RESUMEN
BACKGROUND: In Argentina, vaccination with Brucella abortus Strain 19 vaccine is mandatory. The objective of the study was to develop and test a method for evaluating, in an innovative way, some farmers' and veterinarians' management practices in relation to brucellosis and to assess the vaccination campaign and coverage. The work took place in Brandsen and Navarro districts. Four questionnaires were designed (for officials from Local Sanitary Entities, vaccinators, vet practitioners and farmers). Responses were coded as "ideal" (0) and "not ideal" (1). To assess the relative weight of each question ("item"), experts ranked the items according to their impact on management practices and vaccination. A weighted score was then calculated. A higher weighted score was assigned to the worse practices. Farmers obtaining a global weighted score above the third quartile were classified as "inappropriately managed farms", to be compared per type of production system and district. To assess the immunization coverage, female calves were sampled 30 to 50 days post vaccination; they were expected to react positively to serological diagnostic tests (DT+). RESULTS: There were significantly more inappropriately managed farms and higher global scores among beef farmers and in Brandsen. Eighty three percent (83%) of female calves were DT+, significantly under the ideal immunization coverage (95%). Only 48% of farms were considered well vaccinated. DT+ results were positively associated with the Brandsen district (OR = 25.94 [4.60-1146.21] and with the farms having more than 200 cow heads ((OR = 78.34 [4.09-1500.00]). On the contrary, DT+ were less associated with vaccinators being veterinary practitioners (OR = 0.07 [0.006-0.78]). Farmers are well advised by their veterinary practitioners but they should improve some management practices. CONCLUSIONS: The vaccination campaign is globally well implemented, but the immunization coverage and some vaccinators' practices should be improved. This study leads to a better understanding of the most common used management and control practices regarding brucellosis, which affect its epidemiology. Any vaccination campaign should be periodically assessed to highlight possible fails. The described methodology can be extrapolated to other countries and different contexts.
Asunto(s)
Vacunas Bacterianas/inmunología , Brucelosis Bovina/prevención & control , Programas de Inmunización , Vacunación/legislación & jurisprudencia , Animales , Argentina/epidemiología , Brucella abortus/inmunología , Brucelosis Bovina/epidemiología , Bovinos , HumanosRESUMEN
Bovine brucellosis is a zoonotic disease spread worldwide. The infection in cattle is predominantly caused by Brucella abortus and is usually detected in pregnant females through abortions. The disease is endemic in Argentina; however, infection in humans is underestimated and often not reported. The prevalence of bovine brucellosis in countries bordering Argentina is quite variable: 0.04% in Uruguay, 10.20% in the north and 0.06% in the south of Brazil, 0.2% in Chile, 3.15% in Paraguay and 2.27% in Bolivia. In 1999, the Argentine National Control and Eradication Program was implemented. Its strategies include identification of vaccinated animals, compulsory vaccination with B. abortus S19 of 100% of 3- to 8-month-old females, negative serological tests before animal movements and categorization of farms in terms of their brucellosis status. The epidemiological surveillance in milk is performed through the milk ring test and the indirect ELISA. The result of a national brucellosis survey performed in 2004 indicates that 12.4% (95% CI: 10.89-14.0) of Argentine beef farms are seropositive to Brucella and that the apparent prevalence in cattle is 2.10% (95% CI: 1.90-2.40). The official serological diagnostic tests are as follows: buffered plate antigen test, as screening, serum agglutination test, 2-mercaptoethanol and fluorescence polarization assay, competitive ELISA, as confirmatory tests, and complement fixation test, as definitive test. Santa Fe and a district in Córdoba have 'Outstanding Plans'. Tierra del Fuego is a 'Zone free from bovine brucellosis'. One question arising when studying the Argentine situation is why the disease remains endemic if good regulations exist to control and eradicate it. In future, some different aspects might be evaluated to understand it, and further studies should be performed to prioritize, select and refine control strategies.
Asunto(s)
Brucella abortus/aislamiento & purificación , Brucelosis Bovina/epidemiología , Animales , Argentina/epidemiología , Brucella abortus/inmunología , Brucelosis Bovina/microbiología , Bovinos , Ensayo de Inmunoadsorción Enzimática , Femenino , Leche/microbiología , PrevalenciaRESUMEN
Brucellaspecies are facultative, intracellular, Gram-negative bacteria with marked tropism for the pregnant reproductive tract of domestic animals. All Brucella species establish persistent infection in the reticuloendothelial system of their natural hosts. The mechanisms of placenta localisation, trophoblast tropism and abortion are poorly understood. A complete picture of the molecular determinants and mechanisms of the cell internalisation process began to emerge only recently. Cyclic beta-1,2-glucan is a molecule secreted into the periplasm of Brucella and is required for intracellular Brucella to avoid fusion of the phagosome with lysosomes. The type IV secretion system translocates Brucella effector proteins into host cells and is critical for both survival and replication of Brucella in infected host cells. Some aspects of the pathogenesis and pathobiology of brucellosis in productive domestic animals are discussed in this section.
Asunto(s)
Brucelosis/veterinaria , Rumiantes , Enfermedades de los Porcinos/microbiología , Animales , Brucelosis/patología , Femenino , Humanos , Embarazo , Porcinos , Enfermedades de los Porcinos/patología , ZoonosisRESUMEN
The study compared the performance of three screening serological tests: buffered plate antigen (BPA), Rose-Bengal produced with 1119-3 Brucella abortus strain (RB1119-3), and Rose-Bengal produced with 99 Brucella abortus strain (RB99). Sera from 696 adult female animals were submitted to BPA, RB1119-3, RB99, 2-mercaptoethanol test (ME), and complement fixation test (FC). The gold standard was the combination of CF and ME. The Kappa values for BPA, RB99, and RB1119-3 were 0.82, 0.74, and 0.70, respectively. The relative sensitivity and specificity for the same tests were 0.98 and 0.96, 0.92 and 0.94, and 0.95 and 0.92, respectively. These results indicate that BPA is a better screening test than RB for buffalo, regardless of the B. abortus strain in RB.
Asunto(s)
Animales , Femenino , Brucelosis Bovina/diagnóstico , Búfalos/inmunología , Pruebas Serológicas/métodos , Ensayos Analíticos de Alto Rendimiento/veterinaria , Pruebas Serológicas/veterinariaRESUMEN
One hundred and seven pregnant cows, which had been calfhood vaccinated with Brucella abortus strain 19 (S-19) were revaccinated with either S-19 or strain RB51 (S-RB51). All S-19-revaccinated animals seroconverted, while none of the RB51-revaccinated animals seroconverted. Two out of 25 (8%) S-19-revaccinated animals aborted, while none of the 57 RB51-revaccinated group aborted. Four of the S-19-revaccinated animals shed S-19 in the milk for at least 7 days, while only 1 cow shed S-RB51 for at least 3 days (but <7 days) post-parturition. Revaccination of strain 19 calfhood-vaccinated, pregnant cattle with S-RB51 appears to be a safe procedure with no diagnostically negative consequences.
Asunto(s)
Aborto Veterinario/prevención & control , Vacuna contra la Brucelosis/inmunología , Brucella abortus/inmunología , Brucelosis Bovina/prevención & control , Enfermedades de los Bovinos/prevención & control , Vacunación/veterinaria , Aborto Espontáneo/prevención & control , Animales , Anticuerpos Antibacterianos/sangre , Argentina , Vacuna contra la Brucelosis/efectos adversos , Vacuna contra la Brucelosis/clasificación , Brucella abortus/clasificación , Brucelosis Bovina/sangre , Brucelosis Bovina/inmunología , Bovinos , Enfermedades de los Bovinos/sangre , Enfermedades de los Bovinos/inmunología , Femenino , Embarazo , Vacunas Atenuadas/efectos adversos , Vacunas Atenuadas/inmunologíaAsunto(s)
Enfermedades de los Bovinos/inmunología , Ixodes , Infestaciones por Garrapatas/veterinaria , Animales , Formación de Anticuerpos , Bovinos , Enfermedades de los Bovinos/sangre , Larva , Recurrencia , Infestaciones por Garrapatas/sangre , Infestaciones por Garrapatas/inmunología , Factores de TiempoRESUMEN
Although several outbreaks of Brucella melitensis infection have been reported among laboratory workers or goat cheese consumers, outbreaks related to rural labour have been rarely studied. An outbreak of human brucellosis among farm workers of Argentina was studied and revealed a close relationship with an epidemic of caprine abortions which occurred shortly before on the same farm. High rates of B. melitensis infection were found among goats. Active brucellosis was diagnosed in 33 subjects (14 with positive blood culture for B. melitensis), while other 27 did not show evidence of illness. While 25 of the brucellosis active patients were rural workers, only 5 of the healthy subjects were engaged in rural labour. Active brucellosis was diagnosed in 91.3% of the subjects in continuous contact with goats and in 32% of those having an occasional contact with the animals. All the 60 subjects denied consumption of goat cheese or milk. As shown here, epidemic human infections by B. melitensis may develop among people frequently in contact with infected goat herds or goat manure.
Asunto(s)
Enfermedades de los Trabajadores Agrícolas/epidemiología , Brucella melitensis/fisiología , Brucelosis/epidemiología , Brotes de Enfermedades , Enfermedades de las Cabras/transmisión , Aborto Veterinario/microbiología , Pruebas de Aglutinación , Animales , Antibacterianos/uso terapéutico , Anticuerpos Antibacterianos/sangre , Argentina/epidemiología , Brucella melitensis/aislamiento & purificación , Brucelosis/tratamiento farmacológico , Brucelosis/transmisión , Calostro/microbiología , Ensayo de Inmunoadsorción Enzimática , Femenino , Enfermedades de las Cabras/epidemiología , Cabras , Humanos , Masculino , Leche/microbiología , Embarazo , Salud RuralRESUMEN
The ability of Brucella to infect and grow within extraplacentomal chorioallantoic explants (CAMs) derived from early and late gestational cattle was compared. Following inoculation of CAMs with equal numbers of strain 2308 B. abortus, the infectivity was approximately the same in CAMs from both ages, however, bacterial replication was significantly greater in late gestational CAMs than in early gestational CAMs. Co-culture of both early and late gestation CAMs or culture of both types of CAMs in the presence of tissue culture media collected from either early or late B. abortus inoculated CAMs failed to alter B. abortus growth rates and/or cytopathic effects.
Asunto(s)
Brucella abortus/patogenicidad , Brucelosis Bovina/microbiología , Membranas Extraembrionarias/microbiología , Animales , Bovinos , Técnicas de Cultivo , Femenino , Edad GestacionalRESUMEN
Bovine brucellosis is a major disease of cattle characterized by abortion during the last trimester of gestation. During many years important pieces of research have been done looking for a better understanding of this particular phenomenon. Yet, the fact that the abortion takes place in the last period of gestation result in a fascinating interrogant for such a unique event. The present review includes most of the information available regarding to this matter. Emphasis is done in the interaction of Brucella abortus with the trophoblastic cells of the bovine placenta.