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1.
Clin Infect Dis ; 73(3): e569-e579, 2021 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-33044509

RESUMEN

BACKGROUND: Shigella is a leading cause of childhood diarrhea and target for vaccine development. Microbiologic and clinical case definitions are needed for pediatric field vaccine efficacy trials. METHODS: We compared characteristics of moderate to severe diarrhea (MSD) cases in the Global Enteric Multicenter Study (GEMS) between children with culture positive Shigella to those with culture-negative, quantitative polymerase chain reaction (qPCR)-attributable Shigella (defined by an ipaH gene cycle threshold <27.9). Among Shigella MSD cases, we determined risk factors for death and derived a clinical severity score. RESULTS: Compared to culture-positive Shigella MSD cases (n = 745), culture-negative/qPCR-attributable Shigella cases (n = 852) were more likely to be under 12 months, stunted, have a longer duration of diarrhea, and less likely to have high stool frequency or a fever. There was no difference in dehydration, hospitalization, or severe classification from a modified Vesikari score. Twenty-two (1.8%) Shigella MSD cases died within the 14-days after presentation to health facilities, and 59.1% of these deaths were in culture-negative cases. Age <12 months, diarrhea duration prior to presentation, vomiting, stunting, wasting, and hospitalization were associated with mortality. A model-derived score assigned points for dehydration, hospital admission, and longer diarrhea duration but was not significantly better at predicting 14-day mortality than a modified Vesikari score. CONCLUSIONS: A composite severity score consistent with severe disease or dysentery may be a pragmatic clinical endpoint for severe shigellosis in vaccine trials. Reliance on culture for microbiologic confirmation may miss a substantial number of Shigella cases but is currently required to measure serotype specific immunity.


Asunto(s)
Disentería Bacilar , Shigella , Vacunas , Estudios de Casos y Controles , Niño , Diarrea/epidemiología , Disentería Bacilar/diagnóstico , Disentería Bacilar/epidemiología , Humanos , Lactante , Reacción en Cadena de la Polimerasa , Shigella/genética
2.
BMC Public Health ; 19(Suppl 3): 477, 2019 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-32326916

RESUMEN

Since 1979, multiple CDC Kenya programs have supported the development of diagnostic expertise and laboratory capacity in Kenya. In 2004, CDC's Global Disease Detection (GDD) program within the Division of Global Health Protection in Kenya (DGHP-Kenya) initiated close collaboration with Kenya Medical Research Institute (KEMRI) and developed a laboratory partnership called the Diagnostic and Laboratory Systems Program (DLSP). DLSP built onto previous efforts by malaria, human immunodeficiency virus (HIV) and tuberculosis (TB) programs and supported the expansion of the diagnostic expertise and capacity in KEMRI and the Ministry of Health. First, DLSP developed laboratory capacity for surveillance of diarrheal, respiratory, zoonotic and febrile illnesses to understand the etiology burden of these common illnesses and support evidenced-based decisions on vaccine introductions and recommendations in Kenya. Second, we have evaluated and implemented new diagnostic technologies such as TaqMan Array Cards (TAC) to detect emerging or reemerging pathogens and have recently added a next generation sequencer (NGS). Third, DLSP provided rapid laboratory diagnostic support for outbreak investigation to Kenya and regional countries. Fourth, DLSP has been assisting the Kenya National Public Health laboratory-National Influenza Center and microbiology reference laboratory to obtain World Health Organization (WHO) certification and ISO15189 accreditation respectively. Fifth, we have supported biosafety and biosecurity curriculum development to help Kenyan laboratories safely and appropriately manage infectious pathogens. These achievements, highlight how in collaboration with existing CDC programs working on HIV, tuberculosis and malaria, the Global Health Security Agenda can have significantly improve public health in Kenya and the region. Moreover, Kenya provides an example as to how laboratory science can help countries detect and control of infectious disease outbreaks and other public health threats more rapidly, thus enhancing global health security.


Asunto(s)
Brotes de Enfermedades/prevención & control , Salud Global , Laboratorios/organización & administración , Administración en Salud Pública/métodos , Creación de Capacidad/organización & administración , Humanos , Kenia
4.
Lancet ; 388(10051): 1291-301, 2016 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-27673470

RESUMEN

BACKGROUND: Diarrhoea is the second leading cause of mortality in children worldwide, but establishing the cause can be complicated by diverse diagnostic approaches and varying test characteristics. We used quantitative molecular diagnostic methods to reassess causes of diarrhoea in the Global Enteric Multicenter Study (GEMS). METHODS: GEMS was a study of moderate to severe diarrhoea in children younger than 5 years in Africa and Asia. We used quantitative real-time PCR (qPCR) to test for 32 enteropathogens in stool samples from cases and matched asymptomatic controls from GEMS, and compared pathogen-specific attributable incidences with those found with the original GEMS microbiological methods, including culture, EIA, and reverse-transcriptase PCR. We calculated revised pathogen-specific burdens of disease and assessed causes in individual children. FINDINGS: We analysed 5304 sample pairs. For most pathogens, incidence was greater with qPCR than with the original methods, particularly for adenovirus 40/41 (around five times), Shigella spp or enteroinvasive Escherichia coli (EIEC) and Campylobactor jejuni o C coli (around two times), and heat-stable enterotoxin-producing E coli ([ST-ETEC] around 1·5 times). The six most attributable pathogens became, in descending order, Shigella spp, rotavirus, adenovirus 40/41, ST-ETEC, Cryptosporidium spp, and Campylobacter spp. Pathogen-attributable diarrhoeal burden was 89·3% (95% CI 83·2-96·0) at the population level, compared with 51·5% (48·0-55·0) in the original GEMS analysis. The top six pathogens accounted for 77·8% (74·6-80·9) of all attributable diarrhoea. With use of model-derived quantitative cutoffs to assess individual diarrhoeal cases, 2254 (42·5%) of 5304 cases had one diarrhoea-associated pathogen detected and 2063 (38·9%) had two or more, with Shigella spp and rotavirus being the pathogens most strongly associated with diarrhoea in children with mixed infections. INTERPRETATION: A quantitative molecular diagnostic approach improved population-level and case-level characterisation of the causes of diarrhoea and indicated a high burden of disease associated with six pathogens, for which targeted treatment should be prioritised. FUNDING: Bill & Melinda Gates Foundation.


Asunto(s)
Costo de Enfermedad , Diarrea/microbiología , Diarrea/virología , Adenoviridae/aislamiento & purificación , Adenoviridae/patogenicidad , África/epidemiología , Asia/epidemiología , Bacterias/aislamiento & purificación , Bacterias/patogenicidad , Infecciones Bacterianas/diagnóstico , Campylobacter/aislamiento & purificación , Campylobacter/patogenicidad , Estudios de Casos y Controles , Preescolar , Coinfección , Cryptosporidium/aislamiento & purificación , Cryptosporidium/patogenicidad , Diarrea/epidemiología , Escherichia coli/aislamiento & purificación , Escherichia coli/patogenicidad , Femenino , Humanos , Incidencia , Lactante , Masculino , Rotavirus/aislamiento & purificación , Rotavirus/patogenicidad , Shigella/aislamiento & purificación , Shigella/patogenicidad , Virosis/diagnóstico , Virus/aislamiento & purificación , Virus/patogenicidad
5.
J Clin Microbiol ; 55(7): 2035-2044, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28404679

RESUMEN

Infections of the central nervous system (CNS) are often acute, with significant morbidity and mortality. Routine diagnosis of such infections is limited in developing countries and requires modern equipment in advanced laboratories that may be unavailable to a number of patients in sub-Saharan Africa. We developed a TaqMan array card (TAC) that detects multiple pathogens simultaneously from cerebrospinal fluid. The 21-pathogen CNS multiple-pathogen TAC (CNS-TAC) assay includes two parasites (Balamuthia mandrillaris and Acanthamoeba), six bacterial pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Mycoplasma pneumoniae, Mycobacterium tuberculosis, and Bartonella), and 13 viruses (parechovirus, dengue virus, Nipah virus, varicella-zoster virus, mumps virus, measles virus, lyssavirus, herpes simplex viruses 1 and 2, Epstein-Barr virus, enterovirus, cytomegalovirus, and chikungunya virus). The card also includes human RNase P as a nucleic acid extraction control and an internal manufacturer control, GAPDH (glyceraldehyde-3-phosphate dehydrogenase). This CNS-TAC assay can test up to eight samples for all 21 agents within 2.5 h following nucleic acid extraction. The assay was validated for linearity, limit of detection, sensitivity, and specificity by using either live viruses (dengue, mumps, and measles viruses) or nucleic acid material (Nipah and chikungunya viruses). Of 120 samples tested by individual real-time PCR, 35 were positive for eight different targets, whereas the CNS-TAC assay detected 37 positive samples across nine different targets. The CNS-TAC assays showed 85.6% sensitivity and 96.7% specificity. Therefore, the CNS-TAC assay may be useful for outbreak investigation and surveillance of suspected neurological disease.


Asunto(s)
Infecciones del Sistema Nervioso Central/diagnóstico , Técnicas Microbiológicas/métodos , Técnicas de Diagnóstico Molecular/métodos , Adolescente , Adulto , África del Sur del Sahara , Anciano , Anciano de 80 o más Años , Amebozoos/aislamiento & purificación , Bacterias/aislamiento & purificación , Infecciones del Sistema Nervioso Central/microbiología , Infecciones del Sistema Nervioso Central/parasitología , Infecciones del Sistema Nervioso Central/virología , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Estándares de Referencia , Sensibilidad y Especificidad , Virus/aislamiento & purificación , Adulto Joven
6.
BMC Infect Dis ; 17(1): 591, 2017 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-28841843

RESUMEN

BACKGROUND: Respiratory diseases cause substantial morbidity and mortality worldwide, with sub-Saharan Africa bearing the greatest burden. Identifying etiologies of respiratory disease is important to inform cost effective treatment, prevention and control strategies. Testing for all of the different pathogens that are potentially associated with respiratory illnesses is challenging. We piloted the use of a multi-pathogen respiratory Taqman Array Cards (TAC) to identify pathogens in respiratory samples collected from non-fatal and fatal cases and their matched asymptomatic controls. METHODS: This is a case control study comparing viral and bacterial pathogens detected among non-fatal and fatal cases to those detected among age and time matched asymptomatic controls. We used McNemar's test to compare proportions of pathogens detected among cases (non-fatal and fatal) to their matched asymptomatic controls. We used Mann-Whitney test to compare the distribution of median Cycle threshold (Ct) values among non-fatal and fatal cases to their corresponding asymptomatic controls. RESULTS: There were 72 fatal and 72 non-fatal cases matched to 72 controls. We identified at least one pathogen in 109/144 (76%) cases and 59/72 (82%) controls. For most pathogens, the median Ct values were lower among cases (fatal and non-fatal) compared to asymptomatic controls. CONCLUSIONS: Similar rates of pathogen detection among cases and controls make interpretation of results challenging. Ct-values might be helpful in interpreting clinical relevance of detected pathogens using multi-pathogen diagnostic tools.


Asunto(s)
Infecciones del Sistema Respiratorio/microbiología , Infecciones del Sistema Respiratorio/virología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Niño , Preescolar , Hospitalización/estadística & datos numéricos , Humanos , Lactante , Kenia/epidemiología , Persona de Mediana Edad , Nasofaringe/microbiología , Proyectos Piloto , Juego de Reactivos para Diagnóstico , Infecciones del Sistema Respiratorio/mortalidad , Adulto Joven
7.
BMC Infect Dis ; 17(1): 60, 2017 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-28077093

RESUMEN

BACKGROUND: We evaluated the performance of the Becton Dickinson Veritor™ System Flu A + B rapid influenza diagnostic test (RIDT) to detect influenza viruses in respiratory specimens from patients enrolled at five surveillance sites in Kenya, a tropical country where influenza seasonality is variable. METHODS: Nasal swab (NS) and nasopharyngeal (NP)/oropharyngeal (OP) swabs were collected from patients with influenza like illness and/or severe acute respiratory infection. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the RIDT using NS specimens were evaluated against nasal swabs tested by real time reverse transcription polymerase chain reaction (rRT-PCR). The performance parameter results were expressed as 95% confidence intervals (CI) calculated using binomial exact methods, with P < 0.05 considered significant. Two-sample Z tests were used to test for differences in sample proportions. Analysis was performed using SAS software version 9.3. RESULTS: From July 2013 to July 2014, 3,569 patients were recruited, of which 78.7% were aged <5 years. Overall, 14.4% of NS specimens were influenza-positive by RIDT. RIDT overall sensitivity was 77.1% (95% CI 72.8-81.0%) and specificity was 94.9% (95% CI 94.0-95.7%) compared to rRT-PCR using NS specimens. RIDT sensitivity for influenza A virus compared to rRT-PCR using NS specimens was 71.8% (95% CI 66.7-76.4%) and was significantly higher than for influenza B which was 43.8% (95% CI 33.8-54.2%). PPV ranged from 30%-80% depending on background prevalence of influenza. CONCLUSION: Although the variable seasonality of influenza in tropical Africa presents unique challenges, RIDTs may have a role in making influenza surveillance sustainable in more remote areas of Africa, where laboratory capacity is limited.


Asunto(s)
Antígenos Virales/análisis , Betainfluenzavirus/genética , Virus de la Influenza A/genética , Gripe Humana/diagnóstico , Pruebas en el Punto de Atención , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Humanos , Inmunoensayo , Lactante , Gripe Humana/virología , Kenia , Masculino , Persona de Mediana Edad , Mucosa Nasal/virología , Nasofaringe/virología , Orofaringe/virología , Valor Predictivo de las Pruebas , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sensibilidad y Especificidad , Adulto Joven
8.
J Infect Dis ; 214(suppl 3): S169-S176, 2016 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-27333914

RESUMEN

West Africa experienced the first epidemic of Ebola virus infection, with by far the greatest number of cases in Guinea, Sierra Leone, and Liberia. The unprecedented epidemic triggered an unparalleled response, including the deployment of multiple Ebola treatment units and mobile/field diagnostic laboratories. The National Institute of Allergy and Infectious Diseases and the Centers for Disease Control and Prevention deployed a joint laboratory to Monrovia, Liberia, in August 2014 to support the newly founded Ebola treatment unit at the Eternal Love Winning Africa (ELWA) campus. The laboratory operated initially out of a tent structure but quickly moved into a fixed-wall building owing to severe weather conditions, the need for increased security, and the high sample volume. Until May 2015, when the laboratory closed, the site handled close to 6000 clinical specimens for Ebola virus diagnosis and supported the medical staff in case patient management. Laboratory operation and safety, as well as Ebola virus diagnostic assays, are described and discussed; in addition, lessons learned for future deployments are reviewed.


Asunto(s)
Servicios de Laboratorio Clínico/organización & administración , Ebolavirus/aislamiento & purificación , Epidemias/prevención & control , Fiebre Hemorrágica Ebola/epidemiología , África Occidental/epidemiología , Centers for Disease Control and Prevention, U.S. , Femenino , Guinea/epidemiología , Fiebre Hemorrágica Ebola/diagnóstico , Fiebre Hemorrágica Ebola/transmisión , Fiebre Hemorrágica Ebola/virología , Humanos , Cooperación Internacional , Liberia/epidemiología , Masculino , National Institute of Allergy and Infectious Diseases (U.S.) , Seguridad , Sierra Leona/epidemiología , Estados Unidos
9.
Clin Infect Dis ; 63(8): 1026-33, 2016 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-27531847

RESUMEN

BACKGROUND: The ongoing Ebola outbreak in West Africa has resulted in 28 646 suspected, probable, and confirmed Ebola virus infections. Nevertheless, malaria remains a large public health burden in the region affected by the outbreak. A joint Centers for Disease Control and Prevention/National Institutes of Health diagnostic laboratory was established in Monrovia, Liberia, in August 2014, to provide laboratory diagnostics for Ebola virus. METHODS: All blood samples from suspected Ebola virus-infected patients admitted to the Médecins Sans Frontières ELWA3 Ebola treatment unit in Monrovia were tested by quantitative real-time polymerase chain reaction for the presence of Ebola virus and Plasmodium species RNA. Clinical outcome in laboratory-confirmed Ebola virus-infected patients was analyzed as a function of age, sex, Ebola viremia, and Plasmodium species parasitemia. RESULTS: The case fatality rate of 1182 patients with laboratory-confirmed Ebola virus infections was 52%. The probability of surviving decreased with increasing age and decreased with increasing Ebola viral load. Ebola virus-infected patients were 20% more likely to survive when Plasmodium species parasitemia was detected, even after controlling for Ebola viral load and age; those with the highest levels of parasitemia had a survival rate of 83%. This effect was independent of treatment with antimalarials, as this was provided to all patients. Moreover, treatment with antimalarials did not affect survival in the Ebola virus mouse model. CONCLUSIONS: Plasmodium species parasitemia is associated with an increase in the probability of surviving Ebola virus infection. More research is needed to understand the molecular mechanism underlying this remarkable phenomenon and translate it into treatment options for Ebola virus infection.


Asunto(s)
Coinfección , Ebolavirus , Fiebre Hemorrágica Ebola/complicaciones , Fiebre Hemorrágica Ebola/mortalidad , Malaria/complicaciones , Malaria/parasitología , Parasitemia , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Niño , Preescolar , Modelos Animales de Enfermedad , Ebolavirus/genética , Femenino , Fiebre Hemorrágica Ebola/diagnóstico , Fiebre Hemorrágica Ebola/epidemiología , Humanos , Lactante , Recién Nacido , Malaria/diagnóstico , Malaria/epidemiología , Masculino , Ratones , Persona de Mediana Edad , Carga de Parásitos , Plasmodium/genética , Tasa de Supervivencia , Carga Viral , Adulto Joven
10.
Emerg Infect Dis ; 22(2): 331-4, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26812583

RESUMEN

Rapid sequencing of RNA/DNA from pathogen samples obtained during disease outbreaks provides critical scientific and public health information. However, challenges exist for exporting samples to laboratories or establishing conventional sequencers in remote outbreak regions. We successfully used a novel, pocket-sized nanopore sequencer at a field diagnostic laboratory in Liberia during the current Ebola virus outbreak.


Asunto(s)
Ebolavirus/genética , Fiebre Hemorrágica Ebola/microbiología , Nanoporos , Análisis de Secuencia de ADN/métodos , Brotes de Enfermedades , Genoma Viral , Fiebre Hemorrágica Ebola/epidemiología , Humanos , Mutación
11.
Emerg Infect Dis ; 22(2): 323-6, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26814608

RESUMEN

Malaria is a major public health concern in the countries affected by the Ebola virus disease epidemic in West Africa. We determined the feasibility of using molecular malaria diagnostics during an Ebola virus disease outbreak and report the incidence of Plasmodium spp. parasitemia in persons with suspected Ebola virus infection.


Asunto(s)
Coinfección , Brotes de Enfermedades , Ebolavirus , Fiebre Hemorrágica Ebola/epidemiología , Malaria/diagnóstico , Malaria/parasitología , Humanos , Malaria Falciparum/diagnóstico , Malaria Falciparum/parasitología , Carga de Parásitos , Plasmodium falciparum/clasificación , Plasmodium falciparum/genética , Prevalencia
12.
J Clin Microbiol ; 54(1): 49-58, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26491176

RESUMEN

Acute febrile illness (AFI) is associated with substantial morbidity and mortality worldwide, yet an etiologic agent is often not identified. Convalescent-phase serology is impractical, blood culture is slow, and many pathogens are fastidious or impossible to cultivate. We developed a real-time PCR-based TaqMan array card (TAC) that can test six to eight samples within 2.5 h from sample to results and can simultaneously detect 26 AFI-associated organisms, including 15 viruses (chikungunya, Crimean-Congo hemorrhagic fever [CCHF] virus, dengue, Ebola virus, Bundibugyo virus, Sudan virus, hantaviruses [Hantaan and Seoul], hepatitis E, Marburg, Nipah virus, o'nyong-nyong virus, Rift Valley fever virus, West Nile virus, and yellow fever virus), 8 bacteria (Bartonella spp., Brucella spp., Coxiella burnetii, Leptospira spp., Rickettsia spp., Salmonella enterica and Salmonella enterica serovar Typhi, and Yersinia pestis), and 3 protozoa (Leishmania spp., Plasmodium spp., and Trypanosoma brucei). Two extrinsic controls (phocine herpesvirus 1 and bacteriophage MS2) were included to ensure extraction and amplification efficiency. Analytical validation was performed on spiked specimens for linearity, intra-assay precision, interassay precision, limit of detection, and specificity. The performance of the card on clinical specimens was evaluated with 1,050 blood samples by comparison to the individual real-time PCR assays, and the TAC exhibited an overall 88% (278/315; 95% confidence interval [CI], 84% to 92%) sensitivity and a 99% (5,261/5,326, 98% to 99%) specificity. This TaqMan array card can be used in field settings as a rapid screen for outbreak investigation or for the surveillance of pathogens, including Ebola virus.


Asunto(s)
Enfermedades Transmisibles/diagnóstico , Enfermedades Transmisibles/epidemiología , Brotes de Enfermedades , Fiebre de Origen Desconocido/diagnóstico , Fiebre de Origen Desconocido/epidemiología , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Adulto , Monitoreo Epidemiológico , Humanos , Técnicas de Diagnóstico Molecular/normas , Reacción en Cadena en Tiempo Real de la Polimerasa/normas , Estándares de Referencia , Sensibilidad y Especificidad , Factores de Tiempo
13.
Clin Infect Dis ; 61 Suppl 4: S302-9, 2015 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-26449945

RESUMEN

BACKGROUND: Invasive infections with nontyphoidal Salmonella (NTS) lead to bacteremia in children and adults and are an important cause of illness in Africa; however, few data on the burden of NTS bacteremia are available. We sought to determine the burden of invasive NTS disease in a rural and urban setting in Kenya. METHODS: We conducted the study in a population-based surveillance platform in a rural setting in western Kenya (Lwak), and an informal urban settlement in Nairobi (Kibera) from 2009 to 2014. We obtained blood culture specimens from participants presenting with acute lower respiratory tract illness or acute febrile illness to a designated outpatient facility in each site, or any hospital admission for a potentially infectious cause (rural site only). Incidence was calculated using a defined catchment population and adjusting for specimen collection and healthcare-seeking practices. RESULTS: A total of 12 683 and 9524 blood cultures were analyzed from Lwak and Kibera, respectively. Of these, 428 (3.4%) and 533 (5.6%) grew a pathogen; among those, 208 (48.6%) and 70 (13.1%) were positive for NTS in Lwak and Kibera, respectively. Overall, the adjusted incidence of invasive NTS disease was higher in Lwak (839.4 per 100,000 person-years of observation [PYO]) than in Kibera (202.5 per 100,000 PYO). The highest adjusted incidences were observed in children <5 years of age (Lwak 3914.3 per 100,000 PYO and Kibera 997.9 per 100,000 PYO). The highest adjusted annual incidence was 1927.3 per 100,000 PYO (in 2010) in Lwak and 220.5 per 100,000 PYO (in 2011) in Kibera; the lowest incidences were 303.3 and 62.5 per 100,000 PYO, respectively (in 2012). In both sites, invasive NTS disease incidence generally declined over the study period. CONCLUSIONS: We observed an extremely high burden of invasive NTS disease in a rural area of Kenya and a lesser, but still substantial, burden in an urban slum. Although the incidences in both sites declined during the study period, invasive NTS infections remain an important cause of morbidity in these settings, particularly among children <5 years old.


Asunto(s)
Infecciones por Salmonella/epidemiología , Salmonella enterica/aislamiento & purificación , Adolescente , Adulto , Factores de Edad , Niño , Preescolar , Costo de Enfermedad , Monitoreo Epidemiológico , Femenino , Humanos , Incidencia , Lactante , Kenia/epidemiología , Masculino , Estudios Retrospectivos , Población Rural , Infecciones por Salmonella/sangre , Infecciones por Salmonella/microbiología , Infecciones por Salmonella/mortalidad , Salmonella enterica/clasificación , Salmonella enterica/genética , Factores de Tiempo , Población Urbana
14.
J Clin Microbiol ; 53(3): 951-60, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25588655

RESUMEN

Shigellae cause significant diarrheal disease and mortality in humans, as there are approximately 163 million episodes of shigellosis and 1.1 million deaths annually. While significant strides have been made in the understanding of the pathogenesis, few studies on the genomic content of the Shigella species have been completed. The goal of this study was to characterize the genomic diversity of Shigella species through sequencing of 55 isolates representing members of each of the four Shigella species: S. flexneri, S. sonnei, S. boydii, and S. dysenteriae. Phylogeny inferred from 336 available Shigella and Escherichia coli genomes defined exclusive clades of Shigella; conserved genomic markers that can identify each clade were then identified. PCR assays were developed for each clade-specific marker, which was combined with an amplicon for the conserved Shigella invasion antigen, IpaH3, into a multiplex PCR assay. This assay demonstrated high specificity, correctly identifying 218 of 221 presumptive Shigella isolates, and sensitivity, by not identifying any of 151 diverse E. coli isolates incorrectly as Shigella. This new phylogenomics-based PCR assay represents a valuable tool for rapid typing of uncharacterized Shigella isolates and provides a framework that can be utilized for the identification of novel genomic markers from genomic data.


Asunto(s)
Disentería Bacilar/diagnóstico , Variación Genética , Genoma Bacteriano , Reacción en Cadena de la Polimerasa Multiplex/métodos , Filogenia , Shigella/clasificación , Shigella/aislamiento & purificación , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , Disentería Bacilar/microbiología , Humanos , Sensibilidad y Especificidad , Análisis de Secuencia de ADN , Shigella/genética
15.
BMC Infect Dis ; 15: 95, 2015 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-25879805

RESUMEN

BACKGROUND: Reducing acute respiratory infection burden in children in Africa remains a major priority and challenge. We analyzed data from population-based infectious disease surveillance for severe acute respiratory illness (SARI) among children <5 years of age in Kibera, a densely populated urban slum in Nairobi, Kenya. METHODS: Surveillance was conducted among a monthly mean of 5,874 (range = 5,778-6,411) children <5 years old in two contiguous villages in Kibera. Participants had free access to the study clinic and their health events and utilization were noted during biweekly home visits. Patients meeting criteria for SARI (WHO-defined severe or very severe pneumonia, or oxygen saturation <90%) from March 1, 2007-February 28, 2011 had blood cultures processed for bacteria, and naso- and oro- pharyngeal swabs collected for quantitative real-time reverse transcription polymerase chain reaction testing for influenza viruses, parainfluenza viruses (PIV), respiratory syncytial virus (RSV), adenovirus, and human metapneumovirus (hMPV). Swabs collected during January 1, 2009 - February 28, 2010 were also tested for rhinoviruses, enterovirus, parechovirus, Mycoplasma pneumoniae, and Legionella species. Swabs were collected for simultaneous testing from a selected group of control-children visiting the clinic without recent respiratory or diarrheal illnesses. RESULTS: SARI overall incidence was 12.4 cases/100 person-years of observation (PYO) and 30.4 cases/100 PYO in infants. When comparing detection frequency in swabs from 815 SARI cases and 115 healthy controls, only RSV and influenza A virus were significantly more frequently detected in cases, although similar trends neared statistical significance for PIV, adenovirus and hMPV. The incidence for RSV was 2.8 cases/100 PYO and for influenza A was 1.0 cases/100 PYO. When considering all PIV, the rate was 1.1 case/100 PYO and the rate per 100 PYO for SARI-associated disease was 1.5 for adenovirus and 0.9 for hMPV. RSV and influenza A and B viruses were estimated to account for 16.2% and 6.7% of SARI cases, respectively; when taken together, PIV, adenovirus, and hMPV may account for >20% additional cases. CONCLUSIONS: Influenza viruses and RSV (and possibly PIV, hMPV and adenoviruses) are important pathogens to consider when developing technologies and formulating strategies to treat and prevent SARI in children.


Asunto(s)
Legionelosis/epidemiología , Neumonía por Mycoplasma/epidemiología , Neumonía Viral/epidemiología , Densidad de Población , Áreas de Pobreza , Población Urbana/estadística & datos numéricos , Enfermedad Aguda , Adenoviridae/genética , Adenoviridae/aislamiento & purificación , Infecciones por Adenoviridae/epidemiología , Infecciones por Adenoviridae/virología , Preescolar , Monitoreo Epidemiológico , Femenino , Humanos , Incidencia , Lactante , Virus de la Influenza A/genética , Virus de la Influenza A/aislamiento & purificación , Gripe Humana/epidemiología , Gripe Humana/virología , Kenia/epidemiología , Legionella/aislamiento & purificación , Legionelosis/microbiología , Masculino , Metapneumovirus/genética , Metapneumovirus/aislamiento & purificación , Mycoplasma pneumoniae/aislamiento & purificación , Orthomyxoviridae/genética , Orthomyxoviridae/aislamiento & purificación , Virus de la Parainfluenza 1 Humana/genética , Virus de la Parainfluenza 1 Humana/aislamiento & purificación , Virus de la Parainfluenza 2 Humana/genética , Virus de la Parainfluenza 2 Humana/aislamiento & purificación , Infecciones por Paramyxoviridae/epidemiología , Infecciones por Paramyxoviridae/virología , Infecciones por Picornaviridae/epidemiología , Infecciones por Picornaviridae/virología , Neumonía por Mycoplasma/microbiología , Neumonía Viral/virología , Reacción en Cadena en Tiempo Real de la Polimerasa , Infecciones por Virus Sincitial Respiratorio/epidemiología , Infecciones por Virus Sincitial Respiratorio/virología , Virus Sincitiales Respiratorios/genética , Virus Sincitiales Respiratorios/aislamiento & purificación , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/virología , Infecciones por Respirovirus/epidemiología , Infecciones por Respirovirus/virología , Rhinovirus/genética , Rhinovirus/aislamiento & purificación , Infecciones por Rubulavirus/epidemiología , Infecciones por Rubulavirus/virología
16.
MMWR Morb Mortal Wkly Rep ; 63(46): 1082-6, 2014 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-25412068

RESUMEN

On March 21, 2014, the Guinea Ministry of Health reported the outbreak of an illness characterized by fever, severe diarrhea, vomiting and a high fatality rate (59%), leading to the first known epidemic of Ebola virus disease (Ebola) in West Africa and the largest and longest Ebola epidemic in history. As of November 2, Liberia had reported the largest number of cases (6,525) and deaths (2,697) among the three affected countries of West Africa with ongoing transmission (Guinea, Liberia, and Sierra Leone). The response strategy in Liberia has included management of the epidemic through an incident management system (IMS) in which the activities of all partners are coordinated. Within the IMS, key strategies for epidemic control include surveillance, case investigation, laboratory confirmation, contact tracing, safe transportation of persons with suspected Ebola, isolation, infection control within the health care system, community engagement, and safe burial. This report provides a brief overview of the progression of the epidemic in Liberia and summarizes the interventions implemented.


Asunto(s)
Epidemias/prevención & control , Fiebre Hemorrágica Ebola/epidemiología , Ebolavirus/aislamiento & purificación , Humanos , Liberia/epidemiología , Admisión del Paciente/estadística & datos numéricos
17.
BMC Infect Dis ; 14: 178, 2014 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-24690157

RESUMEN

BACKGROUND: A recent longitudinal study in the Dadaab refugee camp near the Kenya-Somalia border identified unusual biannual respiratory syncytial virus (RSV) epidemics. We characterized the genetic variability of the associated RSV strains to determine if viral diversity contributed to this unusual epidemic pattern. METHODS: For 336 RSV positive specimens identified from 2007 through 2011 through facility-based surveillance of respiratory illnesses in the camp, 324 (96.4%) were sub-typed by PCR methods, into 201 (62.0%) group A, 118 (36.4%) group B and 5 (1.5%) group A-B co-infections. Partial sequencing of the G gene (coding for the attachment protein) was completed for 290 (89.5%) specimens. These specimens were phylogenetically analyzed together with 1154 contemporaneous strains from 22 countries. RESULTS: Of the 6 epidemic peaks recorded in the camp over the period, the first and last were predominantly made up of group B strains, while the 4 in between were largely composed of group A strains in a consecutive series of minor followed by major epidemics. The Dadaab group A strains belonged to either genotype GA2 (180, 98.9%) or GA5 (2, < 1%) while all group B strains (108, 100%) belonged to BA genotype. In sequential epidemics, strains within these genotypes appeared to be of two types: those continuing from the preceding epidemics and those newly introduced. Genotype diversity was similar in minor and major epidemics. CONCLUSION: RSV strain diversity in Dadaab was similar to contemporaneous diversity worldwide, suggested both between-epidemic persistence and new introductions, and was unrelated to the unusual epidemic pattern.


Asunto(s)
Epidemias , Refugiados/estadística & datos numéricos , Infecciones por Virus Sincitial Respiratorio/epidemiología , Infecciones por Virus Sincitial Respiratorio/virología , Virus Sincitiales Respiratorios/aislamiento & purificación , Preescolar , Femenino , Variación Genética , Genotipo , Humanos , Lactante , Kenia/epidemiología , Masculino , Filogeografía , Virus Sincitiales Respiratorios/clasificación , Virus Sincitiales Respiratorios/genética
18.
J Infect Dis ; 208 Suppl 3: S207-16, 2013 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-24265480

RESUMEN

BACKGROUND: Information on the epidemiology of respiratory syncytial virus (RSV) infection in Africa is limited for crowded urban areas and for rural areas where the prevalence of malaria is high. METHODS: At referral facilities in rural western Kenya and a Nairobi slum, we collected nasopharyngeal/oropharyngeal (NP/OP) swab specimens from patients with influenza-like illness (ILI) or severe acute respiratory illness (SARI) and from asymptomatic controls. Polymerase chain reaction assays were used for detection of viral pathogens. We calculated age-specific ratios of the odds of RSV detection among patients versus the odds among controls. Incidence was expressed as the number of episodes per 1000 person-years of observation. RESULTS: Between March 2007 and February 2011, RSV was detected in 501 of 4012 NP/OP swab specimens (12.5%) from children and adults in the rural site and in 321 of 2744 NP/OP swab specimens (11.7%) from those in the urban site. Among children aged <5 years, RSV was detected more commonly among rural children with SARI (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.2-3.3), urban children with SARI (OR, 8.5; 95% CI, 3.1-23.6), and urban children with ILI (OR, 3.4; 95% CI, 1.2-9.6), compared with controls. The incidence of RSV disease was highest among infants with SARI aged <1 year (86.9 and 62.8 episodes per 1000 person-years of observation in rural and urban sites, respectively). CONCLUSIONS: An effective RSV vaccine would likely substantially reduce the burden of respiratory illness among children in rural and urban areas in Africa.


Asunto(s)
Infecciones por Virus Sincitial Respiratorio/epidemiología , Virus Sincitial Respiratorio Humano/aislamiento & purificación , Infecciones del Sistema Respiratorio/epidemiología , Población Rural/estadística & datos numéricos , Población Urbana/estadística & datos numéricos , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Incidencia , Lactante , Kenia/epidemiología , Masculino , Vigilancia de la Población/métodos , Infecciones por Virus Sincitial Respiratorio/fisiopatología , Infecciones por Virus Sincitial Respiratorio/virología , Virus Sincitial Respiratorio Humano/genética , Infecciones del Sistema Respiratorio/fisiopatología , Infecciones del Sistema Respiratorio/virología , Índice de Severidad de la Enfermedad , Adulto Joven
19.
J Clin Sleep Med ; 20(2): 201-210, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-37767791

RESUMEN

STUDY OBJECTIVES: Our 2019 survey of sleep medicine fellowship program directors (PDs) indicated that fellows' contact with telemedicine was limited. Within months, the coronavirus disease 2019 (COVID-19) pandemic significantly impacted the field. This survey describes fellows' telemedicine exposure, their PDs' attitudes toward it, and their formalized telemedicine training during the pandemic's third year. METHODS: A 33-item SurveyMonkey questionnaire was developed. Many quantitative (Likert scale) items were identical to items on the 2019 survey for direct comparison. An open-ended question was added for qualitative analyses. All 91 sleep medicine fellowship PDs were invited to participate. The SurveyMonkey platform provided quantitative item descriptive statistics. Qualitative data underwent thematic analyses using codebook methodology. RESULTS: Forty (97.5%) PDs indicated their program offers a telemedicine experience. Thirty-two (80%) PDs observed at least a 10% increase in sleep fellows' telemedicine encounters compared with prepandemic times. Although 27 (67.5%) PDs agreed that a national telemedicine curriculum could be useful, 8 (20%) of them offer a sleep telemedicine curriculum. Qualitative feedback revealed diverging attitudes toward telemedicine's place in sleep medicine practice, fellowship training, and the utility of a national curriculum. CONCLUSIONS: Sleep telemedicine utilization during fellowship training was markedly higher on this 2022 survey (97.5%) compared with a similar 2019 survey (33.3%), and most PDs agreed a standardized curriculum could be useful. However, relatively few programs offer formalized telemedicine training. These findings imply that, while most sleep medicine fellows participate in telemedicine, they lack the formalized training that may optimize their utilization of the medium in their postfellowship careers. CITATION: Fields BG, Kaur K, Dholakia S, Ioachimescu O. The COVID-19 pandemic's impact on sleep medicine fellowship telemedicine training: a follow-up survey of program directors. J Clin Sleep Med. 2024;20(2):201-210.


Asunto(s)
COVID-19 , Humanos , Pandemias , Educación de Postgrado en Medicina/métodos , Becas , Estudios de Seguimiento , Curriculum , Encuestas y Cuestionarios , Sueño
20.
J Clin Microbiol ; 51(6): 1740-6, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23536399

RESUMEN

Estimates of the prevalence of Shigella spp. are limited by the suboptimal sensitivity of current diagnostic and surveillance methods. We used a quantitative PCR (qPCR) assay to detect Shigella in the stool samples of 3,533 children aged <59 months from the Gambia, Mali, Kenya, and Bangladesh, with or without moderate-to-severe diarrhea (MSD). We compared the results from conventional culture to those from qPCR for the Shigella ipaH gene. Using MSD as the reference standard, we determined the optimal cutpoint to be 2.9 × 10(4) ipaH copies per 100 ng of stool DNA for set 1 (n = 877). One hundred fifty-eight (18%) specimens yielded >2.9 × 10(4) ipaH copies. Ninety (10%) specimens were positive by traditional culture for Shigella. Individuals with ≥ 2.9 × 10(4) ipaH copies have 5.6-times-higher odds of having diarrhea than those with <2.9 × 10(4) ipaH copies (95% confidence interval, 3.7 to 8.5; P < 0.0001). Nearly identical results were found using an independent set of samples. qPCR detected 155 additional MSD cases with high copy numbers of ipaH, a 90% increase from the 172 cases detected by culture in both samples. Among a subset (n = 2,874) comprising MSD cases and their age-, gender-, and location-matched controls, the fraction of MSD cases that were attributable to Shigella infection increased from 9.6% (n = 129) for culture to 17.6% (n = 262) for qPCR when employing our cutpoint. We suggest that qPCR with a cutpoint of approximately 1.4 × 10(4) ipaH copies be the new reference standard for the detection and diagnosis of shigellosis in children in low-income countries. The acceptance of this new standard would substantially increase the fraction of MSD cases that are attributable to Shigella.


Asunto(s)
Diarrea/diagnóstico , Diarrea/epidemiología , Disentería Bacilar/diagnóstico , Disentería Bacilar/epidemiología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Shigella/aislamiento & purificación , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Estudios de Casos y Controles , Preescolar , Países en Desarrollo , Diarrea/microbiología , Disentería Bacilar/microbiología , Heces/microbiología , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Prevalencia , Sensibilidad y Especificidad , Shigella/genética
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