Nelson Morés

Prevalence, distribution, and molecular characterization of Salmonella recovered from swine finishing herds and a slaughter facility in Santa Catarina, Brazil

Swine can carry Salmonella strains that may be transmitted to humans by pork products. This investigation determined the distribution and types of Salmonella in 12 swine finishing herds and a slaughter facility in Santa Catarina, Brazil. A total of 1258 samples, consisting of environmental, feed, carcass, lymph node, and fecal material were collected and submitted to bacteriological isolation of Salmonella. From 487 positive samples, 1255 isolates were recovered and confirmed to be Salmonella. The distribution of positive samples was as follows: finishing pen floors 26% (16/61); feed 29% (42/143); feces 44% (52/119); pooled feces 59% (35/59); slaughter holding pens 90% (36/40); lymph nodes 46% (220/478); pre-chilled carcass surfaces 24% (24/98); and post-chilled carcass surfaces 24% (62/260). The most prevalent serovars were Typhimurium, Panama, Senftenberg, Derby, and Mbandaka. By pulsed-field gel electrophoresis, 1071 isolates were subtyped using XbaI, and duplicate isolates were removed. From the remaining 747 isolates, 163 macrorestriction profiles (pulsotypes) were identified. Six pulsotypes were considered very frequent, occurring in 33 isolates or more. The multiple correspondence analyses showed correlations between pulsotypes from shedding pigs (feces), herd environment (pen floors), and subiliac and prescapular lymph nodes and between lairage and carcass surface samples before and after chilling. All sources of Salmonella investigated contributed to the carrier state; however, pre-slaughter contamination at lairage was the variable most strongly associated with carcass contamination. A total of 59 different antimicrobial resistance profiles were observed in 572 Salmonella isolates. From these isolates, 17% (97/572) were susceptible to all 15 antibiotics tested, 83% (475/572) were resistant to at least one, and 43% (246/572) were resistant to four or more antibiotics (multi-resistant). The AmpGenKanTet profile was the most prevalent in carcass isolates and was associated with farm origin.

Isolation and Identification of Chicken Infectious Anemia Virus in China

A chicken infectious anemia virus (CIAV) isolate was obtained from broiler flocks aged 25-40 days with anemia and poor performance and was designated SR43. The CIAV isolate was resistant to treatment with chloroform and induced thymus atrophy, bone marrow aplasia, and low hematocrit values when inoculated into 1-day-old, susceptible, specific-pathogen-free chicks. CIAV-specific antigens could be demonstrated in SR43-infected MDCC-MSB-1 cells, a cell line derived from a Mareks disease lymphoma, with the use of a monoclonal antibody specific for CIAV. CIAV DNA in infected MDCC-MSB-1 cell cultures was detected by using a polymerase chain reaction assay. These findings demonstrate that CIAV is present in China.

Isolamento e caracterização do vírus da influenza pandêmico H1N1 em suínos no Brasil

Influenza A virus (IAV) infections are endemic in pork producing countries around the world. The emergence of the pandemic 2009 human H1N1 influenza A virus (pH1N1) raised questions about the occurrence of this virus in Brazilian swine population. During a 2009-2010 swine influenza virus research project at Embrapa Swine and Poultry (CNPSA), an outbreak of a highly transmissible H1N1 influenza A virus disease was detected in a pig herd in Santa Catarina State, Brazil. The virus caused a mild disease in growing pigs and sows without mortality. Three clinically affected piglets were euthanized. Gross lesions included mild to moderate consolidation of cranioventral areas of the lung. Microscopically, the lesions were characterized by necrotizing obliterative bronchiolitis and bronchointerstitial pneumonia. Immunohistochemistry using a monoclonal antibody against type A influenza virus nucleoprotein revealed positive staining in the nuclei of the bronchiolar epithelial cells. Lung tissue from three piglets and nasal swabs from five sows and four piglets were positive for influenza A by RT-PCR. Influenza virus was isolated from one lung, later confirmed by the hemagglutination test (HA titer 1:128) and RT-PCR. Sequence analyses of Hemmaglutinin (HA) and Matrix (M) genes revealed that the virus was consistent with the pandemic (A/H1N1) 2009 influenza virus strain that circulated in humans. This is the first report of an outbreak of pandemic A/H1N1 influenza virus in pigs in Brazil.

Natural co-infection of torque teno virus and porcine circovirus 2 in the reproductive apparatus of swine

This work aimed to detect and study natural co-infection of Circoviridae torque teno virus (TTV) and porcine circovirus 2 (PCV2) in the swine reproductive apparatus. Semen and organs from 17 boars were tested by nested and real-time PCR. PCV2 was amplified from semen (47%), lymph nodes (84.6%) and testicles (35.3%). TTV2 was amplified from 16/17 testis and 13/13 lymph nodes. TTV1 DNA was detected in fewer testicle samples (2/17), which were also TTV2 positive. Analyzed ovaries, follicular fluid and uteri of 83 culled sows showed TTV2, TTV1 and PCV2 from 49.3%, 30.1% and 6.0% of the sows, respectively. Sperm analysis indicated insignificant differences between PCV2 and TTVs positive and negative boars. The most frequent pathologic lesion in sows was endometritis (28.9%), but this was unassociated with PCV2 or TTVs detection. These findings question the importance of PCV2 and TTV2 natural co-infection in the pathology of porcine reproductive failures.

Caracterization of Aujeszky's disease virus isolated from South Brazil in the last twenty years by restriction enzyme analysis

Aujeszkys disease virus (ADV) belongs to Herpesviridae family and is an important etiological agent which infects pigs causing economic losses in swine producing countries worldwide and international trade restrictions to products of swine origin. An eradication program for ADV was established in Santa Catarina State since 2001. The last outbreak was reported in July 2004 and since then none has been reported. The disease has been controlled with the use of a genetic modified vaccine and elimination of seropositives. Aiming the characterization of ADV isolated in the South of Brazil in the last twenty years (1983-2003), a retrospective study based on the genomic analysis of the isolates through a digestion of viral genomic DNA with restriction enzyme Bam HI was done. Thirty-seven ADV samples isolated from swine from the States of Santa Catarina, Parana and Rio Grande do Sul were analyzed. These isolates were compared to the reference strains NIA-4, Bartha and Begonia. The most predominant genomic arrangement was type II found in 33 samples isolated in Santa Catarina State and in one isolate from Rio Grande do Sul State. Genomic arrangement type I, characteristic of vaccine strains was identified in 2 isolates from Parana State and in 1 isolate from Rio Grande do Sul State.

Identificação do circovírus suíno tipo 2 por reação em cadeia da polimerase e por imunoistoquímica em tecidos suínos arquivados desde 1988 no Brasil

Postweaning multisystemic wasting syndrome (PMWS) is of economical importance a disease caused by porcine circovirus type 2 (PCV2). A retrospective investigation was performed on paraffin-embedded organs samples from swine submitted to Embrapa Swine and Poultry Research Center between 1985 and 1998 for histopathologic diagnosis. A total of 25 cases were chosen from the archival collection of the Animal Health Laboratory at Embrapa Swine and Poultry based on characteristic pathological lesions of PMWS, such as lymphadenopathy, interstitial pneumonia, hepatitis and interstitial nephritis. The sections were investigated by nested-PCR (polymerase chain reaction) which used specific primers for the ORF2 sequence of the PCV2 and by immunohistochemistry using a monoclonal antibody specific for PCV2 capsid antigen. Virus specific DNA and antigen were detected in tissue samples of two out of 25 analyzed cases. The earliest positive sample originated from 1988. These results indicate that PCV2 is present in Brazil since 1988.

Fatores de risco associados aos problemas dos leitões na fase de creche em rebanhos da região Sul do Brasil

Epidemiological essay was carried out in 65 herds of southern Brazil, with the objective to identify risk factors that better explain the occurrence of problems with the pigs during post-weaning phase. In each herd, a batch of pigs was followed during the first three post-weaning weeks, when variables like building conditions, nutrition, management, environment and health were taken into account. Descriptive and multivariate methods had been used to analyze the data. Target variable used to describe pig problems during post-weaning phase had been: weight daily gain, weight coefficient of variation at 21 days post-weaning, occurrence of diarrhea in the batch, mortality rate and the medicine use dressings against the diarrhea. With the help of these variables a synthetic variable was created for discriminating the farms in three categories: good, intermediate and bad. Among explicative variables, 10 risk factors had been selected as more important, making it possible to identify farms with high trend to present problems during post-weaning phase. One concludes that in many herds of the south region of Brazil some risk factors exist that favor the occurrence of problems with the pigs during the weaning phase, some of as consequence of others from maternity phase.

Efeito de diferentes fontes protéicas sobre desempenho, composição corporal e morfologia intestinal em leitões

A study was carried out to evaluate the effect of dried skim milk (LDP) in weaning diets containing different levels of high-protein soybean meal (PCS), for piglets weaned at 21 days of age. Five diets were compared, from weaning to 14 days post-weaning: T1 - basal diet, soybean meal (FS) as the main protein source; T2 and T4 - replacement of 30 and 50%, respectively, FS from basal diet by PCS; T3 and T5 - replacement of 30 and 50%, of FS from basal diet by PCS and 20% by LDP, respectively. The partial replacement of FS by PCS or LDP did not affect the performance neither the body composition or deposition tissues ratios of piglets in anyone of the evaluated period. The mucous membrane height and villus height at 14 days post-weaning were not affected by the protein source of the diet, but crypt depth was reduced by PCS, regardless of diet supplementation with LDP. The protein source did not affect performance neither body composition of piglets, but PCS provided a reduction of morphologic changes of the intestinal mucous membrane, signed by the reduction of the crypt depth.A study was carried out to evaluate the effect of dried skim milk (LDP) in weaning diets containing different levels of high-protein soybean meal (PCS), for piglets weaned at 21 days of age. Five diets were compared, from weaning to 14 days post-weaning: T1 - basal diet, soybean meal (FS) as the main protein source; T2 and T4 - replacement of 30 and 50%, respectively, FS from basal diet by PCS; T3 and T5 - replacement of 30 and 50%, of FS from basal diet by PCS and 20% by LDP, respectively. The partial replacement of FS by PCS or LDP did not affect the performance neither the body composition or deposition tissues ratios of piglets in anyone of the evaluated period. The mucous membrane height and villus height at 14 days post-weaning were not affected by the protein source of the diet, but crypt depth was reduced by PCS, regardless of diet supplementation with LDP. The protein source did not affect performance neither body composition of piglets, but PCS provided a reduction of morphologic changes of the intestinal mucous membrane, signed by the reduction of the crypt depth.

Transmission of porcine circovirus 2 (PCV2) by semen and viral distribution in different piglet tissues

Porcine circovirus infections are caused by the porcine circovirus 2 (PCV2). Among six different clinical manifestations involving respiratory, enteric, nervous and reproductive signs, the postweaning multisystemic wasting syndrome (PMWS) is the most important and studied disease. However, reproductive failures associated with PCV2 have been increasingly reported. Some studies have shown the possible contamination of sows by semen of PCV2 positive boars. In order to investigate the transmission of PCV2 by contaminated semen and its ability to infect the sow and piglets, 20 PCV2 negative sows were inseminated, 10 with negative boar semen and 10 with previously nested-PCR tested positive boar semen. The sows were weekly monitored and blood samples were collected. Based on the results, 4 out 20 sows were selected (1 sow was PCR negative and inseminated with a negative semen, 2 sows were PCR negative and inseminated with a positive semen and 1 sow was PCR negative and inseminated with a positive semen, but became PCR positive around the 30 days of pregnancy). After weaning, 12 male piglets, 3 of each sow, were selected and maintained under isolation. In order to investigate which organs harbored the virus, the young pigs were necropsied around 9 months of age. Samples of serum collected monthly were tested by immunocitochemistry (ICC), and all 12 pigs serum converted. Samples of lymphoid, systemic and reproductive organs were analyzed by nested-PCR and immunohistochemistry (IHC). Evaluation of the samples by nested-PCR, revealed that several tissues were positive in 10 of 12 pigs, mainly the lymph nodes, bone marrow and spleen. Various samples were positive by IHC in 8 of 12 piglets, being the lymph nodes, tonsils and bulbourethral glands the most frequently positive. Thus, the results of testing different samples, in the 3 tests (ICC, nested-PCR and IHC) were complementary. These results show that PCV2 transmission through semen to the sows and piglets may occur and may also represent a potential risk for the herd.

Comparação entre métodos de tuberculinização no diagnóstico da infecção por agentes do complexo Mycobacterium avium ou M. bovis em suínos

The efficiency of the tuberculin delayed-type skin hypersensitivity test was evaluated in swine. A comparison of the tuberculin skin tests was performed with avian and bovine protein derivatives (PPD), in the detection of Mycobacterium avium-Complex or M. bovis infected swine. The methods were evaluated as to define criteria for readings and results interpretation, to determine their capacity in detecting Mycobacterium avium complex (MAC) infected swine and their performance in differentiating MAC from M. bovis-infected individuals. Three trials were performed with naturally MAC-infected swine, experimentally MAC-infected or experimentally M. bovis-infected animals. The skin test readings positive or negative were, respectively, correlated to the presence or absence of gross lesions and histological alterations in lymph nodes at slaughter age. Reaction with both antigens were observed in MAC and M. bovis-inoculated animals as well. Reactions wider then 0.5cm in diameter or showing skin thickness increasing more then 0.2cm in the time frame between inoculation and reading were considered to be positive, as compared to the average results of the group. Herds with MAC-infected swine could be detected with either avian or bovine PPD. Both diameter and skin thickness were efficient in detecting MAC-infected swine, however, reading the diameter of the reaction was shown to be more easily and economically performed.