Coxiella burnetii seroprevalence in sheep herd from Paraguay: First evidence of bacterial circulation in the country

Coxiella burnetii is the agent of Q fever, a disease that poses risks to public health and damages livestock. We discovered the circulation of C. burnetii for the first time in Paraguay, based on the seropositivity of a flock of >300 sheep. The animals were tested by IFA for anti-C. burnetii antibodies and by SAM for anti-Leptospira spp. antibodies, an important differential diagnosis for reproductive disorders in sheep in Paraguay. C. burnetii seropositivity was determined in 45%, in contrast to Leptospira spp. which had no reactive samples. Cases of miscarriage and fetal resorption were associated with high seropositivity titers. This study suggests the circulation of a unique genotype in the country and an imminent risk to public health, since in addition to being highly transmissible and infectious to humans, Q fever is still not a cause for concern on the part of government and health agencies in the country.

Serosurvey of Coxiella burnetii in Descendants of Former Black Slaves (Quilombola Communities) of Southern Brazil

Brazilian descendants of former Black-slave (quilombola) communities have been predisposed to several zoonotic diseases due to social vulnerability, characterized by subsistence and close contact with livestock and companion animals. Accordingly, the present study has assessed anti-Coxiella burnetii antibodies in 200 individuals and 20 dogs from four quilombola communities located in Paraná State, southern Brazil. Serum samples were tested by indirect immunofluorescence assay (IFA) using in-house and commercial diagnostic protocols, with analysis of seropositive titers and antibody type. Fisher's exact test was used to compare seropositivity to C. burnetti with binary variables, with variables with three or more possible responses submitted to logistic regression. In total, 44/200 (22%; 95% CI 16.82-28.24) people tested positive, and 4.5% had titers higher than 128, indicating a recent onset of C. burnetii infection. Seropositive individuals were statistically associated with the Limitão community (p = 0.0013), urban workers as occupations (p = 0.0475), consumption of undercooked meat (p = 0.0159), and contact with animal abortion (p = 0.0276). No seropositivity association was found for age, sex, education, habit of entering forest areas, consumption of game meat, consumption of raw milk, flea and tick bites, dog contact, or history of female miscarriage. Only one of 20 dogs was seropositive with a titer of 128, probably related to an acute animal infection. Despite the prevalence here being higher than previous Brazilian reports, including with symptomatic populations, the results were within range for worldwide outbreaks and occupational risk populations. To the reader's knowledge, this is the first human survey of Q fever in southern Brazil and should be considered a warning for C. burnetii in vulnerable populations, particularly Quilombola communities.

Comparison of Three Serologic Tests for the Detection of Anti-Coxiella burnetii Antibodies in Patients with Q Fever

The performance of a commercial immunofluorescence assay (IFA commercial), an in-house immunofluorescence assay (IFA in-house) and an indirect enzyme-linked immunosorbent assay (ELISA) were evaluated in the detection of antibodies anti-C. burnetii in the serum of Q fever patients and persons without the disease. For the study, seropositive and seronegative samples for Q fever (n = 200) from a serum bank of the Instituto Adolfo Lutz in Brazil were used. Commercial IFA was considered in this study as the gold standard for diagnosing Q fever. The in-house IFA demonstrated good agreement with the commercial test, showing high sensitivity (91%) and specificity (97%) compared to the gold standard, with a Kappa coefficient of 0.8954. The indirect ELISA test showed lower agreement with the gold standard, showing low sensitivity (67%), although the specificity of the technique was high (97%) and the Kappa coefficient was moderate (0.6631). In-house IFA is an excellent alternative for diagnosing Q fever.

Overview of Q fever in Brazil: an underestimated zoonosis

This review aims to provide current information about Q fever, elucidating the etiological, epidemiological, pathogenic, clinical, diagnostic, therapeutic, and prophylactic aspects of the disease for the medical community. We discuss the main forms of presentation of the agent, its ability to persist in the body, the infinite possibilities of susceptible hosts, the main known forms of transmission, its importance in populations at occupational risk, and the role of arthropods in the natural history of the disease. Focusing on Brazil, we present the cases already described and studies developed since its first report, and how there is still much to unravel. We are aware of the possibilities of the persistence of the agent and the development of severe clinical pictures and the specific treatments currently instituted. We also wish to raise awareness about the future, the new genotypes that are emerging, the need to study the effects of vaccines, and the impact of Q fever on the population. Q fever is a poorly understood disease in Latin America, and recent studies, especially in Brazil, have revealed the importance of developing new studies.

Plastination with low viscosity silicone: strategy for less tissue shrinkage

Plastination is an anatomical technique for preserving biological tissues based on the principle of replacing body fluids with a curable polymer. An inconvenient aspect of this technique is the tissue shrinkage it causes; several studies seek ways to reduce or avoid this shrinkage. Additionally, there are no studies in the literature that quantitatively evaluate the use of low viscosity silicones in plastination having shrinkage of tissue as a parameter. Therefore, this study aimed to evaluate the use of Silicones S10 (Biodur) and P1 (Polisil) in the plastination of different types of biological tissues of a sliced human body, having as a parameter the tissue shrinkage caused in the forced impregnation stage. Human cardiac, pulmonary, splenic, renal, hepatic, muscular, and bone tissues were analyzed. For such purpose, a male human body was used, sliced in 13-15-mm-thick pieces, having as a parameter the before and the after plastination with the different silicones. The standard protocol of the plastination of the slices was followed: dehydration, forced impregnation, and curation. Half of the pieces obtained were plastinated with silicone P1 (group P1) and the other half with S10 (group S10). All tissues and anatomical segments analyzed in this study showed less or equal shrinkage when plastination of the control group (S10) was compared with that of the P1 group. Therefore, we concluded that the lower viscosity silicone promoted less tissue shrinkage, making it a viable alternative to the reference.

Seropositivity for Coxiella burnetii in suspected patients with dengue in São Paulo state, Brazil

Q fever and brucellosis are zoonoses that cause fever and other systemic clinical signs in humans; their occurrences are neglected and the differential diagnosis for some diseases is disregarded. This study aimed to investigate the seropositivity for Coxiella burnetii and Brucella spp. antibodies in patients suspected of dengue from 38 municipalities in the state of São Paulo, Brazil. The samples (n = 604) were obtained by convenience from the Adolfo Lutz Institute serum bank. Sera were subjected to an indirect immunofluorescence assay (IFA) using in-house and commercial diagnostic protocols to evaluate C. burnetii positivity. For Brucella spp., sera were subjected to rapid plate serum agglutination with buffered acidified antigen (AAT), slow tube serum agglutination (SAL), and 2-mercaptoethanol (2-ME) techniques. Associations and statistical inferences of the results were performed by logistic regression according to the clinical and demographic variables collected from the patients. Statistical analyses were performed using Statistical Analysis Software (SAS) and associations were considered when p value was <0.05. In all, 129 patients showed positive results for Q fever, indicating a seropositivity of 21.4% (95% CI 18.15–24.85). Patients with 14–20 days of symptoms had 2.12 (95% CI 1.34–3.35) times more chances of being seropositive for Q fever than patients with 7–13 days, and patients with 21–27 days of fever had 2.62 (95% CI 1.27–5.41) times more chances of being seropositive for Q fever than patients with 7–13 days. For the other variables analyzed, there were no significant associations between the groups. No positivity for brucellosis was observed. This is the most comprehensive study of people seropositive for Q fever in São Paulo state and provides additional data for the medical community in Brazil. It is suggested that Q fever may be an important differential diagnosis of febrile illnesses in the region, demanding the government’s attention and investment in health.

Brazil is a tropical country with a warm climate and large animal herds that favor many zoonotic agents that circulate in the territory. Due to the high prevalence of some tropical diseases, such as dengue, malaria, and chikungunya, important zoonoses have been neglected during the clinical evaluation of patients, resulting in misdiagnosis. Examples include Q fever and brucellosis, zoonoses that occur in animals in Brazil and are easily transmitted to humans through contaminated air and food products. There is not much data on these diseases in humans in the country representing their actual health situation. The current knowledge is supported by a few serological surveys developed by research groups and case reports. In this study, sera from patients with fever of unknown origin were positive for Q fever and brucellosis. The authors found that, contrary to brucellosis, Q fever has affected many people in São Paulo, the most populous state in the country. In addition, other findings regarding patient profile and disease behavior have been established. This research highlights the need for surveillance and control of Q fever in humans and animals to prevent acute cases and treat chronic patients.

The ongoing COVID-19 epidemic in Minas Gerais, Brazil: insights from epidemiological data and SARS-CoV-2 whole genome sequencing

The recent emergence of a coronavirus (SARS-CoV-2), first identified in the Chinese city of Wuhan in December 2019, has had major public health and economic consequences. Although 61,888 confirmed cases were reported in Brazil by 28 April 2020, little is known about the SARS-CoV-2 epidemic in this country. To better understand the recent epidemic in the second most populous state in southeast Brazil - Minas Gerais (MG) - we sequenced 40 complete SARS-CoV-2 genomes from MG cases and examined epidemiological data from three Brazilian states. Both the genome analyses and the geographical distribution of reported cases indicate for multiple independent introductions into MG. Epidemiological estimates of the reproductive number (R) using different data sources and theoretical assumptions suggest the potential for sustained virus transmission despite a reduction in R from the first reported case to the end of April 2020. The estimated date of SARS-CoV-2 introduction into Brazil was consistent with epidemiological data from the first case of a returned traveller from Lombardy, Italy. These findings highlight the nature of the COVID-19 epidemic in MG and reinforce the need for real-time and continued genomic surveillance strategies to better understand and prepare for the epidemic spread of emerging viral pathogens..

Genomic and epidemiological monitoring of yellow fever virus transmission potential

The yellow fever virus (YFV) epidemic in Brazil is the largest in decades. The recent discovery of YFV in Brazilian Aedes species mosquitos highlights a need to monitor the risk of reestablishment of urban YFV transmission in the Americas. We use a suite of epidemiological, spatial, and genomic approaches to characterize YFV transmission. We show that the age and sex distribution of human cases is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally reveals an early phase of sylvatic YFV transmission and spatial expansion toward previously YFV-free areas, followed by a rise in viral spillover to humans in late 2016. Our results establish a framework for monitoring YFV transmission in real time that will contribute to a global strategy to eliminate future YFV epidemics.