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1.
A total number of 2125 serum samples collected from indigenous sheep and goats and locally-raised cattle from different localities in Saudi Arabia, were screened for Akabane virus-neutralizing antibodies. The overall prevalence of antibodies was 32% in the animals examined. However the prevalence in cattle was 49%, while in sheep and goats it was 17%. No clinical cases of Akabane have been confirmed so far in Saudi Arabia; but virus isolation attempts are ongoing.  相似文献   

2.
Five bluetongue virus (BTV) diagnostic tests were evaluated for use in free-ranging bighorn sheep. We sampled one bighorn sheep population four times between 1989 and 1995. The tests evaluated included virus isolation (VI), polymerase-chain reaction (PCR), serum neutralization (SN), agar-gel immunodiffusion (AGID), and competitive enzyme-linked immunosorbent assay (c-ELISA). The c-ELISA, AGID and SN tests had high levels of agreement in determining serogroup exposure in bighorn sheep. We used maximum-likelihood algorithms to estimate the parameters of each diagnostic test used. Although the c-ELISA and AGID had high sensitivity and specificity, the SN had perfect specificity but lower apparent sensitivity. Due to the potential of cross-reactions among multiple serotypes, results of the SN must be interpreted with caution when assessing serotype exposure in an area where multiple serotypes are endemic. The PCR assay delineated convalescent antibody titers from more-recent infections, and consequently, was pivotal in distinguishing a different exposure pattern between the bighorn sheep and cattle in an adjacent herd. Based on an increasing seroprevalence (50% to 100%), BTV circulated through this bighorn sheep population between 1989 and 1993. This increase in seroprevalence coincided with a bighorn die-off due to BTV infection in June, 1991. An adjacent cattle herd was sampled in 1995 for comparison. The bighorn sheep and adjacent cattle had different patterns of exposure to BTV between 1994 and 1995. There was no evidence that BTV circulated through the bighorn sheep population from 1994 to 1995. In 1995, seroprevalence to BTV decreased to 72%, none of yearling bighorn was seropositive, and all of the 39 bighorn sheep were PCR-negative. In contrast, all adult cattle were seropositive to BTV by c-ELISA and SN, and 4 of the calves were seropositive; 11 of the 24 cattle were PCR-positive, including all five calves. Overall, the pattern of temporal herd immunity in the bighorn sheep appeared to follow a classic epidemic curve, with the appearance and subsequent disappearance of herd immunity coinciding with the 1991 die-off in this population. As low levels of herd immunity and high proportions of susceptible animals are key factors in the development of epidemics, this population of bighorn sheep may be at increased risk for a BTV epidemic in the future.  相似文献   

3.
An abattoir survey of sheep and goats was carried out in The Gambia for one year. A total of 1248 goats and 438 sheep, predominantly young females, were slaughtered and sampled. Sixty per cent of the females of both species were pregnant. There were no significant differences between the dressing percentages of different breeds and age groups. Sex and stage of pregnancy had a significant influence on carcase yields in both species. In goats the highest carcase yields were obtained during the early dry season. Most of the animals were clinically healthy and there were few pathological findings postmortem. In both species, there was a seasonal fluctuation of packed cell volume (PCV), with a minimum during the rains, and although the prevalence of trypanosomiasis was low it reduced the PCV. Faecal egg counts of Trichostrongylidae were highest during the rainy season and goats had higher faecal egg and coccidial oocyst counts than sheep. In sheep, a breed difference was observed for PCV and an age difference for egg excretion. The peak or higher rates of egg excretion occurred during the rains in both species. The immune status against peste des petits ruminants was significantly lower in goats (39 per cent) than in sheep (49.5 per cent). Antibodies against bluetongue virus were found in 62.6 per cent of goats and 55.8 per cent of sheep.  相似文献   

4.
With regard to BHV1 eradication programs in cattle it is important to know whether sheep can be a reservoir of BHV1. We therefore performed an experiment that consisted of three phases. In phase 1, 10 sheep were inoculated with high doses of BHV1 and kept in close contact with 5 sheep and 5 calves. All inoculated sheep excreted BHV1 between 8 and 15 days post inoculation and seroconverted. Although BHV1 was isolated from the nasal mucosa of 3 out of 5 sentinel sheep, none of the sentinel sheep produced antibodies against BHV1. One sentinel calf excreted BHV1 through days 12-17; the remaining 4 calves excreted BHV1 between days 18 and 24 suggesting that the first calf was infected by sheep and the remaining 4 sentinel calves were infected by that calf and not by sheep. The bacic reproduction ratio (R0) of BHV1 between sheep and calves was estimated at 0.1, and among calves it was estimated at > or = 9. In phase 2, all inoculated sheep were treated with dexamethasone and kept in close contact with 5 sheep and 5 calves. All dexamethasone treated sheep re-excreted BHV1 over a 6- to 9-day period. None of the sentinel animals seroconverted. In phase 3, the sentinel sheep and calves of phase 1 were kept in two groups and were treated with dexamethasone. None of the sentinel sheep re-excreted BHV1, whereas 3 out of 5 sentinel calves did. It is concluded that while BHV1 infection in sheep is possible, BHV1 does not spread from sheep easily to cattle.  相似文献   

5.
OBJECTIVE: To determine the prevalence of antibody to bovine adenovirus (BAdV) serotypes 1-8 and 10 in calves at a farm and after 5 weeks in a feedyard. ANIMALS: 2- to 5-month-old calves of mixed English breeding (n = 100) from 4 farms. PROCEDURE: Serum BAdV antibody was measured by use of a microtitration test. RESULTS: Serum antibodies were found to the 9 BAdV serotypes studied. Seroconversion to each virus had occurred in some calves by the time the second serum sample had been obtained, indicating that the BAdV were present and inducing active infection in these calves. CONCLUSIONS: Antibody to BAdV serotypes 1-8 and 10 are present in cattle populations of the United States, indicating existence of these serotypes, although only BAdV serotypes 1-4, 7, and 10 have been isolated.  相似文献   

6.
A total of 3735 sera were examined for the presence of CF antibody to Coxiella burneti. Of the samples tested 724 sera were from humans, 1507 from cattle, 525 from sheep, 575 from goats and 404 from game collected in the Serengeti National Park or Selous Game Reserve. It has been demonstrated that Q fever is well established in the above mentioned species in Tanzania (humans 3-9 per cent, cattle 13-3 per cent, sheep 17-1 per cent, goats 13-6 per cent and in game mainly in ruminants). Possible transmission links in the maintenance cycle of the disease are discussed.  相似文献   

7.
Brucella abortus and Brucella melitensis have surface lipopolysaccharides and polysaccharides carrying B. melitensis-type (M) and B. abortus-type (A) epitopes as well as common (C) epitopes present in all smooth Brucella biotypes. Crude lipopolysaccharides, hydrolytic O polysaccharides, and native hapten polysaccharides of MC or AC specificity were evaluated in indirect enzyme-linked immunosorbent assays with polyclonal, monoclonal, or protein G conjugates by using sera from cattle, sheep, and goats infected with AC, MC, or AMC Brucella biotypes. Regardless of the antigen, the levels of antibodies were lower in goats than in sheep and highest in cattle. The diagnostic performance of the assay was not affected by the absence of lipid A-core epitopes, the presence of contaminating outer membrane proteins, the AC or MC epitopic structure of the absorbed antigen, or the conjugate used. Moreover, with sera from cattle vaccinated with B. abortus S19 (AC) or from sheep and goats vaccinated with B. melitensis Rev 1 (MC), AC and MC antigens showed similar levels of reactivity. The results show that antibodies to the C epitopes largely dominate in infection, and this is consistent with the existence of multiple overlapping C epitopes (V. Weynants, D. Gilson, A. Cloeckaert, A. Tibor, P. A. Denoel, F. Godfroid, J. N. Limet, and J.-J. Letesson, Infect. Immun. 65:1939-1943, 1997) rather than with one or two C epitopes. It is concluded that, by adaptation to the corresponding antibody levels, brucellosis in cattle, sheep, and goats can be diagnosed by immunosorbent assay with a single combination of conjugate and antigen.  相似文献   

8.
The prevalence of ruminant trypanosomosis and tsetse flies was investigated in Katsina-Ala Local Government Area--a sleeping sickness endemic area--between the valleys of River Benue, Katsina-Ala and Donga in Central Nigeria. Analysis of three hundred and twenty blood samples showed that among semi-nomadic animals, about one cattle (21.3%; 0.213, confidence interval C1 +/- 0.06) and two sheep (38.0%; 0.380, C1 +/- 0.10) out of five carried mature trypanosome infections. Significantly lower (P < 0.05) values (12.5%; 0.125, C1 +/- 0.08) were recorded among peri-domestic West African Cross Red Sokoto (WAD x RS) goats. Trypanosoma vivax was the most prevalent species encountered; it was diagnosed in 10.3% of the ruminant population and responsible for 42.8% of the infections in all animals. Corresponding figures for T. congolense were 5.9% and 24.6%, respectively. T. brucei infections were low in cattle (1.8%) and absent in goats. Males and young stock had lower infection but the difference was not significant (P > 0.05) except between the ages in cattle. Glossina tachinoides was the only tsetse species encountered and responded to acetone odour attractant in biconical traps.  相似文献   

9.
Serum samples from 2000 cows, 3311 sheep and 638 goats from Iran were examined for antibodies to Toxoplasma gondii by use of the latex agglutination (LAT) and indirect hemagglutination tests (IHAT). Antibodies to T. gondii were found in 24.50% sheep and 19.25% of goats. Antibodies to T. gondii were not detected in cow sera by LAT and IHAT in 1:8 and 1:64 dilutions of bovine sera, respectively. Toxoplasma gondii was not found in tissues of 300 aborted fetuses from cows by direct microscopy and bioassay in mice.  相似文献   

10.
Highly purified recombinant gag and env proteins derived from Icelandic strain 1514 of maedi-visna virus were used in an indirect enzyme immunoassay (ELISA) to detect antibodies to small ruminant lentiviruses in sheep and goat sera. The recombinant protein-based ELISA performed very well relative to whole maedi-visna virus and whole caprine arthritis-encephalitis-virus-based ELISAs in its ability to detect anti-maedi visna virus and anti-caprine arthritis-encephalitis virus antibodies, despite the antigenic and genomic variability that is known to exist within and between these two small ruminant lentiviruses. The data suggest that these recombinant maedi-visna virus proteins can be reliably used in an ELISA for the routine serodiagnosis of lentiviral infections in sheep and goats.  相似文献   

11.
Epidemiological aspects of bovine viral diarrhoea virus (BVDV) infections were studied longitudinally in a large dairy herd for three years. At the start of the study, practically all the cows more than four years old had BVDV antibody titres, whereas the younger stock were almost all seronegative. The spread of the virus was monitored in a part of the population that contained only transiently viraemic cattle and in another part that contained persistently viraemic calves. Among the lactating cows the virus circulated for two-and-a-half years, although they had no direct contact with persistently viraemic cattle during this period. The highest transmission rate occurred when a large number of susceptible heifers was added to the population of cows that contained transiently viraemic cattle. The circulation of BVDV among the lactating cows ceased while 27 seronegative cows were still present. Both findings are in accordance with predictions from simple epidemic models. The susceptibility of the cows that remained seronegative was confirmed experimentally. In contrast with the limited circulation of BVDV caused by transiently viraemic cattle, virtually all susceptible cattle that came into contact with a persistently viraemic calf became seropositive within three months. Transplacental BVDV infections were not detected in the calves born to cows that had antibodies against the virus due to an infection that had occurred at least four years earlier. Transplacental transmission of BVDV did not occur in most of the pregnant cows that were infected before approximately the 60th day of gestation, but when cows became infected later in gestation the virus virtually always invaded the fetus.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
The results of a 15 months' intensive study on seven flocks of indigenous goats in the Southern Darfur region of the Sudan are discussed in this paper. Birth rates in the region approached 2-1 kids per doe per year. A high total offtake of 28 per cent and a weighted average death rate of about 16-5 per cent were insufficient to offset this high birth rate and flock numbers are increased. Mortality in kids was unrelated to number of births. Weighted average rate of gain for all surviving kids was 87 g per day to 3 months and 67 g per day to 6 months of age. The growth rates of twin and single were similar, but triplet kids grew at a slower rate. For each kilogramme liveweight of breeding females, goats produced 1-5 and 8 times the weight of meat produced by sheep and cattle respectively under the same management and environmental conditions.  相似文献   

13.
Bulk tank milk samples from 5,024 dairy herds in Lower Austria were tested by ELISA for antibodies to bovine virus diarrhoea virus (BVDV). Approximately 54 per cent of the herds had a low level of bulk tank antibody unsuspected of recent infection with BVDV. In 512 herds, which had a high level of bulk tank antibody suggestive of recent infection with BVDV, milk samples from 5-10 primiparous cows, respectively were tested by ELISA for antibodies to BVDV. In 287 (56.1%) of these 512 herds only antibody-negative primiparous cows were detected. In 759 herds blood samples from 8-10 young stock, respectively were tested by ELISA for antibodies to BVDV. The majority of the tested animals was seronegative in 583 (76.8%) herds. The whole stock from 154 herds was tested for persistent BVDV infections. From 51 herds in all 149 cattle persistently infected with BVDV were detected. Because of the low prevalence of BVDV infections it seems possible to control BVDV without vaccination in Lower Austrian dairy farms.  相似文献   

14.
Sheep (3918) from 137 farms in the regions of North-, West- and Mid-Netherlands and Gelderland were serologically investigated for the presence of antibodies against Leptospira hardjo. Antibodies were detected in 3.3% of the sheep. There were large regional differences with respect to both the percentage of positive sheep and the percentage of positive flocks. All sera from sheep in Gelderland were negative. In West- en Mid-Netherlands there were 0.9 and 6.5% positive sera, respectively, and 19.4 and 32.7% positive flocks. The percentage of positive sheep per positive flocks varied from 1 tot 51.6. Serological positive sheep were from farms with and without cattle. On farms with cattle, there was no clear relationship between serologically sheep and the presence of hardjo antibodies in cattle. It thus seems plausible that sheep can be infected with hardjo independently of cattle.  相似文献   

15.
Approximately 0.2% (n = 4397) of the bovids (cattle and buffalo) in Sri Lanka were sampled, from June 1992 using a multi-stage sampling procedure. Serum antibodies for the rinderpest virus were detected using the competitive enzyme-linked immunosorbent assay. The age, the agroclimatic zone, the management system practiced in the farms, and the vaccination history of the sampled bovids were studied as potential risk factors for being seropositive. The prevalence of rinderpest antibodies in non-vaccinated bovids was 3.5% (n = 4101). The prevalence was higher in the dry zone (9%; where the outbreak emerged in 1987), compared to bovids in the other zones (1%). Seropositive bovids over three years of age were approximately at fourfold higher chances of being seropositive compared to those that were < or = 3 years old. The higher prevalence in older animals is probably due to exposure to the virus during the 1987 epidemic. Bovids from the dry zone (annual rainfall 20 to 35 inches) were at higher odds of being seropositive even after controlling for the possible effects of age, agroclimatic zone, management system and vaccination. The fact that 62% of bovids from the dry zone in this study were reared under extensive management system (free grazing) which allow unrestricted contact between animals, may be the reason for the above finding. A relatively poor response to vaccination observed in vaccinated bovids (seroprevalence = 12%; n = 296) could be attributed to difficulties in maintaining the vaccine at recommended temperatures in the field. This is the first island-wide study on seroprevalence of rinderpest in Sri Lanka.  相似文献   

16.
A vaccination study was conducted for infectious bovine keratoconjunctivitis (IBK) in 440 purebred Hereford cattle (cows and their newborn calves) of the USDA Meat Animal Research Center cattle herd at Clay Center, Ne. The cattle were allotted to 4 groups: 60 calves were vaccinated with an autogenous Moraxella bovis bacterin (group 1); 60 calves that were matched with group 1 calves were designated nonvaccinated matched controls (group 2); 99 calves were peer group nonvaccinated controls (group 3); and 219 cows, the dams of the calves, were nonvaccinated consorts (group 4). The infection rates in cattle groups 1, 2, 3, and 4 during the summer were 96.6, 98.3, 100, and 79.1%, respectively, and the disease rates were 90, 93, 85, and 20%. The infection and the disease rates were significantly (P less than 0.01) different between claves and cows. The disease rate was also significantly different between older and younger cows. A larger percentage of the affected calves and cows had mild or moderate (61%) signs of IBK rather than severe (39%) signs. The rate of body weight gain was reduced in calves with severe signs of IBK. The results seemed to indicate that little would be gained by vaccinating cattle against IBK under the conditions of study.  相似文献   

17.
The expression of inducible nitric oxide synthase (iNOS) was studied in the brains of cattle, sheep, and goat that succumbed to a natural infection with Listeria monocytogenes. The lesions in infected brains are characterized by microabscesses, perivascular cuffs, gliosis, glial nodules, and large areas of malacia. Using immunocytochemistry, we detected bacteria in microabscesses, particularly in sheep and goats, and in areas without signs of inflammation, but not in perivascular infiltrates. iNOS was expressed by macrophage (Mphi)-type cells of microabscesses and glial nodules but rarely by Mphi in areas of malacia, as determined by immunohistochemistry with iNOS-specific antibodies. iNOS was not detected in perivascular cuffs. Major histocompatibility complex class II molecules (MHC-II), another marker of cell activation, showed a different pattern of distribution. Perivascular cuffs contained high numbers of MHC-II-positive cells, including some with Mphi characteristics. Microabscesses in sheep and goats showed low expression of MHC-II, particularly in iNOS-expressing cells. In cattle, the expression of markers for activated or recruited phagocytes, the calcium-binding proteins S100A8 and S100A9 (formerly called MRP-8 and MRP-14, respectively), was largely restricted to cells showing weak or undetectable iNOS expression; iNOS-positive Mphi showed a low expression of S100A8 and S100A9. Thus, iNOS is expressed by a restricted subset of Mphi in listeric encephalitis. In cultured sheep and goat Mphi, a low proportion of cells expressed iNOS upon activation by L. monocytogenes and gamma interferon, resulting in nitrite generation at least 1 order of magnitude lower than that in similarly treated cattle Mphi. Since these species differences were much less obvious in vivo, it appears that the well-known species variation in iNOS expression by Mphi could reflect an in vitro phenomenon.  相似文献   

18.
A fresh isolate of Akabane virus was inoculated intravenously into 11 seronegative pregnant cows at 62 to 96 days of gestation. Two of the cows were slaughtered 18 days post-inoculation, and the fetuses were examined; the remaining cows were allowed to give birth. All the inoculated cows developed viremia and neutralizing antibody for the virus, indicating that the cows were actually infected with the virus, although fever or any other clinical abnormalities were not noted. The virus further infected the fetuses. This was proved by virus isolation in one of the two fetuses from the slaughtered cows, and polymyositis was noted in both fetuses. Six of seven calves born alive had anti-Akabane antibody in their precolostral sera, indicating that in utero infection with the virus took place in these calves. Some of the in utero-infected calves demonstrated congenital abnormalities such as cerebral defect, hydranencephaly, and arthrogryposis. These findings provide additional evidence that Akabane virus is the etiological agent of epizootic abortion and congenital arthrogryposis-hydranencephaly syndrome in cattle.  相似文献   

19.
A series of brains from sheep, cattle, goats and pigs was examined histopathologically and illuminated by ultraviolet light to test the specificity of autofluorescence in the diagnosis of cerebrocortical necrosis. Fluorescence was seen in only four cases of porcine encephalopathy. In the ruminant brains it occurred in seven out of eight cases of cerebral oedema of lambs; otherwise it was confined to cases of cerebrocortical necrosis, although a few false negative cases were encountered. Ovine cerebral oedema is a disease of unweaned lambs which is unlikely to be confused with cerebrocortical necrosis. Thus bright cerebrocortical autofluorescence in a naturally occurring disease of cattle, sheep and goats is a likely indicator of cerebrocortical necrosis; however, a small proportion of cases will escape detection by this method.  相似文献   

20.
Listeriosis is a zoonosis of world-wide importance in many different animal species, especially cattle, sheep and goats. This report presents results of examinations of Listeria monocytogenes strains from sheep and goats in Northern Norway.  相似文献   

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