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1.
Using an agar dilution method we measured the minimum inhibitory concentration (MIC) of 12 antimicrobial agents against 11 strains of iota-toxigenic strains of Clostridium spiroforme. Each strain was isolated from a separate outbreak of toxic diarrhoea of rabbits. Vancomycin and bacitracin, both agents used to treat intestinal clostridioses of humans and other animals, had a relatively high MIC (8 micrograms/ml or more). Metronidazole was uniformly active against C. spiroforme. With MIC of 8 micrograms/ml or more, both lincomycin (11 strains) and erythromycin (9 strains) were relatively inactive against C. spiroforme, conversely, penicillin G was active (MIC for 8 strains was 0.5 micrograms/ml or less). Exposure to any one of these drugs has been implicated as a predisposing factor for C. spiroforme mediated diarrhoea of rabbits. The greatest variation in MIC was seen for erythromycin (8-fold), penicillin G (8-fold) and tetracycline (16-fold).  相似文献   

2.
Commercial rabbits showing clinical signs of enteritis-complex were examined for the presence of Clostridium spiroforme and its iota-like toxin. The bacterium was detected by Gram stain in 52.4% of 149 cecal samples and iota-like toxin in 7.4%. From 29 strains of C. spiroforme tested, 26 were toxigenic, originating from 24 of 29 rabbitries. In 13.4% of the samples, C. spiroforme was present as the only known disease agent. Gross and microscopic lesions were similar to those described in the literature. In the other samples, C. spiroforme was associated with attaching effacing Escherichia coli (29.5%), Bacillus piliformis (10.3%), rotaviruses (25.6%), coronavirus (2.6%), Eimeria spp. (44.9%) and cryptosporidia (6.4%). In 33.3% of C. spiroforme-containing samples, more than one of these agents was present. There was no significant difference between the presence of these organisms in C. spiroforme-positive and negative samples. On the basis of these results as well as that of previous data, we suggest that C. spiroforme-mediated diarrhea is favoured by maldigestion, initiated by infectious agents and/or nutritional factors.  相似文献   

3.
Not all E. coli that cause diarrhoea in farm animals act by elaborating the classical heat-labile or heat-stable enterotoxins. These newly recognised animal enteropathogenic E. coli (EPEC) attach to and efface the microvilli of the gut epithelium and resemble the well known human EPEC. In rabbits, only this type of E. coli enteritis is known to be important and a similar disease has been shown to occur in cattle also. There is no doubt that adherence factors are important in the pathogenesis of animal EPEC, but they are not well understood when compared with the adhesion of human EPEC, or to the adhesion of animal ETEC. The enteropathogenic effect is probably due to Shiga-like toxin, a cytotoxin that is active on Vero cells and has also been called Verotoxin. A different type of Verotoxin is produced by most serotypes that are associated with post-weaning diarrhoea and oedema disease in pigs. This toxin is suspected to play a role in the pathogenesis of the latter.  相似文献   

4.
The subject is introduced by a brief historical resumé and account of campylobacter enterocolitis in man. Published figures on the prevalence of campylobacters in normal dogs and cats show a wide range. It is highest (49% dogs, 45% cats) in immature animals, particularly strays or those living in kennels, and lowest (<1.6% dogs and cats) in adult animals living in households. Several studies have shown no significant difference between the prevalence in normal animals and those suffering from diarrhoea, but two surveys did show such a difference. It seems that while most animals are unaffected by infection with campylobacters, a few suffer an illness like that seen in man. Longitudinal studies to determine incidence — as opposed to prevalence — of infection are required. A small proportion of human infections are acquired from dogs. These are usually puppies that are themselves suffering from diarrhoea. Only four infections associated with cats (all kittens with diarrhoea) have been reported. Contact is invariably close and the victims are often small children. The application of simple hygienic measures should prevent such infections.  相似文献   

5.
Experimental production of fatal mucosal disease in cattle   总被引：22，自引：0，他引：22  
Three outbreaks of mucosal disease were investigated. Careful examination of 47 cattle that were persistently viraemic with bovine virus diarrhoea virus (BVDV) revealed no clinical disease, no or low levels of BVDV antibody and only non-cytopathic virus in their blood. The four animals with mucosal disease all showed clinical disease and both cytopathic and non-cytopathic virus in their blood. Following post mortem examination, there were particularly high levels of cytopathic virus in gut tissue. A hypothesis for the induction of mucosal disease is suggested. It states that animals become persistently infected with non-cytopathic virus following in utero infection and when, in post natal life, they become superinfected with a cytopathic virus, then mucosal disease ensues. The experimental reproduction of mucosal disease in support of this hypothesis is described.  相似文献   

6.
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   

7.
Serogroups of Campylobacter jejuni from man and animals   总被引：1，自引：0，他引：1  
A total of 186 campylobacter strains from aborted calf and sheep fetuses, from scouring dogs, rabbits and man, and from retailed poultry were isolated and examined biochemically and serologically for heat stable antigens. Immune sera were produced in rabbits against Penner reference strains from 1 to 60, and against two field isolates. Out of 186 biochemically tested strains 179 (96.2%) proved C. jejuni and only 6 (3.2%) C. coli. One strain has been identified as C. laridis. In cattle and sheep 3.2 and 21.7% respectively of all campylobacter abortions were due to C. jejuni infection. The same agent caused 12.7% of diarrhoea of dogs. The campylobacter infection rate of freshly slaughtered and dressed chicken varied between 25 and 64.3%. Out of the serologically examined 140 C. jejuni strains 118 (84.3%) could be assigned to 16 Penner serogroups and 13 (9.3%) to 2 further serogroups. Serogroups 8 (31.4%), 1 (19.3%) and 2 (12.1%) occurred most frequently. The human isolates represented the widest serotype distribution, as 32 tested strains belonged to 12 serogroups. All those serogroups which caused abortion or diarrhoea in animals or were isolated from poultry carcases were isolated also from man with diarrhoea, but some serogroups were found only in man.  相似文献   

8.
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   

9.
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   

10.
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   

11.
Investigations were conducted into an enterotoxaemia caused by Clostridium spiroforme responsible for significant losses in commercial rabbit farms in Western Australia. Two trials using laboratory and farm bred rabbits were performed to evaluate the protective value of a toxoid prepared from the supernatant of C. spiroforme cultures against intraperitoneal challenge with the trypsin-activated toxin of C. spiroforme. The trials showed clearly that a single vaccination at weaning (four weeks) was protective against toxin but more complete and lasting protection was conferred following a second vaccination administered 14 days after the first. Adults likewise showed similar levels of protective antibodies but did not appear to pass on this protection to their kits although ELISA results indicated levels of antibody in kits from unvaccinated mother to be lower than progeny from vaccinated mothers. However antibody levels in kits from vaccinated mothers were very low and did not protect against challenge with toxin.  相似文献   

12.
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   

13.
Thirteen adult rabbits and 15 weanling rabbits exhibiting signs of diarrhea were subjected to pathological and bacteriological examination. The lesions in 11 of the adult rabbits consisted of a cecocolitis that was characterized by edema of the gut wall, necrosis of the mucosa, and serosal hemorrhages. Also, five of these 11 rabbits exhibited liver lesions consistent with Tyzzer's disease. Lesions in the weanling rabbits were minimal with only two animals exhibiting focal necrosis of the mucosa and one animal exibiting necrosis of the mesenteric lymph nodes. All animals of each age group exhibited pneumonitis. Escherichia coli was present in high numbers (approximately 1012 organisms per g dry wt contents) in the cecum of eight of 13 adult and 12 of 15 weanling rabbits. Thirteen of these isolates were serotype O128:B12. Preliminary attempts to reproduce the disease in young adult rabbits by a series of per os inoculations of an isolate of E. coli (serotype O128:B12) plus intramuscular inoculation of prednisone resulted in the induction of diarrhea in two of four rabbits. The gross and histological lesions in these two animals were similar to those of the spontaneously occurring cases, consisting of edema of the cecal wall, necrosis of the mucosa, and serosal hemorrhages. Numerous white spots of focal necrosis occurred in the liver. No intracellular organisms resembling Tyzzer's disease agent were evident in any sections examined. Inoculation of either E. coli or prednisone alone did not induce diarrhea. Subsequent attempts to reproduce the disease by these methods were unsuccessful. In spite of this inability to repeat the experimental results, it was felt that this study indicated a possible role of E. coli in rabbit diarrhea, either as an etiological agent or as a secondary invader.  相似文献   

14.
Bovine viral diarrhoea virus (BVDV) is an important pathogen of cattle that can naturally infect a wide range of even-toed ungulates. Non-bovine hosts may represent reservoirs for the virus that have the potential to hamper BVDV eradication programs usually focused on cattle. Rabbits are very abundant in countries such as the United Kingdom or Australia and are often living on or near livestock pastures. Earlier reports indicated that rabbits can propagate BVDV upon intravenous exposure and that natural infection of rabbits with BVDV may occur but experimental proof of infection of rabbits by a natural route is lacking. Therefore, New Zealand White rabbits were exposed to a Scottish BVDV field strain intravenously, oro-nasally and by contaminating their hay with virus. None of the animals showed any clinical signs. However, the lymphoid organs from animals sacrificed at day five after exposure showed histological changes typical of transient infection with pestivirus. Most organ samples and some buffy coat samples were virus positive at day five but saliva samples remained negative. Development of antibodies was observed in all intravenously challenged animals, in all of the nebulised group and in four of six animals exposed to contaminated hay. To our knowledge this is the first report of BVDV propagation in a species other than ruminants or pigs after exposure to the virus by a natural route. However, to assess the role of rabbits as a potential reservoir for BVDV it remains to be determined whether persistent infection caused by intra-uterine infection is possible and whether BVDV is circulating in wild rabbit populations.  相似文献   

15.
Congenital infections with nonarbo togaviruses   总被引：1，自引：0，他引：1  
The present review deals with the similarities and differences of selected aspects of prenatal pestivirus infections of domestic animals and congenital rubella of man. Hog cholera virus, bovine virus diarrhoea virus and border disease virus are antigenically closely related, but unrelated to rubella virus. The nonarbo togaviruses are capable of producing congenital infections resulting in a wide spectrum of abnormalities. The infected foetus can die in utero, in the neonatal period, or it may be born with teratogenic defects. In addition, apparently healthy progeny can be delivered that develop a late onset disease, months, or years after birth, or remain clinically normal for life. The ultimate outcome of a congenital infection is mainly determined by the stage of foetal development, at which infection occurs. Foetuses exposed to rubella virus raise an antibody response to the virus, whereas domestic animals frequently fail to respond immunologically to a congenital pestivirus infection. In congenital rubella the virus usually disappears from the host's body 1-2 years after birth. However, congenital pestivirus infections may be characterized by a lifelong and widespread persistence of virus in clinically healthy animals. Such animals are of significance in the epizootiology of bovine virus diarrhoea, border disease or hog cholera.  相似文献   

16.
An epizootic of acute diarrhoea of adult cattle occured in Japan during the winter of 1976 to 1977. A majority of adult cattle clinically diagnosed as having the disease, showed a significant rises in antibody titres to bovine coronavirus, whereas only a smal; minority showed serological evidence of recent infection with calf rotavirus, bovine adenovirus type 7, parainfluenza virus type 3, or bovine viral diarrhoea-mucosal disease virus. A coronavirus-like agent was detected by electron-microscopy in faecal material from a cow with diarrhoea, and was subsequently isolated in primary bovine kidney cell cultures.  相似文献   

17.
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   

18.
An account is given of an outbreak of malignant catarrhal fever which occurred in a 98-cow dairy herd. Ten animals died or were slaughtered and the disease was confirmed by clinical and histological examination. Serological tests for malignant catarrhal fever virus were positive in three of four animals. The diagnosis of malignant catarrhal fever was complicated by the presence of bovine virus diarrhoea virus infection in three of the early cases. The initial cases of malignant catarrhal fever occurred in a group of nine-month-old calves which were housed in an old milking parlour with 19 pedigree Suffolk ewes at lambing time. Later cases occurred in two adult cows and in two heifers. Investigations of the remainder of the herd for evidence of bovine virus diarrhoea virus did not reveal the presence of any persistently infected cattle. Serological examinations for antibody to malignant catarrhal fever and bovine virus diarrhoea virus were carried out on the 19 Suffolk ewes. Six of them had neutralising antibody titres to malignant catarrhal fever virus and three were positive in the indirect immunofluorescence test. The possible roles of bovine virus  相似文献   

19.
In three Austrian rabbit units (two in the west, one in the east) heavy losses occurred in April/May 1989. The clinical course (deaths in adult animals, haemorrhagic diathesis) of the disease was indicative for an infection with the RHD-virus. Necropsy confirmed the suggestive clinical diagnosis as bleeding of the nostrils, hyperaemia in the respiratory tract, spleen tumor, partly decolorized livers, hyperaemia of kidneys with rare petechias could be observed. Histologic examination revealed centrolobular liver necrosis, lung bleeding and edema, tumor of spleen and atrophy of spleen follicles. Rabbits infected with organ suspensions died within 48 hours. The organ suspensions and the suspensions of the already necropsied animals showed a haemagglutination titer for above 1:100. This reaction could be inhibited with a specific RHD-antiserum. The intramuscular application of a RHD-reference strain in one hare, two wild rabbits and a rabbit did not induce clinical disease or death of the leporids during a six week observation period. The rabbit died within 48 hours post infection. However the hare and wild rabbits showed high antibody titers by ELISA at the end of the observation period. Before infection the two wild rabbits were serologically negative.  相似文献   

20.
We report the genetic and biological characterisation of a novel pantropic canine coronavirus (CCoV), strain 450/07, which caused the death of a 60-day-old miniature pinscher. At the genetic level, this virus was strictly related to the prototype strain CB/05, but displayed some unique features. After experimental infection with the new pantropic isolate, most inoculated dogs showed diarrhoea and acute lymphopenia. Gross lesions and histological changes were mainly evident in the gut and lymphoid tissues, although some animals showed remarkable changed also in parenchymatous organs. The viral RNA was detected in the faeces and/or internal organs of most pups. These findings seem to indicate that strain 450/07 is able to spread to internal organs (mainly lymphoid tissues), causing lymphopenia but inducing a mild disease.  相似文献   

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