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1.
The naturally occurring disease caused by San Miguel sea lion virus in fur seals was characterized by small fluid-filled vesicles 1 to 25 mm in diameter on the nonhaired portions of the flippers. Early epithelial lesions contained multifocal sites of cell lysis. The resultant microvesicles enlarged and coalesced, forming grossly visible macrovesicles. Mature vesicles progressed to involve all layers of the epithelium but did not involve the underlying dermis. Intradermal inoculation of vesicular exanthema of swine virus type A48 or San Miguel sea lion virus type 2 into otarid (fur) seal pups caused plaque-like lesions around inoculated coronary bands. These swellings regressed without rupture by 96 hours postinoculation. One seal inoculated with San Miguel sea lion virus had a linear lingual erosion at ten days postinoculation. Virus was isolated from this site and from two uninoculated sites, the tonsil and testicle. Contact controls showed no evidence of infection. Virus was isolated in low titers from some sites of inoculation and draining lymph nodes from seals infected with vesicular exanthema of swine virus. Virus was recovered more easily, in higher titers, and from more tissues, from seals infected with San Miguel sea lion virus. Inoculated seals tested after four to ten days seroconverted. Feeding swine seal tissues from the inoculation experiments resulted in seroconversion in swine which were fed tissues from seals infected with vesicular exanthema of swine virus but not in those which were fed tissues from seals infected with San Miguel sea lion virus.  相似文献   

2.
The indirect immunofluorescence test is a rapid method for detecting the presence of vesicular exanthema of swine virus or San Miguel sea lion virus in cell culture. A serological relationship exists between vesicular exanthema of swine virus and San Miguel sea lion virus, as shown by the fluorescence-positive reactions between swine antisera to vesicular exanthema of swine virus A48 and San Miguel sea lion virus type 5 and cell cultures infected with San Miguel sea lion virus types 1, 2, 3, 4 and 5 as well as vesicular exanthema of swine virus B51, C52, D53, E54, F55, G55, H55, I55, J56 and K55. The indirect immunofluorescence test detects group-specific antibody to caliciviruses in swine sera.  相似文献   

3.
Mink became infected with San Miguel sea lion virus when fed ground meat from seal carcasses showing vesicular-like lesions in the skin. The mink also contracted the infection when they were fed San Miguel sea lion virus infected pig meat or cell culture propagated virus. San Miguel sea lion virus infection in mink was inapparent but the virus was isolated from blood and rectal swabs. Pigs treated similarly with the same virus preparations given to mink developed a severe vesicular disease syndrome similar to that produced by vesicular exanthema of swine. In a separate trial, pigs fed a large sample of commercial ground seal meat did not develop disease signs or antibodies. Further work is needed to assess the hazard of introducing San Miguel sea lion virus into swine on the same premises when potentially San Miguel sea lion virus infective seal meat is fed to mink.  相似文献   

4.
Immunoelectron microscopic comparisons of caliciviruses   总被引：4，自引：0，他引：4  
Using immunoelectron microscopy, 9 serotypes of vesicular exanthema of swine virus (VESV) were compared with 5 serotypes of San Miguel sea lion virus and 7 additional calicivirus isolates from marine animals. In addition, swine caliciviruses and marine caliciviruses were compared with the vaccinal strain of feline calicivirus (FCV) F-9. Of 9 VESV types, 8 showed common antigenicity with San Miguel sea lion virus. Of 9 VESV types, 2 showed common antigenicity with FCV F-9. All 12 marine caliciviruses showed common antigenicity with VESV, but not with FCV F-9.  相似文献   

5.
Virus isolation was attempted from 262 field samples of vesicular material collected during the outbreaks of vesicular exanthema of swine in the U.S.A. from 1952-54. Using primary swine kidney culture, viral cytopathogenic agents were isolated from 76.3% of the samples. However, an overall recovery rate of 82.1% was obtained after samples negative in tissue culture were inoculated intradermally in susceptible swine. All vesicular exanthema of swine virus isolates were identified as serotype B51 using complement fixation and serum neutralization tests. Two isolates did not react with antisera to known vesicular agents of swine and failed to produce vesicles or clinical signs of disease upon inoculation in swine. One vesicular exanthema of swine virus isolate from tissue of equine origin was pathogenic for swine but produced limited vesiculation at the site of intradermalingual inoculation in the tongue of a pony infected experimentally. Type B51 virus was reisolated from lesions produced in the pony and the pony became seropositive for virus type B51.  相似文献   

6.
A virus was isolated from California sea lions (Zalophus californianus californianus) and northern fur seals (Callorhinus ursinus) in 1972. It was later named San Miguel sea lion virus (SMSV). State and federal livestock disease control agencies became concerned, because SMSV was found to be indistinguishable from vesicular exanthema of swine virus and to cause (in laboratory trials) clinical signs in swine similar to those produced by vesicular exanthema of swine virus. Ground carcasses of northern fur seals, salvaged after harvesting pelts, are fed to mink on ranches in the United States. Domestic swine are kept on some of these same ranches. Samples withheld from lots of this seal carcass mink food were found to contain SMSV (serotype 5) in titers of 10(6.1) and 10(6.8) tissue culture infective doses.  相似文献   

7.
Two new serotypes of San Miguel sea lion virus (SMSV), designated SMSV-4 and SMSV-5, were studied in vivo and in vitro. The host cell spectrums were compared with SMSV-1, SMSV-2, and vesicular exanthema of swine virus type A-48. Based on the result of these broad host spectrums, a numerical scoring system was devised for ranking each virus on the basis of its potential for infecting terrestrial mammals, including the important domestic species.  相似文献   

8.
A new serotype of calicivirus was isolated from California sea lions (Zalophus californianus) with severe vesicular disease. Neutralizing antibodies were found in 27 of 82 (32.9%) serum samples from California sea lions and in 15 of 146 (10.3%) serum samples from Steller sea lions (Eumetopias jubatus) tested. The seropositive animals were widely dispersed along the margins of the eastern Pacific basin, from the Bering Sea to the Santa Barbara Channel. Seropositive samples were found from as early as 1976 through the present time. This new calicivirus serotype, San Miguel sea lion virus type 13, was inoculated into weaned pigs, resulting in induction of severe vesicular disease, which spread to all pigs, including uninoculated pen contacts. Virus was continually shed by most of the pigs throughout the 2-week duration of the experiment.  相似文献   

9.
Pigs exposed to swine vesicular disease virus developed vesicular lesions by postinoculation day 2. Lesions first appeared on the coronary band and then on the dewclaw, tongue, snout, lips, and bulbs of the heels. The onset of viremia coincided with febrile response and the appearance of vesicles. Virus was isolated from the nasal discharge, esophageal-pharyngeal fluid, and feces as early as postinoculation day 1. Greater amounts of virus were isolated from samples collected during the first week of infection, and lesser amounts from samples collected during the second week. The appearance and the distribution of specific fluorescence in various tissues indicated that during the development of swine vesicular disease virus infection, the epithelial tissues were initially involved, followed by a generalized infection of lymph tissues, and subsequently, a primary viremia. Seroconversion was detectable as early as postinoculation day 4. A mild nonsuppurative meningoencephalomyelitis throughout the CNS was observed in both inoculated and contact-exposed pigs. The olfactory bulbs were most severely and were frequently affected, particularly in contact pigs. The most severe brain lesions were found in pigs 3 to 4 days after the onset of viremia; contact pigs showed more severe brain lesions than inoculated pigs. Microscopic changes were also found in the coronary band, snout, tongue, and heart.  相似文献   

10.
Colostrum-deprived neonatal Northern fur seal pups (Callorhinus ursinus) were exposed to San Miguel sea lion virus type 5 (SMSV-5) by feeding them fish (Girella nigricans) infected with virus or fish infected with both the sea lion lung worm larvae (Parafilaroides decorus) and virus. Virus infection was demonstrated in 8 of 9 pups, and 1 of these developed a vesicular lesion on the flipper. In this sequence, P decorus larvae exposed to SMSV-5 were fed to G nigricans held at 15 C in a salt water aquarium; 32 days later, these fish were killed, then fed to the fur seal pups. The vesicle developed 22 days subsequent to this and SMSV-5 was reisolated from the lesion. The SMSV-5 was shown to persist for at least 23 days in infected neonatal fur seals. Attempts to establish P decorus infection in Northern fur seal pups were apparently unsuccessful.  相似文献   

11.
An indirect solid-phase microradioimmunoassay (IRIA) was developed for detection and quantitation of antibodies to pseudorabies virus (PRV) in swine serum. Qualitative results of the IRIA compared closely with results of the serum neutralization test (NT) and the microimmunodiffusion test (MIDT). The IRIA was more sensitive than the NT for detection of antibodies to PRV in swine serum. The IRIA result is expressed numerically. With the IRIA and NT, antibody to PRV was first detectable in 3 experimentally infected pigs at 9 days after inoculation. With MIDT, antibody was detected in the 3 experimentally infected pigs at 9 days after inoculation. With the MIDT, antibody was detected in the 3 experimentally infected pigs at 7, 8, and 9 days after inoculation. The IRIA results are obtainable within a few hours; the NT and MIDT require 48 hours for completion.  相似文献   

12.
Expression of Mx protein and interferon-alpha (IFN-alpha) was examined by immunohistochemistry in pigs experimentally infected with swine influenza virus. In infected pigs euthanatized at 1 day postinoculation (dpi), the lumen of bronchioles were filled with large numbers of mononuclear cells, small numbers of neutrophils, sloughing epithelial cells, and proteinaceous fluid. Lesions at 3 and 5 dpi were similar but less severe. Alveolar spaces were filled with neutrophils. By 7 and 10 dpi, microscopic lesions were resolved. The immunohistochemical signals for Mx protein and IFN-alpha antigen were confined to cells in areas that had hybridization signal for swine influenza virus. In situ hybridization and immunohistochemistry of serial sections of lung indicated that areas containing numerous swine influenza virus RNA-positive cells also have numerous Mx and IFN-alpha antigen-positive cells. Mean immunohistochemical scores for Mx protein-positive cells were correlated with mean immunohistochemical scores for IFN-alpha antigen-positive cells (r(s) = 0.8799, P < 0.05). These results indicated that Mx protein and IFN-alpha antigen were expressed in the lung from pigs experimentally infected with swine influenza virus, but their biological functions remain to be examined.  相似文献   

13.
OBJECTIVE: To examine clinical signs, virus infection and shedding, and transmission of swine influenza virus (SIV) subtype H1N2 among seropositive pigs. ANIMALS: Eighteen 3-week-old pigs with maternal antibodies against SIV subtypes H1N1, H3N2, and H1N2. PROCEDURE: Ten pigs (principal) were inoculated intranasally with subtype H1N2 and 2 groups of contact pigs (n = 4) each were mixed with principal pigs on day 7 (group 1) or 28 (group 2). Two principal pigs each were necropsied on days 4, 14, 21, 28, and 42 days after inoculation. Four pigs in each contact group were necropsied 35 and 14 days after contact. Virus excretion was evaluated after inoculation or contact. Lung lesions and the presence of SIV in various tissues were examined. RESULTS: Mild coughing and increased rectal temperature were observed in principal pigs but not in contact pigs. Nasal virus shedding was detected in all principal pigs from day 2 for 3 to 5 days, in group 1 pigs from day 2 for 4 to 9 days after contact, and in group 2 pigs from day 4 for 2 to 6 days after contact. Trachea, lung, and lymph node specimens from infected pigs contained virus. Antibody titers against all 3 subtypes in all pigs gradually decreased. CONCLUSIONS AND CLINICAL RELEVANCE: Protection from viral infection and shedding was not observed in pigs with maternal antibodies, but clinical disease did not develop. Vaccination programs and good management practices should be considered for control of SIV subtype H1N2 infection on swine farms.  相似文献   

14.
Studies on the aetiological agents of rabbit haemorrhagic disease (RHD) and European brown hare syndrome show that the viruses responsible for these infections can be placed in the family Caliciviridae. Established members of this group are vesicular exanthema virus (prototype), San Miguel sea lion virus and feline calcivirus. The human hepatitis E virus and the Norwalk agent may soon be included. The RHD virus genome consists of a positive stranded RNA molecule composed of 7437 nucleotides. A major subgenomic RNA of 2.2 kb, colinear with the 3' end of the genomic RNA, can also be recovered from infected liver tissue, and both RNAs are enclosed within viral capsids formed by a single major protein of approximately 60 kDa. Electron microscopic examination of organ suspensions from diseased animals shows two types of particle; 35-40 nm complete virions have the regularly arranged cup-shaped depressions typical of calcivirus morphology, and 23-25 nm smooth particles resulting from degradation of the outer surface structures of the complete virions.  相似文献   

15.
Direct diagnosis of swine influenza infection by an indirect immunofluorescence technique using anti-nucleoproteine monoclonal antibody was compared with virus isolation. Five 8-week-old pigs were inoculated with 2 x 10(7) EID50 of strain A H1N1Sw/4115/85. Clinical signs developed in only three pigs. Antigen was detected in nasal epithelial cells obtained from all animals the first day after inoculation; the antigen was detected in one pig 6 days after the infection. Fluorescence was present in the nucleus, nucleolus and cytoplasm of infected cells. The indirect immunofluorescence test was specific and as sensitive as virus isolation in embryonated eggs, allowing a rapid diagnosis that could be achieved within hours.  相似文献   

16.
Stomoxys calcitrans can act as an efficient mechanical vector of capripox virus and African swine fever virus. Capripox virus was transmitted to a susceptible goat by flies infected 24 hours previously and the virus survived in some flies for at least four days. African swine fever virus was transmitted to susceptible pigs by flies infected one hour and 24 hours previously and the virus survived in these flies for at least two days without apparent loss of titre.  相似文献   

17.
Megakaryocytic infection and thrombocytopenia in African swine fever   总被引：1，自引：0，他引：1  
Pigs infected with an African swine fever field isolate of modified virulence became acutely thrombocytopenic four to five days after the onset of fever and viremia. By eight days after inoculation, all pigs were thrombocytopenic. Immunofluorescence microscopy demonstrated that 2 to 10% of the megakaryocytes were infected. By 13 days after inoculation, platelet counts returned to within normal limits, and there was megakaryocytic hyperplasia despite a continued viremia. Secondary complications delayed the return of normal circulating platelet levels in some pigs. The clinical findings of African swine fever are discussed in light of the gross and histologic lesions.  相似文献   

18.
The pathogenicity and pathogenesis of Lelystad virus was studied in six 6-day-old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re-isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum. Although the respiratory tract seems to be the target organ for this virus, macrophages in other organs, such as the spleen, can also be infected. This preference for macrophages may impair immunological defences.  相似文献   

19.
The 'sand tampan', Ornithodoros savignyi, is susceptible to oral infection with African swine fever (ASF) virus in the laboratory. Infected ticks can transmit the virus transstadially and are able to maintain it for at least 106 days. Transmission of ASF virus by infected ticks to healthy pigs was achieved on five separate occasions between 50 and 106 days after infection. Pigs infected in this way developed typical acute African swine fever. The distribution of O savignyi in Africa suggests that this tick could be a natural field vector of ASF.  相似文献   

20.
Summary

Direct diagnosis of swine influenza infection by an indirect immunofluorescence technique using anti‐nucleoproteine monoclonal antibody was compared with virus isolation. Five 8‐week‐old pigs were inoculated with 2 × 107 EID50 of strain A H1N1 Sww//4115/85. Clinical signs developed in only three pigs. Antigen was detected in nasal epithelial cells obtained from all animals the first day after inoculation; the antigen was detected in one pig 6 days after the infection. Fluorescence was present in the nucleus, nucleolus and cytoplasm of infected cells. The indirect immunofluorescence test was specific and as sensitive as virus isolation in embryonated eggs, allowing a rapid diagnosis that could be achieved within hours.  相似文献   

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