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1.
A cross-sectional study was conducted from June through December 1996 to identify management-related risk factors for herd-level M. paratuberculosis infection. Data were collected from 121 participating herds. A two-part questionnaire was administered to gather data on current and previous management practices and herd productivity. A random sample of cows aged ≥24 months was selected from each herd and tested for antibodies to M. paratuberculosis using the IDEXX Antibody ELISA (sensitivity 64%, specificity 96%). A positive herd was one in which ≥2 animals tested positive for antibodies to M. paratuberculosis. A negative herd was one in which no animal tested positive. Herds in which only one animal tested positive were dropped from statistical analysis to reduce the risk of including false-positive herds in the statistical analyses. There were 80 herds with one or more positive animals and 41 herds with no positive animals in the sample (66% herd-level prevalence). Twenty-six herds (21%) were dropped from further analyses because they had only one positive cow. Twelve herds (10%) were dropped from analysis because of missing data. The resulting sample used for statistical modeling included 46 positive herds and 37 negative herds (55% herd-level prevalence). A multi-variable logistic-regression model was used to evaluate the results. The variable ‘use of an exercise lot for lactating cows' was associated with a three-fold increase in odds of a herd being positive for M. paratuberculosis infection (O.R.=3.01, C.I.=1.03–8.80); ‘cleaning of maternity pens after each use' was associated with a three-fold reduction in odds of a herd being positive for M. paratuberculosis infection (O.R.=0.28, C.I.=0.08–0.89); ‘application of lime to pasture areas in 1993' resulted in a ten-fold decrease in odds of a herd being positive for M. paratuberculosis infection (O.R.=0.10, C.I.=0.02–0.56). 相似文献
2.
We investigated the seroprevalence and risk factors for Brucella seropositivity in cattle in Jordan. The sera from 671 cows were randomly collected from 62 herds. The antibodies against Brucella were detected using a Rose Bengal plate test and indirect ELISA. A structured questionnaire was used to collect information on the cattle herds'' health and management. A multiple logistic regression model was constructed to identify the risk factors for Brucella seropositivity. The true prevalence of antibodies against Brucella in individual cows and cattle herds was 6.5% and 23%, respectively. The seroprevalence of brucellosis in cows older than 4 years of age was significantly higher than that in the younger cows. The seroprevalence of brucellosis in cows located in the Mafraq, Zarqa and Ma''an governorates was significantly higher than that of the other studied governorates. The multiple logistic regression model revealed that a larger herd size (odd ratio = 1.3; 95% CI: 1.1, 2.6) and mixed farming (OR = 2.0; 95% CI: 1.7, 3.7) were risk factors for cattle seropositivity to Brucella antigens. On the other hand, the use of disinfectants (OR = 1.9; 95% CI: 1.1, 2.1) and the presence of adequate veterinary services (OR = 1.6; 95% CI: 1.2, 3.2) were identified as protective factors. 相似文献
3.
A cross-sectional study was conducted to identify risk factors for herd infection by Brucella spp. in dairy cattle in the suburbs of Asmara, Eritrea. Data were collected from 64 herds, randomly selected from a total of 99 herds with a minimum herd size of 9 cows. A questionnaire was used to gather data on management, hygiene and herd structure. Serum samples collected from all pregnant heifers, cows and bulls, were screened for Brucella infection by the Rose Bengal test (RBT), and all RBT-positive sera re-tested with the complement-fixation test (CFT) for confirmation. A seropositive herd was defined as one in which at least one animal tested positive in the CFT. There were 23 (36%) positive herds among the 64 studied. Both multiple logistic and multiple betabinomial regression modeling were used to analyze the data. Mixed-breed herds, compared to single (exotic)-breed herds, were found to be independently associated with increased herd seroprevalence (OR=5.2, 95% confidence interval 1.4–18.7) in the multiple logistic model with the herd infection status as the dependent variable. The importance of this variable was supported by the multiple betabinomial regression model (OR=3.3, 1.4–7.6) with animal-level prevalence within herd as the outcome variable. Both models also revealed the presence of a negative association between seropositivity and cattle stocking density. 相似文献
4.
An extensive questionnaire was developed and used to collect data from 33 herds that were on the New York State Paratuberculosis Control Program, to study farm factors associated with the presence of Mycobacterium paratuberculosis infection in dairy herds. The results of the last whole herd paratuberculosis fecal culture were used to indicate presence of infection in a herd, with herds having one or more animals positive classified as ‘infected’. The average prevalence within herds was 5.2%. Fourteen herds were uninfected and 19 herds had prevalences ranging from 0.7%–28.2%. Data on 31 continuous and 67 categorical risk factors were collected by questionnaire. Ten factors were significantly associated with prevalence risk of infection in the univariable logistic regression. These factors were: the type of farm operation (commercial/registered or both); earlier diagnosis of the disease before entering the control program; number of clinical cases in the previous year; whether clinical cases were raised or purchased animals; typical signs in clinical cases; exposure of calves 0–6 weeks of age to feces of adult cows; contact of young stock with adult animal feces from using the same equipment to clean the housing for both groups of animals; spreading feces on fields from which forage is later harvested and fed to animals of any age group; what is done with animals that are suspected of having paratuberculosis or test positive on culture; and frequency of cleaning the cow barn. Stepwise logistic regression was used to determine the significance of each risk factor while controlling simultaneously for the effect of other factors. The significant factors were the type of farm operation, clinical signs, and exposure of calves to feces of adult cows. Commercial herds, presence of clinical signs typical of paratuberculosis in animals, and exposure of calves 0–6 weeks old to feces of adult cows all indicate a higher likelihood that a herd is infected with M. paratuberculosis. 相似文献
5.
Our objectives were to estimate the seroprevalence of Brucella melitensis, and to identify some risk factors associated with goat seropositivity in Michoacan, Mexico. Blood samples were collected from 5114 animals from 79 herds. Sera were tested for antibodies against B. melitensis using the Rose Bengal plate test and the complement-fixation test. Information regarding the herds and each animal sampled were recorded through a personal interview at the farm. We used random-effects multivariable logistic regression to analyze our data. Fifty-six herds of the 79 tested had at least one seropositive animal. The animal-level true seroprevalence was 9.8% (CI = 8.8, 10.7). Animals in large herds (>34 animals), in herds with high stock density (>3.5 animals/m 2) or animals >24 months old had higher odds of seropositivity (2.0, 1.7 and 1.8, respectively) than those in small herds, in herds with low stock density or animals ≤24 months old. 相似文献
6.
An epidemiological study was conducted in Orne (France) on randomly selected dairy herds (42 herds including 1,924 cows and heifers, which were at least 15 months old). The aim was primarily to estimate the seroprevalence of Neospora caninum infection from two blood samples per cow, using an enzyme-linked immunosorbent assay (ELISA) for N. caninum (one positive result indicating infection). The second aim was to test the association between some individual and herd factors and N. caninum seropositivity with a logistic model including a random term effect. The prevalence was estimated at 5.6% (107 seropositive animals). At least 27 of the 42 herds had one seropositive cow or heifer. The intra-herd seroprevalence varied from 1.1 to 8% for 18 positive herds (66.7%). Dogs were present in 36 farms and 104 of the 107 seropositive animals were exposed to them. The factors associated with individual seropositivity were the presence of cats (OR = 0.17; P < 0.001), dogs (OR = 4.35; P = 0.02), rabbits and/or ducks (OR = 2.10; P = 0.04), long calving periods (12 months) (OR = 0.44; P = 0.007), tethered housing (OR = 2.50; P = 0.01), somatic cell counts (200-400 x 10(3) cells/mL) (OR = 0.24; P < 0.001) and pond water supply (OR = 2.43; P = 0.04). In conclusion, the animal and intra-herd seroprevalences were low in dairy cows from Normandy, France. 相似文献
7.
The prevalence and distribution of seropositivity towards the protozoan parasite Neospora caninum were studied in single blood samples from 1561 cows from 31 Danish dairy herds. Blood samples were analysed by an indirect enzyme-linked immunoassay and an indirect fluorescent-antibody test. Seroprevalence in 15 herds with previous abortions assigned to neosporosis ranged from 1% to 58%, with a mean frequency of 22%. In eight out of 16 herds without a history of N. caninum related abortions, no seroreactors were found. In the remaining eight herds, the seroprevalence ranged from 6% to 59%. The prevalence and distribution of seropositivity, gestation number prior to sampling, and breed were related to abortions and perinatal deaths using a random-effects logistic-regression model. Abortion risk was significantly increased in seropositive animals (OR=3) and in 2nd-gestation cows (OR=3). Perinatal death was significantly influenced by gestation number and breed, but not by serostatus. Reproductive performance and culling risk of cows were not affected by serostatus. Seropositivity increased with “age” (i.e. gestation number) ( P=0.02). In open cows, seropositivity tended to decrease with distance from calving ( P=0.05). The proportion of seropositive pregnant cows increased with trimester ( P=0.02). 相似文献
8.
After encountering antigen, dendritic cells (DC) must differentiate into a fully mature phenotype to induce a protective, lasting T cell immunity. Paratuberculosis is a disease caused by the intracellular pathogen Mycobacterium avium subspecies paratuberculosis ( M. paratuberculosis) and is characterized by a transient cell mediated immune response, that when dissipates correlates to the onset of clinical disease. In order to study the mechanism of early cellular immunity associated with M. paratuberculosis infection, we tested the hypothesis that M. paratuberculosis infected bovine DC have impaired activation and maturation thus are defective in the initiation of a sustainable and protective Th1 immune response locally. Our results demonstrate that M. paratuberculosis infected DC showed decreased endocytosis of ovalbumin, indicating some functional maturation. Co-stimulatory molecules CD40 and CD80 mRNA expression from M. paratuberculosis infected DC was increased over untreated immature DC. M. paratuberculosis infection induced chemokine receptor CCR7 increase in DC, yet CCR5 remained high. MHC II surface expression remained low on M. paratuberculosis infected DC. M. paratuberculosis infection inhibited pro-inflammatory cytokine IL-12 production and promoted IL-10 secretion by bovine DC. Together, our findings showed evidence of phenotypic and functional maturation of DC. However, we did not see the expected antigen presentation via MHC II and cytokine responses as a fully mature DC. This may suggest semi-mature DC phenotype induced by M. paratuberculosis infection. 相似文献
9.
A cross-sectional study was carried out to determine the seroprevalence and to identify risk factors associated with bovine
viral diarrhea virus (BVDV) infection in 62 non-vaccinated dairy herds (671 cows) in Jordan between January and June 2007.
Information regarding herd management was recorded through a personal interview with farmers. Antibodies against BVDV were
detected using an indirect ELISA test. Chi-square analysis and multivariable logistic regression model were used to identify
risk factors for BVDV seropositivity. The true prevalence of antibodies against BVDV in individual cows and cattle herds was
31.6% and 80.7%, respectively. The seroprevalence of BVDV in medium and large size herds was significantly higher than that
in smaller herds. There was no significant difference in BVD seroprevalence between different age groups. Random-effects logistic
regression model revealed two major factors associated with seropositivity to BVDV; exchange of visits between adjacent farm
workers and not isolating newly purchased animals before addition to the herd. The seroprevalence of BVDV in cows located
in the northern Jordanian governorates was significantly higher than that in other studied governorates. Results of this study
indicated that BVDV is highly prevalent in Jordan and BVDV infection could be controlled by livestock-trade control, and applying
strict biosecurity measures in the dairy farms. 相似文献
10.
A case–control study involving 255 small ruminants herds randomly selected was carried out in Portugal between January and December 2004, to identify risk factors associated with brucellosis seropositivity. To achieve this objective, two groups of herds selected according their prevalence status were compared: “cases” (farms with seroprevalence higher than 5%, n = 123) and “controls” (farms seronegatives, n = 132). A carefully structured questionnaire was used to collect data from each herd. A statistical analysis to compare “case” versus “control” herds was performed with the variables obtained from the questionnaire and the seroprevalence results. The effects on seroprevalence of several variables such as: individual characteristics; farm management practices; farm characteristics; animal health; knowledge and characteristics of farmers were evaluated. Data were analysed using logistic regression. Univariable analysis was used to screen the variables used in the logistic regression model. Nine variables were associated with brucellosis seropositivity in univariable analysis p < 0.10. These variables were retained for multivariable logistic regression model. Regression model identified five variables as risk factors for seropositivity. The odds of brucellosis were increased: herds with more than 116 animals (OR = 2.99); in herds with no cleaned-watering places (OR = 3.05); in herds with insufficient manure removal and insufficient cleaning of premises (OR = 2.87); in introduction of animals from non-free brucellosis herds or from herds of unknown status (OR = 12.11). In the other hand, farmers’ age (the eldest) was related to decreased odds (OR = 0.4). Potential risk factors identified in this study were consistent factors associated with brucellosis seropositivity and support current recommendations for the control of brucellosis. Considering the paucity of epidemiological reports on brucellosis in the Northeast of Portugal and the absence of any data concerning factors related to either the prevention or the spread of the disease, our results could make a useful contribution towards the prevention of small ruminants brucellosis in the area. 相似文献
11.
Multiple logistic regression was used on serological data collected in the context of the Sardinian African swine fever (ASF) eradication program from pig farms in the province of Nuoro, Sardinia. The monthly percentage of ASFV-positive herds decreased significantly from October 1994 through March 1996 ( P < 0.001). The farm-level risk of seropositivity to African swine fever virus (ASFV) was higher in free-range farms than in partial-confinement farms (odds ratios (OR) varied between 4.9 in October 1994, and 5.7 in March 1996, P < 0.001). The risk of infection for total-confinement farms was one-fifth of the risk for partial-confinement farms in October 1994 (OR = 0.2, P < 0.001), whereas in March 1996, the estimated OR was 0.57 and not significant (upper confidence limit = 1.1). The maintenance of ASFV in Sardinia was primarily associated with free-range pig farms. The natural logarithm of the number of pigs tested per visit in a farm was positively associated with the risk of herd seropositivity (OR = 2.6, P < 0.001). 相似文献
12.
The main objective of this cross-sectional study was to estimate the seroprevalence of infectious bovine rhinotracheitis (IBR) in a population of non-vaccinated beef cattle in the livestock region of Yucatan, Mexico and to determine potential risk factors related to the seroprevalence. Also, we estimated the intraherd correlation ( re) and design effect ( D) of IBR seropositivity. Cattle were selected by two-stage cluster sampling. Blood samples were collected from 564 animals from 35 herds. Sera were tested for antibodies against IBR using the serum-neutralisation test. Information regarding the herd and each animal sampled were recorded through a personal interview with the farmer or farm manager. The data were analysed using fixed-effects logistic multiple regression. Thirty-four of the 35 herds had at least one seropositive animal. The animal true seroprevalence was 54.4%. Animals in large herds or in production had higher odds of seropositivity than those in small herds or growing. The re and D were 0.17 and 3.62, respectively. 相似文献
13.
A survey of bovine viral diarrhoea virus (BVDV) infection was carried out from June 2001 to July 2002 in a non-vaccinated beef cattle population from the livestock region of Yucatan, Mexico, to assess seroprevalence and identify risk factors related to seroprevalence. The aim was also to estimate the intra-herd correlation ( re) and design effect ( D) of BVDV seropositivity. Cattle were selected by a two-stage cluster sampling. Blood samples were collected from 560 animals originating from 40 herds. Sera were tested for antibodies against BVDV using an indirect ELISA test. The sensitivity and specificity of the test was 97.9 and 99.7%, respectively. Risk factors regarding the herd and each animal sampled were recorded through a personal interview at the time of blood sampling. Twenty-four of the 40 herds had at least one seropositive animal. The animal true seroprevalence was estimated as 14%. The marginal logistic regression model used to describe the data found a significant ( p < 0.05) association of herd size–cow-origin interaction. The interaction was due to a higher risk of seropositivity in the category of herds with ≤100 animals and purchased cows (OR = 1) as compared to herds with ≤100 animals and cows born in the farm (OR = 0.23). Seropositivity between cows purchased and cows born in the farm was similar for herd sizes of 101–196 and >196 animals. The re and D values were 0.17 ± 0.05 and 3.16 ± 0.57, respectively. 相似文献
14.
An experimental oral infection of goats with a caprine isolate of Mycobacterium a. subsp. paratuberculosis was used to investigate immunological and bacteriological events during the subclinical phase of infection. Seven goats at 5–8 weeks of age were given a bacterial suspension in milk-replacement three times weekly for 9 weeks. Six animals were kept as controls. Cellular recall responses against M. a. paratuberculosis were analysed by means of a lymphocyte proliferation test, an IFN-γ assay and an IL-2 receptor assay. All inoculated animals had detectable CMI responses from 9 weeks post-inoculation and through the 2 years of study, although the responses were highest during the first year. Antibodies against M. a. paratuberculosis could be detected from weeks 15–20 in four of the seven animals, and one additional animal became antibody positive at week 35, while two inoculated animals did not produce significant antibody titres during the experiment. At about 1-year post-inoculation, two animals became faecal shedders, while two others started to excrete bacteria into faeces about 2 years post-inoculation. The appearance of M. a. paratuberculosis in faeces was not associated with a decline in cellular responses as far as could be assessed using the current methods for measuring CMI. Pathological lesions due to M. a. paratuberculosis infection and presence of bacteria were recorded in the intestine and/or mesenteric lymph nodes of five animals while lymph node changes suggestive of paratuberculosis were observed in one animal. Only the two animals with no signs of an active infection at necropsy showed a considerable decline in the cellular parameters during the last year of the study, particularly in the IFN-γ assay. The two animals with the highest levels of M. a. paratuberculosis responsive CD8+ lymphocytes in the circulation about 1-year post-inoculation had no detectable lesions in the distal ileum and colon at necropsy, while high numbers of γδ T-cells responsive to M. a. paratuberculosis in the circulation were associated with disseminated lesions in the distal ileum and colon. 相似文献
15.
Chronic pleuritis (CP) in Danish pigs for slaughter is by far the most frequent finding at the routine post-mortem meat inspection. An initial investigation published in 1990 demonstrated infectious and management-related risk factors. Serological testing for additional infectious agents, as well as the need to consider the effect of disease clustering at the herd level, required a re-analysis of the data. Our re-analysis used a representative sample of 4800 pigs originating from 623 Danish herds. Each pig was examined for the presence of CP and progressive atrophic rhinitis (PAR). The gender of the pig, the weight of the carcass, and the herd of origin were also recorded. Individual blood samples were examined for seropositivity for Actinobacillus pleuropneumoniae (AP) serotypes 2, 6, 7, 12, Haemophilus parasuis, Mycoplasma hyopneumoniae (MYC) and swine influenza (SI). Herd-level information retrieved through a questionnaire included health status, production type, herd size (i.e. pigs per year) and vaccination procedures. Associations between CP and infectious, individual and herd-related factors were investigated by logistic regression with random effects. Among pigs from herds with conventional health status, seropositivity for AP serotypes 2 and 6, and MYC had odds ratios (ORs) of CP of 9.0, 1.6 and 1.8, respectively. Neither seropositivity for AP serotype 7 nor SI were associated with CP by themselves, but interacted: OR of CP of 5.3 (1.8) when present at the same time among pigs exhibiting (not exhibiting) PAR. An association of PAR with CP was found, and PAR interacted with AP serotype 7: OR=10.0 (4.3) when both factors were present among pigs exposed (non-exposed) to SI. The OR (0.97) for an increase of carcass weight by 1 kg was negligible. In pigs from specific pathogen-free (SPF) herds, seropositivity for MYC and herd size were associated with CP. Moreover, for a herd size of 1000 pigs, CP was associated with exposure to MYC by an OR of 3.3 (decreasing to 1.9 when the herd size was increased by 1000). Farrow-to-finish as opposed to finishing herd had an OR of CP of 3.2. In conventional herds, seropositivity for AP serotype 2 and MYC were associated with 51% and 29% of the occurrence of CP. In SPF herds, farrow-to-finish as opposed to finishing herds was associated with 47% of the occurrence of CP. Seropositivity for MYC was associated with 33% (39%) of the occurrence of CP in herds with a size > (≤) 1500 pigs. 相似文献
16.
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
17.
The association of herd characteristics and intervention strategies with time under quarantine was evaluated for 163 farrow-to-finish swine herds enrolled in the voluntary phase (1986–1987) of the pseudorabies virus (PRV) eradication program in the state of Illinois (USA). Vaccination was the intervention strategy used most widely (69% of herds), particularly in larger herds. Depopulation was used primarily when PRV seroprevalence was high, and test-and-removal when seroprevalence was low. Approximately 50% of the herds were released from quarantine within 3 years of developing a herd clean-up plan. Multiple regression analysis using the Cox proportional hazards model indicated the following. Vaccination had a strong association with a longer time until release from quarantine (P<0.001). This is attributed to the lack of a vaccine differential test during this time, which made diagnosis of natural infection more difficult. Offspring segragation was associated with a longer time under quarantine (all herds: P=0.05; non-vaccinated herds: P=0.004). Delay in implementation of a herd clean-up plan was also associated with longer time under quarantine (all herds: P=0.012; non-vaccinated herds: P<0.001). Herds with higher seroprevalence at the time of agreement to a herd plan required a longer time under quarantine (all herds: P<0.001). This result was apparent for non-vaccinated herds (P=0.001), and thus is not merely a consequence of vaccination. Herds in areas with a high geographic density of quarantined herds required a longer time before release from quarantine (all herds: P=0.003), although this trend was not apparent for non-vaccinated herds (P=0.39). After taking PRV seroprevalence into account, there was no apparent association of time under quarantine with sow herd size (all herds: P=0.057; non-vaccinated herds: P=0.81) or confinement housing (all herds: P=0.19; non-vaccinated herds: P=0.91). 相似文献
18.
As a part of a research-and-action partnership between public health and veterinary medicine, the relationships between the seroprevalences of brucellosis and Q-fever in humans and livestock were evaluated in three nomadic communities of Chad (Fulani cattle breeders, and Arab camel and cattle breeders). Nomad camps were visited between April 1999 and April 2000. A total of 860 human and 1637 animal sera were tested for antibodies against Brucella spp., and 368 human and 613 animal sera for Coxiella burnetii. The same indirect ELISA was used for livestock and human sera, and the test characteristics for its use on human sera were evaluated. Twenty-eight people were seropositive for brucellosis (seroprevalence 3.8%). Brucella seroprevalence was higher in cattle (7%) than other livestock, and brucellosis seropositivity was a significant factor for abortion in cattle (OR=2.8). No correlation was found between human brucellosis serostatus and camp proportions of seropositive animals. Q-fever-seropositive blood samples were taken from 11 Arab camel and 4 Arab cattle breeders (seroprevalence 1%). Being a camel breeder was associated with Q-fever seropositivity in humans (OR=9). Camels had the highest Q-fever seroprevalence (80%) among livestock species. Although there was high-risk human behaviour for the acquisition of brucellosis and Q-fever from livestock through raw-milk consumption (98%) and contact with placentas of livestock (62%), we concluded that seroprevalences in humans were relatively low (likely due to limited active foci in livestock). 相似文献
19.
OBJECTIVE: To determine the association between soil type and paratuberculosis in cattle. SAMPLE POPULATION: Soil samples and test results for paratuberculosis in 92 Indiana cattle herds. PROCEDURE: Testing records from herds in which > or = 20 cattle were tested for paratuberculosis by use of an ELISA between 1998 and 2002 were identified. Soil type was characterized on the basis of herd location. Clusters of herds with seroprevalence greater than the median seroprevalence were identified. Association between clusters and soil types was estimated by logistic regression, adjusted for herd type (dairy or beef). RESULTS: A spatial cluster of greater than the median seroprevalence was identified in northeast Indiana. Soils with low silt content were associated (odds ratio [OR], 7.2; 95% confidence interval [CI], 2.1 to 24.5) with this cluster. Adjusting for herd type did not substantially alter this association (OR, 6.7). Herds located in areas with sandy loam (OR, 6.2; 95% CI, 1.4 to 27.4) and loam (OR, 3.6; 95% CI, 1.0 to 13.2) soils were also more likely to be within the cluster of greater than the median seroprevalence. Herds located in areas of silt loam soils were less likely (OR, 0.2; 95% CI, 0.1 to 0.7) to be included in this cluster. CONCLUSIONS AND CLINICAL RELEVANCE: Spatial distribution of herds with greater than the median seroprevalence of paratuberculosis was associated with soil characteristics. Survival of Mycobacterium avium subsp paratuberculosis may be enhanced by silt or sand content in loamy soils. These results may be used to modify paratuberculosis control programs. 相似文献
20.
In this cross-sectional study, we assessed and mapped the seroprevalence of brucellosis in small-scale dairy farming in an urban and peri-urban area of Tajikistan and investigated factors associated with seropositivity. As urban and peri-urban farming is both an opportunity to improve the livelihood for small-scale farmers and a potential public health hazard, studies are warranted to reveal possible peculiarities in the epidemiology of brucellosis in this type of dairy farming. In total, 904 cows of breeding age belonging to 443 herds in 32 villages were serologically tested with indirect enzyme-linked immunosorbent assay (ELISA) and positive samples confirmed with competitive ELISA. Two logistic regression models were used to investigate an association between seropositivity and risk factors at herd and individual level. The herd and individual seroprevalences were 4.1 and 2.0 %, respectively. Herds with a history of abortions were found to be associated with seropositivity [odds ratio (OR)?=?5.3; 95 % confidence interval (CI), 1.3–21.3]. Large herds with more than eight cattle were more likely to be seropositive compared to smaller herds with one to two cattle (OR?=?13.9; 95 % CI, 1.6–119). The number of calves produced per cow (indicating age) was found to be associated with seropositivity. Younger cows with one to two produced calves were less likely to be seropositive compared to older cows with more than six produced calves (OR?=?0.24; 95 % CI, 0.06–1.0). Neither introduction of new cattle to the herd nor communal grazing was associated with seropositivity. This study shows that infection with Brucella (1) is present in small-scale urban and peri-urban dairy farming in Tajikistan and (2) has significant negative effects on reproductive performance in this farming system and (3) that some previously known risk factors for seropositivity in rural farming system were absent here. 相似文献
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