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1.
Cattle herd breakdown (HBR) with bovine tuberculosis (BTB) was investigated for farms in four counties of England and Wales outside southwest England from 1986 to early 2000. Data from the national database of TB testing history (VETNET) were used. Factors that influenced HBR included calendar time, herd size, number of cattle tested, the test type, the inter-test interval and spatial grouping of farms. Herd tests other than routine herd tests had an increased risk of HBR in all four counties. In all counties, the risk of HBR increased with calendar time and in Shropshire a test interval of 3 years was associated with an increased risk of HBR compared with a 1-year test interval. In Staffordshire and Sussex, a 4-year test interval was associated with a lower risk of HBR compared with a 1-year test interval. There was no evidence of spatial clustering of HBR in West Glamorgan (equal spatial risk in a 15–30 km radius) and weak evidence of spatial clustering in Shropshire (7–15 km) and Sussex (5–10 km). In Staffordshire, there was evidence of spatial (2–4 km) and time (3–4 years) clustering of HBR. The locally increased rate of testing following a confirmed HBR increased the detection of infected herds but did not prevent local spread in two of the four counties (Shropshire and Staffordshire) since the rate of HBR increased linearly from 1988 to 2000. The main conclusion is that there were both local and distant components of spread.  相似文献   

2.
A cross-sectional study based on clinical examination, inspection of herd health records and a questionnaire was designed to determine the epidemiology, economics and potential impact of immunisation against theileriosis in Tanzania. The results showed annual theileriosis costs to be US$ 205.40 per head, whereas the introduction of immunisation reduced this by 40-68% depending on the post immunisation dipping strategy adopted. Morbidity risk due to theileriosis was 0.048 in immunised and 0.235 in non-immunised cattle, and the difference was significant (chi(2)=66.7; P=0.000). The questionnaire results indicated that immunised cattle had a significantly (chi(2)=6; P=0.015) higher risk of anaplasmosis compared with non-immunised cattle, whereas the risk of bovine babesiosis did not differ significantly (chi(2)=0.06; P=0.807) between the two groups. Mortality risk due to anaplasmosis was 0.046 in immunised and 0.018 in non-immunised cattle and this difference was statistically significant (chi(2)=4.48; P=0.043). The theileriosis mortality risk was 0.203 in the non-immunised cattle, while the risk was 0.009 in the immunised cattle and these differences were also significant (chi(2)=103; P=0.000). It was concluded that farmers who have immunised their cattle may cautiously cut down acaricide application by 50% for extensively grazed herds and by 75% for zero grazed animals depending on the level of tick challenge at the herd level.  相似文献   

3.
Protothecosis is a severe form of mastitis in dairy cows caused by colorless algae of the genus Prototheca. Since P. zopfii is highly resistant to all known chemotherapeutics, infected cows must be removed from the herd. Eradication measures are difficult since many chronically infected cows may become intermittent shedders. Therefore, cultural methods are insufficient for control measures. In order to eradicate Prototheca zopfii-mastitis in dairy cattle herds, two isotype specific indirect ELISA for detection of IgA and IgG1 in whey were used in a dairy herd highly affected with protothecal mastitis. All cows (n = 313) were tested four times in intervals of six months. Milk specimens were examined in parallel by cultivation and serologically using two indirect ELISA systems for specific IgA and IgG1 in whey. Cows tested Prototheca positive were consequently separated from the herd and slaughtered. At the first examination, 15.6% of the animals were found positive by culture, and 23.3% were positive in at least one of the ELISA systems. Within two years, protothecal prevalence and incidence decreased to zero indicating that the eradication strategy used was successful. In summary, serological identification of P. zopfii-infected lactating cows is an useful tool to eradicate protothecal bovine mastitis in infected herds.  相似文献   

4.
A total of 2126 herds, an attack rate of 0.82 per cent, were affected during an epidemic of foot-and-mouth disease in Argentina in 2001. The spatial and temporal distribution of the epidemic was investigated using nearest-neighbour and spatial scan tests and by estimating the frequency distributions of the times to intervention, and distances and times between outbreaks. The outbreaks were clustered and associated significantly (P<0.01) with herd density; 94 per cent were located in the Pampeana region, where the cattle population is concentrated, which had an attack rate of 1.4 per cent. The clustering results suggested that the virus had spread locally between outbreaks. Most of the outbreaks were separated by one day and the maximum distance between outbreaks was almost 2000 km, indicating that the infection spread rapidly over large distances. The index outbreak was detected more than 15 days after the primary outbreak, and restrictions on the movement of cattle were probably not enforced until about one month after infection occurred. As in other major epidemics, the period between the first outbreaks and the effective application of control strategies was probably crucial in determining the progress of the epidemic.  相似文献   

5.
Ten years after the first outbreak of infectious bovine rhinotracheitis (IBR) in Swiss dairy cows, the national cattle herd is almost free from infection with IBR virus (bovine herpesvirus 1, BHV 1). The national programme for the eradication of IBR was divided into four phases: (1) Prevention of transmission of the infection by restrictions on trade of bovines and assessment of the prevalence of cattle with antibodies to BHV 1. (2) Slaughtering animals with antibodies to BHV 1 in order to eradicate BHV 1 from breeding herds. (3) Detection and eradication of further BHV 1 reservoirs (e.g. fattening cattle). (4) Monitoring programme and legal actions in order to maintain the favourable situation. Approximately 50,000 animals were slaughtered in the course of the eradication of IBR. The total costs amounted to approximately SFr. 110,000,000 over 10 years. The costs for maintaining the situation are estimated at approximately SFr. 5,000,000 per annum.  相似文献   

6.
This study investigated the distribution of bovine spongiform encephalopathy (BSE) in herds of cattle in Ireland over the years 1996 through 2000, prior to the introduction of widespread active surveillance. Mappings of index herds, herd density, and standardized morbidity ratios, by county, were employed to help visualize areas of potential clustering of BSE. The hypothesis of spatial clustering was tested using a spatial scan statistic applied to the location of the herd where exposure likely occurred. Both Bernoulli and Poisson spatial models indicated marked clustering of BSE herds centred on Monaghan county, with secondary clusters detected by Bernoulli approaches and some Poisson models in Wexford and Cork. The number of cases increased with time, but clear temporal-spatial clusters were rarely detected, except in the case of a cluster in Wexford. The focussed spatial scan analyses using the location of large-scale feed suppliers provided support for the hypothesis that clustering of BSE may be associated with feed source. The results of our analyses provided strong evidence in support of the hypothesis that herds, in which animals were most likely to have been exposed to the BSE agent, cluster geographically.  相似文献   

7.
The seroprevalence of Neospora caninum infection was estimated from a sample of 889 cattle from 43 dairy herds in three counties in the Asturias region of Spain. The true prevalence of infection was estimated to be 30.6 per cent (95 per cent confidence interval (CI) 27.6 to 33.6). Seropositivity was associated with abortion during the previous year (odds ratio (OR)=3.31, P<0.001) and was slightly higher among purchased cattle (37.6 per cent), than among cattle raised on the farm (29.1 per cent) (P=0.078). Seropositive cows were more likely than seronegative cows to have had a seropositive dam (OR=2.3, P=0.011), suggesting that congenital transmission contributed to about 56 per cent of the infections. Herds with a true seroprevalence above 10 per cent had more dogs on the farm, than herds with a lower prevalence (P=0.032). The ORS relating abortion to seropositivity in individual herds ranged from 0.7 to 19, indicating that some herds experienced few abortions caused by N. caninum, while others experienced more abortions due to the organism. Overall, 38.7 per cent of the abortions were estimated to have been attributable to N. caninum.  相似文献   

8.
All the cattle in 14 dairy herds in England were tested for Neospora caninum-specific antibodies with a commercial ELISA. Three of the herds had had sporadic abortions, eight had had endemic abortions and three had had epidemic abortions associated with N caninum before the study. Of 4295 cattle tested, 17.1 per cent were seropositive and the herd-specific prevalence ranged from 7.3 per cent to 44.8 per cent. No significant effect of either herd size (P = 0.988), endemic (P = 0.869) or epidemic (P = 0.138) patterns of abortion on herd-specific prevalence was found by using logistic regression analysis. There was no evidence in any herd of a significant increase in prevalence with age; the prevalence in seven-to 12-month-old cattle was not significantly different (P > 0.400) from the prevalence in older cattle, except that there was a significantly lower prevalence (P = 0.017) in 13-to 24-month-old cattle. The results of this study are consistent with vertical transmission being the major route of N caninum transmission in these herds.  相似文献   

9.
In Ireland, factory surveillance of cattle for gross lesions is an important supplementary method for detecting herds infected with bovine tuberculosis (tb), and in recent years between 27 and 46 per cent of all new herd breakdowns in any year have been detected by this method. The aim of this study was to determine the relative efficiency of factories in detecting lesions among attested cattle slaughtered during 2003 and 2004. National databases were available on animal slaughter, programmes of tuberculin testing for bovine tb and laboratory confirmation of suspected lesions. Factories were ranked according to their submission risk (number of animals submitted with lesions/number of attested animals killed) and confirmation risk (number of animals with laboratory-confirmed lesions/number of animals submitted with lesions), adjusting for the risk profile of the animals slaughtered, including potential confounding factors such as their age and sex, whether they were purchased or homebred, the test history of their herd, the prevalence of bovine tb in the area and the season of slaughter. Approximately 3.7 million cattle were slaughtered in 42 Irish export-licensed factories during the two years. Complete data were available for 2,374,987 animals from 84,510 attested herds in 2845 District Electoral Divisions. Samples from 7398 animals with suspected tb lesions were submitted for laboratory examination; 4767 (64.4 per cent) were positive, 2011 were negative and 620 were inconclusive. The average unadjusted submission risk for all the factories was 22 per 10,000, ranging from 0 to 58 per 10,000. The unadjusted factory confirmation risk (excluding factories that had sent in fewer than 10 lesions) varied between 34.3 per cent and 86.3 per cent. The unadjusted and adjusted submission and confirmation risks were highly correlated, and animal-related factors (including their characteristics and origin) therefore did not contribute to the variations in factory-level submission and confirmation risks.  相似文献   

10.
Data on the geographic distribution of swine herds tested for pseudorabies virus (PRV) in the state of Illinois (USA) were analyzed to determine whether the prevalence of PRV-infected herds was clustered geographically at the county level. Second-order analysis of spatial dependence indicated there was a spatial clustering of counties of high PRV prevalence rates and that this clustering was greater than the observed clustering of counties with a large number of swine herds. The clustering of county PRV prevalence rates was most apparent within a radius of 120 km (on the average, approximately two couties away). The association of county PRV prevalence rates with average herd size, geographic density of swine herds in the country and regional (within 120 km) density of PRV-infected herds was analyzed using multiple linear regression. The primary factor affecting county PRV prevalence rates was the regional PRV density, which interacted with the other model variables. For counties with a low regional density of PRV infection, county PRV prevalence rates charged little with a change in county herd density or average herd size. In contrast, for counties with a high regional density of PRV infection, PRV prevalence within a county increased with increasing average herd size and increasing geographic density of swine herds in the county. The results of the current and previous studies implicate an important role for the geographic proximity of infected herds in the spread of PRV among swine herds.  相似文献   

11.
Few cases of infection with Paramphistomum spp. have been reported from cattle in Canada. During the course of a recent study of bovine fascioliasis both P. microbothrioides and P. liorchis were found in the rumen of dairy cattle slaughtered in a Quebec abattoir. Eggs in feces were distinguished on the basis of their size. Coprological analysis of 932 samples from 601 cows on 17 selected farms in Portneuf County (Quebec) revealed that 34% of the animals were infected with P. microbothrioides and 1% with P. liorchis. Based on data from one herd there appears to be significant seasonal variation in egg passage for P. microbothrioides. Furthermore, old cows exhibited a higher prevalence of infection.  相似文献   

12.
Our objective was to determine the seroprevalence of Hypoderma spp. and to develop a spatial model describing the risk surface of warble-fly infection in Belgian cattle herds (adjusting for herd size, herd type, local temperature, rainfall, relative air humidity and land-cover). This survey was carried out in 390 selected herds of all types (dairy, mixed and beef) from December 1997 to March 1998, which were included in a national infectious bovine rhinotracheitis and paratuberculosis (Johne's-disease) survey. All animals >24 months old were blood sampled and an ELISA was used on pooled serum samples (10 animals per pool). The herd seroprevalence was 48.7% (95% confidence interval: 43.6-53.8); positive herds were mainly in the south of the country and along the North Sea coast. The logistic multiple-regression model of herd-level seropositivity indicated that mixed-type and beef-cattle herds have more than four-fold and two-fold increases in the odds of being Hypoderma-positive, respectively, compared with dairy herds.  相似文献   

13.
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14.
OBJECTIVES: To determine epidemiologic factors associated with tuberculosis (TB) in dairy cattle slaughtered in 6 important regions for milk production in Mexico. ANIMALS: 2,500 cattle. PROCEDURE: Tissue specimens with lesions typical of TB were obtained during routine inspection of carcasses at abbatoirs between July 1996 and January 1997. Infection with Mycobacterium organisms was confirmed by histologic examination and bacteriologic culture. Species identification was made by use of selective growth medium, conventional biochemical tests, and radiometric procedures. Epidemiologic information for affected cattle was obtained by personal interviews with cattle dealers and owners. RESULTS: 400 (16%) of 2,500 cattle carcasses had gross lesions typical of TB. Of the 400 infected cattle, 336 (84%) had lesions in > or = 1 lymph node. Infection was confirmed in 87% of cattle with gross lesions by histologic examination, in 77% by bacteriologic culture at a laboratory in the United States, and in 59% by bacteriologic culture at a laboratory in Mexico. Most cattle were adult females in fair to good body condition that came from large herds (> 500 cattle) and were not included in the Mexican TB control program. CONCLUSIONS AND CLINICAL RELEVANCE: Mean prevalence of lesions typical of TB in dairy cattle at 6 locations in Mexico was 16%. Mycobacterium infection was confirmed by various techniques in most lesions. Recognition of typical gross lesions at slaughter may expedite TB control procedures.  相似文献   

15.
The associations between herd bovine herpesvirus 1 (BHV-1) seroprevalence, along with other infectious and farm management factors with bovine respiratory disease (BRD) in dairy calves and heifers, were investigated. Serum samples from 103 dairy cattle herds were analyzed for antibodies against BHV-1, bovine respiratory syncytial virus (BRSV), bovine viral diarrhea virus (BVDV), and Mycoplasma bovis (M. bovis). A questionnaire was used to record herd management practices. A high occurrence of respiratory disease in unweaned calves was associated with low to moderate and high prevalence of BHV-1 among cows (OR=14.8, p=0.005 and OR=19.2, p=0.002, respectively) and positive BVDV status of a herd (OR=5.1, p=0.02). The presence of BVDV in a herd was related to a high incidence of respiratory disease in heifers 3-16 months old (OR=4.3, p=0.027). Based on the results of multiple correspondence analysis, holding youngstock separately from cows until pregnancy, introducing new animals and the activities of on-farm employees may contribute to a higher incidence of BRD.  相似文献   

16.
As tuberculosis is still a worldwide infection and buffalo breeding represents an important economic activity in various countries, the purpose of this study was to employ an enzyme-linked immunosorbent assay (ELISA) using MPB70 as a capture antigen for the diagnosis of naturally occurring tuberculosis in water buffaloes in Brazil. After the introduction of newly acquired cattle onto a tuberculosis (TB) free farm, an outbreak of TB was recorded in a mixed herd comprising water buffaloes (21) and cattle (46). The entire herd was tested by intradermal tuberculin injection (ITT) and positive animals were slaughtered and tested by culture, polymerase chain reaction (PCR), and ELISA. From the 21 buffaloes sampled, three were reactive by ITT. All the three had positive culture and ELISA, while PCR was positive in two of them. Besides that, one ITT-negative buffalo was slaughtered and presented positive results by both culture and ELISA, and was considered as anergic. Although there were only few animals, those findings demonstrate the diagnostic usefulness of an MPB70-ELISA to correctly detect Mycobacterium bovis tuberculosis in water buffaloes.  相似文献   

17.
Bovine cysticercosis is an important food safety issue that is of economic concern. In Belgium, in the last years an increase in the number of cases, mostly light infections, was observed. The role of contact with contaminated surface water has been hypothesized as the main route of transmission. Based on abattoir records from 2001 till 2003 the distribution and risk factors of bovine cysticercosis among dairy and mixed farms were studied in four provinces, using Geographic Information Systems (GIS) and questionnaires. The risk factors were analysed using a case-control study design. The case group consisted of herds from which homebred cattle with cysticercosis had been detected at the abattoir; the control group was composed of herds where no cases had been detected. Case herds were distributed over the study area. A logistic regression analysis revealed that the location (province), the number of slaughtered cattle, the flooding of pastures, free access of cattle to surface water and the proximity of wastewater effluent were significant explanatory variables for bovine cysticercosis to be recorded in a herd.  相似文献   

18.
This paper reports the investigation of farm-level risk factors for confirmed bovine tuberculosis (TB), based on a retrospective cohort study of a population of cattle in the lower North Island of New Zealand. Data were obtained from the TB testing surveillance programme operational in this area since the mid-1970s and comprised 190,665 cattle-years at risk from July 1980 to June 2004 (inclusive). A mixed-effects Poisson regression model was used to investigate the influence of farm-level covariates on the number of cattle confirmed with TB throughout the study period. This model was interpreted in context of depopulation strategies for the wildlife reservoir for TB, the brushtail possum Trichosurus vulpecula, that were applied in this area. The model showed that, despite intensification of possum control strategies over time, proximity to forest parks (a principal possum habitat in this area) remained a significant predictor of the number of confirmed cases of TB detected per farm per year. Our analyses showed a significant, three-fold increase in TB risk in dairy cattle relative to beef conditional on the size of local possum habitat, and confirmed the positive influence of cattle population size and the presence of previous infection status as a determinant of the number of confirmed TB cases per farm per year.  相似文献   

19.
The performance of the secretory protein MPB70 of Mycobacterium bovis, bovine PPD, and lipoarabinomannan (LAM) were evaluated as antigens in ELISA for detection of tuberculosis (TB) infected cattle. Sera were from 120 M. bovis infected cattle and 223 cattle from a TB free herd. ELISA results were analyzed using receiver operating characteristic (ROC) curves in relation to culture results. The areas under the three ROC curves were 71 ± 49% SE (MPB70), 71 ± 27% SE (bovine PPD), and 56 ± 4% SE (LAM).  相似文献   

20.
Objective To assess quantitatively the spatial distribution of seroconversion of Queensland cattle to bluetongue viruses.
Design A sentinel herd study. Sample population Sixty-nine sentinel herds at 30 locations.
Procedure Spatial clustering of seroconversion to blue-tongue viruses was investigated during the period from 1990 to 1994.
Results Seroconversion to only two bluetongue virus serotypes, 1 and 21, was observed. The 14 herds, in which seroconversion to bluetongue virus serotype 1 was detected, were located only along the eastern coastal and subcoastal region of Queensland, and were significantly (P < 0.05) clustered. Locations at which seroconversion to serotype 21 was detected, were not significantly clustered. The results generally agree with field observations, except for the failure to detect seroconversion to bluetongue viruses in north-western Queensland.
Conclusion Bluetongue infection of cattle in north-western Queensland may be temporally sporadic. The dominance of serotype 1 in the Queensland cattle population may be the result of differential transmission by potential vector species. Long-term surveillance programs are important for defining disease status of animal populations.  相似文献   

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