Unraveling swine hepatitis E in the central region of Argentina through ELISA development and epidemiological insights.

Hepatitis E virus (HEV) is a public health concern globally, causing acute viral hepatitis in humans. Genotype-3 HEV (HEV-3), the most frequently genotype detected in South America, is zoonotic and the main reservoirs are the domestic pig and wild boar. Circulation of HEV-3 in Argentina has been confirmed in humans as well as in pig herds, wild boar and environmental waters. However, data are scarce mainly due to the inaccessibility of serological assays in this country. In order to provide insights in the epidemiology of HEV in swine in Argentina, we developed an indirect ELISA based on the native recombinant protein ORF2 and conducted a serological survey to determine the prevalence of seropositive swine in small-scale pig farms in the central region of Argentina. The method was evaluated in a panel of 157 serum samples, resulting in relative sensitivity of 98.6 % (95 % CI 95 %-100 %) and relative specificity of 97.7 % (95 % CI 94 %-100 %) compared to a commercial test. An almost perfect agreement was obtained between the two tests (Kappa index of 0.961). A survey on 294 samples from 49 small-scale farms resulted in a seropositivity rate of 54 %. Seropositive animals were found in 34 out of 49 (69.4 %) farms. Most of the farms (70.6 %) had over 50 % of seropositive animals. The wide spreading of HEV in the swine population of Tandil, Argentina, underscore the need to better understand the epidemiology of HEV in the region, enabling the implementation of targeted interventions to mitigate the impact of this virus on public health.

Exploring hepatitis E virus seroprevalence and associated risk factors among the human population in Tandil, Buenos Aires, Argentina.

Background: Hepatitis E virus (HEV) infection is a common cause of acute clinical hepatitis worldwide and is emerging as a disease in Argentina. It is primarily transmitted through contaminated water and food, following the fecal-oral route. Furthermore, is a zoonotic disease with swine as the primary reservoir. Prevalence of HEV infection in humans in several regions of Argentina remains unknown. Objectives: (i) Determine the seroprevalence of HEV among the human population in Tandil, Buenos Aires, Argentina; (ii) Evaluate its association with demographic, socioeconomic and other risk exposures variables, and (iii) Describe and analyze spatial patterns related to HEV infection. Methods: From August 2020 to July 2021, serum samples were collected from 969 individuals aged 1-80 years. Seroprevalence and 95% Confidence Interval was determined. To assess the factors associated with the presence of anti-HEV antibodies, associations between the variables and seropositivity were evaluated through bivariate and multivariate analysis. Spatial scanning for clusters of positivity was carried out. Factors associated with these clusters were also assessed. Results: Anti-HEV antibodies were detected in 4.64% (IC 95% 3.27-6.02) of samples. Dark urine was associated with seropositivity (p = 0.02). Seropositivity was linked with the presence of natural water courses near their households (p = 0.02); the age (p = 0.04); and previous travel to Europe (p = 0.04). A spatial cluster of low rates of HEV seropositivity was detected, with greater distance of the households to water courses associated to the cluster, and male sex inversely associated to it. Discussion and conclusion: This study is the first study to investigate the prevalence of HEV in the population from Tandil, Buenos Aires, Argentina. Considering HEV infection in the differential diagnosis in individuals presenting acute hepatitis is highlighted. The incorporation of HEV testing into blood screening policies should be mandatory. Factors related to the infection and spatial patterns of high and low risk were determined, and should be considered when implementing specific preventive measures.

A multispecies competitive nanobody-based ELISA for the detection of antibodies against hepatitis E virus.

The hepatitis E virus (HEV) is an emergent zoonotic virus causing viral hepatitis worldwide. Clinically, hepatitis E is not easily distinguished from other types of acute viral hepatitis. There is a need for HEV diagnostic assays to detect and prevent interspecies transmission among susceptible populations. Nanobodies (Nbs) are expressed recombinantly in different systems, produced with high yields, and have superior physicochemical properties compared with conventional antibodies (Ab). Several Nbs against ORF2, the capsid protein and main antigen, were selected and produced in E. coli. Nb39 and Nb74 specifically recognized HEV ORF2 (genotypes 3 and 4). A competitive ELISA (cELISA) was developed and validated using a reference panel of human (n = 86) and swine sera (n = 116) tested in comparison with a commercial kit. The optimal cutoff values determined by ROC analysis were 69.16% (human) and 58.76% (swine); the sensitivity and specificity were high: 97.4% (95% CI 86.5-99.5%) and 95.8% (95% CI 86.0-98.8%) for human vs. 100% (95% CI 93.5-100%) and 98.3% (95% CI 91.0-99.7%) for swine. Further, the cELISA detected total anti-HEV antibodies in wild boar, deer, and mice. To our knowledge, this is the first report of production of Nbs against HEV-3 ORF2 for diagnostic purposes.

Parasitemia and Associated Immune Response in Pregnant and Non-Pregnant Beef Cows Naturally Infected With Neospora caninum.

The aim of this longitudinal study was to characterize the parasitemia of Neospora caninum and the associated immunological parameters in naturally infected beef cows for 10 months. The following groups were established: Neospora caninum seropositive pregnant cows (+Preg, n = 7), seropositive non-pregnant cows (+Npreg, n = 7), seronegative pregnant cows (-Preg, n = 4), and seronegative non-pregnant cows (-Npreg, n = 4). Several samples were obtained for absolute and relative leukocyte counting, cytokines IL-10, IL-12, α-TNF, and γ-IFN quantification, specific IgG, IgG1, and IgG2 and avidity and N. caninum DNA molecular detection and quantification. The +Preg group had a higher frequency and concentration of N. caninum DNA in PBMC in the last third of pregnancy compared to +Npreg (p <0.05), with 22 and 8% of detection, respectively. Parasitemia correlated positively with IgG titers and negatively with IgG1/IgG2 ratio (p <0.05). On day 222 of the assay, the +Preg group had the lowest total leukocyte counting (p <0.05). The +Preg group had a higher concentration of IgG and higher avidity in the last third of gestation compared to +Npreg (p <0.05). Avidity correlated with total IgG and IgG2 (p <0.05). All +Preg cows gave birth to clinically healthy but seropositive calves before colostrum intake, therefore, the congenital transmission was 100% efficient. Only a complete N. caninum genotype from a placenta and a partial genotype from cow #3 of the group +Preg were achieved by multilocus microsatellite analysis. Overall, N. caninum parasitemia is frequent in seropositive beef cows during the last third of gestation. This correlates with higher antibody levels and a decrease in total leukocyte counting. The precise timing of the parasitemia may be used for diagnosis purposes and/or for design strategies to avoid vertical transmission. Further studies are needed to identify the immune molecular mechanisms that favor parasitemia during gestation in chronically infected cattle.

Spray-drying-microencapsulated Minthostachys verticillata essential oil and limonene as innovative adjuvant strategy to bovine mastitis vaccines.

Design of innovative adjuvant strategies with an appropriate safety profile is relevant to developed subunit or inactivated microorganism vaccines for bovine mastitis. Minthostachys verticillata essential oil (EO) has demonstrated ability to stimulate the innate immune response and adjuvant effect similar to Al(OH)3. Here we evaluated the adjuvant effect of EO and its metabolite, limonene (L) alone and microencapsulated by spray-drying, using an inactivated Enterococcus faecium strain bovine-mastitis inducer. The gas chromatography-mass spectrometry analysis showed that microencapsulation process did not alter the EO or L chemistry. Microencapsulated EO (McEO) or L (McL) (2.0, 2.5 and 5.0 mg/ml) decreased the viability of bovine mammary gland epithelial cells in a dose-dependent way. Balb/c mice (n = 32) were subcutaneously inoculated (day 0) and revaccinated (day 14 and 28) with saline solution, inactivated bacteria alone or combined with Incomplete Freund's Adjuvant; EO or L (2.5 mg/ml); McEO or McL (5.0 mg/ml); or microcapsule wall material (Mc) alone (2.5 mg/ml). EO, L, McEO and McL stimulated E. faecium-specific IgG (IgG1 or IgG2a) with opsonizing capacity and increased the proportion of CD4+ and CD8+ T cells producers of IFN-γ. Microencapsulation was an effective strategy to increase the adjuvant potential of EO or L. These new adjuvants deserve further study to evaluate their incorporation into vaccines for bovine mastitis.

Leptospiral infection: a serosurvey in urban and rural communities in Olavarría county, Argentina.

INTRODUCTION: Leptospirosis is a neglected zoonotic disease, affecting mainly poor and vulnerable populations. METHODOLOGY: A cross sectional-study was carried out in 557 subjects from Olavarría county (Argentina) to estimate the seroprevalence of leptospirosis and the factors associated with seropositivity. A survey was carried out to obtain clinical and epidemiological data. Serum was tested for anti-leptospiral antibodies by Microscopic Agglutination Test (MAT). Chi-square or Fisher Exact tests were used to assess association between the MAT results and the exploratory variables. For the variables statistically associated, odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated. Individuals from Olavarría city were georeferenced to describe the spatial distribution and to detect clusters of seropositivity for leptospiral antibodies. RESULTS: The overall prevalence of leptospirosis infection was 7.00%, higher in rural (19.66%) than in urban populations (3.64%) (p < 0.001). Sejroe was the most predominant serogroup in rural communities while Icterohaemorrhagiae was the most prevalent in urban populations. The factors associated with Leptospira infection were the presence of rodents inside households (OR = 3.9) in rural populations, while contact with cats (OR = 4.97) and male gender (OR = 7.75) represented higher risk of infection for the urban ones. Cases with positive serology have been found near Tapalqué stream or in the peripheral areas of Olavarría city. CONCLUSIONS: The results from data obtained during the study period were similar to other reports and demonstrate the importance of continuous epidemiological surveillance system and specific community educational campaigns to prevent the leptospirosis infection in Olavarría county and other communities with similar characteristics especially in rural areas.

Evaluation of the efficacy of polymeric antigen BLSOmp31 formulated in a new cage-like particle adjuvant (ISPA) administered by parenteral or mucosal routes against Brucella ovis in BALB/c mice.

Brucella ovis is an economically important cause of epididymitis in rams worldwide. Polymeric BLSOmp31 was previously identified as a protective immunogen against this pathogen. In this study, BLSOmp31 was formulated with a modified version of ISCOMATRIX adjuvant called ISPA (BLSOmp31/ISPA) and was administered in BALB/C by the subcutaneous and ocular route. The systemic and mucosal immune responses, the opsonic activity of antibodies and the protection conferred against B. ovis were evaluated. BLSOmp31+ISPA injected subcutaneously or by ocular route induced significantly higher IgG antibody levels with a mixed Th1/Th2 profile compared to non-immunized mice. IgA and IgG were detected in sera and nasal, tracheobronchial, vaginal secretions, tears and faeces, from SC immunized mice while in the group immunized by the ocular route a slight increase in both isotypes was mainly observed in all secretions, except in vaginal fluid. Opsonic antibodies stimulated binding and increased uptake of PHrodo™ Green-labelled B. ovis by neutrophils and monocytes. BLSOmp31 administered subcutaneously induced the highest levels of IFN-É£. The ocular immunization not only produced significant levels of this cytokine but also IL-4 compared to non-immunized mice. Both, subcutaneous and ocular routes of immunization, significantly protected against B. ovis infection. These results indicate that BLSOmp31/ISPA administered parenterally or by ocular route is a safe and effective vaccine against B. ovis in the murine model.

Lead exposure in consumers of culled invasive alien mammals in El Palmar National Park, Argentina.

Consumption of meat from animals hunted with Pb ammunition can cause toxic accumulation with consequent health risks, even if relatively small amounts are consumed in each exposure. In El Palmar National Park, Argentina, invasive alien mammals, wild boar (Sus scrofa) and axis deer (Axis axis), are culled with Pb ammunition and their meat is consumed. In this study, we evaluated blood Pb concentrations in 58 consumers of culled game and examined Pb exposure risk according to their demographics, duty, and consumption habits. Likewise, the likelihood of exposure was evaluated by quantifying Pb concentrations in meat samples of seven culled axis deer. Twenty-seven participants (46%) had detectable blood Pb levels (limit of detection = 3.3 µg/dL), with an average 4.75 ± 1.35 µg/dL (geometric mean ± geometric S.D.); the average for all participants was 3.25 ± 1.51 µg/dL. Blood Pb concentrations were significantly higher in hunters, in participants who reported consuming game meat more than 5 times per week, and in participants who reported frequently consuming cured game meat (compared to cooked or pickled). Pb concentration varied significantly along the trajectory of the bullet in deer muscle, being highest at mid-point but with detectable Pb levels even in distant tissue samples (control), suggesting potential for dietary intake by consumers. These findings provide evidence of Pb exposure risk in consumers and emphasize the relevance of replacing Pb ammunition with non-toxic alternatives. This change would reduce dietary exposure in frequent consumers and allow the use of game meat as safe food for people whilst eliminating collateral risks to wild animals and the environment.

Polymeric antigen BLSOmp31 formulated with class B CpG-ODN in a nanostructure (BLSOmp31/CpG-ODN/Coa-ASC16) administered by parenteral or mucosal routes confers protection against Brucella ovis in Balb/c mice.

Previously, we demonstrated that the chimera BLSOmp31 formulated in chitosan microspheres or Poloxamer407-Chitosan administered via the nasal and the ocular mucosa conferred partial protection in sheep against B. ovis. In this work, we tested a new delivery system for mucosal immunization with BLSOmp31 in the murine model to improve the efficacy of previously used formulations. First, we evaluated the protective efficacy against B. ovis induced by BLSOmp31 administered by the subcutaneous route using either BLSOmp31 alone, co-administered with immunostimulatory synthetic oligodeoxynucleotides containing unmethylated cytosine-guanine motifs (CpG-ODN) or with CpG-ODN in a nanostructure called Coa-ASC16 compared with BLSOmp31 emulsified in Incomplete Freund Adjuvant. Then, we evaluated the protection conferred by the best performing formulation (BLSOmp31/CpG-ODN/Coa-ASC16) administered by both subcutaneous and ocular routes. BLSOmp31/CpG-ODN/Coa-ASC16 injected subcutaneously did not induce higher IgG antibody levels compared to BLSOmp31 alone or BLSOmp31/CpG-ODN but it did stimulate a mixed immune Th1-Th2 response with the highest levels of IFN-É£ and conferred significant protection against the B. ovis challenge. Although ocular instillation of BLSOmp31/CpG-ODN/Coa-ASC16 showed a similar degree of protection compared to the parenteral route (3.66 and 3.60 logs of protection, respectively), it induced lower levels in serum of specific IgG (with mixed IgG1/IgG2a) and IgA antibodies and, less IFN-É£ and IL-4 than the subcutaneous route. No antibodies were detected in vaginal lavages or saliva. Fecal antigen-specific IgA was slightly higher in mice immunized with BLSOmp31/CpG-ODN/Coa-ASC16 subcutaneously compared with the ocular route. These results indicate that BLSOmp31/CpG-ODN/Coa-ASC16 was a safe and effective vaccine against B. ovis in mice.

Mucosal immunization with polymeric antigen BLSOmp31 using alternative delivery systems against Brucella ovis in rams.

Subcellular vaccines against ovine contagious epididymitis due Brucella ovis can solve some shortcomings associated with the use of Brucella melitensis Rev 1. We have demonstrated that the parenteral immunization with polymeric antigen BLSOmp31 emulsified in oil adjuvant conferred significant protection against B. ovis in rams. In our previous studies, we have characterized chitosan microspheres (ChMs) and a thermoresponsive and mucoadhesive in situ gel (Poloxamer 407-Ch) as two novel formulation strategies for the delivery of BLSOmp31 in nasal as well as conjunctival mucosa. In the present work, we evaluated the immunogenicity and protection conferred by the intranasal and conjunctival immunization with these two mucosal delivery systems against B. ovis in rams. BLSOmp31-ChM administered by intranasal route and BLSOmp31-P407-Ch applied by intranasal or conjunctival routes induced systemic, local and preputial IgG and IgA antibody response. Neither formulation showed interference in the serological diagnosis. Thus, mucosal immunization using either formulation induced significant specific cellular immune responses (in vitro and in vivo) and it prevented the excretion of B. ovis in semen. Although these vaccines did not prevent infection in immunized rams, colonization reduction of infected organs and bacterial distribution differed significantly between vaccinated and unvaccinated rams.

MapB, the Brucella suis TamB homologue, is involved in cell envelope biogenesis, cell division and virulence.

Brucella species are Gram-negative, facultative intracellular pathogens responsible for a worldwide zoonosis. The envelope of Brucella exhibits unique characteristics that make these bacteria furtive pathogens and resistant to several host defence compounds. We have identified a Brucella suis gene (mapB) that appeared to be crucial for cell envelope integrity. Indeed, the typical resistance of Brucella to both lysozyme and the cationic lipopeptide polymyxin B was markedly reduced in a ∆mapB mutant. MapB turned out to represent a TamB orthologue. This last protein, together with TamA, a protein belonging to the Omp85 family, form a complex that has been proposed to participate in the translocation of autotransporter proteins across the outer membrane (OM). Accordingly, we observed that MapB is required for proper assembly of an autotransporter adhesin in the OM, as most of the autotransporter accumulated in the mutant cell periplasm. Both assessment of the relative amounts of other specific outer membrane proteins (OMPs) and a proteome approach indicated that the absence of MapB did not lead to an extensive alteration in OMP abundance, but to a reduction in the relative amounts of a protein subset, including proteins from the Omp25/31 family. Electron microscopy revealed that ∆mapB cells exhibit multiple anomalies in cell morphology, indicating that the absence of the TamB homologue in B. suis severely affects cell division. Finally, ∆mapB cells were impaired in macrophage infection and showed an attenuated virulence phenotype in the mouse model. Collectively, our results indicate that the role of B. suis TamB homologue is not restricted to participating in the translocation of autotransporters across the OM but that it is essential for OM stability and protein composition and that it is involved in cell envelope biogenesis, a process that is inherently coordinated with cell division.

Anemia inflamatoria: fisiopatología, diagnóstico y tratamiento / Inflammatory anemia: phisiopathology, diagnosis and treatment / Anemia inflamatória: fisiopatologia, diagnóstico e tratamento

La anemia de la Inflamación (AI) es considerada la segunda causa más frecuente de anemia a nivel mundial después de la deficiencia de hierro. Se observa comúnmente en infecciones crónicas, tumores, traumas, y desórdenes inflamatorios. La AI es típicamente normocítica normocrómica usualmente moderada y se produce por una hipoferremia como resultado del secuestro de hierro en el sistema retículo endotelial, de la reducción de la eritropoyesis y de la inhibición de la absorción del hierro en intestino. La patogenia de la AI está mediada por citoquinas inflamatorias y hepcidina, péptido producido en el hígado, que regulan la homeostasis del hierro, actúan suprimiendo la eritropoyesis, y la vida media de los eritrocitos se encuentra ligeramente acortada. Los métodos diagnósticos de rutina que se describen en esta revisión pueden ser de utilidad, pero quedará un grupo de estados anémicos con alta sospecha de AI que no podrán ser fácilmente clasificados. Recientemente se han desarrollado inmunoensayos para determinar hepcidina y citoquinas inflamatorias que podrán colaborar, en un futuro, para un diagnóstico correcto. Existen actualmente modelos experimentales de AI en ratones, los cuales podrían ser útiles para evaluar diferentes tratamientos. En este sentido, los inhibidores de la hepcidina y diversos moduladores inflamatorios aparecen como terapias prometedoras.

Anemia da inflamação (AI) é considerada a segunda causa mais comum de anemia em todo o mundo após a deficiência de ferro. É geralmente observada em infecções crônicas, tumores, traumas e distúrbios inflamatórios. A AI é tipicamente normocítica normocrômica comumente moderada e ocorre por uma hipoferremia como resultado do sequestro de ferro no sistema retículo endotelial, da redução da eritropoiese e da inibição da absorção do ferro no intestino. A patogenia da AI é mediada por citocinas inflamatórias e hepcidina, peptídeo produzido no fígado, que regulam a homeostase do ferro, agem suprimindo a eritropoiese e a meia-vida dos eritrócitos é levemente diminuída. Os métodos de diagnóstico de rotina descritos nesta revisão podem ser úteis, mas ficará um grupo de estados anêmicos com alta suspeita de AI que não poderão ser classificados facilmente. Recentemente têm sido desenvolvidos imunoensaios para determinar hepcidina e citocinas inflamatórias, que poderão colaborar no futuro, para um diagnóstico certo. Existem atualmente modelos experimentais de AI em ratos que poderiam ser úteis para avaliar diferentes tratamentos. A este respeito, os inibidores de hepcidina e vários moduladores inflamatórios aparecem como terapias promissoras.

Immune response induced by conjunctival immunization with polymeric antigen BLSOmp31 using a thermoresponsive and mucoadhesive in situ gel as vaccine delivery system for prevention of ovine brucellosis.

Control of ovine brucellosis with subcellular vaccines can solve some drawbacks associated with the use of Brucella melitensis Rev.1. Previous studies have demonstrated that the polymeric antigen BLSOmp31 administered by parenteral route was immunogenic and conferred significant protection against B. ovis in rams. Immunization with BLSOmp31 by conjunctival route could be efficient for the induction of mucosal and systemic immune responses. In this work, we evaluated the conjunctival immunization using a thermoresponsive and mucoadhesive in situ gel composed of Poloxamer 407 (P407) and chitosan (Ch) as vaccine delivery system for BLSOmp31 in rams. Serum samples, saliva, lacrimal, preputial and nasal secretions were analyzed to measure specific IgG and IgA antibodies. Cellular immune response was evaluated in vivo and in vitro. Immunization with BLSOmp31-P407-Ch induced high IgG antibody levels in serum and preputial secretions which remained at similar levels until the end of the experiment. Levels of IgG in saliva, lacrimal and nasal secretions were also higher compared to unvaccinated control group but decreased more rapidly. IgA antibodies were only detected in nasal and preputial secretions. BLSOmp31-P407-Ch stimulated a significant cellular immune response in vivo and in vitro. The induction of systemic and local immune responses indicates a promising potential of P407-Ch for the delivery of BLSOmp31 by conjunctival route.

Spray dried microspheres based on chitosan: A promising new carrier for intranasal administration of polymeric antigen BLSOmp31 for prevention of ovine brucellosis.

Previous studies have demonstrated that parenteral immunization with polymeric antigen BLSOmp31 induced a strong immune response and conferred protection against Brucella ovis in rams. This work describes the development of a novel formulation strategy for the delivery of BLSOmp31 in the nasal mucosa. Chitosan microparticles were prepared by spray-drying technology processes and recombinant chimera BLSOmp31 was loaded by passive adsorption onto chitosan microspheres, which were characterized by means of the evaluation of size, zeta potential, morphology, and loading and release rate of BLSOmp31. The mucoadhesive properties of microspheres were evaluated by studying the interaction between microparticles and mucin. The antigen BLSOmp31 integrity was investigated by SDS-PAGE. The yield of production of spray-drying process was 68.95%. Microspheres had a good sphericity, 1-10 µm of particle size and had a positive charge. The loading capacity was found to be 45.19%. The initial fast release of BLSOmp31 from chitosan microparticles was 60%. The BLSOmp31 integrity was not affected by passive adsorption (ionic interaction). The amount of mucin adsorbed on the surface of CMs-BLSOmp31 was lower than on the surface of blank CMs at neutral pH. In vivo studies were carried out in rams. Intranasal immunization induced systemic and local antibodies. In conclusion, the use of BLSOmp31-loaded chitosan spray-drying microspheres offers a promising way for nasal mucosal vaccination in sheep against brucellosis.

Vaccination with Brucella recombinant DnaK and SurA proteins induces protection against Brucella abortus infection in BALB/c mice.

The immunogenicity and protective efficacy of recombinant SurA (rSurA) and rDnaK from Brucella spp. were evaluated in BALB/c mice. Immunization with rSurA in adjuvant induced a vigorous immunoglobulin G (IgG) response, with higher IgG2a than IgG1 titers. In addition, after in vitro stimulation with rSurA, spleen cells from rSurA-immunized mice produced interleukin-2 (IL-2), interferon (IFN)-gamma, IL-4 and IL-5. Immunization with rDnaK plus adjuvant induced a strong humoral response resulting in similar anti-rDnaK IgG titers than immunization with rDnaK alone. IgG2a titers predominated over IgG1 in mice injected with rDnaK alone or rDnaK plus adjuvant. Spleen cells from mice immunized with rDnaK plus adjuvant secreted IFN-gamma and IL-2 upon stimulation with rDnaK and induced a specific cytotoxic response. On the contrary, mice immunized with rDnaK alone did not exhibit a specific T helper or cytotoxic response in vitro. Mice given rSurA or rDnaK with adjuvant exhibited a significant degree of protection whereas immunization with rDnaK alone induced a low but still statistically significant level of protection against B. abortus infection. All studied vaccines were less protected than mice immunized with H38 or B. abortus strain 19 control vaccines. Altogether these results suggest that rSurA or rDnaK induce partial protection against B. abortus infection and could be useful candidates for the development of subunit vaccines against brucellosis.