Epidemiología de la brucelosis caprina y ovina en la provincia de Formosa, Argentina / Epidemiology of caprine and ovine brucellosis in Formosa province, Argentina

Se realizó un estudio epidemiológico de brucelosis en 516 majadas caprinas o mixtas (caprinos/ovinos) de las 3 regiones agroecológicas de la provincia de Formosa, Argentina. Mediante las pruebas de aglutinación en placa con antígeno tamponado y de fijación del complemento en suero se estudiaron un total de 25.401 caprinos y 2.453 ovinos. Además, se realizaron cultivos bacteriológicos y PCR en muestras de leche de cabras de 3 majadas con brucelosis y abortos recientes. Se detectó brucelosis en 4 de los 9 departamentos de la provincia, la prevalencia global fue del 2 % y la intrapredial varió entre el 1 y el 40%. La proporción de majadas positivas fue del 3,6, el 12 y el 36 % para las regiones este, centro y oeste, respectivamente. Se aisló Brucella melitensis bv. 1 de cabras por primera vez en la provincia. La PCR amplificó fragmentos esperados de 827 pb correspondiente al gen omp2ab (Brucella spp.) y de 731 pb correspondiente al inserto IS711 (B. melitensis). La detección de anticuerpos en ovinos que cohabitan con caprinos sugiere que las infecciones habrían sido causadas por B. melitensis, lo que constituye un riesgo adicional para la salud pública. Los programas de control y erradicación de la brucelosis deberían considerar las majadas mixtas como una sola unidad epidemiológica. Los resultados indican que la brucelosis por B. melitensis bv. 1 es altamente endémica en las regiones centro y oeste de la provincia de Formosa.

An epidemiological study of brucellosis was carried out in 516 goats and mixed flocks (goat/sheep) from the three agro-ecological regions of Formosa province, Argentina. Serum samples from a total of 25401 goats and 2453 sheeps were analyzed using buffered plate agglutination test (BPAT) and complement fixation test (CFT). Bacteriological and PCR analyses on milk samples from goats in three flocks with a history of brucellosis and recent abortions were also performed. Brucellosis was detected in four of the nine departments of the province with an overall prevalence of 2 % and an intra-flock prevalence ranging between 1 % and 40 %. The proportion of infected flocks was 3.6 %, 12 % and 36 % for the eastern, central and western regions, respectively. Brucella melitensis bv. 1 was isolated efrom goats for the first time in the province. The expected fragments of 827 bp from the omp2ab gene (Brucella spp.) and 731 bp from the insert IS711 (B. melitensis) were amplified by PCR. Detection of antibodies by BPAT and FCT in sheep cohabiting with goats suggests that infections could have been caused by B. melitensis, posing an additional risk to public health. Control and eradication programs for brucellosis should consider mixed flocks as a single epidemiological unit. The results indicate that brucellosis by B. melitensis bv1 is highly endemic in the central and western regions of Formosa province.

Serum Levels of Interferon Gamma in Patients with Brucellosis in a Saudi Hospital.

Background: Brucellosis is a major zoonotic disease that is endemic in Saudi Arabia and it remains a major health problem that has not been eradicated in the country yet. Place and Duration of Study: This retrospective study was conducted in a Saudi Hospital at Al Madinah city during the period of 1 November, 2010 to 31 October, 2011. Methodology: All sera of patients suspected to have brucellosis (n= 65) and 18 healthy subjects were tested for brucella antibody using slide latex agglutination (SAT) and ELISA. Quantitation of IFN-ɣ was also done using ELISA. Results: Brucellosis was detected in all age groups but the incidence was higher and reached 33.3% in age group (40- <50) years with average of 43.9±2.53 years. Male to female ratio in infected patients was 2:1 by using SAT. The incidence of seropositive cases was high (80.1%) in the three months (April, May and June), with the highest peak in May (46.7%). Drinking raw milk was the most encountered risk factor with a prevalence of 66.1% followed by consumption of milk products (11.9%). The most prevalent species among the examined cases was B. melitensis (93.3%). Among the studied cases, 60 cases (92.3%) were serologically positive for brucellosis by SAT. Among the 60 cases yielding significant titers against brucella, 14 sera (23.3%) had agglutinin levels of 1:80, 34 sera (56.7%) had titers of 1:160 and 12 sera (20%) had titers of 1:320. By estimating IgM and IgG levels in the sera of examined cases using ELISA, 52 cases (80%) had brucellaIgM while 42 cases (64.6%) had brucella IgG. Sensitivities of SAT, IgM ELISA and IgG ELISA were 91.5%, 88.1% and 71.2%, respectively compared with combined ELISA. Mean IFN-ɣ levels ± SD in the subacute phase was 136.7±70.07pg/ml, 120.2±54.25pg/ml in the acute phase, and 121.3±51.09 pg/ml in the chronic phase of brucellosis. Conclusion: The sensitivity and specificity of ELISA to diagnose human brucellosis was higher when combined ELISA (IgM/IgG or both) was used. Mean IFN-ɣ levels were lower, but not significantly, in the chronic phase of the disease than in the sub acute phase and healthy subjects.

Sero-diagnostic efficacy of antigens prepared from B. abortus and B.melitensis used for agglutination tests and IELISA

In this study, 120 bovine and ovine serum samples were collected and tested for brucellosis with Rose Bengal test [RBT], modified Rose Bengal test [mRBT], buffered acidified plate test [BAPT] using conventional Rose Bengal antigen [RBA] and buffered acidified plate antigen [BAPA] and antigens prepared from B. melitensis [the main cause of brucellosis in Egypt] strain 16-M. Indirect ELISA was used for testing the same serum samples using 4 different coating antigens which were S-LPS and OMP antigens prepared from 16-M strain and S-LPS and OMP prepared from S19 strain. There were some differences between the results of conventional Rose Bengal and BAPA antigens prepared from B. melitensis 16-M strain. In the same time, there were no characteristic differences in results of Indirect ELISA

Fenómeno de Weisser-Wechsberg (inhibición de la bacteriólisis): II. Inmunoglobulinas (IgG) de recién nacidos compiten con anticuerpos bactericidas del suero humano inmune a nivel del núcleo del lipopolisacárido (LPS-f5) de Brucella melitensis / Weisser-Wachsberg phenomenon (bactericidal inhibition): II. Newborn's immunoglobulins (IgG) compete with human immune serum's bactericide antibodies to level of lipopolysaccharide nucleus (LPS-f5) of Brucella melitensis

Introducción. El modelo de Brucellas melitensis lisa patólogena muestra que las inmunoglobulinas (IgG) de recién nacidos producen una inhibición de la bacteriólisis. No se sabe cual es la molécula implicada. Material y métodos. Por medio de liposomas se insertó lipopolisacárido (LPS) purificado de B. melitensis lisa patógena fracción 5 (LPS-f5). Se utilizó inmunotrasferencia en papel de nitrocelulosa para identificación del LPS-f5 por anticuerpos naturales e inmunes. Una prueba de bacteriólisis en cepas de B. melitensis M15 rugosa exenta de cadena lateral sirvió como modelo de inhibición al incubarse con IgG de recién nacidos y suero inmune. Resultados. Las IgG de recién nacidos remedan la bacteriólisis en un modelo liposomal. En la inmunotransferencia en papel de nitrocelulosa reconocen el núcleo de la molécula del LPS-f5 y producen inhibición de la bacteriólisis en la bacteria exenta de cadena lateral del PLS. Conclusiones. El núcleo del LPS en B. melitensis está implicado en el fenómeno de inhibición de la bacteriólisis por anticuerpos naturales

Vacuna fenol-insoluble contra la brucelosis humana: evaluacion del poder inmunogenico en cobayos / Phenol-insoluble vaccine against human brucellosis: evaluation of the immunogenic power in guinea pigs

Se examino una vacuna diseñada para inmunizar al hombre, preparada con extracto de fenol insoluble, para determinar si protegia a cobayos contra el desafio con la cepa virulenta B. abortus 2308. Se incluyeron en el experimento las vacunas vivas atenuadas B. abortus cepa 19 y B. melitensis Rev. 1, para comparar los resultados. Se vacunaron 93 animales en cada grupo, que fueron subdivididos en subgrupos de 31 y se los desafio con '10 POT. 4', '10 POT. 3' Y '10 POT. 2' unidades formadoras de colonias de la cepa B. abortus 2308 virulenta. El analisis global de los resultados demostro una proteccion del 11.9 por ciento en animales vacunados con el extracto de fenol insoluble, 65 por ciento en los vacunados con B. abortus cepa 19 y 95 por ciento en el grupo que recibio vacuna B. melitensis Rev. 1.