An ELISA to Detect Antibodies to Bovine Alphaherpesviruses 1 and 5 and Bubaline Alphaherpesvirus 1 in Cattle Sera.

Bovine alphaherpesvirus 1 (subtypes 1.1, 1.2a, and 1.2b), type 5 (subtypes 5a, 5b, and 5c), and bubaline herpesvirus 1 (BuHV-1) induce highly, though not fully cross-reactive serological responses. Most types and subtypes of these viruses circulate particularly in countries of the southern hemisphere, notably Brazil and Argentina. Therefore, the detection of infected animals is important in defining prevention and control strategies, particularly when flocks are destined for international trade. Identification of infected herds is most often achieved by assays that detect antibodies, such as enzyme immunoassays (ELISAs). However, to date, no ELISA has been evaluated in its capacity to detect antibodies to these alphaherpesviruses. Here, an ELISA was developed to detect antibodies to all currently recognized BoAHV-1, BoAHV-5, and BuAHV-1 types/subtypes, and its sensitivity and specificity were determined. Six hundred bovine sera were screened in serum neutralization tests (SN) against the seven viruses. ELISAs prepared with each of the viruses were compared to SN. Subsequently, a combined assay with multiple antigens LISA was prepared by mixing five viral antigens, chosen for their highest sensitivity in the preparative assays. In comparison to SN, the mAgELISA sensitivity was 96.5% with 96.1% specificity (κ = 0.93; PPV = 95.0%; NPV = 97.3%). The findings reveal that the mAgELISA developed here is highly suitable for the detection of antibodies, comparable in sensitivity and specificity to that of SN when performed with all known types and subtypes of bovine and bubaline alphaherpesviruses.

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)

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.