Identification of Immunogenic Linear B-Cell Epitopes in C. burnetii Outer Membrane Proteins Using Immunoinformatics Approaches Reveals Potential Targets of Persistent Infections.

Coxiella burnetii is a global, highly infectious intracellular bacterium, able to infect a wide range of hosts and to persist for months in the environment. It is the etiological agent of Q fever-a zoonosis of global priority. Currently, there are no national surveillance data on C. burnetii's seroprevalence for any South American country, reinforcing the necessity of developing novel and inexpensive serological tools to monitor the prevalence of infections among humans and animals-especially cattle, goats, and sheep. In this study, we used immunoinformatics and computational biology tools to predict specific linear B-cell epitopes in three C. burnetii outer membrane proteins: OMP-H (CBU_0612), Com-1 (CBU_1910), and OMP-P1 (CBU_0311). Furthermore, predicted epitopes were tested by ELISA, as synthetic peptides, against samples of patients reactive to C. burnetii in indirect immunofluorescence assay, in order to evaluate their natural immunogenicity. In this way, two linear B-cell epitopes were identified in each studied protein (OMP-H(51-59), OMP-H(91-106), Com-1(57-76), Com-1(191-206), OMP-P1(197-209), and OMP-P1(215-227)); all of them were confirmed as naturally immunogenic by the presence of specific antibodies in 77% of studied patients against at least one of the identified epitopes. Remarkably, a higher frequency of endocarditis cases was observed among patients who presented an intense humoral response to OMP-H and Com-1 epitopes. These data confirm that immunoinformatics applied to the identification of specific B-cell epitopes can be an effective strategy to improve and accelerate the development of surveillance tools against neglected diseases.

Serological evidence of Bartonellosis in an indigenous community in the Brazilian Legal Amazonia.

BACKGROUND: Due to immunological susceptibility, close contact with the environment and way of life, indigenous communities are in a highly vulnerable condition to be affected by zoonoses, such as bartonellosis. METHODS: Seventy three paired serum samples were collected from indigenous people from a region of the Brazilian Legal Amazon, in cohorts carried out in 2014 and 2015, with the performance of serological tests by indirect immunofluorescence to detect anti-Bartonella IgG antibodies. The interviews and laboratory results were double entered in the EpiInfo 7 software, and the data processing was performed in the MiniTab 17 software. RESULTS: 5.47% of the indigenous people were seroreagent. The female gender was predominant (65.75%), aged between 20 and 39 years old (39.73%) with complete elementary school (42.47%). As for housing, wooden residences predominated (50.68%). Rodents were seen by 46.58% of the interviewees, and 55.88% of them reported that the animal was close to or inside the house. It was identified that each indigenous family, in its majority, had four to six cats, for the function of hunters of rodents. CONCLUSION: The high concentration of domestic cats, the close contact of indigenous people with wild rodents and the lack of care and poor hygiene of both are aspects that imply the possibility of infection by Bartonella sp. Health surveillance through seroepidemiological studies is essential to find evidence of the circulation of bartonellosis in these populations.

Q Fever in Military Firefighters during Cadet Training in Brazil.

We report five cases of Q fever among cadets during a training program for Military Firefighters Academy in the state of Rio de Janeiro, Brazil. This cluster confirms the significance of Coxiella burnetii as an infectious agent in Brazil, where the occurrence of this zoonosis is poorly documented and highlights the potential risk for Q fever transmission in rural areas or farms with infected animals.