A five-year surveillance study of vaccination schedules using viral-vectored vaccines against infectious laryngotracheitis in a high-density layer region / Cinco anos de monitoramento de esquemas vacinais com vacinas virais vetorizadas contra laringotraqueíte infecciosa em uma região altamente povoada por galinhas poedeiras

The effectiveness of vectored recombinant vaccines to control infectious laryngotracheitis (ILT) in chickens from a region (State of Minas Gerais, Brazil) with ~10 million layers was evaluated under field conditions from 2014-2018. During this period, only recombinant turkey herpesvirus (rHVT) or fowl poxvirus (rFPV) vaccines that express antigens of infectious laryngotracheitis virus (Gallid herpesvirus-1; GaHV-1) were used. Layer chickens (n=1,283), from eight different egg-producing companies, were individually sampled and examined (active surveillance), and in instances when government poultry health veterinarians were notified due to respiratory disease (passive surveillance). Clinical, macroscopic, and histopathology examinations were performed to diagnose ILT as well as molecular techniques for the detection and characterization of the GaHV-1 DNA from the trachea and trigeminal ganglia (TG). The layer hens sampled and examined belonged to flocks and farms that used different vaccination protocols (non-vaccinated, single dose vaccination, and prime/ boost vaccination). This is the first long-term field study of the effectiveness of ILT vectored vaccines in a high-density multiple age layer hen region. Using various diagnostic methods, the occurrence of GaHV-1 infection and ILT clinical disease in layer hens vaccinated with vectored recombinant vaccines in one quarantined region of Brazil were investigated. The number of ILTV positive chickens by PCR and ILT clinical disease cases was lower in farms when all chickens were vaccinated with at least one vaccine. However, the difference in the detection rates of GaHV-1 infection was significant only when compared farms with prime/ boost and farms using single dose of HTV-LT.

A efetividade das vacinas recombinantes vetorizadas para o controle da laringotraqueíte infecciosa (LTI) nas aves de uma região (Minas Gerais, Brasil) com aproximadamente 10 milhões de poedeiras foi avaliada em condições de campo, no período de 2014 a 2018. Durante este período, somente as vacinas recombinantes "turkey herpesvirus" (rHVT) ou "fowl poxvirus" (rFPV), que expressam antígenos do vírus da laringotraqueíte (Gallid herpesvirus-1; GaHV-1) foram utilizadas. Galinhas poedeiras (n=1.283), de oito diferentes granjas produtoras de ovos, foram individualmente amostradas e examinadas por monitoramento ativo e, na ocorrência de notificação de doença respiratória aos veterinários do serviço oficial, por monitoramento passivo. Exames clínicos, macroscópicos e histopatológicos foram realizados para o diagnóstico de LTI, bem como técnicas moleculares para a detecção e caracterização do DNA de GaHV-1 da traqueia e gânglio trigêmeo. As galinhas poedeiras pertenciam a lotes e granjas que usavam diferentes protocolos de vacinação (não vacinadas, uma dose ou tipo de vacina e duas doses ou tipos de vacina). Este é o primeiro longo estudo a campo sobre a efetividade das vacinas vetorizadas em uma região com população elevada de poedeiras de múltiplas idades. Utilizando vários métodos de diagnóstico, a ocorrência da infecção por GaHV-1 e a LTI clínica em poedeiras de uma região interditada do Brasil foi investigada. O número de galinhas positivas para o vírus GaHV-1 e para casos clínicos de LTI nas granjas foi menor quando todas as aves estavam vacinadas com, pelo menos, um tipo ou dose de vacina. Entretanto, a diferença na taxa de detecção da infecção por GaHV-1 foi significativa somente quando a comparação foi realizada entre granjas com aves vacinadas com duas doses e aves de granjas vacinadas com uma única dose de HVT-LT.

West Nile Virus: Veterinary Health and Vaccine Development.

West Nile virus (WNV) (Flaviviridae: Flavivirus) was discovered in Africa more than 80 yr ago and became recognized as an avian pathogen and a cause of neurologic disease in horses largely during periodic incursions into Europe. Introduction of WNV into North America stimulated great anxiety, particularly in the equine industry, but also for pet owners and livestock producers concerned about the effect of WNV on other domestic animals. Numerous subsequent studies of naturally occurring and experimentally induced disease greatly expanded our understanding of the host range and clinical consequences of WNV infection in diverse species and led to rapid development and deployment of efficacious vaccines for horses. In addition to humans, horses are clearly the animals most frequently affected by serious, sometimes lethal disease following infection with WNV, but are dead-end hosts due to the low-magnitude viremia they develop. Dogs, cats, and livestock species including chickens are readily infected with WNV, but only occasionally develop clinical disease and are considered dead-end hosts for the virus.

Effects of polysaccharide from Ophiopogon japonicus on immune response to Newcastle disease vaccine in chicken

In order to investigate the immune enhancement effects of Ophiopogon japonicus polysaccharide Ophiopogon japonicus (OJPS) on Newcastle disease (ND) live vaccine, chickens vaccinated against ND live vaccine was orally administered with the OJPS at high, medium and low concentrations respectively. In negative control group, chickens were given orally equal volume of physiological saline. On day 14, 21 and 28, the serum antibody titer, erythrocyte-C3b receptor rosette rate (E-C3bRR), erythrocyte-C3b immune complex rosette rate (E-ICRR) and peripheral lymphocyte proliferation were measured. The results showed that at most time points, the antibody titer, peripheral lymphocyte proliferation, E-C3bRR and elimination rate of immune complex of three OJPS administrating groups were significantly higher (P<0.05) than those in negative control group. It indicated that OJPS could significantly improve the immune efficacy of Newcastle disease live vaccine, Ophiopogon japonicus polysaccharide possessed synergistical immunoenhancement.(AU)

Immune response in holstein calves vaccinated at six months of age

Background: Calves are agammaglobulinemic and immature at birth and their immunological defense must be improved by colostrum, although, maternal antibodies decrease after two months of age and calves are susceptible to Bovine Respiratory Disease Complex (BRDC). Then, this research evaluated the immune response to BVDV and BoHV-1 in young calves to prevent BRDC.Materials, Methods & Results: Ten male Holstein calves were distributed in two groups with five animals on each: nonvaccinated VAC (-) and vaccinated VAC (+). Calves were vaccinated twice at 180 and 210 days of age. It was selected a commercial multivalent vaccine containing inactivated isolated of BVDV type-1 (strains 5960) and BVDV type-2 (strains 53637), and modified-live BoHV-1 (strains RLB103), with Quil A, cholesterol and Amphigen as adjuvant. The immune response (IR) was evaluated at 180 (T0), 210 (T1) and 240 (T2) days of life by serum neutralization (SN) and immunophenotyping. Specific antibodies to BVDV were detected in 40% (2/5) and 60% (3/5) of vaccinated calves at T1 and T2, respectively. Specific antibodies (Abs) to BoHV-1 were observed in 40% (2/5) at T1 and 100% (5/5) at T2 in the VAC (+) group. Titers of Abs to BoHV-1 increase from T0 to T2 (P = 0.034) in VAC (+). Moreover, geometric mean titer (GMT) to BoHV-1 in VAC (+) group was higher than VAC (-) after secondary IR in T2 (P = 0.006). The proportion of the markers T lymphocytes subpopulation (CD3+ , CD4+ , CD8+ and WC1+ ) and B lymphocytes (CD21+ ) were similar in the two experimental groups, while the expression of the CD25+ marker by gamma-delta (WC1+ ) was higher in VAC (+) at T1.Discussion: Low titers of circulating Abs could be observed just for BoHV-1 in the calves from VAC (-) at T0, probably due to remaining Abs from dams transferred by colostrum intake. This fact indicates the need of appropriate vaccination schedules to prevent the virosis in dairy heifers.[...]

Immune response in holstein calves vaccinated at six months of age

Background: Calves are agammaglobulinemic and immature at birth and their immunological defense must be improved by colostrum, although, maternal antibodies decrease after two months of age and calves are susceptible to Bovine Respiratory Disease Complex (BRDC). Then, this research evaluated the immune response to BVDV and BoHV-1 in young calves to prevent BRDC.Materials, Methods & Results: Ten male Holstein calves were distributed in two groups with five animals on each: nonvaccinated VAC (-) and vaccinated VAC (+). Calves were vaccinated twice at 180 and 210 days of age. It was selected a commercial multivalent vaccine containing inactivated isolated of BVDV type-1 (strains 5960) and BVDV type-2 (strains 53637), and modified-live BoHV-1 (strains RLB103), with Quil A, cholesterol and Amphigen as adjuvant. The immune response (IR) was evaluated at 180 (T0), 210 (T1) and 240 (T2) days of life by serum neutralization (SN) and immunophenotyping. Specific antibodies to BVDV were detected in 40% (2/5) and 60% (3/5) of vaccinated calves at T1 and T2, respectively. Specific antibodies (Abs) to BoHV-1 were observed in 40% (2/5) at T1 and 100% (5/5) at T2 in the VAC (+) group. Titers of Abs to BoHV-1 increase from T0 to T2 (P = 0.034) in VAC (+). Moreover, geometric mean titer (GMT) to BoHV-1 in VAC (+) group was higher than VAC (-) after secondary IR in T2 (P = 0.006). The proportion of the markers T lymphocytes subpopulation (CD3+ , CD4+ , CD8+ and WC1+ ) and B lymphocytes (CD21+ ) were similar in the two experimental groups, while the expression of the CD25+ marker by gamma-delta (WC1+ ) was higher in VAC (+) at T1.Discussion: Low titers of circulating Abs could be observed just for BoHV-1 in the calves from VAC (-) at T0, probably due to remaining Abs from dams transferred by colostrum intake. This fact indicates the need of appropriate vaccination schedules to prevent the virosis in dairy heifers.[...](AU)

Development of an in process control filtration-assisted chemiluminometric immunoassay to quantify foot and mouth disease virus (FMDV) non-capsid proteins in vaccine-antigen batches.

In many countries, foot and mouth disease (FMD) is controlled by vaccination and surveillance against non-capsid proteins (NCP); therefore vaccines are required not to induce antibodies against NCP. Vaccine purity is evaluated by repeated inoculation of naïve cattle, an expensive and time consuming protocol that raises several animal welfare concerns. We have developed an in process control filtration-assisted chemiluminometric immunoassay (FAL-ELISA), to detect and quantify NCP in vaccine-antigen batches regardless of its volume and composition. Samples are filtered through PVDF-filter microplates pre-coated with a monoclonal antibody against NCP. Filtration removes all unbound components in the sample and captured NCP are detected by anti-NCP conjugate followed by incubation with the substrate, luminol/peroxide. Analytical detection limit was 2 ng for purified NCP and 4 ng for vaccine-antigen batches spiked with NCP, which makes this assay sensitive enough to be applied to purity control of FMD vaccines. Vaccine components did not interfere with the antibody and substrate reactions in the assay. FAL-ELISA is an alternative for the in vivo tests, observing the objective to Replace, Reduce and Refine the use of animals for quality control of immunobiologicals.

Caracterização molecular de genotipos de rotavírus do grupo A em Belém, Pará, no período de 1990 a 2003: estudo em neonatos, crianças diarréicas de 0-3 anos e ensaio clínico com vacinas / Molecular characterization of genotypes of rotavirus of the group in Belem, Para, in the period of 1990 the 2003: study in neonates, diarrhoeic children of 0-3 years and clinical assay with vaccines

Os rotavírus (RVs) do grupo A (RVs-A) são os principais agentes de gastroenterite infantil e uma significativa causa de morbidade e mortalidade entre crianças menores de 5 anos nos países em desenvolvimento, e um importante fator de morbidade no mesmo grupo etário nos países desenvolvidos. Constitui-se característica marcante nos países em desenvolvimento a ampla diversidade antigênica e genotípica das amostras circulantes. Este estudo objetivou a caracterização dos sorotipos/genotipos de RVs-A provenientes de neonatos hospitalizados com e sem diarréia; de crianças menores de 5 anos com diarréia aguda, admitidas em hospital ou fazendo uso da terapia de reidratação oral; e de crianças participantes de ensaios clínicos com as vacinas anti-RVs...no período de 1990 a 2003. As amostras fecais foram coletadas no período de 1990 a 2003 e os espécimes fecais sob análise foram caracterizados com base em testes imunoenzimáticos e moleculares, incluindo a semi-nested-PCR e o seqüenciamento de nucleotídeos. Das 437 amostras de neonatos, 51 foram positivas (11,7 por cento) para RV-A. Destas crianças, 42 (82 por cento) desenvolveram infecção nosocomial assintomática, 5 (10 por cento) diarréia nosocomial e 4 (8 por cento) quadro diarréico adquirido na comunidade. Vinte e sete amostras de neonatos... Paralelamente, todas as G2 pertencendo às linhagens llb, llc e lld. Infecção mista pelo genotipo G foi observada no neonato NB-150...A análise genética das proteínas NSP4 e VP4... embora 7 amostras tenham sido mais similares aos protótipos humanos (linhagem P[6]-la) e 7 denotando maior identidade às sublinhagens suínas Ib e Ic. No estudo com a RIX4414 em Belém, Brasil, o genotipo P[8]G9 predominou na primeira metade da pesquisa representando 64 por cento das amostras, enquanto que, foi observado que o genotipo P[8]G1 emergiu como o mais comum com 57,6 por cento das amostras genotipadas durante o restante do estudo. As infecções mistas pelos genotipos G e P representaram 12,8 por...

RNA fingerprinting of South American prototype aphthovirus strains.

Aphthovirus strains used in South America for vaccine production or as reference for diagnostic purposes were analysed by RNA fingerprinting (RNase T1 maps, one- and two-dimensional gels). The results obtained constitute the basis for a data bank containing available information about the genome structure of strains of aphthovirus prevalent in this continent and can be used as an adjunct to serological and immunological information. These data are currently being used in South American countries to assess the genetic stability of strains during vaccine production; to establish possible vaccine origin of field outbreaks and to monitor the origin, behaviour and fate of new strains in the field.