RESUMO
Infection with Erysipelothrix rhusiopathiae has a significant economic impact on pig production systems worldwide. Both inactivated and attenuated vaccines are available to prevent development of clinical signs of swine erysipelas. The ability of a live attenuated E. rhusiopathiae strain to become persistently established in pigs after intranasal exposure and its potential to cause clinical signs consistent with swine erysipelas after being administered directly into the nasopharynx of healthy pigs was evaluated. Five, E. rhusiopathiae-negative pigs were vaccinated by deep intranasal inoculation then followed for 14 days. Nasal swabs were collected daily for 5 days and clinical observations were made daily for 14 days post-vaccination. Nasal swabs were cultured for E. rhusiopathiae with the intent of back-passaging any recovered organisms into subsequent replicates. No organism was recovered from nasal swabs in the first vaccination replicate. A second replicate including 10 pigs was initiated and followed in an identical manner to that described above. Again, no E. rhusiopathiae was recovered from any pigs. No pigs in either replicate showed any signs of clinical swine erysipelas. The live attenuated E. rhusiopathiae strain evaluated in this study did not appear to become persistently established in pigs post-vaccination, did not cause any local or systemic signs consistent with swine erysipelas, and was therefore unlikely to revert to a virulent state when used in a field setting.
Assuntos
Vacinas Bacterianas/uso terapêutico , Infecções por Erysipelothrix/imunologia , Erysipelothrix/imunologia , Doenças dos Suínos/imunologia , Vacinas Atenuadas/uso terapêutico , Administração Intranasal , Animais , Vacinas Bacterianas/administração & dosagem , Temperatura Corporal , Erysipelothrix/isolamento & purificação , Erysipelothrix/patogenicidade , Infecções por Erysipelothrix/fisiopatologia , Mucosa Nasal/microbiologia , Nariz/microbiologia , Segurança , Suínos , Virulência , Aumento de PesoRESUMO
We have constructed an aromatic amino acid auxotrophic mutant of Bordetella bronchiseptica, harbouring mutations in aroA and trpE to investigate the use of such a strain as a live-attenuated vaccine. B. bronchiseptica aroA trpE was unable to grow in minimal medium without aromatic supplementation. Compared to the parental wild-type strain, the mutant displayed significantly reduced abilities to invade and survive within the mouse macrophage-like cell line J774A.1 in vitro and in the murine respiratory tract following experimental intranasal infection. Mice vaccinated with B. bronchiseptica aroA trpE displayed significant dose-dependent increases in B. bronchiseptica-specific antibody responses, and exhibited increases in the number of B. bronchiseptica-reactive spleen cells in lymphoproliferation assays. Immunised animals were protected against lung colonisation after challenge with the wild-type parental strain. With such a broad host range displayed by B. bronchiseptica, the attenuated strain constructed in this study may not only be used for the prevention of B. bronchiseptica-associated disease, but also for the potential delivery of heterologous antigen.
Assuntos
Aminoácidos Aromáticos/metabolismo , Vacinas Bacterianas/imunologia , Infecções por Bordetella/prevenção & controle , Bordetella bronchiseptica/imunologia , Mutação , Vacinas Atenuadas/imunologia , 3-Fosfoshikimato 1-Carboxiviniltransferase , Alquil e Aril Transferases/química , Alquil e Aril Transferases/genética , Alquil e Aril Transferases/imunologia , Animais , Antranilato Sintase/química , Antranilato Sintase/genética , Antranilato Sintase/imunologia , Anticorpos Antibacterianos/sangue , Vacinas Bacterianas/administração & dosagem , Infecções por Bordetella/microbiologia , Bordetella bronchiseptica/genética , Bordetella bronchiseptica/crescimento & desenvolvimento , Bordetella bronchiseptica/patogenicidade , Linhagem Celular , Modelos Animais de Doenças , Feminino , Ativação Linfocitária , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Óperon , Análise de Sequência de DNA , Vacinação , Vacinas Atenuadas/administração & dosagemRESUMO
The current Asian H5N1 highly pathogenic avian influenza virus has spread over much of Asia and into Europe and Africa. As well as affecting village and commercial chicken operations in many South East Asian countries, it differs from past H5 avian influenza viruses in that it causes morbidity and mortalities in other domesticated birds, such as ducks and turkeys and in wild water birds. Effective vaccines that can prevent infection, as well as disease, and be used in a variety of avian species are needed for field use. In this report, a bivalent H5N9+H7N1 oil emulsion vaccine is compared, in ducks, to a monovalent H5N3 oil emulsion vaccine that has been derived by reverse genetics with an H5 from A/chicken/Vietnam/C58/04. While both vaccines protected against morbidity, the monovalent vaccine provided effective protection, with no evidence of shedding of the challenge virus and no serological response to the H5N1 challenge virus.
Assuntos
Virus da Influenza A Subtipo H5N1/imunologia , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Animais , Anticorpos Antivirais/sangue , Patos , Feminino , Virus da Influenza A Subtipo H5N1/patogenicidade , Virus da Influenza A Subtipo H5N1/fisiologia , Masculino , Vacinas de Produtos Inativados/imunologia , Eliminação de Partículas ViraisRESUMO
Canine coronavirus (CCV) UWSMN-1 was originally identified from an outbreak of fatal gastroenteritis in breeding colonies. In this report, we examined whether UWSMN-1 represents a novel divergent strain or is the result of recombination events between canine and feline coronavirus strains. Sequencing of various regions of the spike and polymerase genes confirms that UWSMN-1 is widely divergent from other CCV and feline coronavirus strains. These data raise the possibility that this strain is the first member of a novel third subtype of CCV.