Search Results (67)

Brucellosis continues to be a significant global zoonotic infection, with diagnosis largely relying on the detection of antibodies against the Brucella O-polysaccharide (O-PS) A and M antigens. In this study, computational methods, including homology modeling, molecular docking, and molecular dynamics simulations, were applied to investigate the interaction of the four murine monoclonal antibodies (mAbs) YsT9.1, YsT9.2, Bm10, and Bm28 with hexasaccharide fragments of the A and M epitopes. Through stringent stability criteria, based on interaction energies and mobility of the antigens, high-affinity binding of A antigen with YsT9.1 antibody and M antigen with Bm10 antibody was predicted. In both the complexes hydrophobic interactions dominate the antigen–antibody binding. These findings align well with experimental epitope mapping, indicating YsT9.1’s preference for internal sequences of the A epitope and Bm10’s preference for internal elements of the M epitope. Interestingly, no stable complexes were identified for YsT9.2 or Bm28 interacting with A or M antigen. This study provides valuable insights into the mechanism of molecular recognition of Brucella O-antigens that can be applied for the development of improved diagnostics, synthetic glycomimetics, and improved vaccine strategies. Full article

This study aimed to determine the prevalence of antibodies against equine brucellosis in three distinct equid groups (farm animal, urban carthorse, and sport horse) in Western Pará, Brazil, and to identify associated risk factors. A cross-sectional study, involving 75 farms across 14 municipalities, sampled 1069 equids composed of urban carthorses and sport horses. Serum samples were tested for antibodies against Brucella spp. using the buffered acidified plate antigen (BAPA) test for screening, followed by the serum agglutination in tubes with 2-mercaptoethanol (2-ME) for confirmation. Univariate and multivariate analyses assessed associations between brucellosis and potential risk factors. Out of the 1059 equids sampled, 4.05% (95% CI: 3–5.5%) tested positive in the BAPA test. Of the 44 BAPA-positive samples, 11 were confirmed positive by 2-ME, 15 were inconclusive, and 18 were negative, yielding an animal-level prevalence of 1.03% (95% CI: 0.5–1.8%) for equine brucellosis in western Pará. Prevalence was higher in the Southwest Pará Mesoregion (p = 0.047) compared to the Lower Amazon Mesoregion. No significant associations were found with animal type, reproductive problems, animal sex, species, breed, and age group. Out of the 75 farms, 8 (10.66%) had at least one seropositive equid. Confirmed cases were identified in five municipalities (Brasil Novo, Uruará, Altamira, Rurópolis, and Itaituba). This first report of equine brucellosis in Western Pará underscores the need for enhanced surveillance and control measures to mitigate its zoonotic risk to humans and transmission to other animals. Full article

The increasing number of owned and stray dogs in large cities is becoming a pressing issue due to rising population densities, urban conditions, and poor control over animal reproduction. This situation poses serious epidemiological risks, as dogs can act as reservoirs and transmitters of infectious and parasitic diseases dangerous to humans. This study aimed to investigate the prevalence and carriage of infectious and parasitic diseases in stray dogs in the city of Uralsk as a factor of epidemiological risk. In 2024, 1213 stray dogs were captured from different city districts and examined at the veterinary clinic and laboratory of Zhangir Khan University. Biological samples (blood, urine, feces) from 10% of the animals were analyzed using molecular (PCR), serological (ELISA), and helminthological methods. Serological and molecular analyses revealed the widespread circulation of bacterial pathogens. Antibodies to additional bacterial agents, including Pasteurella multocida, Mycobacterium spp., Listeria monocytogenes, and Leptospira spp., were detected in the samples, indicating an unfavorable sanitary and epidemiological situation in the urban environment. An enzyme-linked immunosorbent assay (ELISA) identified antibodies against Toxocara canis in 50.9% of the dogs and against Echinococcus granulosus in 76.4%, reflecting both active and past infections. The polymerase chain reaction (PCR) results showed the presence of Brucella canis DNA in blood and urine samples, while antibodies to Brucella spp. were detected in 57.8% of the examined dogs, underscoring the significant zooanthroponotic importance of this pathogen and its potential threat to human health. Additionally, T. canis DNA was found in 39.2% of the samples and E. granulosus DNA in 16.6%. A helminthological examination using the Fülleborn method revealed a high rate of helminth infection: Ancylostoma caninum—35.3%, T. canis—32.3%, and Toxascaris leonina—29.4%. The obtained results highlight the significant role of stray dogs as epizootiological and epidemiological reservoirs of zooanthroponotic infections. This poses a serious threat to public health and necessitates the implementation of effective control and prevention measures for infectious and parasitic diseases within urban fauna. Full article

Cell-mediated immunity is an important component of the immune response for intracellular pathogens. Live vaccines containing different pathogens are used concurrently in the field but are generally licensed individually. Concurrent administration of these vaccines has led to concerns about immune interference. The goal of this study was to characterize BVDV-specific responses to vaccination and determine the effect of concurrent Brucella abortus strain RB51 (RB51) vaccine administration. Peripheral blood mononuclear cells (PBMCs) from cattle vaccinated with a modified-live viral (MLV) vaccine containing BVDV, both RB51 and an MLV, or unvaccinated controls were utilized to evaluate antibody titers and the frequency of interferon gamma (IFN-γ) production within CD4⁺, CD8⁺ T cells, and NK cell populations via flow-cytometry. Our data demonstrated the lack of vaccine interference following concurrent administration of two common bovine MLVs and may even suggest some level of enhanced IFN-γ production with concurrent administration. Full article

False-positive serologic results (FPSRs) of brucellosis occur from time to time in various livestock with all the consequences (quarantine, compulsory slaughter, etc.) that follow true-positive laboratory results. A method based on the Polyacrylamide Gel Electrophoresis/Western Blot of a protein panel for resolving the FPSRs in the diagnosis of brucellosis was developed. Within the context of limited positive serum sample availability in Europe, the method successfully discriminates Brucella-positive sera from samples containing antibodies raised against infections caused by other Gram-negative bacteria causing FPSRs. An average CV% of 1.36 was determined for both repeatability and reproducibility for the whole separation mw range, and the test achieved 1.00 Diagnostic Sensitivity and 1.00 Diagnostic Specificity. The method with pre-prepared WB panels provides a rapid (less than 3 h), easily standardizable, and validatable alternative to existing confirmation methods. The whole WB process of the Brucella proteins and the subsequent densitometry can be accomplished with commercially available equipment, ready-to-use reagents, and open-source software, providing cost-effectiveness. The results of this study could attract broader attention, since molecular species in the 35.0–75.0 kDa range can serve as antigens in Brucella serology and the same fraction can be considered in the development of synthetic Brucella vaccines. Full article

Brucellosis is a zoonosis that affects domestic and wild animals, causing reproductive disorders and significant economic losses in livestock. Brucella melitensis, B. abortus, and B. suis are the main agents of brucellosis in livestock and humans, thereby their control and eradication are crucial. Serological tests based on identification of antibodies against Brucella smooth lipopolysaccharides (sLPS) in the serum of infected animals are traditionally used. This approach shows two main limits: (i) tests can give false positives due to the similarity of Brucella sLPS with the LPS of other Gram-negative bacteria; (ii) antigen production represents a possible risk of zoonoses. In this work, a proteomic approach, starting from B. melitensis Brucellergene, was employed to identify possible Brucella antigenic proteins useful for a more specific and safe serological diagnosis. Four proteins binding to the infected swine serum were identified: (i) “probable sugar-binding periplasmic protein B. abortus str 2308A”; (ii) “peptide ABC transporter substrate-binding protein B. melitensis”; (iii) “GntR family transcriptional regulator B. melitensis”; (iv) “conserved hypothetical protein B. melitensis M28”. These proteins could be promising specific antigens for serological investigations in swine. In the near future, these antigenic proteins could be synthesized in vitro and used to produce a safer and more specific diagnostic kit. Full article

Brucellosis is still the most common zoonosis worldwide despite advanced technology and animal husbandry. Since there is still no effective Brucella vaccine for humans, it is crucial to control the disease in ruminants through eradication and vaccination. Although some countries around the world have achieved this circumstance, every country aims to become free of Brucellosis through vaccination, animal movements, and various eradication measures. For this purpose, the Brucella abortus S19 strain has been used safely for about 100 years. However, due to the O-polysaccharide (OPS) antigen in its structure, the antibody response created by the vaccine causes confusion in serological tests. For this purpose, researchers have provided both mucosal immunity and short-term antibody response by using the B. abortus S19 vaccine in conjunctival form instead of subcutaneous form. This study aimed to determine how long the post-vaccination titer levels persisted in animals vaccinated with vaccines from 3 different companies and different routes. In this study, a total of 115 calves aged 3 to 4.5 months were created in five groups, with 23 animals in each group: group 1 (vaccine brand A), group 2 (vaccine brand B), and group 3 (vaccine brand C) received the two-dose conjunctival vaccine, group 4 received the single-dose subcutaneous vaccine (vaccine brand C), and group 5 received the subcutaneous vaccine (vaccine brand C) plus the booster dose conjunctival vaccine (vaccine brand B). Brucellosis antibody titers were monitored each 21 days until the cattle were 26–28 months old. The collected sera were analyzed using the Rose Bengal Plate Test (RBPT), Serum Agglutination Test (SAT), and Complement Fixation Test (CFT), which are the preferred serological methods for Brucellosis eradication plans worldwide. In the conjunctival vaccination groups, only 3 (13%) of the animals in group 1 developed antibody titers one month after vaccination, and there was no antibody response detected against Brucellosis in group 2 and group 3. In animals that were stimulated conjunctivally, the threshold value of 30 International CFT Units (ICFTUs) (for distinguishing between infective titers and vaccination titers) was observed in one animal each in group 1 and group 2 and 0 animal in group 3. It was found that antibody titers turn to Brucellosis negative in all conjunctival vaccine groups at 7 months after vaccination. In groups 4 and 5, the first-month serological screening detected over 30 ICFTUs in 17 (89.47%) animals and 16 (69.5%) animals, respectively. In group 4, CFT titers were found to fall below 30 on the 17th month and 9.3 on the 22nd month. On the 14th month, the CFT titers of group 5 were found to be below 30, and all animals in this group turned negative after the 19th month. It was found that the single dose B. abortus S19 subcutaneous vaccination in calves caused persistent antibodies in 5% of the population. It is believed that persistent and high antibody titers created by subcutaneous vaccines will cause false positivity and create confusion in Brucellosis eradication programs. Therefore, although there is no clear distinction between vaccinated and infected animals, it has been observed that conjunctival Brucellosis vaccines create more stable antibody titers and decrease rapidly compared to subcutaneous vaccines. Based on the results of this study and the advantages of conjunctival vaccines, more effective eradication programs and antibody monitoring can be carried out in vaccinated herds where Brucellosis outbreaks are observed. Full article

Rose Bengal antigen and smooth lipopolysaccharide (s-LPS) were produced from a field strain of Brucella ceti (“homologous” antigens) and from the reference strain B. abortus S99 (“heterologous” antigens); they are currently used for the diagnosis of brucellosis in cattle, water buffaloes, sheep, goats, and pigs, as recommended in the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals of the World Organization for Animal Health (WOAH). “Homologous” and “heterologous” antigens were used in a rapid serum agglutination test (Rose Bengal test, RBT) and a competitive ELISA assay (c-ELISA) to test a panel of sera, blood, and other body fluids (cerebrospinal fluid, pericardial fluid, tracheal fluid, and aqueous humor) collected from 71 individuals belonging to five cetacean species (Stenella coeruleoalba; Tursiops truncatus; Grampus griseus; Globicephala melas; and Ziphius cavirostris), which were found stranded on the Italian coastline. Six animals were positive for Brucella spp. for bacterial isolation and/or PCR, and 55 animals were negative; for the remaining 10 animals, no PCR/isolation data were available. A total of 90 samples were tested. Results obtained from the two tests were compared in order to identify the most suitable antigen for the serological diagnosis of Brucella infection in cetaceans. The RBT performed with the “homologous” antigen showed the best results in comparison with the “heterologous” antigen: diagnostic sensitivity, specificity, and accuracy were 80.0%, 44.1%, and 46.9% for the “homologous” antigen and 80.0%, 17.0%, and 21.9% for the “heterologous” antigen. For the c-ELISA, “homologous” and “heterologous” s-LPS showed similar results (diagnostic sensitivity 66.7%, diagnostic specificity 97.3%, and diagnostic accuracy 95.0%). Therefore, the RBT using the “homologous” antigen and c-ELISA with “homologous” or “heterologous” s-LPS could be used in parallel for the detection of antibodies against Brucella spp. in cetaceans. Full article

Bovine brucellosis (bB) is a zoonosis mainly caused by the Brucella abortus species in cattle. Bovine brucellosis can present with either a range of clinical symptoms, including spontaneous abortions in the last trimester of pregnancy, retained fetal membranes, and decreased milk production, or it can be asymptomatic. In Ecuador, vaccination against bB with S19 and/or RB51 is not mandatory and is the responsibility of the farmer. As serology is a convenient method for detecting antibodies against Brucella, evaluating the diagnostic performance and discriminative ability of such tests in various epidemiological settings is required. To estimate and compare the diagnostic sensitivity (Se) and specificity (Sp) of two screening tests, a new competitive (cELISA) and an indirect ELISA based on a new synthetic antigen (iELISA), a randomized, stratified, cross-sectional, serological survey was performed on the cattle population (3299 bovine sera from 223 farms) in continental Ecuador. A Bayesian approach was used to evaluate the two tests by estimating their respective diagnostic Se and Sp, as well as the true prevalence of bB in different sub-populations (non-vaccinated, vaccinated with S19 or RB51). The Se of both tests was similar across Bayesian models, with values around 94%. In contrast, the Sp of the iELISA, ranging between 97 and 98%, was significantly higher than that of the cELISA, which was approximately 94–95%. The true prevalence of bB was 1.63% (95% CrI: 0.56–2.54) in non-vaccinated cattle, decreased to 0.97% (95% CrI: 0.005–2.54) in S19-vaccinated cattle and was 2.75% (95% CrI: 0.50–5.32) in RB51-vaccinated cattle. The results of this study suggest that, with similar Se and higher Sp, the iELISA based on an innovative synthetic antigen (which is more standardizable) should be recommended as a possible screening test for bB in Ecuador. Also, the proposed approach suggests insights into the quality of the vaccination campaign and highlights the need for refining the Ecuadorian national brucellosis control program. Full article

Our preliminary data using bone marrow-derived macrophages (BMDMs) collected from ICR mice treated with anti-sirtuin (anti-SIRT) 1 antibody showed that Brucella uptake was significantly attenuated. We then further investigated the effect of an inhibitor of SIRT1/2, cambinol, in the progression of Brucella. The in vitro results using RAW264.7 cells revealed that cambinol treatment had no effect on adhesion, uptake, intracellular survival and nitric oxide (NO) production during B. abortus infection, nor did it directly affect bacterial growth for up to 72 h. Finally, intraperitoneal treatment of 8-week-old female ICR mice infected with Brucella showed no differences in the total average weights of spleens and livers; however, the treated mice displayed higher Brucella colony-forming units (CFUs) from the spleens. Furthermore, the interleukin (IL)-10 serum level was observed to be lower in treated mice at 7 d post-infection, and none of the cytokines tested showed a change at 14 d post-infection. The overall findings showed that cambinol treatment had no effect on the proliferation of Brucella in RAW264.7 macrophages but exacerbated the splenic proliferation of the bacteria in mice and displayed reduced anti-inflammatory cytokine IL-10 at the first week of infection, suggesting that cambinol as an inhibitory of SIRT1/2 could be beneficial in the context of Brucella dissemination in animal hosts and that exploration of activating SIRTs could be an alternative treatment against Brucella infection. Full article

Brucellosis is a common zoonotic disease affecting livestock and humans globally. The disease is endemic in Ethiopian livestock. This study was conducted to estimate Brucella seropositivity and identify its risk factors in livestock, and practices that may expose pastoralists to the disease. Data were collected from 2133 animals across 149 households (HHs) in Dubti and Amibara districts, Afar region, Ethiopia. Blood samples from livestock and household data were collected, and interviews were conducted on husbandry and dairy consumption practices. Sera were serially tested using the Rose Bengal test and indirect enzyme-linked immunosorbent assay. The overall seropositivity to anti-Brucella antibodies was 8% (95% CI, 6.6–9.2). The antibodies were found in 12.4%, 6.5%, 6%, and 3% of the goats, cattle, camels, and sheep, respectively. Among the HHs, 59.7% had at least one seropositive animal. A mixed-effects logistic regression analysis revealed species and the acquisition of new animals (in cattle and camels), and age and district (in sheep, goats, and cattle) as significant risk factors. Goats, cattle, and camels had significantly higher odds of Brucella seropositivity than sheep (p < 0.05). Seropositivity was significantly higher (p < 0.05) in adults than in young animals, in acquired than in homebred (cattle and camels), and in those with reproductive disorders than those without. Pastoralists lacked knowledge of brucellosis and its modes of transmission, while practices exposing humans and livestock to brucellosis were common. The findings underscore the need for public awareness campaigns and implementation of brucellosis control measures in pastoral systems. Full article

Bovine brucellosis and neosporosis are reported as potential abortifacient infections in cattle worldwide. Brucellosis is additionally a zoonotic bacterial infection caused by numerous Brucella species. Meanwhile, neosporosis is a protozoan parasitic disease that is implicated in causing high economic losses in the cattle industry. Herein, we attempted to investigate the seroprevalence of specific antibodies to Brucella spp. and Neospora caninum using commercially available ELISAs. In addition, we conducted risk factor analysis and estimated the correlation of seropositivity of both pathogens with the recorded abortions in the tested herds. Serum samples from cattle (n = 460) collected from various governorates in the Delta region, northern Egypt, were targeted in this study. Overall, a seroprevalence of 5.4%, 33.3%, and 1.3% was revealed for Brucella spp., N. caninum, and mixed seropositivity, respectively. The location (Kafr El Sheikh vs. Dakahlia vs. Al-Qalyubiya vs. Damietta governorates) and a history of abortion (yes vs. no vs. unknown) were analyzed as risk factors of infection. Kafr El Sheikh governorate (57.7%, p = < 0.0001) and a history of abortion (54.1%, p = < 0.0001) were considered risk factors for Brucella spp. seropositivity compared to the reference factors Al-Qalyubiya (1.1%) and unknown abortion history (0.6%). In the case of N. caninum, the location was also considered a risk factor because the seropositive rates were significantly higher in Damietta (51%, p = 0.001) and Dakahlia (33.4%, p = 0.026) compared to Kafr El Sheikh (11.3%, set as a reference). Conversely to Brucella, animals without a history of abortion exhibited a higher seropositive rate for N. caninum (47.6%, p = 0.009) compared to those with a history of abortion (21.6%, set as reference). For further investigations into the association between abortion and the obtained seropositive rates, we also analyzed the reactivity by comparing samples of animals with, without, and unknown history of abortion. We detected high seroreactivity for Brucella spp. in samples collected from animals with a history of abortion, as demonstrated in the recorded antibody levels and correlation coefficient (Pearson r = 0.919). Based on our data, despite the higher seroprevalence of N. caninum compared to that of Brucella species, Brucella spp. might be the primary cause of abortion in our tested cattle population. Full article

Brucellosis is a zoonotic infectious disease that has long endangered the development of animal husbandry and human health. Currently, vaccination stands as the most efficacious method for preventing and managing brucellosis. Alum, as the most commonly used adjuvant for the brucellosis vaccine, has obvious disadvantages, such as the formation of granulomas and its non-degradability. Therefore, the aims of this study were to prepare an absorbable, injectable, and biocompatible hydroxypropyl chitin (HPCT) thermosensitive hydrogel and to evaluate its immunization efficacy as an adjuvant for Brucella antigens. Specifically, etherification modification of marine natural polysaccharide chitin was carried out to obtain a hydroxypropyl chitin. Rheological studies demonstrated the reversible temperature sensitivity of HPCT hydrogel. Notably, 5 mg/mL of bovine serum albumin can be loaded in HPCT hydrogels and released continuously for more than one week. Furthermore, the L929 cytotoxicity test and in vivo degradation test in rats proved that an HPCT hydrogel had good cytocompatibility and histocompatibility and can be degraded and absorbed in vivo. In mouse functional experiments, as adjuvants for Brucella antigens, an HPCT hydrogel showed better specific antibody expression levels and cytokine (Interleukin-4, Interferon-γ) expression levels than alum. Thus, we believe that HPCT hydrogels hold much promise in the development of adjuvants. Full article

We surveyed 159 American black bears (Ursus americanus) over a period of three years for the occurrence of ticks, tick-borne diseases, and intestinal parasites in Wisconsin. We collected blood from the bears to test for the presence of antibodies to Borrelia burgdorferi (Lyme disease), Rickettsia rickettsii (Rocky Mountain spotted fever (RMSF)), Babesia, Ehrlichia, Ehrlichia canis, Brucella canis, and Anaplasma phagocytophilum. We also examined scat samples for intestinal parasites. We commonly found the tick Dermacentor variabilis, but also present the first report of Rhipicephalus sanguineus on black bears. We detected antibodies to Lyme disease and RMSF. We detected antibodies to E. canis for the first time in a bear and both antibodies to R. rickettsii and A. phagocytophilum for the first time in a black bear in Wisconsin. No antibodies for Babesia or Br. canis were detected. We found eggs of the intestinal parasite Baylasascaris transfuga as well as a low number of Toxascara leonina and unknown Capillaria species occurrences in the examined feces. Full article

Brucellosis in animals is an infectious disease caused by bacteria of the genus Brucella. Known methods for diagnosing brucellosis face some challenges, due to the difficulties in isolating and standardizing the natural brucellosis antigen. In this work, we investigated the possibility of using the fluorescence polarization assay (FPA) with synthetic glycoconjugate biosensing tracers to detect antibodies against Brucella as a new methodology for diagnosing brucellosis. Based on the received results, the synthetic fluorescein-labeled trisaccharide tracer is most effective for Brucellosis detection. This tracer is structurally related to the immune determinant fragment of the Brucella LPS buildup of N-formyl-d-perosamine units, connected via α-(1→3)-linkage at the non-reducing end and α-(1→2)-linkage at the reducing end. The sensitivity and specificity in the case of the use of trisaccharide tracer 3b were 71% and 100% (Yuden’s method) and 87% and 88% (Euclidean method), respectively, which is comparable with the diagnostic efficiency of traditionally used serological methods, such as the agglutination test (AT), complement fixation test (CFT), and Rose Bengal test (RBT). Given the known advantages of FPA (e.g., speed, compactness of the equipment, and standard reagents) and the increased specificity of the developed test system, it would be appropriate to consider its widespread use for the diagnosis of brucellosis in animals, including rapid testing in the field. Full article