[Impact of the ''Enhanced Recovery After Surgery'' program in knee arthroplasty at the institutional level]. / Impacto del programa ''Enhanced Recovery After Surgery'' en artroplastía de rodilla a nivel institucional.

INTRODUCTION: total knee arthroplasty has gained popularity over decreasing pain, restoring mobility and improving patients' quality of life. At the institutional level, there is no multidisciplinary model in the treatment of our patients, and in our environment, physical rehabilitation starts late, making it difficult for patients to reincorporate and attain adequate pain control. MATERIAL AND METHODS: a controlled, randomized, prospective and longitudinal study was conducted, 55 patients underwent total knee arthroplasty, assigned to two study groups: the ERAS (enhanced recovery after surgery) group (n = 27) and the usual group (n = 28). Inclusion criteria were patients with Kellgren-Lawrence classification grade 4 gonarthrosis, age between 30-70 years and follow-up for six months. Descriptive statistics were performed using medians and interquartile range, while inferential statistics were performed using the Kruskal-Wallis test. RESULTS: the results obtained at six months showed no statistically significant differences in age (p = 0.327) and gender (p = 0.588). The results obtained in the scales of VAS, WOMAC and IKDC showed statistically significant difference (p = 0.000). The rapid recovery group with a 120° flexion median and the usual group with 90° flexion, both groups with 0° extension. CONCLUSIONS: the enhanced recovery after surgery pathway in joint replacement procedures showed good results on pain, function, mobility and complications compared to patients undergoing usual management.

INTRODUCCIÓN: la artroplastía total de rodilla ha ganado popularidad sobre la disminución del dolor, restablecer la movilidad y mejorar la calidad de vida de los pacientes. A nivel institucional, no existe un modelo multidisciplinario en el tratamiento de nuestros pacientes y en nuestro medio la rehabilitación física se inicia de manera tardía, dificultando la reincorporación de los pacientes y el control analgésico. MATERIAL Y MÉTODOS: se realizó un estudio clínico controlado, aleatorizado, prospectivo y longitudinal que incluyó 55 pacientes sometidos a artroplastía de rodilla, asignados a dos grupos de estudio: el grupo ERAS (Enhanced Recovery After Surgery) (n = 27) y el grupo habitual (n = 28). Los criterios de inclusión fueron pacientes con gonartrosis grado IV de Kellgren y Lawrence, edad comprendida entre 30-70 años y seguimiento de seis meses. La estadística descriptiva se realizó mediante medianas y rango intercuartílico, mientras la estadística inferencial mediante la prueba de Kruskal-Wallis. RESULTADOS: los resultados obtenidos a los seis meses no mostraron diferencias estadísticas significativas de edad (p = 0.327) y género (p = 0.588). Los resultados obtenidos en las escalas de EVA, WOMAC e IKDC mostraron diferencia estadística significativa (p = 0.000). El grupo de recuperación rápida con una mediana de flexión de 120° y el grupo habitual con flexión de 90°, ambos grupos con extensión de 0°. CONCLUSIONES: el programa de recuperación rápida en procedimientos de remplazo articular, mostró buenos resultados sobre el dolor, función, movilidad y complicaciones en comparación con los pacientes sometidos al manejo habitual.

[Functional results of a rapid recovery program compared to the usual protocol in total knee arthroplasty]. / Resultados funcionales de un programa de recuperación rápida comparado con el protocolo habitual en artroplastía total de rodilla.

INTRODUCTION: rapid recovery programs in joint replacement surgery are effective in developed countries; The objective of this study was to evaluate the functional outcomes of a rapid recovery program in our population and to compare them with the results of the usual protocol. MATERIAL AND METHODS: a randomized single blinded clinical trial was conducted with patients who were candidates for total knee arthroplasty (n = 51) recruited from May 2018 to December 2019. group A (n = 24) received a rapid recovery program and group B (n = 27) received the usual protocol, with follow-up for 12 months. For statistical analysis, the Student's t test (parametric continuous variables), Kruskal-Wallis (nonparametric continuous variables) and the chi-square test (categorical variables) were used. RESULTS: statistically significant differences were found between groups in pain at two months (group A 3.4 ± 1.3 vs group B 4.2 ± 1.4, p = 0.04) and six months (1 ± 0.8 vs 1.7 ± 1.2, p = 0.01), with the WOMAC questionnaire at two months (group A 74.5 ± 7.2 vs group B 67.2 ± 7.5, p 0.01), six months (88.7 ± 5.3 vs 83.0 ± 4.8, p 0.01) and 12 months (90.1 ± 4.5 vs 86.7 ± 4.3, p 0.01), and with the IDKC questionnaire at two months (group A 62.9 ± 7.0 vs group B 55.9 ± 6.1, p 0.01), six months (74.3 ± 2.7 vs 71.1 ± 3.9, p 0.01) and 12 months (75.4 ± 3.0 vs 72.6 ± 3.5, p 0.01). CONCLUSIONS: the results obtained in this study suggest that the implementation of these programs can be a safe and effective alternative in terms of reducing pain and functional capacity in our population.

INTRODUCCIÓN: los programas de recuperación rápida en cirugía de reemplazo articular son eficaces en países desarrollados; el objetivo de este estudio fue evaluar los resultados funcionales de un programa de recuperación rápida en nuestra población y comprarlos con los resultados del protocolo habitual. MATERIAL Y MÉTODOS: se realizó un ensayo clínico no ciego simple aleatorizado con pacientes candidatos a artroplastía total de rodilla (n = 51) reclutados de Mayo de 2018 a Diciembre de 2019. El grupo A (n = 24) recibió un programa de recuperación rápida y el grupo B (n = 27) recibió el protocolo habitual, con seguimiento durante 12 meses. Para el análisis estadístico se utilizó la prueba de t de Student (variables continuas paramétricas), Kruskal-Wallis (variables continuas no paramétricas) y la prueba de 2 (variables categóricas). RESULTADOS: se encontraron diferencias estadísticamente significativas entre grupos en el dolor a los dos meses (grupo A 3.4 ± 1.3 versus grupo B 4.2 ± 1.4, p = 0.04) y seis meses (1 ± 0.8 versus 1.7 ± 1.2, p = 0.01), con el cuestionario WOMAC a los dos meses (grupo A 74.5 ± 7.2 versus grupo B 67.2 ± 7.5, p 0.01), seis meses (88.7 ± 5.3 versus 83.0 ± 4.8, p 0.01) y 12 meses (90.1 ± 4.5 versus 86.7 ± 4.3, p 0.01) y con el cuestionario IDKC a los dos meses (grupo A 62.9 ± 7.0 versus grupo B 55.9 ± 6.1, p 0.01), seis meses (74.3 ± 2.7 versus 71.1 ± 3.9, p 0.01) y 12 meses (75.4 ± 3.0 versus 72.6 ± 3.5, p 0.01). CONCLUSIONES: los resultados obtenidos en este estudio sugieren que la implementación de estos programas puede ser una alternativa segura y eficaz en cuanto a la disminución del dolor y a la capacidad funcional en nuestra población.

Genetic identification of novel poxviruses of cetaceans and pinnipeds.

Novel poxviruses were identified in skin lesions of several species of cetaceans and pinnipeds using polymerase chain reaction targeting DNA polymerase and DNA topoisomerase I genes of members of the subfamily Chordopoxvirinae. With the exception of parapoxviruses, no molecular data of marine mammal poxviruses were available to infer genetic and evolutionary relatedness to terrestrial vertebrate poxviruses. Viruses were assigned to a cetacean poxvirus 1 (CPV-1) group based on nucleotide and amino acid identities of gene fragments amplified from skin lesions of Asian bottlenose (Tursiops aduncus), Atlantic bottlenose (Tursiops truncatus), rough-toothed (Steno bredanensis), and striped (Stenella coeruleoalba) dolphins. A different poxvirus was detected in skin lesions of a bowhead whale (Balaena mysticetus) and provisionally assigned to a CPV-2 group. These viruses showed highest identity to terrestrial poxviruses of the genera Orthopoxvirus and Suipoxvirus. A novel species-specific poxvirus was also identified in skin lesions of Steller sea lions (Eumetopias jubatus). None of these poxviruses were found to have amplifiable hemagglutinin gene sequences. Novel parapoxviruses were also identified in skin lesions of Steller sea lions and spotted seals (Phoca largha). A significant degree of divergence was observed in sequences of Steller sea lion parapoxviruses, while those of spotted seals and harbor seals (Phoca vitulina) were highly conserved.

Experimental transmission of a herpesvirus in Greek tortoises (Testudo graeca).

An experimental transmission study aimed at fulfilling Koch's postulates for a herpesvirus-associated stomatitis-rhinitis in Mediterranean tortoises is presented. Clinical, pathologic, serologic, and molecular studies were performed linking tortoise herpesvirus with the pathogenesis of stomatitis-rhinitis. Four adult Greek tortoises received either intranasally or intramuscularly two tortoise herpesvirus isolates by primary experimental infection and secondary challenge 11 months later. After the primary experimental infection and the secondary challenge, clinical signs of illness developed, which included conjunctivitis, diphtheritic oral plaques, and oral discharge. At 4 weeks after the secondary challenge, all tortoises were humanely euthanatized and evaluated. Although neutralizing antibodies developed after the primary experimental infection, they apparently did not prevent the later development of recurrent clinical signs. Polymerase chain reaction (PCR) and reverse transcription-PCR analyses allowed sensitive characterization of the systemic distribution of the herpesvirus DNA sequences and their presence in the cranial nerves and brains of the infected tortoises. Despite the failure to recover the herpesviruses used in the transmission study, the findings support the premise that tortoise herpes-virus is a primary pathogen of Greek tortoises.

Fate of plasmid DNA encoding infectious bursal disease virus VP2 capsid protein gene after injection into the pectoralis muscle of the chicken.

The objective of this study was to determine whether recombinant plasmid DNA injected intramuscularly into chickens expressed the gene of interest in vivo and could be subsequently detected in primary and secondary lymphoid tissues with polymerase chain reaction (PCR). The VP2 capsid protein gene of the standard challenge strain (STC) of infectious bursal disease virus (IBDV) was cloned into a eukaryotic plasmid, and purified DNA was prepared. Fourteen 2-wk-old chickens were injected in the pectoral musculature with 500 microg of plasmid DNA dissolved in sterile PBS. Seven chickens were similarly injected with PBS alone. Pectoral muscle, thymus, spleen, bursa of Fabricius, and cecal tonsils were collected at 12, 24, 36, 48, 72, 96, and 168 h postinjection for detection of protein expression (in muscle) and to extract total DNA for PCR amplification of the VP2 capsid gene. Expression of VP2 was demonstrated in muscle tissue at 12 and 24 h postinjection by using an indirect immunofluorescence assay. PCR amplification with primers specific for the VP2 gene showed that the DNA was present in the thymus, spleen, and bursa of Fabricius but not in cecal tonsils. These results demonstrate that plasmid DNA injected directly into the pectoral muscle of chickens is transcribed and translated at the injection site and promptly distributed to primary and secondary lymphoid tissues.

Venereal transmission of pseudorabies viruses indigenous to feral swine.

Between 1995 and 1998, we designed a series of studies in which we attempted to determine the main routes of transmission involved in the natural infection of pseudorabies virus (PRV) indigenous to free-ranging feral swine (Sus scrofa). Naturally infected feral sows transmitted the infection to uninfected feral boars, with which they had been commingled for a 6-wk period. Pseudorabies virus was isolated from boar preputial swabs, but not from nasal swabs. Three of the same PRV-infected feral sows did not transmit the infection to domestic boars during a 16 wk commingling period, despite the fact that they became pregnant. Feral boars, naturally infected with PRV transmitted the virus to domestic gilts while penned together during 6 wk. Pseudorabies virus was isolated from vaginal swabs, but not from nasal swabs of gilts, after 2 and 3 wk of commingling. When the same infected boars were commingled with either feral or domestic boars for 13 wk, PRV transmission did not occur. None of the exposed boars developed neutralizing antibodies or yielded virus from their preputial or nasal swabs. Our results indicate that PRV indigenous to feral swine is preferentially transmitted to feral or domestic swine of the opposite sex by the venereal route. This mode of transmission differs from that seen in the natural transmission of PRV prevalent in domestic swine, where contaminated secretions, excretions and aerosols are responsible for the spread of the virus. Based on these results, we feel that as long as feral swine do not come into direct contact with domestic swine, PRV-infected feral swine probably pose only a limited risk to the success of the National Pseudorabies Eradication Program. The fact that PRV is usually transmitted from feral to domestic swine at the time of mating would indicate that the isolation of domestic herds by the use of a "double fence," should be adequate protection against reinfection with PRV.

Sequence analysis of feline caliciviruses isolated from the oral cavity of clinically normal domestic cats (Felis catus) in Florida.

Four isolates (7.3 per cent) of feline calicivirus (FCV), from oropharyngeal swabs taken from 55 unvaccinated apparently healthy cats, were identified by electron microscopy and reverse transcription-polymerase chain reaction (RT-PCR). A 671-bp fragment, comprising part of region B, all of regions C, D, and E and part of region F of the FCV capsid protein gene, was amplified from each isolate by RT-PCR and cloned for sequence analysis. Amino acid sequence comparison of these regions revealed significant sequence divergence from the F9 vaccine strain within regions C, E, and F. The hypervariable region E of the four Florida isolates and the NADC isolate contained three fewer amino acids than the commonly used F9 vaccine strain. This work provides support to the idea that currently circulating FCV strains may differ substantially from presently used vaccine strains.

Newcastle disease virus in double-crested cormorants in Alabama, Florida, and Mississippi.

In order to understand the epidemiology of Newcastle disease (ND) outbreaks in double-crested cormorants (Phalacrocorax auritus), a study was conducted on wintering migratory cormorants (P. a. auritus) in Alabama and Mississippi (USA) and non-migratory cormorants (P. a. floridanus) that breed in Florida (USA). Antibodies against ND virus were detected by the hemagglutination-inhibition method in sera from 86 of 183 (47%) migratory cormorants over-wintering in eight roosting sites in Alabama and Mississippi between November, 1997 and April, 1999. Titers ranged from 5 to 40. Antibody prevalences in sera collected from females in early winter (November and December) (26%) and late winter (February and March) (56%) were significantly different (P = 0.0007). None of 45 serum samples from 1- to 7-wk-old nestlings from 11 colonies in Florida during the 1997-98 and 1998-99 breeding seasons was positive. However, antibodies were detected in yolk samples from 98 of 126 (78%) eggs collected in these same colonies. Titers ranged from 4 to 256. The prevalence of antibodies in eggs collected from fresh-water colonies (63% prevalence, n = 30) and salt-water colonies (82% prevalence, n = 96) was significantly different (P = 0.041). ND virus was not isolated from tissues of 18 cormorants and cloacal and tracheal swabs from 202 cormorants collected in Alabama and Mississippi; virus was also not isolated from cloacal and tracheal swabs from 51 nestlings from Florida.

Genital infection and transmission of pseudorabies virus in feral swine in Florida, USA.

Seventeen feral swine (FS) naturally infected with pseudorabies virus (PRV) and treated with dexamethasone (4 mg/kg body wt) on five consecutive days shed virus primarily from the genital tract and less frequently from the upper respiratory tract. The FS isolates were identified as PRV by virus neutralization with specific polyclonal antiserum and by direct immunofluorescence. Restriction endonuclease analysis with BamHI showed that representative samples from a total of 62 isolates were identical to each other, but differed in at least 5 DNA bands from the PRV Shope reference strain profile. DNA purified from FS isolates propagated in Vero cells or DNA extracted directly from genital swabs were amplified in the polymerase chain reaction using primers specific for the gpII (gB) gene of PRV. This amplification yielded a product of the expected size (200 bp), which specifically hybridized to a digoxigenin-labelled 30-mer probe complementary to an area within the region defined by the primers. In a transmission experiment, PRV was recovered from the vagina at 1 and 6 weeks after uninfected feral gilts were mixed with infected feral boars. PRV was not isolated from the upper respiratory tract of either gilts or boars. At eight weeks, 4 of the 5 gilts had developed low titer neutralizing antibodies to PRV. Our results indicate that PRV in FS is transmitted through sexual contact.

Expression of the major core structural protein (VP7) of bluetongue virus, by a recombinant capripox virus, provides partial protection of sheep against a virulent heterotypic bluetongue virus challenge.

A recombinant capripox virus was constructed containing a cDNA copy of genome segment 7 of bluetongue virus (BTV) serotype 1 from South Africa (BTV 1SA), which expressed high levels of the major BTV core protein VP7 in infected lamb testis (LT) cells. Sheep vaccinated with this recombinant virus developed antibodies to VP7 (detected by ELISA) but no neutralizing antibodies to either the homologous or heterologous BTV serotype, prior to challenge (BTV 1 or BTV 3, respectively). Following challenge with a virulent heterotypic strain of BTV (BTV3 SA), all of the animals developed clinical signs of disease, indicating that they were infected and that the challenge virus did replicate. While all of the control animals died, six of the eight animals that were vaccinated with the recombinant capripox virus expressing VP7 recovered fully. This is the first report of a significant level of cross serotype protection against the lethal effects of a challenge with virulent BTV, produced by vaccination with a single BTV core protein, which did not generate a neutralizing antibody response.

Protection of goats against peste des petits ruminants with recombinant capripoxviruses expressing the fusion and haemagglutinin protein genes of rinderpest virus.

Goats were protected against a lethal challenge of peste des petits ruminants (PPR) virus following vaccination with a recombinant capripoxvirus containing either the fusion (F) gene of rinderpest virus or the haemagglutinin (H) gene of rinderpest virus. The H gene recombinant produced high titres of neutralizing antibody to rinderpest virus in the vaccinated goats, whereas the F gene recombinant failed to stimulate detectable levels of neutralizing antibody. A similar response to the two recombinant vaccines has previously been reported for cattle. Neither recombinant produced detectable levels of specific antibodies to PPR virus.

Recombinant capripoxvirus expressing the hemagglutinin protein gene of rinderpest virus: protection of cattle against rinderpest and lumpy skin disease viruses.

A cDNA clone containing the complete coding sequence of the hemagglutinin (H) protein gene of the RBOK vaccine strain of rinderpest virus, under the control of the vaccinia late promoter p11, was inserted by homologous recombination into the thymidine kinase gene of the KS-1 strain of capripoxvirus. The recombinant virus produced authentic H protein as judged by its electrophoretic mobility, transport to the cell surface of infected lamb testis cells, and reactivity with monoclonal antibodies specific for the H protein of rinderpest virus. The recombinant virus induced significant levels of rinderpest virus neutralizing antibodies in vaccinated cattle and protected them from clinical rinderpest after challenge with a lethal dose of a highly virulent heterologous strain of the virus. Protection was achieved using vaccine doses lower than those used with a similar recombinant expressing the fusion protein gene of rinderpest. The parental KS-1 virus is widely used as a vaccine against capripox viruses and so the rinderpest recombinant acts as a dual vaccine to protect cattle against both rinderpest and lumpy skin disease.

Protection of cattle against rinderpest and lumpy skin disease with a recombinant capripoxvirus expressing the fusion protein gene of rinderpest virus.

Cattle were protected against challenge with rinderpest and lumpy skin disease viruses by vaccination with a recombinant capripoxvirus containing the fusion protein (F) gene of rinderpest virus. The minimum protective immunising doses for rinderpest and lumpy skin disease were 5.5 x 10(4) plaque forming units (pfu) and 1.5 x 10(3) pfu, respectively.

Single capripoxvirus recombinant vaccine for the protection of cattle against rinderpest and lumpy skin disease.

A recombinant capripoxvirus has been constructed containing a full-length cDNA of the fusion protein gene of rinderpest virus. The gene was inserted in the thymidine kinase gene of the capripox genome under the control of the vaccinia virus major late promoter p11 together with the Escherichia coli gpt gene in the opposite orientation under the control of the vaccinia early/late promoter p7.5. A vaccine prepared from this recombinant virus protected cattle against clinical rinderpest after a lethal challenge with a virulent virus isolate. In addition, the vaccine protected the cattle against lumpy skin disease.

Non-pathogenic strains of Aujeszky's disease virus are not reactivated in swine after corticosteroid treatment

The Bartha-K and NIA-4 strain of Aujeszky's disease virus (ADV) were readily isolated from oropharyngeal swabs up to 7 days after intranasal vaccination of young piglets. Neither strain could be reisolated 14 days after starting treatment with 10 mg of the corticosteroid isoflupredone acetate per kg of body weight, administered intramuscularly for 4 consecutive days when pigs were 7-9 months of age. Similar treatment with corticosteroid pigs infected with two virulent ADV strains resulted in the reactivation of infection and recovery of ADV from oropharyngeal swabs. Serum neutralizing antibodies were present in all pigles vaccinated twice (2 week interval) intranasally with the attenuated ADV strains, 4 weeks after primary vaccination. However, these antibodies were no longer detectable in some pigs at 12(NIA-4) and 20(Bartha-K) weeks of age even in undilluted sera. Neutralizing antibodies resulting from infection virulent ADV were always detectable, were higher in titer than those produced by the vaccine strains and did not vary in a clear pattern after corticosteroid treatment. These results indicated that the Bartha-K and NIA-4 strains undergo little or no latency in swine and confirm the latency of virulent strains of ADV

Non-pathogenic strains of Aujeszky's disease virus are not reactivated in swine after corticosteroid treatment.

1. The Bartha-K and NIA-4 strains of Aujeszky's disease virus (ADV) were readily isolated from oropharyngeal swabs up to 7 days after intranasal vaccination of young piglets. 2. Neither strain could be reisolated 14 days after starting treatment with 10 mg of the corticosteroid isoflupredone acetate per kg of body weight, administered intramuscularly for 4 consecutive days when pigs were 7-9 months of age. 3. Similar treatment with corticosteroid pigs infected with two virulent ADV strains resulted in the reactivation of infection and recovery of ADV from oropharyngeal swabs. 4. Serum neutralizing antibodies were present in all piglets vaccinated twice (2 week interval) intranasally with the attenuated ADV strains, 4 weeks after primary vaccination. However, these antibodies were no longer detectable in some pigs at 12 (NIA-4) and 20 (Bartha-K) weeks of age even in undiluted sera. 5. Neutralizing antibodies resulting from infection with virulent ADV were always detectable, were higher in titer than those produced by the vaccine strains and did not vary in a clear pattern after corticosteroid treatment. 6. These results indicate that the Bartha-K and NIA-4 strains undergo little or no latency in swine and confirm the latency of virulent strains of ADV.

Experimental transmission of bovine leukosis virus by leucocytes recovered from the stable fly Stomoxys calcitrans L.

1. Wild stable flies (Stomoxys calcitrans) feeding on heifers infected with bovine leukosis virus (BLV) carried viable bovine leucocytes in the midgut and proboscis that, when inoculated by the subcutaneous route into lambs aged 5 to 60 days, elicited the development of antibodies to glycoprotein (gp51) and polypeptide 25 (p25). 2. Antibodies were detected as early as one month later and persisted for an experimental period of 24 or 36 months. Uninoculated control lambs reared together with the experimental animals did not acquire the infection, indicating the lack of horizontal transmission. 3. S. calcitrans reared in the laboratory were intermittently allowed to feed on the skin of BLV-infected heifers and on five lambs over a period of 3-10 months. Although some of these lambs were bitten about 500 times, none developed antibodies to BLV (gp51 or p25) over observation periods of 30 or 36 months.

Experimental transmission of bovine leukosis virus by leucocytes recovered from the stable fly Stomoxys calcitrans L

1. Wild stable flies (stomoxys calcitrans) feeding on heifers infected with bovine leukosis virus (BLV) carried viable bovine leucocytes in the midgut and proboscis that, when inoculated by the subcutaneous route into lambs aged 5 to 60 days, elicited the development of antibodies to glycoprotein (gp51) and polipeptide 25 (p25). 2. Antibodies were detected as early as one month later and persisted for an experimental period of 24 or 36 months. Uninoculated control lambs reared to gether with the experimental animals did not acquire the infection, indicating the lack of horizontal transmission. 3. S. calcitrans reared in the laboratory were intermittently allowed to feed on the skin of BLV-infected heifers and on five lambs over a period of 3-10 months. Although some of these lambs were bitten about 500 times, none developed antibodies to BLV (gp51 or p25) over observation periods of 30 or 36 months

Experimental vaccination of rabbits with non-pathogenic strains of Aujeszky's disease virus.

1. The Bartha K and NIA-4 strains of Aujeszky's disease virus (ADV) were non-pathogenic for rabbits vaccinated once or twice by nasal instillation or intramuscular injection. Neutralizing antibodies were detected in 68% of the rabbits two weeks after primary vaccination and in all rabbits at challenge. 2. Challenge doses of virulent ADV greater than 10(5.0) median tissue culture infective doses (TCID50) resulted in the death of most vaccinated and all unvaccinated rabbits with typical signs of Aujeszky's disease within 4 days. ADV was recovered from brain and lung suspensions of vaccinated and unvaccinated rabbits who had died as a result of the challenge. 3. When the challenge dose was reduced to approximately 10(3.0) TCID50, rabbits vaccinated twice survived while all unvaccinated controls died within 3 days.

Experimental vaccination of rabbits with non-pathogenic strains of Aujeszky's disease virus

1. The Bartha K and NIA-4 strains of Aujeszky's disease virus (ADV) were non-pathogenic for rabbits vaccinated once or twice by nasal instillation or intramuscular injection. Neutralizing antibodies were detected in 68% of the rabbits two weeks after primary vaccination and in al rabbits at challenge. 2. Challenge doses of virulent ADV greater than 10**5.0 median tissue culture infective doses (TCID50) resulted in the death of most vaccinated and all unvaccinated rabbits with typical signs of Aujeszky's disease withing 4 days. ADV was recovered from braim and lung suspensions of vaccinated and unvaccinated rabbits who had died as a result of the challenge. 3. When the challenge dose was reduced to approximately 10**3.0 TCID50, rabbits vaccinated twice survived while al unvaccinated controls died within 3 days