Veterinaria Italiana (Journal)
Not a member yet
578 research outputs found
Sort by
P8-06 Brucella infection in stray cattle reared in cow shelters (gaushalas) in Punjab, India: Lessons learned from an observational study
No full textBovine brucellosis is an important zoonosis across several states of India.,and has been reported in domestic animals and people. Data on the prevalence of brucellosis in stray cattle in India is limited, however this information would be helpful to provide epidemiological information to develop control policies to combat this infection and its further transmission to humans and animals. Study was conducted in stray cattlereared in animal shelters (also called gaushalas in local language) in Punjab, India; of 23 gaushalas visited (one from each district of Punjab), 587 blood samples were collected and tested to assess the exposure to Brucella spp. Of 587 sera, 62 [10.56% (95% CI: 8.33%, 13.31%)], 63 [10.73% (95% CI: 8.48%, 13.50%)] and 68 [11.58% (95% CI: 9.24%, 14.43%)] were positive for the presence of antibodies to Brucella using Rose Bengal Plate Agglutination Test (RBPT), Standard Tube Agglutination Test (STAT) and Indirect Enzyme Linked Immu-no Sorbent Assay (I- ELISA), respectively. The estimated true prevalence of 11.48 % (95% CI: 8.9%, 14.64%), 10.69 % (95% CI: 8.27%, 13.67%), and 13.28 % (95% CI: 10.50%, 16.66%) was observed using RBPT, STAT and I-ELISA, respectively. Exposure to Brucella spp. in animals was detected in 22 out of 23 cow shelters (gaushalas) and shelter/herd level prevalence was determined using combination of tests in series, i.e. if it was positive in RBPT or STAT result, and a positive indirect ELISA result. The shelter/herd level prevalence was estimated to be 96 % (95% CI: 79%, 99%). After adjusting for other variables in the final model, history of abortion was associated with very large odds of having a positive test (adjusted odds ratio 7.43, 95% confidence interval: 3.25-16.99, p = < 0.001). History of ROP was also associated with greater odds of having a positive Brucella infection test (adjusted odds ratio 5.25, 95% confidence interval: 1.38-19.88, p = 0.01). Infection with Brucella spp. in stray cattle indicates a potential risk to the farm workers and dairy farms. Further investigations are required to generate more epidemiological data on status of bovine brucellosis in stray cattle as well as shelter workers in Punjab and India
O1-4 Evolution towards pathogenicity: phylogenomic insights into Brucellaceae
No full textDuring evolution, some α-Proteobacteria like Brucella have become stealthy intracellular pathogens, not easily detected by the innate immune system. To gain knowledge into the emergence of this strategy and the virulence mechanisms of Brucella, we sought to compare phylogenetically close but biologically divergent bacteria. Accordingly, the aim of this work was to search for the genomic characteristics thatmight explain the biological differences between Brucella, a pathogen of livestock and humans, and the closely related genera Ochrobactrum and Pseudochrobactrum, which are mainly free-living bacteria and only occasionally opportunistic human pathogens. For this purpose, we focused the comparison on P. algeriensis, a recently described species isolated from lymph nodes of cattle. Genomic analyses suggest that Pseudochrobactrum, conserves the lipid A structure of Brucella LPS, a trait already observed in O. intermedium that could delay immunity activation and hamper a prompt clearance of the bacteria. In addition, P. algeriensis contains putative genes for free-lipid modifications, probably explaining its extreme resistance in vitro to cationic peptides that mimic the bactericidal peptides of innate immune system. Finally,P. algeriensis, unlike other Pseudochrobactrum species, presents the genomic capacity of producing a rhamnose based O-polysaccharide LPS, being in this regard similar to B. inopinata BO2, an early diverging Brucella strain. Likewise, P. algeriensis carries part of the operon coding for the Type IV secretion system (T4SS) that, while essential for intracellular multiplication of Brucella, has been described as involved in plasmid transfer in Ochrobactrum. This work supports the notion that lipid A and free-lipid modifications are conserved in Brucellaceae as mechanisms of resistance to cationic peptide antibiotics in soil or to their innate immunity counterparts, while the T4SS have diverged to different functions
P3-10 Control of the subcellular localization of host nuclear proteins by Brucella effectors
No full textBacterial targeting of the nucleus is a major virulence strategy shared by a number of plant and animal pathogens. In order to manipulate nuclear functions and eukaryotic gene expression, bacteria inject into host cells nuclear-targeting effector proteins, known as nucleomodulins. We have recently identified two such effectors from Brucella abortus that we named NyxA and NyxB. We have found that these two effectors modulate subcellular spatial dynamics of nuclear proteins during infection. We show that NyxA and NyxB target the host de-SUMOylase SENP3, extensively impacting nuclear dynamics. SENP3 is required for efficient intracellular replication within host cells. Furthermore, we have found that key components of ribosomal biogenesis machinery accumulate in the host cytosol of infected cells, suggesting a novel host response to infection. The consequences of these interactions will be further discussed in the context ofBrucella pathogenesis
P6-08 Clinical and laboratory surveillance of suspected infections in kennel workers in an outbreak of Brucella canis.
No full textHumans and dogs commonly share the same domestic environment. Zoonotic pathogens may be harboured by dogs, and potentially be transmitted to humans and owners that often consider their dogs as family members. Brucella canis is one of those pathogens at risk of transmission to humans. The first evidence of B. canis in a dog in Italy was reported in 2010, based on serological and PCR findings. More recently, B. canis was isolated for the first time in Italy, during a large outbreak occurred in a commercial breeding kennel. Although canine brucellosis is considered a zoonosis, confirmed human cases are relatively uncommon, with roughly 50 cases identified in the US since 1973. Lab employees, voluntaries, veterinarians, owners and people having close and frequent contacts with infected dogs are considered at higher risk of infection. However, human brucellosis caused by B. canis is underestimated due to the general lack of specific serological tests and misconceptions concerning its prevalence. Uncontrolled spread of infection in dogs may have important public health implications so that actions are required to acquire data on distribution of this underhanded zoonosis of pets, as well as to control its spread in high-risk environments. Following detection of canine brucellosis in the Italian breeding kennel, more than one person among veterinarians and kennel’s operators reported symptoms compatible with Brucella infection. Since all these people had an active and long lasting role in the management and handling of the dogs in the brucellosis outbreak, B. canis was not excluded as the possible cause of their illness. Diagnosis of human brucellosis relies on bacterial culture, molecular or mass spectrometry identification, and serological tests. Unfortunately, sen-sitivity of culture is extremely low and serological tests available for classical Brucella, are not effective to detect B. canis antibodies. Thus, the same tests available for dogs where applied to investigate suspect clinical cases arose in workers involved in the outbreak. In the view of a public health approach controlling for canine brucellosis, it would be important and urgent to develop validated laboratory protocols to support diagnosis of infection in humans
P9-02 Antibody detection in heifers challenged with local strains of Brucella suis biovar 1 previously isolated from Armadilo (Chaetophractus villosus) and Hares (Lepus europaeus)
No full textBovine brucellosis is an infectious disease caused mainly by Brucella abortus; however, B. melitensis and occasionally B. suis may infect cattle. In Argentina brucellosis has been controlled in most of the cattle; however, routine serological surveillance detects animals which are positive on standard serological tests with low titers that are persistent or in many cases become negative later. In the geographic zone known as “La pampa” where most of the Argentinian cattle are concentrated, bovines share the habitat with wildlife present in the region. Previous documents indicate that in animals like armadillo and hares, the prevalence of Brucella antibodies is 16 and 6 % respectively. Interestingly, only B. suis biovar 1 has been isolated from those species. The objective of this research was to evaluate the serological pattern of heifers challenged with 1.5×107 IC of three different strains of B. suis biovar 1. Twelve pregnant cows, 2 years old, were utilized.Three of them (group A) were inoculated with B. suis isolated from armadillo; 3 heifers were challenged with B. suis isolated from hare; 3 were challenged with B. suis 1330; and 3 animals (group 4) were not challenged as a control. Blood was collected prior to challenge and every 20 days until the end of the study 150-day post challenge. For serological analysis, the Buffer plate antigen test (BPAT) was used as a screening test and fluorescent polarization (FPA) as the confirmatory test. All animals were negative 20 days before and the same day of challenge. All animals in group A and C, as well as two animals from group B were positive on BPA and FPA after challenge and remained so until day 60. Two heifers, one from group A and another from group B, persisted as positive until the end of the experiment (day 150) with high titers on the FPA test. All animals delivered their calves normally. We concluded that in this experiment B. suis inoculated into pregnant animals does not cause abortions but does induce serological titers which interfere the with test results and may cause confusion with the status of this animals
P8-12 First confirmed domestic transmission of Brucella canis between dogs in the UK: outbreak investigation and public health risk assessment
No full textBrucella canis (B. canis) causes a zoonotic infection of dogs. It is primarily transmitted to humans via exposure to reproductive fluids, particularly from parturition and abortions. Human infections are rarely reported world-wide but could pose a serious risk for vulnerable individuals. Historically, UK B. canis cases have only been reported in imported dogs. In June 2020, a canine infected with B. canis was reported to Public Health England and an Incident Management Team convened. We aim to describe the outbreak and implications for the public health risk assessment. Self-reported information from the index and linked households, microchip database searches and site visits were used to identify humans and dogs potentially exposed to B. canis and assess ongoing risks. Humans and dogs were tested for B. canis serologically and cultures were performed on tissue samples from two dogs. Dogs were categorised as positive, non-infected or suspected for B. canis according to the long-term management plan. Nine households were potentially exposed to B. canis. There were nine canine abortions or stillbirths in the households in the preceding 18 months. Three humans had a single positive Rapid Slide Agglutination (RSA) test at 6 weeks, but negative results for subsequent samples. The positive results were determined to be of uncertain significance. Thethree patients were asymptomatic and did not receive treatment. 75% (27/36) of dogs tested were seropositive and both cultures grew B. canis. All seropositive dogs originated from the index household. Puppies born to seropositive parents were sold to a further six households and are being followed up. This outbreak of B. canis identified the first documented transmission of B. canis between dogs in the UK. Despite highrisk exposures over a prolonged period no humans developed symptoms of brucellosis during the investigation. Increased awareness is needed among dog owners, veterinarians and health professionals about the risks and prevention of transmission of B. canis
O6-1 Investigation into efficacy of rLPS based serodiagnostic antigens
No full textAntigens produced from Brucella rough lipopolysaccharide (rLPS) antigens have the potential to aid in the serodiagnosis not only of infection due to rough species and strains of Brucella but also infection due to smooth strains. In the latter case this would assist in resolving samples where a false positive result against smooth antigens (i.e. those containing O polysaccharide) may be suspected. A ‘Rough Antigen’ extract prepared from B. abortus RB51 using phenol/chloroform/petroleum ether (PCP) has been evaluated for the serodiagnosis of porcine (B. suis) and canine brucellosis (B.canis) and found to be highly effective. Analysis of the PCP fraction revealed it to be a protein free mixture of rLPS (~60%) and outer membrane phospholipids (~40%). We investigated if further purification of the rLPS may yield a diagnostically superior antigen and produced an antigen that was higher in rLPS purity (>95%). However, this antigen was diagnostically inferior. Furthermore, the depleted material (~5% rLPS) remained diagnostically similar to the original PCP extract. Fragmentation Mass Spectrometry of the depleted antigen suggested the predominance of phospholipids (including phosphatidyl choline) and ornithine lipids. Thin Layer Chromatography (TLC) of the depleted antigen confirmed this predominance and elution of the TLC fractions enabled the specific components to be tested by ELISA. This evaluation confirmed that the major antibody binding material in the extract was rLPS rather than any of the co-extractants. This finding raised the possibility that the presence of surfactants such as phospholipids is enabling and enhancing the diagnostic efficacy of the rLPS in the ELISA. To investigate this we evaluated a range of surfactants by using them to dilute the purified rLPS. The ELISA result from these dilutions showed no increase in the response to a positive serum in the case of dilution with octyl glucoside and CHAPS, but an increase of tenfold or more in the titre of the response after dilution with phospholipids or dodecylmaltoside. We believe that this observation is related to the critical micellar concentration of these compounds and demonstrates that for some antigens, the inclusion of non-antibody binding components can enhance diagnostic performance
O4-1 Antibody response elicited by Brucella abortus strain RB51 vaccine in young water buffaloes (Bubalus bubalis) using a triple dose and the OIE vaccination schedule. A long term trial
No full textBrucella RB51 is a live modified vaccine, obtained from a rough phase mutant of the virulent strain B. abortus 2308. The RB51 strain lacks the side chain O of the LPS thus RB51 vaccinated and non-infected animals do not react to official serological tests (RBT and CFT). This supports the use of the vaccine for a DIVA strategy. RB51 vaccine has been shown to be safe and effective in cattle and bison. Its use in water buffalo has been proposed using a different vaccination protocol but knowledge of long term effects of RB51 vaccination in this species remain incomplete. Aim of the study was to evaluate the kinetics of RB51- antibodies in water buffaloes vaccinated according to the protocol described for the bovine species in the WOAH Manual, modified with the use of a triple dose. Thirty buffaloes 5-9 months old were vaccinated with the commercial vaccine RB51 (CZ Veterinaria, Spain) using a triple dose. Six buffaloes were included as controls. A boostervaccination was administered at 12 month of age. When turning 19-21 months, female animals (both vaccinated and controls) were induced to pregnancy. Blood samples were collected all along the trial, covering vaccination, pregnancy and lactation time. RB51 - specific antibodies were detected and quantified using a specific CFT based on RB51 antigen. All vaccinated animals showed a positive serological reaction following each vaccine injection, but titres and duration of the humoral response differed among animals. For 259 days after booster vaccination, comparison of CFT values between vaccinated and control groups remained significant, despite some of the vaccinated animals turned seronegative. Subsequently, a decrease of antibody titres was recorded with a fluctuating trend observed in several animals, alternating periods of negativity with periods of CFT positivity with titres close to the test cut-off (1:4 serum dilution). Positive animals were still recorded after 2,5 years post vaccination. No relevant changes in antibody titres were recorded during pregnancy or lactation. In conclusion, with the vaccination schedule applied, CFT-RB51 clearly discriminates between vaccinated and unvaccinated controls up to 8 months after the booster. Afterwards, results interpretation becomes less clear-cut considering CFT-RB51 only
K7 Challenges in human brucellosis
No full textBrucellosis remains one of the most common zoonotic human infections, over a century after core methods of prevention were first implemented in Malta. Despite successful eradication in animals and humans from some countries, there has been expanded recognition of human brucellosis throughout southeast and east Asia. Infection has re-emerged in zones of conflict and it is a common cause of fever in North and East Africa. In Western Europe and North America, increasing canine infections with B. canis pose an uncertain threat to humans. The protean clinical features of human disease are well described but diagnostic awareness among clinicians is variable, especially outside endemic areas. Differentiation from tuberculosis is critical when deciding on therapy, particularly in resource poor settings. Diagnostic needs include: implementation of standardized serological tests; development of serological tests for organisms such as B. canis; consensus on the role of PCR and interpretation of significance of prolonged PCR positivity after treatment. Reference databases for matrix assisted laser desorption ionization-time of flight mass spectrometry (MAL-DI-TOF MS) and similar diagnostic tools need enhancement to differentiate Brucella spp. from each other and from newly incorporated species such as Brucella (Ochrobactrum) intermedium, which are rarely pathogenic. Therapy requires at least two antimicrobial agents to reduce the risk of clinical relapse, but there have been no well-designed prospective trials for decades to determine: the optimum dose, duration and safety of modern aminoglycosides instead of streptomycin; the role of fluoroquinolones; optimum duration of treatment for focal skeletal disease; the best therapeutic combinations and duration for children. Staff exposure to live organisms is still a problem in human and veterinary diagnostic laboratories. The need for dual therapy regimens for post exposure prophylaxis (PEP) is debatable and could be reduced to a single drug, with simpler post exposure monitoring programmes to improve PEP adherence. If safe vaccines become available, their use is likely to be limited to selected groups. Mortality should not exceed 1% but human morbidity is substantial, yet clinical research is difficult to fund and poses logistic challenges. This mightimprove if human brucellosis was formally recognized as a neglected tropical disease
K3 Metabolic interaction between Brucella abortus and its host
No full textBrucella abortus has been shown to colonize many different cell types and tissues in the host. At sites such as spleen and lymph nodes, the bacterium persists intracellularly, eliciting only a mild granulomatous inflammatory response. In contrast, in the placenta B. abortus elicits a massive inflammatory response, and many of the bacteria are found to be growing in the extracellular space. This presentation will discuss our lab’s modeling of B. abortus infection in mice and our approaches to understand the metabolic interactions between B. abortus and its replication niches within different types of macrophages and in the placenta. Ultimately, we aim to better understand how the pathogen exploits each environment to replicate and spread to the next host