one disinfectant.O objetivo deste trabalho foi avaliar a eficácia de quatro desinfetantes em inativar o vírus da influenza A [H1N1] 0-hora e 72-horas após a diluição dos produtos. Um vírus H1N1 pandêmico isolado previamente de um suíno com doença respiratória foi utilizado e foram obtidas quatro concentrações de inóculo contendo 6,4log10 EID50/mL; 5,4log10 EID50/mL; 4,4log10 EID50/mL and 3,4log10 EID50/mL. Para compor o teste em suspensão foram adicionados 400μL de inóculo viral, 100μL de matéria orgânica e 500μL de cada desinfetante diluído individualmente e a mesma foi incubada por 10 minutos. Após a etapa neutralizante, a suspensão foi filtrada em membrana 0,22μm e 0,2mL foi inoculado em seis ovos de galinha embrionados de nove dias de incubação, via rota alantóide. O fluido alantóide foi colhido após 72 horas para testes de hemaglutinação e RT-PCR. O mesmo protocolo experimental foi repetido usando as soluções desinfetantes 72 horas após a diluição. O vírus da influenza foi inativado pelo composto oxidante e também pelo desinfetante fenólico em todas as concentrações virais testadas 0-hora após diluição. O desinfetante com associação de amônia quaternária e glutaraldeído inativou o vírus na concentração de até 5,4log10 EID50/mL. O desinfetante à base de amônia quaternária não inativou o vírus. Os resultados 72-horas após a diluição não diferiram quando comparado com 0-hora, exceto o desinfetante fenólico, o qual inativou o vírus da influenza somente até a concentração 5,4log10 EID50/mL. Concluindo, três dos quatro desinfetantes testados foram efetivos ao inativar o vírus da influenza [H1N1] pandêmico na presença de matéria orgânica. Os resultados do teste com produtos diluídos após 72 horas sugerem redução da efetividade em, pelo menos, um desinfetante

Agentes patogênicos de pneumonia em suínos abatidos no sul do Brasil

A high prevalence of pneumonic lesions has been reported to affect slaughtered pigs in southern Brazil. In order to identify which microorganisms have been causing those lesions, 30 pig lungs presenting pneumonic gross lesions were collected from five different slaughterhouses, totaling 150 lungs. Samples for bacterial isolation, molecular, histopathologic and immunohistochemistry (IHC) evaluation were taken from each lung. The pneumonic lesion scoring ranged from 1.53 to 2.83. The most frequent histopathological lesions found was the concomitant Influenza A virus (IAV) and Mycoplasma hyopneumoniae infection, corresponding to 55.3% (83/150), and Pasteurella multocida type A was isolated in 54.2% (45/83) of these cases. In 102 samples (68%), there was histopathologic suggestion of involvement of more than one infectious agent. M. hyopneumoniae was the most frequent agent associated with pneumonic lesions, being present in 92.1% (94/102) of the lungs with coinfections, followed by IAV in 89.2% (91/102). Besides the coinfections, IAV lesions were observed also in six samples without another pathogenic microorganism detected. A total of 46 samples with acute and subacute IAV suspected lesions in histopathological examination were assessed for IHC and real time RT-PCR for IAV. A total of 35% (16/46) of them were positive by IHC and 13% (6/46) by real time RT-PCR. Regarding M. hyopneumoniae, 79.3% (119/150) of samples were positive by qPCR and 84.9% (101/119) of them also presented M. hyopneumoniae suspected lesions in the histopathological examination. The results of this study suggest the importance of IAV in respiratory diseases in finishing pigs, even though this virus is more frequently reported in the nursery phase. In addition, our results emphasize the importance of lung coinfections in finishing pigs.Lesões sugestivas de pneumonia são frequentemente encontradas em altas prevalências em suínos abatidos no sul do Brasil. Para identificar quais microrganismos causam essas lesões, foram coletados 30 pulmões de suínos com lesão macroscópica sugestiva de pneumonia em cinco frigoríficos diferentes, totalizando 150 pulmões. Amostras para isolamento bacteriano, avaliação molecular, histopatológica e imuno-histoquímica (IHC) foram coletadas de cada pulmão. O escore de lesão pulmonar variou entre 1,53 a 2,83. O achado histopatológico mais observado foi a lesão sugestiva de infecção concomitante pelo vírus Influenza A (IAV) e Mycoplasma (M.) hyopneumoniae, correspondendo a 55,3% (83/150), e em 54,2% (45/83) desses casos Pasteurella (P.) multocida tipo A foi isolado. Em 102 amostras (68%), houve lesão histopatológica sugestiva do envolvimento de mais de um agente infeccioso. M. hyopneumoniae foi o microrganismo mais frequente associado a lesões de pneumonia, estando presente em 92,1% (94/102) dos pulmões com coinfecções, seguido de IAV, que foi encontrado em 89,2% (91/102). Além das coinfecções, lesões de IAV foram observadas em mais seis amostras que não aparentavam envolvimento de outro agente infeccioso. Um total de 46 amostras com suspeita de lesão aguda e subaguda de IAV no exame histopatológico foram avaliadas para IHC e RT-PCR em tempo real para IAV e 35% (16/46) delas foram positivas por IHC e 13% (6/46) foram positivas por RT-PCR em tempo real. Com relação a M. hyopneumoniae, 79,3% (119/150) das amostras foram positivas por qPCR e 84,9% (101/119) delas também apresentaram lesões suspeitas de M. hyopneumoniae no exame histopatológico. Os resultados deste trabalho sugerem a importância do IAV como agente causador de pneumonias em suínos de terminação, embora esse vírus seja mais frequentemente relatado na fase de creche. Além disso, os achados deste trabalho demonstram a presença frequente de coinfecções pulmonares em suínos de terminação

Coristoma ósseo mesentérico em uma porca

Background: Osseous choristomas represent the production of osseous tissue in abnormal regions, such as subcutaneous, fibrous or perivascular tissues, skeletal muscle and skin. These structures have been found in humans, dogs (lungs and dura mater), horses (large intestines) and cattle (lungs and mesenteric lymph nodes). They were also found in the mesenteric region and thoracic cavity of sows and piglets. The aim of this paper was to describe the macro and microscopic lesions found in a sow which died suddenly by a rare mesenteric osseous choristoma.Case: A lactating sow, parity four, from the Swine Department of the Federal University of Rio Grande do Sul (UFRGS), Brazil, showed appetite loss, hyperthermia (41.5ºC) and sudden death. The animal was submitted to necropsy at the Department of Veterinary Pathology, UFRGS. On external examination, the sow showed conjunctival and perioral cyanosis, proximal colon region with a firm structure with approximately 3.0 cm length in mesenteric area. Moreover, the colon was ruptured and fibrin deposition and intestinal content in abdominal cavity were observed. Fragments of organs were collected in 10% formalin, routinely processed for histology and colored with hematoxylin and eosin stain (H&E). Histologically, it was found bone trabeculae with osteoid, periosteum, spaces with osteocids and endochondral ossification with bone marrow composed by adipose tissue and intense proliferation of conjunctive stroma. The mesenteric lymph nodes showed intense lymphoid hyperplasia with multifocal centrilobular necrosis. There was fibrin in serosa of colon, acute peri-spleen and acute fibrinopurulent perihepatitis.Discussion: Macroscopic and microscopic findings were consistent with mesenteric osseous choristoma. This condition is unusual in domestic animals, however it has been already described in pigs. Osseous choristoma could be related to previous mesenteric torsions, which could occur in growing phase, causing inflammation and hemorrhage, stimulating its generation. These structures may cause lesions in adjacent organs. The abrupt movements of the sow or intestinal peristalsis could have broken the bone, raising two tips, which in contact with the colon, ruptured it. Because of this, shedding of intestinal content was observed, which resulted in an acute peritonitis and sudden death of the animal. The annual mortality rates of sows (natural deaths or euthanasia) varies from 4.0 to 6.0%, but may be variable. Sow sudden deaths represent 17.5% of all sows and boars deaths, and gilts, pregnant and lactating sows are more susceptible. The most common causes of sow sudden death are gastrointestinal problems, such as ulcer, enteritis, torsions and ruptures; pneumonia; urinary infections, such as cystitis and pyelonephritis; heart failure; dystocia, and septicemia. However, one third of sudden death causes are not identified. The necropsy is the only way to identify the cause of death, through observation of macroscopic lesions and subsequent laboratory tests. Better knowledge of causes is important to establish control measures and possibly reduce culling of swine females. The causes of sudden death in sows should be better understood. Case reports of mesenteric osseous choristomas are rare in pigs, however it is not possible to assert if its occurrence is low, since few sudden deaths in sows are investigated

Efeito da ordem de parto segregada sobre a dinâmica de infecção de Mycoplasma hyopneumoniae e lesões pulmonares ao abate

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). A prevalência ao desmame foi maior na granja A (OP1) (P < 0,05). No entanto, dos 100 dias de idade até o abate a prevalência de leitões positivos para M. hyopneumoniae foi maior na granja B (OP2-6) (P < 0,05). A ocorrência e severidade de lesões pulmonares foram maiores na granja B. Os autores sugerem que a falta de uma aclimatação adequada das leitoas pode ter influenciado nos resultados, levando à detecção de matrizes positivas ao parto, independente da ordem de parto

Mesenteric osseous choristoma in a sow

Background: Osseous choristomas represent the production of osseous tissue in abnormal regions, such as subcutaneous, fibrous or perivascular tissues, skeletal muscle and skin. These structures have been found in humans, dogs (lungs and dura mater), horses (large intestines) and cattle (lungs and mesenteric lymph nodes). They were also found in the mesenteric region and thoracic cavity of sows and piglets. The aim of this paper was to describe the macro and microscopic lesions found in a sow which died suddenly by a rare mesenteric osseous choristoma. Case: A lactating sow, parity four, from the Swine Department of the Federal University of Rio Grande do Sul (UFRGS), Brazil, showed appetite loss, hyperthermia (41.5ºC) and sudden death. The animal was submitted to necropsy at the Department of Veterinary Pathology, UFRGS. On external examination, the sow showed conjunctival and perioral cyanosis, proximal colon region with a firm structure with approximately 3.0 cm length in mesenteric area. Moreover, the colon was ruptured and fibrin deposition and intestinal content in abdominal cavity were observed. Fragments of organs were collected in 10% formalin, routinely processed for histology and colored with hematoxylin and eosin stain (H&E). Histologically, it was found bone trabeculae with osteoid, periosteum, spaces with osteocids and endochondral ossification with bone marrow composed by adipose tissue and intense proliferation of conjunctive stroma. The mesenteric lymph nodes showed intense lymphoid hyperplasia with multifocal centrilobular necrosis. There was fibrin in serosa of colon, acute peri-spleen and acute fibrinopurulent perihepatitis. Discussion: Macroscopic and microscopic findings were consistent with mesenteric osseous choristoma. This condition is unusual in domestic animals, however it has been already described in pigs. Osseous choristoma could be related to previous mesenteric torsions, which could occur in growing phase, causing inflammation and hemorrhage, stimulating its generation. These structures may cause lesions in adjacent organs. The abrupt movements of the sow or intestinal peristalsis could have broken the bone, raising two tips, which in contact with the colon, ruptured it. Because of this, shedding of intestinal content was observed, which resulted in an acute peritonitis and sudden death of the animal. The annual mortality rates of sows (natural deaths or euthanasia) varies from 4.0 to 6.0%, but may be variable. Sow sudden deaths represent 17.5% of all sows and boars deaths, and gilts, pregnant and lactating sows are more susceptible. The most common causes of sow sudden death are gastrointestinal problems, such as ulcer, enteritis, torsions and ruptures; pneumonia; urinary infections, such as cystitis and pyelonephritis; heart failure; dystocia, and septicemia. However, one third of sudden death causes are not identified. The necropsy is the only way to identify the cause of death, through observation of macroscopic lesions and subsequent laboratory tests. Better knowledge of causes is important to establish control measures and possibly reduce culling of swine females. The causes of sudden death in sows should be better understood. Case reports of mesenteric osseous choristomas are rare in pigs, however it is not possible to assert if its occurrence is low, since few sudden deaths in sows are investigated