phenylephrine-hydrochloride and Viremia

Equine herpesvirus-1 is a cause of outbreaks of abortion and neurological disease. The pathogenesis of both these diseases depends on establishment of viremia. An experiment was performed to determine the protective efficacy of two commercially available vaccines used with an optimized 3-dose vaccination regime: a modified-live viral (MLV) and a high antigen load killed vaccine licensed for abortion control. The study design was a blinded, randomized challenge trial. Three groups of 8 yearling ponies received one of three treatments: MLV vaccine (Rhinomune, Boehringer Ingelheim Vetmedica, Inc.); killed vaccine (Pneumabort-K, Pfizer Animal Health); or a placebo (control group). Three vaccinations were administered at intervals of 27 and 70 days followed by challenge infection 24 days later. Clinical disease after challenge was significantly reduced in both vaccine groups; the reduction was greater in the MLV vaccine group. Nasal shedding was reduced by at least 1-2 logs in both vaccine groups. The number of days of viremia was significantly reduced in the killed vaccine group only. This study demonstrated that both commercial vaccines significantly suppressed EHV-1 disease and nasal viral shedding, and one vaccine suppressed days of viremia.

Topics: Animals; Antibodies, Neutralizing; Antibodies, Viral; Antibody Formation; Female; Herpesviridae Infections; Herpesvirus 1, Equid; Horse Diseases; Horses; Immunization Schedule; Neutralization Tests; Nose; Single-Blind Method; Viral Vaccines; Viremia; Virus Shedding

Equid Gamma herpesvirus (eGHV) infections have been reported worldwide and may be correlated with clinical signs, e.g., affecting the respiratory tract in young horses. eGHV are shed by healthy horses as well as horses with respiratory tract disease. The prevalence in healthy Swiss horses is unknown to date but this data would provide valuable information for causal diagnosis in clinical cases and formulation of biosecurity recommendations. Nasal swabs from 68 healthy horses from 12 Swiss stables and 2 stables near the Swiss border region in Germany were analyzed by panherpes nested PCR. Positive samples were sequenced. A multivariable model was used to determine if sex, age, breed, canton, or stable had a significant effect on the shedding status of each detected eGHV. Overall, the eGHV prevalence was 59% (

Topics: Animals; Antibodies, Viral; DNA, Viral; Female; Gammaherpesvirinae; Germany; Herpesvirus 1, Equid; Horse Diseases; Horses; Male; Nose; Respiratory Tract Diseases; Switzerland; Viremia; Virus Shedding

Recently, a novel PCV species (PCV3) has been detected in cases associated with sow mortality, lesions consistent with porcine dermatitis and nephropathy syndrome, reproductive failure and multisystemic inflammation. The pathogenesis and clinical significance of PCV3 is still unclear. In this study, we investigated the immunopathogenesis of PCV3 in CD/CD pigs. Four treatment groups, PCV3 (

Topics: Animals; Antibodies, Viral; Circoviridae Infections; Circovirus; Immunoglobulin G; Inflammation; Nose; Swine; Swine Diseases; Viremia; Virus Replication; Virus Shedding

The equine herpesvirus type 1 (EHV-1) ORF1 and ORF71 genes have immune modulatory effects in vitro. Experimental infection of horses using virus mutants with multiple deletions including ORF1 and ORF71 showed promise as vaccine candidates against EHV-1. Here, the combined effects of ORF1 and ORF71 deletions from the neuropathogenic EHV-1 strain Ab4 on clinical disease and host immune response were further explored. Three groups of EHV-1 naïve horses were experimentally infected with the ORF1/71 gene deletion mutant (Ab4ΔORF1/71), the parent Ab4 strain, or remained uninfected. In comparison to Ab4, horses infected with Ab4ΔORF1/71 did not show the initial high fever peak characteristic of EHV-1 infection. Ab4ΔORF1/71 infection had reduced nasal shedding (1/5 vs. 5/5) and, simultaneously, decreased intranasal interferon (IFN)-α, interleukin (IL)-10 and soluble CD14 secretion. However, Ab4 and Ab4ΔORF1/71 infection resulted in comparable viremia, suggesting these genes do not regulate the infection of the mononuclear cells and subsequent viremia. Intranasal and serum anti-EHV-1 antibodies to Ab4ΔORF1/71 developed slightly slower than those to Ab4. However, beyond day 12 post infection (d12pi) serum antibodies in both virus-infected groups were similar and remained increased until the end of the study (d114pi). EHV-1 immunoglobulin (Ig) G isotype responses were dominated by short-lasting IgG1 and long-lasting IgG4/7 antibodies. The IgG4/7 response closely resembled the total EHV-1 specific antibody response. Ex vivo re-stimulation of PBMC with Ab4 resulted in IFN-γ and IL-10 secretion by cells from both infected groups within two weeks pi. Flow cytometric analysis showed that IFN-γ producing EHV-1-specific T-cells were mainly CD8+/IFN-γ+ and detectable from d32pi on. Peripheral blood IFN-γ+ T-cell percentages were similar in both infected groups, albeit at low frequency (~0.1%). In summary, the Ab4ΔORF1/71 gene deletion mutant is less virulent but induced antibody responses and cellular immunity similar to the parent Ab4 strain.

Topics: Animals; Antibodies, Viral; Body Temperature; Cytokines; Female; Herpesviridae Infections; Herpesvirus 1, Equid; Horse Diseases; Horses; Immunity, Cellular; Immunoglobulin G; Male; Mutation; Nose; Random Allocation; Viral Proteins; Viremia; Virulence; Virus Shedding

Murine cytomegalovirus (MCMV) infection in mice is a commonly used animal model for studying human cytomegalovirus (HCMV) infections. In our previous studies, a mouse model based on an oronasal MCMV infection was set up for mimicking a natural infection, and the spleen was hypothesized to regulate viremia and virus dissemination to distal organs such as submandibular glands. Here, the role of the spleen during an MCMV infection was investigated by the comparison of intact and splenectomized Balb/c mice. Both highly passaged MCMV Smith and low passaged MCMV HaNa1 were used. Various samples were collected at 7, 14, and 21 days post inoculation (dpi) for analyses by virus isolation/titration, co-cultivation and qPCR. The results showed that for both virus strains, 1) cell-associated virus in PBMC (determined by co-cultivation) was detected in intact mice but not in splenectomized mice; 2) the mean viral DNA load in PBMC of splenectomized mice was 4.4-(HaNa1)/2.7-(Smith) fold lower at the peak viremia (7dpi) in contrast to that of intact mice; and 3) infectious virus in the submandibular glands was detected later in splenectomized mice (14dpi) than in intact mice (7dpi). Moreover, the average virus titers in submandibular glands of splenectomized mice were 10-(HaNa1)/7.9-(Smith) fold lower at 14dpi and 1.7-(HaNa1)/2.1-(Smith) fold lower at 21dpi compared with that of intact mice. Upon inoculation with MCMV Smith, infectious virus was found in the kidneys and liver of intact mice, but not in splenectomized mice. Taken together, all these data clearly demonstrate that virus dissemination to distant organs is reduced in splenectomized mice, further confirming the importance of the spleen as a viremia booming site for a natural MCMV infection.

Topics: Animals; Cells, Cultured; Female; Herpesviridae Infections; Leukocytes, Mononuclear; Mice, Inbred BALB C; Mouth; Muromegalovirus; Nose; Spleen; Splenectomy; Viremia

Current porcine reproductive and respiratory syndrome virus (PRRSV) vaccines sometimes fail to provide adequate immunity to protect pigs from PRRSV-induced disease. This may be due to antigenic differences among PRRSV strains. Rapid production of attenuated farm-specific homologous vaccines is a feasible alternative to commercial vaccines. In this study, attenuation and efficacy of a codon-pair de-optimized candidate vaccine generated by synthetic attenuated virus engineering approach (SAVE5) were tested in a conventional growing pig model. Forty pigs were vaccinated intranasally or intramuscularly with SAVE5 at day 0 (D0). The remaining 28 pigs were sham-vaccinated with saline. At D42, 30 vaccinated and 19 sham-vaccinated pigs were challenged with the homologous PRRSV strain VR2385. The experiment was terminated at D54. The SAVE5 virus was effectively attenuated as evidenced by a low magnitude of SAVE5 viremia for 1-5 consecutive weeks in 35.9% (14/39) of the vaccinated pigs, lack of detectable nasal SAVE5 shedding and failure to transmit the vaccine virus from pig to pig. By D42, all vaccinated pigs with detectable SAVE5 viremia also had detectable anti-PRRSV IgG. Anti-IgG positive vaccinated pigs were protected from subsequent VR2385 challenge as evidenced by lack of VR2385 viremia and nasal shedding, significantly reduced macroscopic and microscopic lung lesions and significantly reduced amount of PRRSV antigen in lungs compared to the non-vaccinated VR2385-challenged positive control pigs. The nasal vaccination route appeared to be more effective in inducing protective immunity in a larger number of pigs compared to the intramuscular route. Vaccinated pigs without detectable SAVE5 viremia did not seroconvert and were fully susceptible to VR2385 challenge. Under the study conditions, the SAVE approach was successful in attenuating PRRSV strain VR2385 and protected against homologous virus challenge. Virus dosage likely needs to be adjusted to induce replication and protection in a higher percentage of vaccinated pigs.

Topics: Administration, Intranasal; Animals; Antibodies, Viral; Disease Models, Animal; Injections, Intramuscular; Nose; Porcine Reproductive and Respiratory Syndrome; Porcine respiratory and reproductive syndrome virus; Sus scrofa; Swine; Vaccine Potency; Vaccines, Attenuated; Vaccines, Synthetic; Viral Vaccines; Viremia; Virus Shedding

Equine herpesvirus myeloencephalitis (EHM) remains one of the most devastating manifestations of equine herpesvirus type 1 (EHV-1) infection but our understanding of its pathogenesis remains rudimentary, partly because of a lack of adequate experimental models. EHV-1 infection of the ocular vasculature may offer an alternative model as EHV-1-induced chorioretinopathy appears to occur in a significant number of horses, and the pathogenesis of EHM and ocular EHV-1 may be similar. To investigate the potential of ocular EHV-1 as a model for EHM, and to determine the frequency of ocular EHV-1, our goal was to study: (1) Dissemination of virus following acute infection, (2) Development and frequency of ocular lesions following infection, and (3) Utility of a GFP-expressing virus for localization of the virus in vivo. Viral antigen could be detected following acute infection in ocular tissues and the central nervous system (experiment 1). Furthermore, EHV-1 infection resulted in multifocal choroidal lesions in 90% (experiment 2) and 50% (experiment 3) of experimentally infected horses, however ocular lesions did not appear in vivo until between 3 weeks and 3 months post-infection. Taken together, the timing of the appearance of lesions and their ophthalmoscopic features suggest that their pathogenesis may involve ischemic injury to the chorioretina following viremic delivery of virus to the eye, mirroring the vascular events that result in EHM. In summary, we show that the frequency of ocular EHV-1 is 50-90% following experimental infection making this model attractive for testing future vaccines or therapeutics in an immunologically relevant age group.

Topics: Animals; Chorioretinitis; Encephalomyelitis; Fluorescein Angiography; Green Fluorescent Proteins; Herpesviridae Infections; Herpesvirus 1, Equid; Horse Diseases; Horses; Neutralization Tests; Nose; Random Allocation; Viremia; Virus Shedding

This study is the first report of experimental infection and transmission of Menangle virus (MenPV) in pigs. Isolated in 1997 from piglets that were stillborn at a large commercial piggery in New South Wales, Australia, MenPV is a recently identified paramyxovirus of bat origin that causes severe reproductive disease in pigs and an influenza-like illness, with a rash, in humans. Although successfully eradicated from the infected piggery, the virus was only isolated from affected fetuses and stillborn piglets during the period of reproductive disease, and thus the mode of transmission between pigs was not established. To investigate the pathogenesis of MenPV, we undertook time-course studies in 6-week-old pigs following intranasal administration of a low-passage, non-plaque-purified isolate from the lung of an infected stillborn piglet. Viraemia was of short duration and low titre, as determined by real-time RT-PCR and virus isolation. Following an incubation period of 2-3 days, virus was shed in nasal and oral secretions, faeces and urine, typically for less than 1 week. Cessation of shedding correlated with the development of neutralizing antibodies in sera. Secondary lymphoid organs and intestine were identified, using quantitative real-time RT-PCR, as major sites of viral replication and dissemination, and this was confirmed by positive immunolabelling of viral antigen within various lymphoid tissues and intestinal epithelium. These data provide new insights into the pathogenesis of MenPV in weaned pigs, and will facilitate future control and eradication programmes should it ever re-emerge in the pig population.

Topics: Animals; Antibodies, Neutralizing; Antibodies, Viral; Bodily Secretions; Feces; Female; Intestinal Mucosa; Lymphoid Tissue; Mouth; Nose; Paramyxoviridae Infections; Paramyxovirinae; Swine; Swine Diseases; Urine; Viral Load; Viral Tropism; Viremia; Virus Shedding

The early identification of classical swine fever epizootics is hampered by difficulties in recognising early signs of infection, due to a lack of specific clinical signs. In addition many textbook descriptions of CSF are based on observations of disease caused by historic, mainly genotype 1, strains. Our objective was to improve our knowledge of the diverse range of signs that different CSFV strains can cause by characterising the experimental infection of domestic pigs with both a recent strain of CSFV and a divergent strain. Conventional pigs were inoculated with a genotype 2.1 isolate, that caused an outbreak in the UK in 2000, and a genotype 3.3 strain that is genetically divergent from European strains. This latter strain is also antigenically distinct as it is only poorly recognised by the CSFV-specific monoclonal antibody, WH303. Transmission was monitored by use of in-contact animals. Clinical, virological and haematological parameters were observed and an extended macro- and histopathological scoring system allowed detailed characterisation of pathological lesions. Infection with the genotype 2.1 isolate resulted in a similar outcome to other recent genotype 2 European strains, whereas the genotype 3.3 strain produced fewer and delayed clinical signs, notably with little fever. This strain would therefore be particularly difficult to detect in the early stages of infection and highlights the importance of encouraging early submission of samples for laboratory diagnosis. As representatives of recent and divergent CSFV isolates, these strains are good candidates to study the pathogenesis of current CSFV isolates and as challenge models for vaccine development.

Topics: Animals; Body Temperature; Classical Swine Fever; Classical Swine Fever Virus; Genotype; Leukopenia; Molecular Sequence Data; Nose; Swine; Thrombocytopenia; Time Factors; Viral Envelope Proteins; Viremia; Virus Shedding

The efficacy of recently developed porcine circovirus type 2 (PCV2) vaccines has not been tested yet against PCV2 isolates of the two proposed genotypes. In the present work, the efficacy of a subunit vaccine containing PCV2 capsid protein was evaluated by using a challenge model with four different PCV2 isolates of different genotype and geographic origin. The vaccine prevented the development of viremia in all cases as well as significantly decreased nasal and faecal shedding of the virus. Also, the vaccine elicited PCV2-specific neutralizing antibodies to PCV2 even in the presence of maternally derived immunity.

Topics: Animals; Antibodies, Viral; Capsid Proteins; Circoviridae Infections; Circovirus; Feces; Genotype; Neutralization Tests; Nose; Phylogeny; Swine; Swine Diseases; Vaccines, Subunit; Viremia; Virus Shedding

Calves persistently infected (PI) with Bovine viral diarrhea virus (BVDV) represent an important source of infection for susceptible cattle. We evaluated vaccine efficacy using calves PI with noncytopathic BVDV2a for the challenge and compared tests to detect BVDV in acutely or transiently infected calves versus PI calves. Vaccination with 2 doses of modified live virus vaccine containing BVDV1a and BVDV2a protected the calves exposed to the PI calves: neither viremia nor nasal shedding occurred. An immunohistochemistry test on formalin-fixed ear notches and an antigen-capture enzyme-linked immunosorbent assay on fresh notches in phosphate-buffered saline did not detect BVDV antigen in any of the acutely or transiently infected calves, whereas both tests had positive results in all the PI calves.

Topics: Animals; Animals, Newborn; Antibodies, Viral; Antibody Formation; Antigens, Viral; Bovine Virus Diarrhea-Mucosal Disease; Cattle; Diarrhea Virus 1, Bovine Viral; Diarrhea Virus 2, Bovine Viral; Diarrhea Viruses, Bovine Viral; Disease Susceptibility; Enzyme-Linked Immunosorbent Assay; Immunohistochemistry; Nose; Vaccines, Attenuated; Vaccines, Inactivated; Viral Vaccines; Viremia; Virus Shedding

Bovine viral diarrhea virus (BVDV) persistently infected (PI) calves represent significant sources of infection to susceptible cattle. The objectives of this study were to determine if PI calves transmitted infection to vaccinated and unvaccinated calves, to determine if BVDV vaccine strains could be differentiated from the PI field strains by subtyping molecular techniques, and if there were different rates of recovery from peripheral blood leukocytes (PBL) versus serums for acutely infected calves. Calves PI with BVDV1b were placed in pens with nonvaccinated and vaccinated calves for 35 d. Peripheral blood leukocytes, serums, and nasal swabs were collected for viral isolation and serology. In addition, transmission of Bovine herpes virus 1 (BHV-1), Parainfluenza-3 virus (PI-3V), and Bovine respiratory syncytial virus (BRSV) was monitored during the 35 d observation period. Bovine viral diarrhea virus subtype 1b was transmitted to both vaccinated and nonvaccinated calves, including BVDV1b seronegative and seropositive calves, after exposure to PI calves. There was evidence of transmission by viral isolation from PBL, nasal swabs, or both, and seroconversions to BVDV1b. For the unvaccinated calves, 83.2% seroconverted to BVDV1b. The high level of transmission by PI calves is illustrated by seroconversion rates of nonvaccinated calves in individual pens: 70% to 100% seroconversion to the BVDV1b. Bovine viral diarrhea virus was isolated from 45 out of 202 calves in this study. These included BVDV1b in ranch and order buyer (OB) calves, plus BVDV strains identified as vaccinal strains that were in modified live virus (MLV) vaccines given to half the OB calves 3 d prior to the study. The BVDV1b isolates in exposed calves were detected between collection days 7 and 21 after exposure to PI calves. Bovine viral diarrhea virus was recovered more frequently from PBL than serum in acutely infected calves. Bovine viral diarrhea virus was also isolated from the lungs of 2 of 7 calves that were dying with pulmonary lesions. Two of the calves dying with pneumonic lesions in the study had been BVDV1b viremic prior to death. Bovine viral diarrhea virus 1b was isolated from both calves that received the killed or MLV vaccines. There were cytopathic (CP) strains isolated from MLV vaccinated calves during the same time frame as the BVDV1b isolations. These viruses were typed by polymerase chain reaction (PCR) and genetic sequencing, and most CP were confirmed as vaccinal or

Topics: Animals; Animals, Newborn; Antibodies, Viral; Antibody Formation; Bovine Virus Diarrhea-Mucosal Disease; Cattle; Diarrhea Virus 1, Bovine Viral; Disease Susceptibility; DNA, Viral; Fluorescent Antibody Technique, Direct; Leukocytes; Lung; Neutralization Tests; Nose; Polymerase Chain Reaction; Random Allocation; Time Factors; Vaccination; Vaccines, Attenuated; Vaccines, Inactivated; Viremia

The natural history and pathogenic potential of the recently identified TT virus (TTV) are currently a matter of intensive investigation. In an attempt to shed some light on these issues, nasal and blood specimens of 1- to 24-month-old children hospitalized with a clinical diagnosis of acute respiratory disease (ARD) were examined for the presence, load, and genetic characteristics of TTV. The results have indicated that at least in young children, the respiratory tract not only represents a route by which abundant TTV can be shed into the environment but also may be a site of primary infection and continual replication. Although we found no compelling evidence that TTV was the direct cause of ARD in some of the children studied, the average loads of TTV were considerably higher in patients with bronchopneumonia (BP) than in those with milder ARD, raising interesting questions about the pathophysiological significance of TTV at this site. Furthermore, group 4 TTV was detected almost exclusively in children with BP.

Topics: Acute Disease; DNA Virus Infections; DNA, Viral; Female; Humans; Infant; Infant, Newborn; Male; Molecular Sequence Data; Mucus; Nose; Polymerase Chain Reaction; Respiratory Tract Diseases; Sequence Analysis, DNA; Severity of Illness Index; Specimen Handling; Torque teno virus; Viral Load; Viremia

The duration of immunity provided by a feline leukemia virus (FeLV) vaccine, Leukocell 2, was determined. Kittens were vaccinated when 9 and 12 weeks of age and were challenged 12 months later with FeLV-A/Glasgow-1. An oronasal challenge protocol without corticosteroid enhancement was developed in order to induce a persistent viraemia in a high proportion of adult cats. Fourteen of 18 (80%) of the vaccinated cats challenged in this way remained non-viraemic while 9/15 (60%) of age-matched controls became persistently infected, a preventable fraction of 63%. This difference was statistically significant (P=0.038). For comparison, 10 of 12 (83%) 15-17-week-old kittens challenged in the same way became persistently infected, confirming the relative resistance of adult animals to FeLV. Tests for virus neutralising and anti-feline oncornavirus-associated cell membrane antigen (FOCMA) antibodies suggested that the former were more important than the latter in protection. Thus, Leukocell 2 protected a significant proportion of cats from FeLV challenge 1 year after primary vaccination as kittens.

Topics: Animals; Antibodies, Viral; Antigens, Viral; Cat Diseases; Cats; Female; Gene Products, gag; Leukemia Virus, Feline; Male; Mouth; Neutralization Tests; Nose; Retroviridae Infections; Retroviridae Proteins; Retroviridae Proteins, Oncogenic; Time Factors; Tumor Virus Infections; Viral Vaccines; Viremia; Virulence

Intranasal infection of BALB/c mice with the WR strain of vaccinia virus leads to pneumonia, profound weight loss and death. Five days after intranasal inoculation, virus from untreated mice was recovered from 11 organs, tissues and whole blood. The highest titres [>10(8) plaque forming units (pfu)/g] were in lungs and nose/sinus tissue, with about 10(7) pfu/g in spleen and blood. Seven other organs contained 30- to > or = 50-fold lower amounts of virus. Mice infected with the related cowpox virus (for comparative purposes) had the majority of virus located in the respiratory tract. The vaccinia mouse model was used to study the efficacy of cidofovir treatments on the infection. Subcutaneous injections of 30 or 100 mg/kg/day, given on days 1 and 4 after virus challenge, reduced mortality by 60-100%. However, lung virus titres on days 2-5 were reduced no more than 10-fold by these treatments. A moderate improvement in drug efficacy occurred with daily treatments for 5 days. The efficacy of cidofovir also increased as the virus challenge dose decreased, where subcutaneous or intraperitoneal treatment routes showed similar degrees of protection. Although it has been known for many years that the WR strain of vaccinia virus can cause lethal infections by intranasal route, its application to antiviral therapy represents a new model for studying anti-orthopoxvirus agents.

Topics: Administration, Intranasal; Animals; Antiviral Agents; Cidofovir; Cowpox virus; Cytosine; Disease Models, Animal; Drug Evaluation, Preclinical; Injections, Intraperitoneal; Injections, Subcutaneous; Lung; Mice; Mice, Inbred BALB C; Nose; Organ Specificity; Organophosphonates; Organophosphorus Compounds; Paranasal Sinuses; Pneumonia, Viral; Spleen; Vaccinia; Vaccinia virus; Viral Load; Viremia

The virus BVD/MD belongs to the genus pestivirus from the family Flaviviridae, as well as viruses responsible for hog cholera and border disease. BVD/MD virus is responsible for two distinct disease entities in cattle: bovine virus diarrhoea (BVD), which is characterized by high morbidity and low mortality, and mucosal disease (MD) which is sporadic but highly fatal. BFV/MD virus exists under two biotypes among which antigenic pairs: a non cytopathic and a cytopathic biotypes. These biological characters are purely cultural and do not correspond to the in vivo pathogenic behaviour. Recent experiments from our group show that the two biotypes of a same antigenic pair differ by their biological properties in the target animal. The cytopathic strain, contrary to the non cytopathic one, induces belated both humoral and cellular immune responses. Only non-cytopathic strain produces viraemia and nasal excretion. These results confirm the fact that non-cytopathic strains represent an epidemiological dead end. These results also permit to envisage a logical modelisation of the infection at a population level.

Topics: Animals; Antigens, Viral; Bovine Virus Diarrhea-Mucosal Disease; Cattle; Diarrhea Viruses, Bovine Viral; Nose; Viremia