Case reports of hemorrhagic diathesis in calves with bovine diarrhea virus infection

The case of a 59-year-old female with a longstanding hemiplegia who developed unilateral psoriatic arthritis and unilateral psoriasis on the non-hemiplegic side only is reported. Investigations showed an erythrocyte sedimentation rate of 58 mm/h, with all classes of rheumatoid factor negative in serum and synovial fluid (SF). An inflammatory infiltrate was demonstrated in both knee joints despite the absence of clinical involvement on the hemiplegic side. In addition, while neurofilament and substance P (SP) immunoreactivity was demonstrated in both synovial specimens, conspicuously less SP was present in the clinically involved synovial membrane. Finally, SF levels of SP and IL1 beta were raised in the clinically involved knee only.     

Cytotoxic T-lymphocyte responses in cattle infected with bovine viral diarrhea virus

CRP1, a Drosophila nuclear protein that can catalyze decondensation of demembranated Xenopus sperm chromatin was cloned and its primary structure was deduced from cDNA sequence. Alignment of deduced amino acid sequence with published sequences of other proteins revealed strong homologies to Xenopus nucleoplasmin and NO38. CRP1 is encoded by one or several closely related genes found at a single locus, position 99A on the right arm of chromosome 3. CRP1 mRNA is expressed throughout Drosophila development; it is highest during oogenesis and early embryogenesis. mRNA levels correlate closely with levels of protein expression measured previously. Results of chemical crosslinking indicate that CRP1 is either tetrameric or pentameric; similar ambiguity was revealed by direct visualization using scanning transmission electron microscopy. Consistent with previously published results, parallel crosslinking studies of Xenopus nucleoplasmin suggested a pentameric structure. Scanning transmission electron microscopic examination after negative staining revealed that CRP1 and Xenopus nucleoplasmin are morphologically similar. CRP1 is able to substitute for nucleoplasmin in Xenopus egg extract-mediated sperm chromatin decondensation. In vitro, CRP1-induced decondensation is accompanied by direct binding of CRP1 to chromatin.     

Evaluation of bovine viral diarrhea virus control using a mathematical model of infection dynamics

A mathematical model for infection with bovine viral diarrhea virus (BVDV) was created comprising a series of coupled differential equations. The model architecture is a development of the traditional model framework using susceptible, infectious and removed animals (the SIR model). The model predicts 1.2% persistent infection (within the range of field estimates) and is fairly insensitive to alterations of structure or parameter values. This model allows us to draw important conclusions regarding the control of BVD, particularly with respect to the importance of persistently infected (PI) animals in maintaining BVD as an endemic entity in the herd. Herds without PI animals are likely to experience episodic reproductive losses at intervals of two to three years, unlike herds with PI animals which will not see such marked episodic manifestations of infection. Instead, these herds will experience an initial peak of disease which will settle to low-level chronic reproductive losses. The model indicates that vaccine coverage for herd immunity (to avoid episodic manifestations of disease) need be only 57% without PI animals, although 97% coverage is required when PI animals are present. Analysis of model behavior suggests a program of detection and removal of PI animals may enhance the effectiveness of a vaccine program provided these animals are in the herd for 10 days or less. The best results would be seen with PI animals in the herd for 5 or fewer days.     

Glycoprotein E2 of bovine viral diarrhea virus expressed in insect cells provides calves limited protection from systemic infection and disease

Calves were vaccinated with a C-terminally truncated baculovirus expression product of E2 from the Singer strain of bovine viral diarrhea virus. The expressed E2 was glycosylated and retained antigenic authenticity. After induction of viral neutralizing antibody, the calves were challenge exposed with either the homologous Singer strain of virus or with the heterologous 890 strain of virus. Vaccine-induced antibody titer of > or = 2 protected calves from clinical signs of disease induced by homologous viral challenge exposure. An antibody titer of > or = 512 reduced replication of homologous challenge virus to a level which did not induce an appreciable increase in serologic titer of viral neutralizing antibody. Vaccine-induced antibody titer of < or = 4096 did not protect calves from systemic spread of virus or from disease after challenge exposure with heterologous bovine viral diarrhea virus.     

The pathologies of bovine viral diarrhea virus infection. A window on the pathogenesis

Pathologic lesions caused by bovine viral diarrhea virus (BVDV) infections comprise a wide spectrum of type, degree, and, by implication, pathogenesis, including congenital defects, necroticerosive lesions in mucosal epithelia and skin, and reactive as well as degenerative changes in lymphoid tissues. At least some of the pathology may not be solely due to BVDV replication per se, but rather caused by a host response to the virus, particularly the production of pro-inflammatory cytokines.     

An experimental study of a concurrent primary infection with bovine respiratory syncytial virus (BRSV) and bovine viral diarrhoea virus (BVDV) in calves

Experimental infections with bovine respiratory syncytial virus (BRSV) and bovine viral diarrhoea virus (BVDV) were performed to study the effect of concurrent BRSV and BVDV infections. Twelve seronegative calves, in 3 groups, were inoculated on a single occasion with pure BRSV (group A), BRSV and noncytopathogenic BVDV (group B) or mock infected (group C). Mild respiratory symptoms were recorded 4 to 5 days post inoculation (dpi) in group A and group B calves. One calf in group A was severely affected and required medical treatment. In group B, fever (40.7-41.4 degrees C) was prominent 7 to 8 dpi. Only calves in group B were BVDV positive in purified lymphocytes at 2 to 14 dpi and showed increased serum interferon levels, with a peak at 4 dpi, indicating BVDV to be responsible for inducing the rise. BRSV was detected in lung lavage fluids up to 7 dpi for group A calves, compared to 11 dpi for group B and calves in this group also seroconverted later displaying lower BRSV titers. The time lag before an antibody response and the titers recorded in group B, indicated that the duration of BVDV infection in lymphocytes negatively influenced the capacity to mount a BRSV antibody response.     

Anti-viral effect of interferon-alpha on bovine viral diarrhea virus

PURPOSE: Lamotrigine (LTG) is recognised as effective add-on therapy for focal epilepsies, but this is the first double-blind, placebo-controlled, crossover study in treatment-resistant generalised epilepsy. METHODS: The study consisted of 2 x 8-week treatment periods followed by a 4-week washout period. Patients received doses of either 75 or 150 mg daily, depending on their concomitant antiepileptic drugs (AEDs). Long-term continuation was offered at the end of the study with open-label LTG. RESULTS: Five centres in Australia recruited 26 patients who were having absence, myoclonic, or generalized tonic-clonic seizures or a combination of these. Twenty-two patients completed the study. There was a significant reduction in frequency of both tonic-clonic and absence seizure types with LTG. A 350% decrease in seizures was observed for tonic-clonic seizures in 50% of cases and for absence seizures in 33% of evaluable cases. Rash was the only adverse effect causing discontinuation. Twenty-three of 26 opted for open-label LTG, with 20 still receiving LTG for a mean of 26 months. In these 20, 80% had > or =50% seizure reduction and five (25%) were seizure free. CONCLUSIONS: This study shows that LTG is effective add-on therapy in patients with refractory generalised epilepsies. Statistically significant reduction in seizures in both absence and tonic-clonic seizure types was seen even with low doses of LTG.     

Experimental reproduction of bovine fetal Neospora infection and death with a bovine Neospora isolate

It is well established that alpha 2-adrenoceptor agonists have sedative and antinociceptive properties. In the current behavioral study we tried to find out if the alpha 2-adrenergic sedative and antinociceptive effects can be dissociated. We tested the hypothesis that alpha 2-adrenergic sedation is mediated by the locus coeruleus (LC) and antinociception by spinal alpha 2-adrenoceptors. Also, we addressed the possibility that intracerebral injection of an alpha 2-agonist might produce its antinociceptive effect by an action directly at the spinal cord. Medetomidine, an alpha 2-adrenergic agonist, or atipamezole, an alpha 2-adrenergic antagonist, were microinjected bilaterally into the LC through chronic cannulae in unanesthetized Han-Wistar rats. The effect on locomotor activity (/vigilance), tail-flick and hot-plate response, and on formalin-induced pain behavior was determined. Medetomidine microinjected into the LC (1-10 micrograms/cannula) produced dose-dependently hypolocomotion (/sedation), increase of response latencies in the hot-plate and the tail-flick tests, and a decrease in the formalin-induced pain behavior. Hypolocomotion (/sedation) was obtained at a lower medetomidine dose (1 microgram/cannula) than antinociception (3-10 micrograms/cannula). The lowest medetomidine dose used (1 microgram/cannula), which induced significant hypolocomotion (/sedation), produced either no antinociception (hot-plate and tail-flick tests) or even a slight hyperalgesia (formalin test). The hypolocomotion (/sedation) but not antinociception (tail-flick test) induced by systemic administration of medetomidine (100 micrograms/kg s.c.) could be reversed by atipamezole (10 micrograms/cannula) microinjected into the LC. Only a high systemic dose of atipamezole (1 mg/kg s.c.) reversed the antinociceptive effects of medetomidine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antigenic characterization of Brazilian bovine viral diarrhea virus isolates by monoclonal antibodies and cross-neutralization

Nineteen Brazilian isolates of bovine viral diarrhea virus (BVDV) were characterized antigenically with a panel of 19 monoclonal antibodies (mAbs) (Corapi WV, Donis RO and Dubovi EJ (1990) American Journal of Veterinary Research, 55: 1388-1394). Eight isolates were further characterized by cross-neutralization using sheep monospecific antisera. Analysis of mAb binding to viral antigens by indirect immunofluorescence revealed distinct patterns of reactivity among the native viruses. Local isolates differed from the prototype Singer strain in recognition by up to 14 mAbs. Only two mAbs--one to the non-structural protein NS23/p125 and another to the envelope glycoprotein E0/gp48--recognized 100% of the isolates. No isolate was recognized by more than 14 mAbs and twelve viruses reacted with 10 or less mAbs. mAbs to the major envelope glycoprotein E2/gp53 revealed a particularly high degree of antigenic variability in this glycoprotein. Nine isolates (47.3%) reacted with three or less of 10 E2/gp53 mAbs, and one isolate was not recognized by any of these mAbs. Virus-specific antisera to eight isolates plus three standard BVDV strains raised in lambs had virus-neutralizing titers ranging from 400 to 3200 against the homologous virus. Nonetheless, many antisera showed significantly reduced neutralizing activity when tested against heterologous viruses. Up to 128-fold differences in cross-neutralization titers were observed for some pairs of viruses. When the coefficient of antigenic similarity (R) was calculated, 49 of 66 comparisons (74.24%) between viruses resulted in R values that antigenically distinguish strains. Moreover, one isolate had R value suggesting that it belongs to a distinct serologic group. The marked antigenic diversity observed among Brazilian BVDV isolates should be considered when planning diagnostic and immunization strategies.     

Cytokine regulation by virus infection: bovine viral diarrhea virus, a flavivirus, downregulates production of tumor necrosis factor alpha in macrophages in vitro

Bovine bone marrow-derived macrophages were infected in vitro with noncytopathic or cytopathic strains of bovine viral diarrhea virus. Infection with both biotypes resulted in a decreased production of tumor necrosis factor alpha upon stimulation with heat-inactivated Salmonella dublin or lipopolysaccharide. Other macrophage functions were not downregulated, indicating that the observed effect was not due to a loss in macrophage viability. The downregulated production of tumor necrosis factor alpha in infected macrophages may contribute to the well-documented immunosuppression in animals infected with bovine viral diarrhea virus.     

Replication of cytopathic and noncytopathic bovine viral diarrhea virus in zona-free and zona-intact in vitro-produced bovine embryos and the effect on embryo quality

The adenomatous polyposis coli gene is mutated in familial adenomatous polyposis and in sporadic colorectal tumours. The adenomatous polyposis coli gene product is a 300,000 mol. wt cytoplasmic protein that binds to at least three other proteins; beta-catenin, a cytoplasmic E-cadherin-associated protein; hDLG, a human homologue of the Drosophila discs large tumour suppressor protein and glycogen synthase kinase 3 beta, a mammalian homologue of the Drosophila ZESTE WHITE 3 protein. The adenomatous polyposis coli gene is highly expressed in the brain, suggesting that it may be involved in nerve function. Here we show that adenomatous polyposis coli is localized in the pericapillary astrocytic endfeet throughout the mouse central nervous system. Adenomatous polyposis coli is also localized in the astrocytic processes in the cerebellar granular layer, and displays concentrated expression in the terminal plexuses of the basket cell fibres around Purkinje cells. Adenomatous polyposis coli is further expressed in neuronal cell bodies and/or nerve fibres in the olfactory bulb, hippocampus, brain stem, spinal cord and dorsal root ganglia. Adenomatous polyposis coli is demonstrated to be co-localized with beta-catenin and/or hDLG in neurons and nerve fibres, but not in astrocytes. From these results, adenomatous polyposis coli is suggested to participate in a signal transduction pathway in astrocytes which is independent of beta-catenin and hDLG, and also in regulation of neuronal functions in association with beta-catenin and hDLG.     

Cell-mediated immune responses of lambs to challenge with bovine respiratory syncytial virus

(-)-Indolactam V (ILV) is a synthetic analog of the teleocidins, a newly described class of tumor promoters. Here we describe the mitogenic and comitogenic effect of (-)-ILV on human adult and fetal/neonatal (cord) lymphocytes. (-)-ILV induced proliferation in a dose-dependent manner, with optimal concentrations between 2.6 and 5.2 microM. Cord lymphocytes gave significantly lower (-)-ILV responses compared to the corresponding a2ult cells (50-60% lower at optimal mitogenic doses). The mitogenic action of (-)-ILV was apparently independent of the presence of adherent monocytes. H-7, a relatively specific protein kinase (PK) C inhibitor, and H-8, a less specific PK inhibitor, suppressed (-)-ILV-induced proliferation by 54 and 36%, respectively. Suboptimal concentrations of (-)-ILV were strongly mitogenic for both adult and cord lymphocytes when added together with calcium ionophore A23187, phytohemagglutinin, or the anti-T cell receptor monoclonal antibodies OKT3 and TCR1. In adult cells, the synergistic effect decreased with increasing concentrations of (-)-ILV or/and the other comitogens, and was, in most (> 60%) cases, converted to inhibition at the combination of optimal doses. The inhibition was invariably reversed by depletion of monocytes. In contrast, among cord lymphocytes (-)-ILV and OKT3 or TCR-1 showed strong cooperative effect at all concentrations tested. The (-)-ILV hyporesponsiveness and distinct comitogenic pattern of cord lymphocytes, together with the previously described lower cord cell response to phorbol ester TPA, suggest functional differences in signal transduction mechanisms between cord (naive) and adult (memory) T cells, possibly at the level of monocytes.     

Nucleotide sequence homology to bovine viral diarrhea virus 2 (BVDV 2) in the 5' untranslated region of BVDVs from cattle with mucosal disease or persistent infection in Japan

Cytopathogenic and non-cytopathogenic bovine viral diarrhea viruses (BVDVs) were isolated from cattle with mucosal disease or persistent infection in Japan. These isolates were compared for antigenic properties by cross-neutralization tests with Japanese reference strains of BVDV belonging to classical type 1. Significantly low cross-reactivity to reference strains was noted, indicating the viruses to possibly represent a new serotype in Japan. Thus, to determine the genotype of the isolates, nucleotide sequences of the 5' untranslated region were determined and compared with those of previously reported BVDV 1 and 2. The isolates were clearly shown to belong to BVDV 2, not to BVDV 1.     

Clinical, virologic and immunologic responses of children with advanced human immunodeficiency virus type 1 disease treated with protease inhibitors

OBJECTIVE: To determine the effects of combination antiretroviral therapy including a protease inhibitor (PI combination therapy) in children with advanced HIV-1 disease. STUDY DESIGN: An observational study of HIV-1 plasma RNA, lymphocyte subsets, delayed type hypersensitivity and physical growth after initiation of PI combination therapy. RESULTS: In nine children the median HIV-1 plasma RNA decreased 1.7 log10 (mean, 1.57; range, 0.7 to 2.2) following PI combination therapy and CD4 cells increased a median of 499 (mean, 528; range, 9 to 1088) cells/microl. A rebound of RNA, associated with the development of resistance to the PI, occurred in three subjects. Three of six children were no longer anergic and all nine achieved normal weight-growth velocities. Ritonavir was well-tolerated, despite its bitter taste; however, four of five children treated with indinavir developed renal complications. CONCLUSIONS: PI combination therapy in children with advanced HIV-1 disease was associated with a decrease in HIV-1 RNA, improved immunologic measures and normal or better weight gain. Of concern was the rebound in plasma HIV-1 associated with resistance to the PI observed in one-third of patients. This emphasizes the need for larger studies to define optimal PI containing regimens with long term efficacy in children.     

Immune response of calves experimentally infected with non-cell-culture-passaged bovine respiratory syncytial virus

The immune response of calves was studied following infection with non-cell-passaged Bovine respiratory syncytial virus (BRSV). Two groups of 6 specific pathogen free (SPF) calves were housed in separate isolation rooms. One group was inoculated intranasally with a non-cell-passaged BRSV strain and the control group was mock-infected. A BRSV specific antibody response was observed for all the BRSV infected calves. These antibodies were shown to have neutralizing activity. No lymphocyte proliferation response was detected in the mock-infected group whereas three animals in the infected group were positive three weeks after the infection. All BRSV-infected calves, except one, produced interferon-gamma (IFN-gamma) one week post-infection and IFN-gamma was observed in all six infected calves after three weeks. The control group showed no IFN-gamma synthesis. In spite of the limits of the BRSV infection model, humoral and cellular immune responses were actively developed by all the calves against this pathogen.     

cis-acting RNA elements required for replication of bovine viral diarrhea virus-hepatitis C virus 5'' nontranslated region chimeras

Pestiviruses, such as bovine viral diarrhea virus (BVDV), share many similarities with hepatitis C virus (HCV) yet are more amenable to virologic and genetic analysis. For both BVDV and HCV, translation is initiated via an internal ribosome entry site (IRES). Besides IRES function, the viral 5' nontranslated regions (NTRs) may also contain cis-acting RNA elements important for viral replication. A series of chimeric RNAs were used to examine the function of the BVDV 5' NTR. Our results show that: (1) the HCV and the encephalomyocarditis virus (EMCV) IRES element can functionally replace that of BVDV; (2) two 5' terminal hairpins in BVDV genomic RNA are important for efficient replication; (3) replacement of the entire BVDV 5' NTR with those of HCV or EMCV leads to severely impaired replication; (4) such replacement chimeras are unstable and efficiently replicating pseudorevertants arise; (5) pseudorevertant mutations involve deletion of 5' sequences and/or acquisition of novel 5' sequences such that the 5' terminal 3-4 bases of BVDV genome RNA are restored. Besides providing new insight into functional elements in the BVDV 5' NTR, these chimeras may prove useful as pestivirus vaccines and for screening and evaluation of anti-HCV IRES antivirals.