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1.
《Research in veterinary science》2007,82(3):362-365
Calicivirus infection causes rabbit haemorrhagic disease (RHD) that kills more than 90% of adult animals, whereas young rabbits are naturally resistant to this viral disease. It has been proposed that the different response of adult and young rabbits to calicivirus infection is due to absence of viral receptors in respiratory and digestive systems of young animals. We have searched for liver disease in 4-week-old rabbits inoculated with a calicivirus suspension by intranasal and oral routes. These young rabbits showed cell damage and mononuclear infiltration of the liver. The hepatic lesions were associated with mild to moderate increase in circulating transaminases. We conclude that the previously reported reduction of viral receptors in the epithelium of respiratory and digestive systems of young rabbits does not inhibit calicivirus from inducing liver disease in these hosts. 相似文献
2.
Ferreira PG Costa-E-Silva A Oliveira MJ Monteiro E Aguas AP 《Veterinary immunology and immunopathology》2005,103(3-4):217-221
Calicivirus infection is lethal for adult rabbits, whereas young rabbits (less than 8-weeks-old) are resistant to the same infectious agent. The virus replicates in the liver and causes a fulminant hepatitis in adult rabbits leading to rabbit haemorrhagic disease (RHD); this is in contrast with the mild and transient hepatitis observed in infected young rabbits. We have used electron microscopy to compare liver leukocyte infiltrates between young (resistant) and adult (susceptible) rabbits, 36-48 h after inoculation of the animals with caliciviruses. In adult rabbits, liver infiltrates were made up mostly of heterophils, and they were located near hepatocytes showing severe cellular damage. In contrast, liver leukocyte infiltrates of RHD-resistant young rabbits were dominated by lymphocytes that depicted membrane contacts with the cell surface of undamaged hepatocytes. We conclude that: (i) the cellular inflammatory response of the liver to calicivirus infection is different in rabbits that are susceptible (adult) or resistant (young) to RHD; (ii) leukocyte infiltration of the adult liver by heterophils is probably directed at the removal of dead hepatocytes, whereas the liver lymphocytic infiltration of young rabbits suggests the expression of viral antigens on the surface of liver cells of the RHD-resistant animals. 相似文献
3.
Ferreira PG Costa-e-Silva A Monteiro E Oliveira MJ Aguas AP 《Research in veterinary science》2004,76(1):83-94
Young rabbits are naturally resistant to rabbit haemorrhagic disease (RHD) caused by the same calicivirus that kills, within 3 days, nearly all adult animals. We have investigated changes in blood leukocytes, and in the morphology and biochemistry of the liver (the organ where caliciviruses replicate) of young rabbits undergoing benign infection by the RHD virus. Four-week-old rabbits were infected with a calicivirus inoculum having a titre of 2(12) haemagglutination units either sacrificed 18, 24, 48 and 72 h later, or kept for follow-up studies up to 21 days after inoculation. The infection caused an acute and transient decrease in blood heterophils, and sustained enhancement in hepatic transaminases. Inflammatory infiltrates of the liver were seen in all animals after 24 h of infection; they had a predominant midlobular location. Hepatocytes could present different degrees of cell damage, including cell death; these lesions were limited to the liver cells located around the inflammatory infiltrates. Liver transaminases peaked 24-48 h after calicivirus infection; this was the same timing when liver infiltration and hepatocyte damage were more evident. No alterations of other parameters of liver biochemistry were observed. We conclude that calicivirus infection of young rabbits causes a subclinical disorder characterised by an acute and transient decrease in circulating heterophils, and focal liver damage that is expressed by intralobular infiltration by heterophils, initially, and, later on, by mononuclear cells. Our finding of persistence of increased values of liver transaminases suggests chronicity of the infection in young rabbits. We propose that, although resistant to RHD, young rabbits infected by calicivirus may be long-term carriers of the infectious agent and, thus, become a major source of transmission of the virus. 相似文献
4.
Ferreira PG Dinís M Costa-E-Silva A Aguas AP 《Veterinary immunology and immunopathology》2008,121(3-4):364-369
Calicivirus infection of adult rabbits induces the so-called rabbit haemorrhagic disease (RHD) that kills 90% or more of the infected animals; in contrast, young rabbits (up to 8-week-old animals) are resistant to the same infectious agent. We report that calicivirus inoculation of young rabbits induced moderate titres of antiviral antibodies. When these rabbits reached adulthood, a second calicivirus inoculation resulted in resistance to RHD and boosting of antibody titres in half of the rabbits. Adoptive transfer of sera from calicivirus-infected young rabbits to na?ve adult rabbits conferred resistance to RHD. We conclude that calicivirus infection of young rabbits induces specific anti-calicivirus antibodies that will protect them from RHD when they reach adulthood. 相似文献
5.
Luzia Teixeira Raquel M. Marques Artur P. Águas Paula G. Ferreira 《Research in veterinary science》2011,91(1):164-166
Rabbit Haemorrhagic Disease Virus (RHDV), a member of the Caliciviridae family, is the etiologic agent of Rabbit Haemorrhagic Disease (RHD); this viral disease is highly contagious and kills more than 90% of infected adult rabbits. Research on experimental calicivirus infection uses inocula obtained from livers of rabbits dying from calicivirus infection. This implies that caliciviruses have to be purified from liver homogenates. Current methods to isolate caliciviruses from rabbit livers are time consuming. We propose here a new procedure for fast purification of rabbit caliciviruses from liver homogenates that uses centrifugation through an iodixanol gradient. This method offers in approximately 2 h a sample with a high degree of calicivirus purity, as shown by its biochemical and immunocytochemistry analysis, which is also able to kill adult rabbits from RHD within 48 h of inoculation. 相似文献
6.
Raquel M. Marques António Costa-e-Silva Artur P. Águas Luzia Teixeira Paula G. Ferreira 《Veterinary research communications》2010,34(8):659-668
Rabbit Haemorrhagic Disease (RHD) is a lethal infection caused by calicivirus that kills 90% of the infected adult rabbits
within 3 days. The calicivirus replicates in the liver and causes a fulminant hepatitis. Most studies on the pathology of
RHD have been focused on the fulminant liver disease. This may not be the only mechanism in the pathogenesis of RHD: calicivirus
infection may also induce leukopenia in the infected adult rabbits. We show now by flow cytometry analysis that the calicivirus
induces an early decrease in B and T cells, in both spleen and liver. The depletion of B and T cells was associated with apoptosis
labelled by annexin V. These changes occurred in rabbits before they showed enzymatic evidence of liver damage and persisted
after liver transaminase values were very high. We conclude that depletion of lymphocytes caused by the calicivirus infection
precedes or attends liver damage. The relative contribution of this lymphocyte depletion for the pathogenesis of the fatal
calicivirus infection of rabbits remains to be investigated. 相似文献
7.
Raquel M Marques Luzia Teixeira Artur P águas Joana C Ribeiro António Costa-e-Silva Paula G Ferreira 《Veterinary research》2014,45(1):14
Rabbit Haemorrhagic Disease (RHD) is caused by a calicivirus (RHDV) that kills 90% of infected adult European rabbits within 3 days. Remarkably, young rabbits are resistant to RHD. We induced immunosuppression in young rabbits by treatment with methylprednisolone acetate (MPA) and challenged the animals with RHDV by intramuscular injection. All of these young rabbits died within 3 days of infection due to fulminant hepatitis, presenting a large number of RHDV-positive dead or apoptotic hepatocytes, and a significant seric increase in cytokines, features that are similar to those of naïve adult rabbits infected by RHDV. We conclude that MPA-induced immunosuppression abrogates the resistance of young rabbits to RHD, indicating that there are differences in the innate immune system between young and adult rabbits that contribute to their distinct resistance/susceptibility to RHDV infection. 相似文献
8.
Teixeira L Marques RM Aguas AP Ferreira PG 《Veterinary immunology and immunopathology》2012,148(3-4):343-347
Rabbit hemorrhagic disease virus (RHDV) is the etiologic agent of rabbit hemorrhagic disease (RHD), an acute lethal infection that kills 90% of adult rabbits due to severe acute liver inflammation. Interestingly, young rabbits are naturally resistant to RHDV infection. Here, we have compared naturally occurring CD4(+)Foxp3(+) regulatory T cells (Tregs) between young and adult rabbits after infection by RHDV. The number and frequency of Tregs was decreased in the spleen of adult rabbits 24h after the RHDV infection; this was in contrast with the unchanged number and frequency of splenic Tregs found in young rabbits after the same infection. Also, serum levels of IL-10 and TGF-β were enhanced in the infected adult rabbits whereas no alteration was observed in infected young rabbits. However, this increase is accompanied by a burst of pro-inflammatory cytokines, but seems not able to prevent the death of the animals with severe acute liver inflammation in few days after infection. Since Tregs downregulate inflammation, we conclude that their decrease may contribute to the natural susceptibility of adult rabbits to RHDV infection. 相似文献
9.
Association of bovine viral diarrhea virus with multiple viral infections in bovine respiratory disease outbreaks 总被引:5,自引:1,他引:4
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Richer L Marois P Lamontagne L 《The Canadian veterinary journal. La revue veterinaire canadienne》1988,29(9):713-717
We investigated eleven outbreaks of naturally occurring bovine respiratory diseases in calves and adult animals in the St-Hyacinthe area of Quebec. Specific antibodies to bovine herpesvirus-1, bovine viral diarrhea virus, respiratory syncytial virus, parainfluenza type 3 virus, reovirus type 3, and serotypes 1 to 7 of bovine adenovirus were found in paired sera from diseased animals. Several bovine viruses with respiratory tropism were involved concomitantly in herds during an outbreak of bovine respiratory disease. In addition, concomitant fourfold rises of antibody titers were frequently observed to two or more viral agents in seroconverted calves (61%) or adult animals (38%). Bovine viral diarrhea virus was found to be the most frequent viral agent associated with multiple viral infection in calves only (92%). 相似文献
10.
An isolated epizootic of a highly fatal feline calicivirus (FCV) infection, manifested in its severest form by a systemic hemorrhagic-like fever, occurred over a 1-month period among six cats owned by two different employees and a client of a private veterinary practice. The infection may have started with an unowned shelter kitten that was hospitalized during this same period for a severe atypical upper respiratory infection. The causative agent was isolated from blood and nasal swabs from two cats; the electron microscopic appearance was typical for FCV and capsid gene sequencing showed it to be genetically similar to other less pathogenic field strains. An identical disease syndrome was recreated in laboratory cats through oral inoculation with tissue culture grown virus. During the course of transmission studies in experimental cats, the agent was inadvertently spread by caretakers to an adjoining room containing a group of four normal adult cats. One of the four older cats was found dead and a second was moribund within 48-72h in spite of symptomatic treatment; lesions in these animals were similar to those of the field cats but with the added feature of severe pancreatitis. The mortality in field cats, deliberately infected laboratory cats, and inadvertently infected laboratory cats ranged from 33-50%. This new isolate of calicivirus, named FCV-Ari, was neutralized at negligible to low titer by antiserum against the universal FCV-F9 vaccine strain. Cats orally immunized with FCV-F9, and then challenge-exposed shortly thereafter with FCV-Ari, developed a milder self-limiting form of disease, indicating partial protection. However, all of the field cats, including the three that died, had been previously immunized with parenteral FCV-F9 vaccine. FCV-Ari caused a disease that was reminiscent of Rabbit Hemorrhagic Disease, a highly fatal calicivirus infection of older rabbits. 相似文献
11.
Ferreira PG Costa-E-Silva A Monteiro E Oliveira MJ Aguas AP 《Veterinary research communications》2006,30(4):393-401
Rabbit haemorrhagic disease (RHD) is caused by a calicivirus infection that kills most adult rabbits 24–72 h after viral inoculation.
Two liver enzymes (AST, aspartate aminotransferase, and ALT, alanine aminotransferase) were monitored in blood samples of
calicivirus-infected rabbits during the short course of RHD. Values of AST were used to differentiate three stages of hepatocellular
degeneration in RHD: mild (up to 20-fold increase in AST), moderate (150–200-fold elevation of AST) and severe (more than
1000-fold elevation in AST). Liver samples of rabbits from these three biochemical stages of hepatocellular degeneration of
RHD were studied by transmission electron microscopy to define the fine structure of the hepatocytes. In the mild hepatocellular
degeneration there was proliferation (microvesiculation) of the smooth endoplasmic reticulum and swelling of mitochondria
into spheroid bodies with loss of cristae. In moderate hepatocellular degeneration, vacuolization of cytoplasm and mitochondrial
damage continued to be present, and there was also formation of autophagic vesicles. In the severe hepatocellular degeneration
of RHD, the altered mitochondria also showed loss of density of their matrix; rupture of cytoplasmic vacuoles led to the formation
of large vesicles. Marked depletion of liver glycogen was also found in this late stage of RHD. These data offer a correlation
between biochemical and cytological features of the liver during the hepatocellular degeneration of RHD. 相似文献
12.
Ferreira PG Costa-e-Silva A Oliveira MJ Monteiro E Cunha EM Aguas AP 《Research in veterinary science》2006,80(2):218-225
Calicivirus infection is the major cause of the severe decrease in the stocks of wild and farm rabbits that has occurred worldwide during the last two decades. Adult rabbits (10-weeks-old) were experimentally infected with a calicivirus inoculum that killed all animals by causing rabbit haemorrhagic disease (RHD) within 24-62 h of infection. The rabbits were used to evaluate blood cell numbers and serum biochemistry every 6h, starting 12h after the inoculation of the caliciviruses. No significant changes in blood parameters were observed in most of the rabbits up to 18 h of infection. Severe leukopenia was seen 6h before death of the infected rabbits; both heterophils and lymphocytes contributed to the decrease in circulating white blood cells. Platelets were also severely decreased in number. Marked enhancement in liver enzymes was seen 6-12 h before death of the infected rabbits. There was also evidence both for cholestasis, as expressed by the elevated levels of direct (conjugated) bilirubin, and for hypoglycemia, an alteration that it is likely to contribute for the seizures that rabbits show during the late stages of RHD. Liver ultrastructure of rabbits that died from RHD revealed extensive hepatocyte vacuolization, severe changes in mitochondrial structure, and depletion of glycogen granules. We conclude that: (i) severe leukopenia characterizes the final hours of calicivirus-induced RHD; (ii) hypoglycemia and cholestasis precede death of rabbits from RHD; (iii) the kinetics of liver enzymes allows an accurate prediction of the time of death of rabbits from calicivirus-induced RHD. 相似文献
13.
A Flagstad 《Acta veterinaria Scandinavica》1972,13(4):462-471
Seventeen viral isolates cytopathic for kitten kidney cells were isolated from 23 cats with symptoms of the respiratory disease feline viral rhinotracheitis or feline influenza. Five of these are classified tentatively as calicivirus, a member of the Picornavirus group, and 12 have the properties of the herpesvirus. Classification is based on the cytopathic effect in cell cultures and physico-chemical characteristics.The five isolates which are classified tentatively as calicivirus produced a quick cytopathic effect without formation of intranuclear inclusion bodies. The isolates were resistant to chloroform, were not inhibited by IDU, were labile at pH 4 and were not stabilized against thermal inactivation by molar MgCl2. The 12 isolates which seem to belong to the herpesvirus produced intranuclear inclusion bodies in cell cultures. They were sensitive to chloroform, and multiplication was inhibited by IDU. Antisera were produced by inoculating rabbits with calicivirus and cats with herpesvirus. The five isolates classified tentatively as calicivirus belong in one serotype, and the 12 isolates which seem to belong to the herpesvirus also belong in one serotype.Keyword: feline Picornavirus, feline calicivirus, feline herpesvirus, feline viral rhinotracheitis, feline influenza, isolation, classification, Denmark 相似文献
14.
15.
Prieto JM Fernandez F Alvarez V Espi A García Marín JF Alvarez M Martín JM Parra F 《Research in veterinary science》2000,68(2):181-187
This study evaluated the time course distribution of rabbit haemorrhagic disease virus (RHDV) structural protein VP60 in tissues from experimentally infected rabbits from three different age groups. Viral VP60 antigen could not be detected in tissue samples from animals under four weeks, and only a few hepatocytes (0.01 to 0.2 per cent) were stained in the 6-week-old animals. A 6-week-old rabbit euthanised at 72 hpi showed VP60-labelling in hepatocytes and macrophages close to areas of inflammation. Viral VP60 antigen was detected as early as 12 hpi in a few hepatocytes (0.03 per cent) from adult animals. Within this age group, the extent of hepatocyte labelling considerably increased at 18 (3.0 per cent), 24 (25.5 per cent), 36 (50 per cent) and 48 (60 per cent) hpi. Extrahepatic viral VP60 antigen was also detected at 36 and 48 hpi in spleen macrophages and lymphocytes from adult rabbits. These findings support the hypothesis that the hepatocyte is the only cell type in the liver able to support RHDV replication almost immediately after viral infection. 相似文献
16.
J H Park H Kida K Ueda K Ochiai M Goryo C Itakura 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1991,38(10):749-754
Causative agent of rabbit haemorrhagic disease (RHD) was purified by CsCl density gradient centrifugation from the liver homogenate of rabbits infected with RHD virus which originated from Korea. The viral particles were 35-40 nm in diameter, and had hollow depressions on their surface. Protein A-gold immunoelectron microscopy clearly showed that the convalescent antisera of diseased rabbits reacted specifically with the virus particles. SDS-PAGE and Western blot analyses demonstrated that the structural protein of the virus was composed of a single major polypeptide of 63 kD. These findings indicate that the causative agent of RHD, tentatively named as picornavirus in Korea, belongs to calicivirus. 相似文献
17.
Evaluation of the rabbit as a laboratory model for infectious bovine rhinotracheitis virus infection 总被引:2,自引:0,他引:2
Experimental infection of rabbits with infectious bovine rhinotracheitis virus (IBRV) produced diverse manifestations of disease which included abortion, conjunctivitis, dermatitis, vulvovaginitis, systemic infection, neonatal death and respiratory tract infection. Each disease syndrome was studied using virus isolation, fluorescent antibody examination and histologic examination. Conjunctivitis, dermatitis and vulvovaginitis lesions were characterized by edema, infiltration of mucosa and submucosa with inflammatory cells and ulceration of epithelium. Systemic infection resulted in severe necrosis of liver and adrenal glands with large numbers of cells containing intranuclear inculsions. Pregnant rabbits aborted within 48 hours following inoculation of IBRV. Virus infection and viral lesions were not demonstrated in aborted fetuses. 相似文献
18.
Abubakar M Rajput ZI Arshed MJ Sarwar G Ali Q 《Tropical animal health and production》2011,43(4):745-747
An outbreak resulting in mortality in Sindh Ibex (Capra aegagrus blythi) was investigated. There was a history of about 36 deaths (both young and adult) during the period of 1 month. Disease appeared
in a generalized form, affecting the respiratory and digestive systems. Major lesions were respiratory distress, pustules
on and in the mouth, ocular–nasal discharges, and severe diarrhea. The most significant lesion was the oculonasal discharges
and diarrhea. Deaths were mainly due to blindness, anorexia, diarrhea, and respiratory arrest. Both adult (mortality = 21)
and young (mortality = 15) animals were affected with the disease. Peste des petits ruminants virus (PPRV) antigen was detected
in the spleen, lung, lymph node, and swab samples by immunocapture enzyme-linked immunosorbent assay. Spleen and lung samples
were also tested and found positive for the presence of F-gene of PPRV by polymerase chain reaction. Thirteen of 20 serum
samples from nearby sheep and goats were found positive for antibodies to PPRV. The disease threatened the huge population
of ibex in the wild life park, which was spread over a large area, but vaccination of the domestic population of sheep and
goats in the surrounding villages appeared to control the disease. 相似文献
19.
The effects of vaccination against myxomatosis and viral haemorrhagic disease (VHD) on long-term mortality rates in European rabbits (Oryctolagus cuniculus) were studied from 1993 to 1996 by radiotracking a free-living population of wild rabbits. During the three months after immunisation, unvaccinated young rabbits weighing between 180 and 600 g were 13.6 times more likely to die than vaccinated young rabbits. In adult rabbits, vaccination did not significantly decrease mortality, mainly owing to the high proportion of rabbits which had previously been exposed to the antigens of both diseases. Compared with adult rabbits with natural antibodies to VHD, rabbits without these antibodies were 5.2 times more likely to die of VHD during annual outbreaks. 相似文献