RESUMO
OBJECTIVE: To compare prevalence estimates of brucellosis (BR) in adult beef cattle that originated from different states and regions of Mexico and that were shipped direct-to-slaughter into Texas during 1995. DESIGN: Epidemiologic survey. ANIMALS: About 65,000 adult beef cattle. PROCEDURE: Blood samples were collected during postmortem examinations and were tested for serum antibodies to Brucella abortus, using the particle concentration fluorescence immunoassay and automated complement-fixation test. Prevalence estimates and 95% confidence intervals of BR were calculated by state of origin in Mexico. The difference among prevalence estimates of BR in cattle from different states and regions was tested for significance (P < 0.05), using the proportion test. RESULTS: On the basis of serologic test results, the overall prevalence estimate of BR was 0.32%. The prevalence estimate of BR in cattle from the state of Chihuahua (0.10%) was significantly different than that in cattle from the states of Nuevo Leon (0.23%), Zacatecas (0.34%), Durango (0.47%), Chiapas (1.81%), Tamaulipas (2.71%), Aguascalientes (7.89%), and Campeche (12.24%). In addition, prevalence estimates of BR in cattle were significantly different among the northern (0.22%), south-central (3.18%), and south coastal (9.42%) regions of Mexico. CLINICAL IMPLICATIONS: Results of this study indicate that the number of cattle exposed to B abortus may be significantly different among states and regions of Mexico. Current import sanitary requirements should continue to mitigate potential risk of transmission of BR from sexually intact cattle of Mexican origin to Texas cattle.
Assuntos
Brucelose Bovina/epidemiologia , Matadouros , Animais , Anticorpos Antibacterianos/sangue , Brucella abortus/imunologia , Bovinos , Intervalos de Confiança , México/epidemiologia , Prevalência , Texas , Meios de TransporteRESUMO
OBJECTIVE: To evaluate differences in prevalence of tuberculosis (TB) in adult beef cattle that originated from different states in Mexico and were shipped direct-to-slaughter into Texas in 1995. DESIGN: Epidemiologic survey. ANIMALS: Approximately 65,000 adult beef cattle. PROCEDURES: Postmortem examinations of carcasses for detection of Mycobacterium bovis infection were conducted at slaughter plants in Texas. Specimens were collected from cattle with granulomatous lesions, stored in neutral-buffered 10% formalin or saturated sodium borate solution, and processed for histologic and bacteriologic diagnosis. Prevalence and 95% confidence intervals were estimated by state of origin. Difference between prevalences for different states was tested for significance (P < 0.05), using the proportion test. RESULTS: Overall prevalence of TB at slaughter in adult beef cattle that originated from Mexico was approximately 0.5/1,000 (34/65,233). Prevalence of TB in cattle that originated from Chihuahua (0.07) was significantly lower than that in cattle from Coahuila (0.80), Nuevo Leon (1.27), and Tamaulipas (1.81). CLINICAL IMPLICATIONS: Prevalence of M bovis infection in adult beef cattle may be significantly different between states in the northern border region of Mexico. On the basis of disease prevalence and numbers of exported cattle and provided safeguards such as TB testing are continued, cattle from Chihuahua may pose a lower risk of TB transmission to Texas cattle than do cattle from Coahuila, Nuevo Leon, and Tamaulipas. To allow interstate/international movement of cattle from northern border states of Mexico, TB testing requirements should be continued. In the context of international trade, southern border states of the United States should continue collaborating with northern border states of Mexico to control and eradicate this disease.
Assuntos
Tuberculose Bovina/epidemiologia , Matadouros , Animais , Bovinos , México/epidemiologia , Prevalência , Texas/epidemiologiaRESUMO
A case-control study was conducted in the Mexicali Valley to identify risk factors for goat-herd seropositivity for Brucella melitensis. Nineteen case herds (> or = 2 positive results with the 8% rose bengal plate test (RBT)) and 55 control herds (zero positive results in RBT), matched for herdsize and geographic location, were enrolled. Conditional logistic regression was used to construct a multivariable model of the odds of seropositivity using variables assessed in a questionnaire administered to goat ranchers. The final model for herd seropositivity included increased risk from importation of goats from other Mexican states, the presence of La Mancha breed does, and the presence of does born outside the herd. Increasing herdsize was also highly significant (p < 0.01). In addition, a significant (p < 0.05) positive association was found between the presence of seropositive dogs (as assessed by RBT) and seropositive goats on the same ranch.
Assuntos
Brucella melitensis , Brucelose/veterinária , Doenças das Cabras/epidemiologia , Animais , Brucelose/epidemiologia , Estudos de Casos e Controles , Cães , Feminino , Cabras , Modelos Logísticos , México/epidemiologia , Fatores de Risco , Estudos SoroepidemiológicosRESUMO
OBJECTIVE: To implement a disease monitoring system in federal, municipal, and private abattoirs in Baja California, Mexico and to estimate annual prevalence of tuberculosis (TB) in beef and dairy cattle slaughtered and inspected in 1995 and 1996. DESIGN: Epidemiologic survey. ANIMALS: About 200,000 cattle (95% beef, 5% dairy). PROCEDURES: Lymph node and tissue specimens with lesions suggestive of TB were fixed in neutral-buffered 10% formalin and embedded in paraffin. Sections were stained with H&E and Ziehl-Neelsen and examined for typical tuberculous lesions and acid-fast bacilli. Annual prevalence and 95% confidence intervals were estimated. RESULTS: Prevalence of TB in all slaughtered cattle was 0.12 and 0.46% in 1995 and 1996, respectively (beef cattle, 0.02 and 0.05%, respectively; dairy cattle, 2.0 and 8.3%, respectively). Tuberculosis cases/1,000 slaughtered cattle were linearly associated with monthly volumes of tissue submissions. CLINICAL IMPLICATIONS: It is critical to quantify the monitoring activity at abattoirs to better estimate the prevalence of TB in slaughtered cattle. Annual prevalence of TB was significantly greater in dairy cattle than in beef cattle. Veterinarians and cattle producers in this region are encouraged to develop and work on herd plans aimed at controlling and eradicating TB.
Assuntos
Matadouros/normas , Notificação de Doenças/normas , Tuberculose Bovina/diagnóstico , Matadouros/legislação & jurisprudência , Animais , Bovinos , Notificação de Doenças/legislação & jurisprudência , Feminino , Linfonodos/microbiologia , Linfonodos/patologia , Masculino , México/epidemiologia , Mycobacterium bovis/isolamento & purificação , Prevalência , Tuberculose Bovina/epidemiologia , Tuberculose Bovina/patologiaRESUMO
This retrospective study of papillomatous digital dermatitis (PDD) was performed using data for cows that calved between July 1993 and June 1994 on a Mexicali, Mexico, dairy farm in order to calculate incidence rates, and to compare milk yield and reproduction data between affected and nonaffected dairy cows. A total of 190 out of 577 (33%) cows were affected during lactation and six (1%) during the dry period. Fifty-two of 77 (68%) cows that had lesions in the previous lactation and were also present on the farm in the current lactation had lesions in the current lactation. The highest risk for PDD occurred during the first month of lactation (9%). The yearly estimated cumulative incidence risk was 35% and the incidence density rate was 44.6 cases per 1000 cow-months. More animals were affected in summer and fall than in winter and spring. Purchased animals were 3.4 times more likely to be affected than animals born on the farm. Survival analyses indicated healthy cows conceived 93 days after calving (median), but affected cows conceived 113 days after calving (median) (P < 0.01). PDD-affected animals produced less milk than healthy cows, but the difference was not statistically significant in the multiple regression.
Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/fisiopatologia , Dermatite/veterinária , Casco e Garras , Lactação/fisiologia , Reprodução/fisiologia , Animais , Bovinos , Dermatite/epidemiologia , Dermatite/fisiopatologia , Feminino , Doenças do Pé/epidemiologia , Doenças do Pé/fisiopatologia , Doenças do Pé/veterinária , Incidência , México/epidemiologia , Gravidez , Modelos de Riscos Proporcionais , Análise de Regressão , Estudos Retrospectivos , Fatores de Risco , Estações do Ano , Análise de SobrevidaRESUMO
An ELISA was compared with the plaque-reduction serum neutralization (PRSN) test, for detection of vesicular stomatitis virus (VSV) antibodies in cattle in a vesicular stomatitis enzootic region of Mexico. A total of 325 bovine serum samples were screened for VSV antibodies. The PRSN test was performed, using Vero cells. The ELISA contained gradient-purified VSV Indiana (Lab strain) and VSV New Jersey (Hazelhurst) as the antigens. Regression analysis and weighted kappa statistic were used to estimate measures of agreement between the 2 assays for detection of VSV antibodies. The ELISA method proved useful for serodiagnosis of vesicular stomatitis. The ELISA and PRSN test results were highly correlated for detection of VSV antibodies.