Construction and characterization of a recombinant vaccine encoding the nucleocapsid protein gene of avian infectious bronchitis virus / Construção e caracterização de uma vacina recombinante codificando o gene da proteina do nucleocapsideo do virus da bronquite infecciosa das galinhas

A vacinação é a forma mais utilizada para prevenir a bronquite infecciosa causada pelo vírus da bronquite infecciosa das galinhas (IBV). Contudo, as vacinas convencionais são incapazes de diferenciar aves infectadas de vacinadas. No presente trabalho foi construído, caracterizado, e avaliado como candidato vacinal, um adenovírus recombinante expressando o gene N do IBV. O gene N foi clonado em um adenovírus humano tipo 5 defectivo e transfectado para as células HEK-293A para gerar rAd5_N. Após o vetor ser obtido como esperado e a confirmação da expressão da proteína N em HEK-293ª, foi realizada inoculação pela via oculo-nasal na dose de 10 7 TCID 50 /0,1mL para imunização de galinhas livres de patógenos específicos (SPF). A resposta imunológica do Ad5_N e a proteção contra o desafio ao IBV foram avaliadas e comparadas com uma vacina viva comercial. Não foram detectados anticorpos anti-IBV em aves vacinadas com o Ad5_N. A vacina comercial induziu anticorpos detectáveis a partir do 7º dia pós-vacinal. Em aves vacinadas com o Ad5_N não houve aumento na expressão de IFNγ. Neste estudo, o rAd5_N obtido não conferiu proteção contra desafio com IBV-M41. Os resultados indicam a necessidade de avaliar adenovírus recombinantes expressando outros genes do IBV.(AU)

Genome-wide association study of periweaning failure-to-thrive syndrome (PFTS) in pigs.

Porcine periweaning-failure-to-thrive syndrome (PFTS) is a condition that affects newly weaned piglets. It is characterised by a progressive debilitation leading to death, in the absence of infectious, nutritional, management or environmental factors. In this study, we present the first report of PFTS in South America and the results of a genome-wide association study to identify the genetic markers associated with the appearance of this condition in a crossbred swine population. Four chromosomal regions were associated with PFTS predisposition, one located on SSCX, one on SSC8, and the two other regions on SSC14. Regions on SSC8 and SSC14 harbour important functional candidate genes involved in human depression and might have an important role in PFTS. Our findings contribute to the increasing knowledge about this syndrome, which has been investigated since 2007, and to the identification of the aetiology of this disease.

Influence of enrichment media and application of a PCR based method to detect Salmonella in poultry industry products and clinical samples.

To attempt the rapid detection of Salmonella enterica, we have coupled a culture procedure with PCR amplification of the genus-specific invE/invA genes. The method was applied to different kinds of samples from the poultry industry and evaluated by using hydrolyzed feather meal, meat meal, litter and viscera, all experimentally inoculated with a known number of Salmonella followed by cultivation in selenite--cystine broth prior to the PCR reaction. The expected 457bp specific DNA fragment could be amplified from dilutions containing as few as 5.7CFU, indicating that the PCR technique can be successfully coupled with culture in an enrichment broth to distinguish Salmonella species from other enteric bacteria present in samples from the poultry industry. Tetrathionate broth proved to be a much better enrichment media compared to selenite-cystine when the presence of Salmonella was evaluated by PCR in 1-day-old chicks experimentally infected with known numbers of Salmonella. Samples included cecal tonsils and viscera, collected at 48h and 7 days postinfection. The PCR technique was more sensitive in detecting infected animals than the standard microbiological procedure, which detected only 47% of all PCR positive samples.

Detection of Chlamydia trachomatis antigens by enzyme immunoassay and immunofluorescence in genital specimens from symptomatic and asymptomatic men and women.

Chlamydia trachomatis antigens were detected in populations with the following infection prevalences: 26.5% (36 of 136) of men and 27.7% (48 of 173) of women attending a sexually transmitted disease clinic, 16.3% (53 of 324) of women attending a Planned Parenthood clinic, and 3.4% (4 of 117) of an obstetrics and gynecologic practice. Compared with cell culture of the combined female cervical specimens (15.8% prevalence), the respective sensitivities of Chlamydiazyme (Abbott Laboratories, North Chicago, Illinois) and Microtrak (Syva, Palo Alto, California) were 98.3% and 87.9%, specificities were 97.5% and 98.4%, positive predictive values were 87.7% and 92.7%, and negative predictive values were 99.7% and 97.5%. Both assays were 70.0% sensitive with male urethral specimens, and the other parameters of performance ranged between 84.0% and 97.2%. The antigen detection assays, compared with culture, performed equally well in subjects without or with clinical signs.