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Zika virus (ZIKV) infection in pregnancy is associated with severe abnormalities of the brain and eye and other adverse outcomes. Zika en Embarazadas y Niños was a prospective cohort study conducted in multiple Colombian cities that enrolled pregnant women in their first trimester. Specimens collected from pregnant women (n = 1,519) during February 2017-September 2018 and their infants (n = 1,080) during June 2017-March 2019 were tested for prenatal ZIKV infection by nucleic acid amplification tests or IgM antibody testing. Zika virus infection in pregnancy was present in 3.2% of pregnant women (incidence rate [IR] per 1,000 person-months = 5.9, 95% CI: 4.3-7.8). Presumptive ZIKV infection was present in 0.8% of infants (IR = 1.6, 95% CI: 0.7-2.9). Five percent of infants with prenatal ZIKV exposure or infection presented with Zika-associated abnormalities; 4.7% were small for gestational age. Understanding the risk of ZIKV infection during pregnancy and associated adverse outcomes can help inform counseling efforts.
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CONTEXT: Health departments (HDs) work on the front lines to ensure the health of their communities, providing a unique perspective to public health response activities. Say Yes! COVID Test (SYCT) is a US federally funded program providing free COVID-19 self-tests to communities with high COVID-19 transmission, low vaccination rates, and high social vulnerability. The collaboration with 9 HDs was key for the program distribution of 5.8 million COVID-19 self-tests between March 31 and November 30, 2021. OBJECTIVE: The objective of this study was to gather qualitative in-depth information on the experiences of HDs with the SYCT program to better understand the successes and barriers to implementing community-focused self-testing programs. DESIGN: Key informant (KI) interviews. SETTING: Online interviews conducted between November and December 2021. PARTICIPANTS: Sixteen program leads representing 9 HDs were purposefully sampled as KIs. KIs completed 60-minute structured interviews conducted by one trained facilitator and recorded. MAIN OUTCOME MEASURES: Key themes and lessons learned were identified using grounded theory. RESULTS: Based on perceptions of KIs, HDs that maximized community partnerships for test distribution were more certain that populations at a higher risk for COVID-19 were reached. Where the HD relied predominantly on direct-to-consumer distribution, KIs were less certain that communities at higher risk were served. Privacy and anonymity in testing were themes linked to higher perceived community acceptance. KIs reported that self-test demand and distribution levels increased during higher COVID-19 transmission levels. CONCLUSION: HDs that build bridges and engage with community partners and trusted leaders are better prepared to identify and link high-risk populations with health services and resources. When collaborating with trusted community organizations, KIs perceived that the SYCT program overcame barriers such as mistrust of government intervention and desire for privacy and motivated community members to utilize this resource to protect themselves against COVID-19.
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COVID-19 , Humanos , COVID-19/diagnóstico , COVID-19/epidemiología , COVID-19/prevención & control , Autoevaluación , Prueba de COVID-19 , Teoría Fundamentada , Salud PúblicaRESUMEN
PURPOSE: Information on incentives for COVID-19 testing is needed to understand effective practices that encourage testing uptake. We describe characteristics of those who received an incentive after performing a rapid antigen test. DESIGN: Cross-sectional descriptive analysis of survey data. SETTING: During April 29-May 9, 2021, COVID-19 rapid antigen testing was offered in 2 Maryland cities. SAMPLE: Convenience sample of 553 adults (≥18 years) who tested and received an incentive; 93% consented to survey. MEASURES: Survey questions assessed reasons for testing, testing history, barriers, and demographics. ANALYSIS: Robust Poisson regressions were used to determine characteristic differences based on testing history and between participants who would re-test in the future without an incentive vs participants who would not. RESULTS: The most common reasons for testing were the desire to be tested (n = 280; 54%) and convenience of location (n = 146; 28%). Those motivated by an incentive to test (n = 110; 21%) were 5.83 times as likely to state they would not test again without an incentive, compared to those with other reasons for testing (95% CI: 2.67-12.72, P < .001). CRITICAL LIMITATIONS: No comparative study group. CONCLUSION: Results indicate internal motivation and convenience were prominent factors supporting testing uptake. Incentives may increase community testing participation, particularly among people who have never tested. Keywords COVID-19, pandemic, incentives, health behavior, community testing.
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COVID-19 , Motivación , Adulto , Humanos , Maryland , Prueba de COVID-19 , Estudios Transversales , COVID-19/diagnósticoRESUMEN
OBJECTIVE: During the COVID-19 pandemic, the unemployment rate in the United States peaked at 14.8% in April 2020. We examined patterns in unemployment following this peak in counties with rapid increases in COVID-19 incidence. METHOD: We used CDC aggregate county data to identify counties with rapid increases in COVID-19 incidence (rapid riser counties) during July 1-October 31, 2020. We used a linear regression model with fixed effect to calculate the change of unemployment rate difference in these counties, stratified by the county's social vulnerability (an indicator compiled by CDC) in the two months before the rapid riser index month compared to the index month plus one month after the index month. RESULTS: Among the 585 (19% of U.S. counties) rapid riser counties identified, the unemployment rate gap between the most and least socially vulnerable counties widened by 0.40 percentage point (p<0.01) after experiencing a rapid rise in COVID-19 incidence. Driving the gap were counties with lower socioeconomic status, with a higher percentage of people in racial and ethnic minority groups, and with limited English proficiency. CONCLUSION: The widened unemployment gap after COVID-19 incidence rapid rise between the most and least socially vulnerable counties suggests that it may take longer for socially and economically disadvantaged communities to recover. Loss of income and benefits due to unemployment could hinder behaviors that prevent spread of COVID-19 (e.g., seeking healthcare) and could impede response efforts including testing and vaccination. Addressing the social needs within these vulnerable communities could help support public health response measures.
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COVID-19 , COVID-19/epidemiología , Etnicidad , Humanos , Incidencia , Grupos Minoritarios , Pandemias , Vulnerabilidad Social , Desempleo , Estados Unidos/epidemiologíaRESUMEN
On December 2, 2021, the Minnesota Department of Health (MDH) notified CDC of a COVID-19 case caused by sequence-confirmed SARS-CoV-2 B.1.1.529 (Omicron) variant in a Minnesota resident (patient A), the first such case identified in the state and one of the earliest identified in the United States. Patient A had attended a large indoor convention in New York, New York with approximately 53,000 attendees from 52 U.S jurisdictions and 30 foreign countries during November 19-21, 2021, and had close contact during 5 days with 29 fellow attendees. The convention required attendees to have received ≥1 COVID-19 vaccine dose and enforced mask-use while indoors. On November 22, these close contact attendees were directly and immediately notified by patient A of their exposure to SARS-CoV-2, and they sought testing over the next few days while quarantined or isolated. As part of the larger investigation into SARS-CoV-2 transmission at the convention, a subinvestigation was conducted during December by CDC, MDH, and respective state and local health departments to characterize the epidemiology of Omicron variant infection among this group of close contacts and determine the extent of secondary household transmission. Among 30 convention attendees that included patient A (the index patient) and the 29 other close contacts, 23 were interviewed, among whom all were fully vaccinated, including 11 (48%) who had received a booster dose; all 23 sought testing, and 16 (70%) received a positive SARS-CoV-2 test result. Fewer attendees who had received a booster dose before the convention received a positive test result (six of 11) compared with those who had not received a booster dose (10 of 12). The 16 attendees with positive test results had a total of 20 household contacts, 18 of whom sought testing after exposure; six received a positive test result for SARS-CoV-2. None of the persons with positive test results was hospitalized or died. There was limited convention-associated transmission identified outside of this cluster; the larger investigation included cases of both SARS-CoV-2 B.1.617.2 (Delta) and Omicron, and all Omicron cases were associated with this group (1). Data from this investigation reinforces the importance of COVID-19 booster doses in combination with early notification and other multicomponent prevention measures to limit transmission and prevent severe illness from Omicron and other SARS-CoV-2 variants.
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COVID-19/epidemiología , Trazado de Contacto/métodos , Brotes de Enfermedades , Reuniones Masivas , SARS-CoV-2 , Adulto , COVID-19/prevención & control , Vacunas contra la COVID-19/administración & dosificación , Femenino , Humanos , Masculino , Ciudad de Nueva York/epidemiología , Red Social , Estados Unidos/epidemiologíaAsunto(s)
COVID-19 , Equidad en Salud , Humanos , Pandemias/prevención & control , SARS-CoV-2 , Estados Unidos/epidemiologíaRESUMEN
During July 2021, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.617.2 variant infections, including vaccine breakthrough infections, occurred after large public gatherings in Provincetown, Massachusetts, USA, prompting a multistate investigation. Public health departments identified primary and secondary cases by using coronavirus disease surveillance data, case investigations, and contact tracing. A primary case was defined as SARS-CoV-2 detected <14 days after travel to or residence in Provincetown during July 3-17. A secondary case was defined as SARS-CoV-2 detected <14 days after close contact with a person who had a primary case but without travel to or residence in Provincetown during July 3-August 10. We identified 1,098 primary cases and 30 secondary cases associated with 26 primary cases among fully and non-fully vaccinated persons. Large gatherings can have widespread effects on SARS-CoV-2 transmission, and fully vaccinated persons should take precautions, such as masking, to prevent SARS-CoV-2 transmission, particularly during substantial or high transmission.
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COVID-19 , Vacunas contra la COVID-19 , Brotes de Enfermedades , Humanos , Massachusetts , SARS-CoV-2 , Estados Unidos/epidemiologíaRESUMEN
Pregnant and recently pregnant women are at increased risk for severe illness and death from COVID-19 compared with women who are not pregnant or were not recently pregnant (1,2). CDC recommends COVID-19 vaccination for women who are pregnant, recently pregnant, trying to become pregnant, or might become pregnant in the future.*, This report describes 15 COVID-19-associated deaths after infection with SARS-CoV-2 (the virus that causes COVID-19) during pregnancy in Mississippi during March 1, 2020-October 6, 2021.
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COVID-19/mortalidad , Complicaciones Infecciosas del Embarazo/epidemiología , Adulto , Vacunas contra la COVID-19/administración & dosificación , Centers for Disease Control and Prevention, U.S. , Femenino , Humanos , Mississippi/epidemiología , Guías de Práctica Clínica como Asunto , Embarazo , Medición de Riesgo , Estados Unidos , Adulto JovenRESUMEN
Project Vigilancia de Embarazadas con Zika (VEZ), an intensified surveillance of pregnant women with symptoms of the Zika virus disease (ZVD) in Colombia, aimed to evaluate the relationship between symptoms of ZVD during pregnancy and adverse pregnancy, birth, and infant outcomes and early childhood neurodevelopmental outcomes. During May-November 2016, pregnant women in three Colombian cities who were reported with symptoms of ZVD to the national surveillance system, or with symptoms of ZVD visiting participating clinics, were enrolled in Project VEZ. Data from maternal and pediatric (up to two years of age) medical records were abstracted. Available maternal specimens were tested for the presence of the Zika virus ribonucleic acid and/or anti-Zika virus immunoglobulin antibodies. Of 1213 enrolled pregnant women with symptoms of ZVD, 1180 had a known pregnancy outcome. Results of the Zika virus laboratory testing were available for 569 (48.2%) pregnancies with a known pregnancy outcome though testing timing varied and was often distal to the timing of symptoms; 254 (21.5% of the whole cohort; 44.6% of those with testing results) were confirmed or presumptive positive for the Zika virus infection. Of pregnancies with a known outcome, 50 (4.2%) fetuses/infants had Zika-associated brain or eye defects, which included microcephaly at birth. Early childhood adverse neurodevelopmental outcomes were more common among those with Zika-associated birth defects than among those without and more common among those with laboratory evidence of a Zika virus infection compared with the full cohort. The proportion of fetuses/infants with any Zika-associated brain or eye defect was consistent with the proportion seen in other studies. Enhancements to Colombia's existing national surveillance enabled the assessment of adverse outcomes associated with ZVD in pregnancy.
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In January 2020, Santa Clara County, California, USA, began identifying laboratory-confirmed coronavirus disease among residents. County staff conducted case and contact investigations focused on households and collected detailed case demographic, occupation, exposure, and outcome information. We describe the first 200 test-positive cases during January 31-March 20, 2020, to inform future case and contact investigations. Probable infection sources included community transmission (104 cases), known close contact with a confirmed case-patient (66 cases), and travel (30 cases). Disease patterns across race and ethnicity, occupational, and household factors suggested multiple infection risk factors. Disproportionately high percentages of case-patients from racial and ethnic subgroups worked outside the home (Hispanic [86%] and Filipino [100%]); household transmission was more common among persons from Vietnam (53%). Even with the few initial cases, detailed case and contact investigations of household contacts capturing occupational and disaggregated race and ethnicity data helped identify at-risk groups and focused solutions for disease control.
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COVID-19 , Trazado de Contacto , California/epidemiología , Humanos , SARS-CoV-2 , VietnamRESUMEN
During February 2021, an opening event was held indoors at a rural Illinois bar that accommodates approximately 100 persons. The Illinois Department of Public Health (IDPH) and local health department staff members investigated a COVID-19 outbreak associated with this opening event. Overall, 46 COVID-19 cases were linked to the event, including cases in 26 patrons and three staff members who attended the opening event and 17 secondary cases. Four persons with cases had COVID-19-like symptoms on the same day they attended the event. Secondary cases included 12 cases in eight households with children, two on a school sports team, and three in a long-term care facility (LTCF). Transmission associated with the opening event resulted in one school closure affecting 650 children (9,100 lost person-days of school) and hospitalization of one LTCF resident with COVID-19. These findings demonstrate that opening up settings such as bars, where mask wearing and physical distancing are challenging, can increase the risk for community transmission of SARS-CoV-2, the virus that causes COVID-19. As community businesses begin to reopen, a multicomponent approach should be emphasized in settings such as bars to prevent transmission* (1). This includes enforcing consistent and correct mask use, maintaining ≥6 ft of physical distance between persons, reducing indoor bar occupancy, prioritizing outdoor seating, improving building ventilation, and promoting behaviors such as staying at home when ill, as well as implementing contact tracing in combination with isolation and quarantine when COVID-19 cases are diagnosed.
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COVID-19/transmisión , Infecciones Comunitarias Adquiridas , Restaurantes/organización & administración , Adolescente , Adulto , Anciano , COVID-19/epidemiología , Niño , Femenino , Humanos , Illinois/epidemiología , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
INTRODUCTION: With the growing use of online study management systems and rapid availability of data, timely data review and quality assessments are necessary to ensure proper clinical trial implementation. In this report we describe central monitoring used to ensure protocol compliance and accurate data reporting, implemented during a large phase 3 clinical trial. MATERIAL AND METHODS: The Tuberculosis Trials Consortium (TBTC) Study 31/AIDS Clinical Trials Group (ACTG) study A5349 (S31) is an international, multi-site, randomized, open-label, controlled, non-inferiority phase 3 clinical trial comparing two 4-month regimens to a standard 6 month regimen for treatment of drug-susceptible tuberculosis (TB) among adolescents and adults with a sample size of 2500 participants. RESULTS: Central monitoring utilized primary study data in a five-tiered approach, including (1) real-time data checks & topic-specific intervention reports, (2) missing forms reports, (3) quality assurance metrics, (4) critical data reports and (5) protocol deviation identification, aimed to detect and resolve quality challenges. Over the course of the study, 240 data checks and reports were programed across the five tiers used. DISCUSSION: This use of primary study data to identify issues rapidly allowed the study sponsor to focus quality assurance and data cleaning activities on prioritized data, related to protocol compliance and accurate reporting of study results. Our approach enabled us to become more efficient and effective as we informed sites about deviations, resolved missing or inconsistent data, provided targeted guidance, and gained a deeper understanding of challenges experienced at clinical trial sites. TRIAL REGISTRATION: This trial was registered with ClinicalTrials.gov (Identifier: NCT02410772) on April 8, 2015.
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Antituberculosos , Tuberculosis Pulmonar , Adolescente , Adulto , Antituberculosos/uso terapéutico , Protocolos Clínicos , Humanos , Resultado del Tratamiento , Tuberculosis Pulmonar/tratamiento farmacológicoRESUMEN
During January 1, 2020-August 10, 2020, an estimated 5 million cases of coronavirus disease 2019 (COVID-19) were reported in the United States.* Published state and national data indicate that persons of color might be more likely to become infected with SARS-CoV-2, the virus that causes COVID-19, experience more severe COVID-19-associated illness, including that requiring hospitalization, and have higher risk for death from COVID-19 (1-5). CDC examined county-level disparities in COVID-19 cases among underrepresented racial/ethnic groups in counties identified as hotspots, which are defined using algorithmic thresholds related to the number of new cases and the changes in incidence. Disparities were defined as difference of ≥5% between the proportion of cases and the proportion of the population or a ratio ≥1.5 for the proportion of cases to the proportion of the population for underrepresented racial/ethnic groups in each county. During June 5-18, 205 counties in 33 states were identified as hotspots; among these counties, race was reported for ≥50% of cumulative cases in 79 (38.5%) counties in 22 states; 96.2% of these counties had disparities in COVID-19 cases in one or more underrepresented racial/ethnic groups. Hispanic/Latino (Hispanic) persons were the largest group by population size (3.5 million persons) living in hotspot counties where a disproportionate number of cases among that group was identified, followed by black/African American (black) persons (2 million), American Indian/Alaska Native (AI/AN) persons (61,000), Asian persons (36,000), and Native Hawaiian/other Pacific Islander (NHPI) persons (31,000). Examining county-level data disaggregated by race/ethnicity can help identify health disparities in COVID-19 cases and inform strategies for preventing and slowing SARS-CoV-2 transmission. More complete race/ethnicity data are needed to fully inform public health decision-making. Addressing the pandemic's disproportionate incidence of COVID-19 in communities of color can reduce the community-wide impact of COVID-19 and improve health outcomes.
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Infecciones por Coronavirus/etnología , Etnicidad/estadística & datos numéricos , Disparidades en el Estado de Salud , Neumonía Viral/etnología , Grupos Raciales/estadística & datos numéricos , COVID-19 , Infecciones por Coronavirus/epidemiología , Humanos , Incidencia , Pandemias , Neumonía Viral/epidemiología , Estados Unidos/epidemiologíaRESUMEN
BACKGROUND: Zika virus infection during pregnancy can cause serious birth defects, which include brain and eye abnormalities. The clinical importance of detection of Zika virus RNA in amniotic fluid is unknown. OBJECTIVE: The purpose of this study was to describe patterns of Zika virus RNA testing of amniotic fluid relative to other clinical specimens and to examine the association between Zika virus detection in amniotic fluid and Zika-associated birth defects. Our null hypothesis was that Zika virus detection in amniotic fluid was not associated with Zika-associated birth defects. STUDY DESIGN: We conducted a retrospective cohort analysis of women with amniotic fluid specimens submitted to Colombia's National Institute of Health as part of national Zika virus surveillance from January 2016 to January 2017. Specimens (maternal serum, amniotic fluid, cord blood, umbilical cord tissue, and placental tissue) were tested for the presence of Zika virus RNA with the use of a singleplex or multiplex real-time reverse transcriptase-polymerase chain reaction assay. Birth defect information was abstracted from maternal prenatal and infant birth records and reviewed by expert clinicians. Chi-square and Fisher's exact tests were used to compare the frequency of Zika-associated birth defects (defined as brain abnormalities [with or without microcephaly, but excluding neural tube defects and their associated findings] or eye abnormalities) by frequency of detection of Zika virus RNA in amniotic fluid. RESULTS: Our analysis included 128 women with amniotic fluid specimens. Seventy-five women (58%) had prenatally collected amniotic fluid; 42 women (33%) had amniotic fluid collected at delivery, and 11 women (9%) had missing collection dates. Ninety-one women had both amniotic fluid and other clinical specimens submitted for testing, which allowed for comparison across specimen types. Of those 91 women, 68 had evidence of Zika virus infection based on detection of Zika virus RNA in ≥1 specimen. Testing of amniotic fluid that was collected prenatally or at delivery identified 39 of these Zika virus infections (57%; 15 [22%] infections were identified only in amniotic fluid), and 29 infections (43%) were identified in other specimen types and not amniotic fluid. Among women who were included in the analysis, 89 had pregnancy outcome information available, which allowed for the assessment of the presence of Zika-associated birth defects. Zika-associated birth defects were significantly (P<.05) more common among pregnancies with Zika virus RNA detected in amniotic fluid specimens collected prenatally (19/32 specimens; 59%) than for those with no laboratory evidence of Zika virus infection in any specimen (6/23 specimens; 26%), but the proportion was similar in pregnancies with only Zika virus RNA detected in specimens other than amniotic fluid (10/23 specimens; 43%). Although Zika-associated birth defects were more common among women with any Zika virus RNA detected in amniotic fluid specimens (ie, collected prenatally or at delivery; 21/43 specimens; 49%) than those with no laboratory evidence of Zika virus infection (6/23 specimens; 26%), this comparison did not reach statistical significance (P=.07). CONCLUSION: Testing of amniotic fluid provided additional evidence for maternal diagnosis of Zika virus infection. Zika-associated birth defects were more common among women with Zika virus RNA that was detected in prenatal amniotic fluid specimens than women with no laboratory evidence of Zika virus infection, but similar to women with Zika virus RNA detected in other, nonamniotic fluid specimen types.
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Líquido Amniótico/virología , Encéfalo/anomalías , Anomalías del Ojo/epidemiología , Microcefalia/epidemiología , Complicaciones Infecciosas del Embarazo/metabolismo , ARN Viral/metabolismo , Infección por el Virus Zika/metabolismo , Virus Zika/genética , Adulto , Líquido Amniótico/metabolismo , Estudios de Cohortes , Colombia/epidemiología , Femenino , Sangre Fetal/metabolismo , Sangre Fetal/virología , Humanos , Recién Nacido , Malformaciones del Sistema Nervioso/epidemiología , Placenta/metabolismo , Placenta/virología , Embarazo , Complicaciones Infecciosas del Embarazo/epidemiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Estudios Retrospectivos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Cordón Umbilical/metabolismo , Cordón Umbilical/virología , Adulto Joven , Infección por el Virus Zika/epidemiologíaRESUMEN
Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic) vs. non-infectious Leptospira, this work provides new insights into the evolution of a genus of bacterial pathogens. This work will be a comprehensive roadmap for understanding leptospirosis pathogenesis. More generally, it provides new insights into mechanisms by which bacterial pathogens adapt to mammalian hosts.
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Genoma Bacteriano , Leptospira/genética , Leptospirosis/microbiología , Leptospirosis/veterinaria , Animales , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sistemas de Secreción Bacterianos , Secuencia de Bases , Evolución Molecular , Genómica , Humanos , Leptospira/clasificación , Leptospira/aislamiento & purificación , Leptospira/patogenicidad , Datos de Secuencia Molecular , Filogenia , Señales de Clasificación de Proteína , VirulenciaRESUMEN
Leptospirosis is the most common zoonotic disease worldwide with an estimated 500,000 severe cases reported annually, and case fatality rates of 12-25%, due primarily to acute kidney and lung injuries. Despite its prevalence, the molecular mechanisms underlying leptospirosis pathogenesis remain poorly understood. To identify virulence-related genes in Leptospira interrogans, we delineated cumulative genome changes that occurred during serial in vitro passage of a highly virulent strain of L. interrogans serovar Lai into a nearly avirulent isogenic derivative. Comparison of protein coding and computationally predicted noncoding RNA (ncRNA) genes between these two polyclonal strains identified 15 nonsynonymous single nucleotide variant (nsSNV) alleles that increased in frequency and 19 that decreased, whereas no changes in allelic frequency were observed among the ncRNA genes. Some of the nsSNV alleles were in six genes shown previously to be transcriptionally upregulated during exposure to in vivo-like conditions. Five of these nsSNVs were in evolutionarily conserved positions in genes related to signal transduction and metabolism. Frequency changes of minor nsSNV alleles identified in this study likely contributed to the loss of virulence during serial in vitro culture. The identification of new virulence-associated genes should spur additional experimental inquiry into their potential role in Leptospira pathogenesis.
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Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Leptospira/metabolismo , Alelos , Proteínas Bacterianas/genética , Técnicas Bacteriológicas , Genoma Bacteriano , Leptospira/genética , Leptospira/patogenicidad , VirulenciaRESUMEN
Human brucellosis is most commonly diagnosed by serology based on agglutination of fixed Brucella abortus as antigen. Nucleic acid amplification techniques have not proven capable of reproducibly and sensitively demonstrating the presence of Brucella DNA in clinical specimens. We sought to optimize a monoclonal antibody-based assay to detect Brucella melitensis lipopolysaccharide in blood by conjugating B. melitensis LPS to keyhole limpet hemocyanin, an immunogenic protein carrier to maximize IgG affinity of monoclonal antibodies. A panel of specific of monoclonal antibodies was obtained that recognized both B. melitensis and B. abortus lipopolysaccharide epitopes. An antigen capture assay was developed that detected B. melitensis in the blood of experimentally infected mice and, in a pilot study, in naturally infected Peruvian subjects. As a proof of principle, a majority (7/10) of the patients with positive blood cultures had B. melitensis lipopolysaccharide detected in the initial blood specimen obtained. One of 10 patients with relapsed brucellosis and negative blood culture had a positive serum antigen test. No seronegative/blood culture negative patients had a positive serum antigen test. Analysis of the pair of monoclonal antibodies (2D1, 2E8) used in the capture ELISA for potential cross-reactivity in the detection of lipopolysaccharides of E. coli O157:H7 and Yersinia enterocolitica O9 showed specificity for Brucella lipopolysaccharide. This new approach to develop antigen-detection monoclonal antibodies against a T cell-independent polysaccharide antigen based on immunogenic protein conjugation may lead to the production of improved rapid point-of-care-deployable assays for the diagnosis of brucellosis and other infectious diseases.
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Anticuerpos Antibacterianos , Anticuerpos Monoclonales , Antígenos Bacterianos/sangre , Brucella abortus/aislamiento & purificación , Brucella melitensis/aislamiento & purificación , Brucelosis/diagnóstico , Lipopolisacáridos/sangre , Adulto , Animales , Brucella abortus/química , Brucella melitensis/química , Ensayo de Inmunoadsorción Enzimática/métodos , Humanos , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Sensibilidad y EspecificidadRESUMEN
Leptospirosis is a globally important, neglected zoonotic infection caused by spirochetes of the genus Leptospira. Since genetic transformation remains technically limited for pathogenic Leptospira, a systems biology pathogenomic approach was used to infer leptospiral virulence genes by whole genome comparison of culture-attenuated Leptospira interrogans serovar Lai with its virulent, isogenic parent. Among the 11 pathogen-specific protein-coding genes in which non-synonymous mutations were found, a putative soluble adenylate cyclase with host cell cAMP-elevating activity, and two members of a previously unstudied â¼15 member paralogous gene family of unknown function were identified. This gene family was also uniquely found in the alpha-proteobacteria Bartonella bacilliformis and Bartonella australis that are geographically restricted to the Andes and Australia, respectively. How the pathogenic Leptospira and these two Bartonella species came to share this expanded gene family remains an evolutionary mystery. In vivo expression analyses demonstrated up-regulation of 10/11 Leptospira genes identified in the attenuation screen, and profound in vivo, tissue-specific up-regulation by members of the paralogous gene family, suggesting a direct role in virulence and host-pathogen interactions. The pathogenomic experimental design here is generalizable as a functional systems biology approach to studying bacterial pathogenesis and virulence and should encourage similar experimental studies of other pathogens.