Strain Of Aujeszky Research Articles

Partial characterization of a Brazilian strain of Aujeszky’s disease virus recovered from a pig with subclinical infection

One Brazilian strain of Aujeszky’s disease virus isolated from a piglet in which the disease had not been observed was studied as for its virulence in pigs. The genome of the virus was molecularly analysed as for their restriction endonuclease cleavage pattern. Fifty-day-old non-immune weanlings exposed to this strain showed no disease although the virus was present in their oropharyngeal area for at least three days. All animals developed moderate titers of neutralizing antibody. Based on number of bands and migration rate of restriction fragments the isolate was classified into Herrmann’s type I group. Latent infection was detected in all pigs by PCR. Some variations were detected in the cleavage pattern of the strain ASB Piau when compared to LA031 virulent Brazilian strain, that could be related to differences in the virulence.

Multiplication and immunogenicity of a temperature-sensitive and thymidine kinase-deficient strain of Aujeszky's disease virus in pigs.

Hysterectomy-produced colostrum-deprived 5- and 27-day-old pigs were inoculated intramuscularly (IM) or intranasally (IN) with the temperature-sensitive and thymidine kinase-deficient ZHtsTK- strain of Aujeszky's disease virus (ADV), and the nasal swabs and organs of the pigs were periodically collected for virus isolation. No abnormal clinical signs were observed in these pigs, except for a mild febrile response. Viral shedding in the nasal swabs with low titers was detected in the pigs inoculated IN between postinoculation day (PID) 1 and 5, but not in those of the pigs inoculated IM. No contact infection, however, occurred in the cohabiting pigs. Viruses with low titers were isolated only from the muscles and lymph nodes at the site of inoculation in the pigs inoculated IM on PID 2 and 4, but not from any organs of the pigs inoculated IN. To investigate the ability of the ZHtsTK- strain to establish a latent infection in pigs, the pigs inoculated IM or IN with the ZHtsTK- strain were treated with prednisolone. No virus was detected in the trigeminal ganglia or the nasal swabs collected after prednisolone treatment by the cocultivation method. The immunological evaluation demonstrated that immunization of pigs with this strain was effective in preventing clinical signs caused by ADV infection. The duration of virus shedding was markedly shortened in immunized pigs, particularly in those immunized twice and the total quantity of virus recovered from immunized pigs was reduced in comparison with unimmunized pigs.

Detection of Aujeszky's disease virus in nasal cells of fattening pigs by immunoassay

Both conventional and specific pathogen free pigs were inoculated intranasally with a strain of Aujeszky's disease virus (ADV). Nasal cells were collected daily by swab, aspiration or wash. The nasal cells were examined for ADV by isolation on cell culture, direct or indirect immunofluorescence and immunoperoxidase staining by monoclonal antibodies. The infected pigs were studied for nasal shedding of infected cells until 30 days after infection. The study was also extended to naturally infected farm pigs. Swabbing, washing and aspiration proved effective methods of collecting between 10(5) and 10(8) pavement or columnar epithelial cells and non-epithelial cells. Macrophages and polymorphonuclear leucocytes were also identified. Infected nasal cells were detected by immunofluorescence and immunoperoxidase from one to 21 days after infection. The viral antigen was detected in both epithelial and non-epithelial cells, the fluorescence was nuclear and, or, 'cytoplasmic', in the latter case only the cell membrane was stained. ADV antigens were detected in nasal cavity cells in pigs infected with a virulent and a hypovirulent strain. Nasal swabs proved effective in confirming infection both by virus isolation and immunological assay, and the latter was shown to be a useful experimental tool for the rapid diagnosis of Aujeszky's disease virus infection in fattening pigs suffering from acute respiratory distress.

Induction of antibodies to glycoprotein I in pigs exposed to different doses of a mildly virulent strain of Aujeszky's disease virus

It has recently been shown that the antibody response to glycoprotein I (gI) of Aujeszky's disease virus can be used to distinguish infected from vaccinated pigs. To examine whether pigs exposed to low doses of a mildly virulent strain of Aujeszky's disease virus produce antibody to gI four groups of four pigs were inoculated intranasally with 10, 10(2), 10(3) or 10(4) plaque forming units (PFU) of the Sterksel strain. Two unvaccinated pigs and two pigs vaccinated intranasally with Bartha's K strain, a gI-negative vaccine, were placed in contact with each group. The pigs given 10 PFU and the in-contact pigs in this group did not become infected. The inoculated and the unvaccinated in-contact pigs in the other groups developed mild signs of illness and produced antibody to gI. Four of six vaccinated in-contact pigs that became infected showed neither clinical signs nor virus shedding and still produced antibody to gI. The other two vaccinated pigs appeared to be resistant to contact-challenge. The antibody response to gI persisted for at least seven months. These results support the idea that Aujeszky's disease virus may be eradicated by a programme based on vaccination with gI-negative vaccines, in conjunction with the detection and subsequent removal of gI-antibody positive, infected, pigs.

Morphogenesis of Aujeszky's Disease Virus in Pig Lung Macrophage Cultures

Smid B., L. Valicek, A. Sab6: Morphogenesis of Aujeszky's Disease Virus in Pig Lung Macrophage Cultures. Acta vet. Brno, 59, 1981: ·79-87. A virulent strain of Aujeszky's disease virus replicated in vitro in pig lung macro­ phages (PLM) from colostrum-deprived piglets aged 14, 23 and 45 days. The infecting dose was 5 PFU/cell. Core-like particles and nucleocapsids were observed in the nucleus 4 and 8 hours after infection, respectively. Single virions in the extra­ cellular space were first observed 10 hours after infection. At later stages of infection the nucleus contained numerous nucleocapsids, frequently arranged in crystalline arrays, and the cytoplasm showed numerous virions both in tubules of the smooth endoplasmic reticulum and in lysosomes. At the same time numerous virions were present also in the extracellular space, but only few of them showed a large amount of electron dense material between the nucleocapsid and the envelope.

Ultrastructural Changes in the Pulmonary Airways of Pigs Infected with a Strain of Aujeszky’s Disease Virus

Summary Thirty-two 4-week-old pigs were killed at intervals during a period of 24 hr. to 14 days after infection with a strain of Aujeszky’s disease virus. The resulting inflammatory changes in the lungs could be divided into an acute stage lasting from 24 hr. to the 6th day, and a repair pitase which commenced on the 4th day and continued until the 14th day. The virus attacked and multiplied in all types of cells and caused necrosis of the epithelium of bronchi, bronchioli and small airways. Necrosis frequently extended through the basement membrane and there was destruction of smooth muscle and connective tissue cells and fibres. Cellular debris and fibrin were removed by the activity of macrophages, which first appeared on the 4th day after infection. Organisation was carried out by fibroblasts, and collagen and elastic fibres were formed in the lumina and walls of airways between the 7th and 14th days. Epithelium was replaced by invasion by epithelial cells which later underwent mitosis followed by differentiation.

The Histopathology of Pneumonia Produced by Aerosol Infection of Pigs with a Strain of Aujeszky’s Disease Virus

Summary Pathogen-free and conventionally reared pigs were exposed to an aerosol cloud of Aujeszky’s disease virus. Mild clinical respiratory disease resulted, and from the third day at necropsy all lobes of the lungs contained numerous small areas of consolidation. Histologically these lesions consisted of necrotising bronchiolitis and alveolitis. From the fifth day a lympho-retiadar reaction developed at the periphery of the lesions and by the tenth day repair had been effected by fibrosis.

The Histopathology of Experimental Rhinitis in Pigs Produced by a Strain of Aujeszky’s Disease Virus

SUMMARY Seventy pigs aged between 4 days and 14 weeks were infected intranasally with Aujeszky’s disease virus and killed daily over a period of 16 days. A focal necrotising rhinitis developed by the second day, and persisted until the seventh day after infection. The lesions primarily affected the surface epithelium and upper mucosa but frequently the necrosis extended into the deeper structures including the nasal glands and, rarely, bone. These changes were accompanied by heavy infiltration of the mucosa by lymphocytes and macrophages. Healing began in some areas on the fifth day with the covering of the ulcerated mucosa by a single layer of squamous cells, which was rapidly converted to a stratified squamous epithelium. Rhinitis was also produced by infection of a further 21 pigs by exposure to an aerosol cloud of Aujeszky’s disease virus, but the lesions were neither as numerous nor as severe as those following the administration of intranasal drops.

Response of Suckling Hamsters to Pseudorabies Virus (Aujeszky Strain) by Peripheral Routes

Response of Suckling Hamsters to Pseudorabies Virus (Aujeszky Strain) by Peripheral Routes