RESUMO
The diagnosis of dengue disease, caused by the dengue virus (DENV) (a flavivirus), often requires serologic testing during acute and early convalescent phases of the disease. Some symptoms of DENV infection, such as nonspecific fever, are similar to those caused by infection with SARS-CoV-2, the virus that causes COVID-19. In studies with few COVID-19 cases, positive DENV immunoglobulin M (IgM) results were reported with various serologic tests, indicating possible cross-reactivity in these tests for DENV and SARS-CoV-2 infections (1,2). DENV antibodies can cross-react with other flaviviruses, including Zika virus. To assess the potential cross-reactivity of SARS-CoV-2, DENV, and Zika virus IgM antibodies, serum specimens from 97 patients from Puerto Rico and 12 U.S.-based patients with confirmed COVID-19 were tested using the DENV Detect IgM Capture enzyme-linked immunosorbent assay (ELISA) (InBios International).* In addition, 122 serum specimens from patients with confirmed dengue and 121 from patients with confirmed Zika virus disease (all from Puerto Rico) were tested using the SARS-CoV-2 pan-Ig Spike Protein ELISA (CDC). Results obtained for DENV, Zika virus IgM, and SARS-CoV-2 antibodies indicated 98% test specificity and minimal levels of cross-reactivity between the two flaviviruses and SARS-CoV-2. These findings indicate that diagnoses of dengue or Zika virus diseases with the serological assays described in this report are not affected by COVID-19, nor do dengue or Zika virus diseases interfere with the diagnosis of COVID-19.
Assuntos
Anticorpos Antivirais/sangue , Vírus da Dengue/imunologia , Imunoglobulina M/imunologia , SARS-CoV-2/imunologia , Testes Sorológicos , Zika virus/imunologia , COVID-19/diagnóstico , Reações Cruzadas/imunologia , Dengue/diagnóstico , Ensaio de Imunoadsorção Enzimática , Humanos , Porto Rico , Sensibilidade e Especificidade , Estados Unidos , Infecção por Zika virus/diagnósticoRESUMO
The aim of the present study is to report the isolation, structural elucidation, and antiviral evaluation of four new withanolide-type steroids, named nicansteroidins A-D (1-4), together with nine related known compounds (5-13) isolated from the aerial parts of Physalis nicandroides. Their structures were established based on an extensive spectroscopic analysis, including 1D and 2D NMR techniques. Outstandingly, nicansteroidins A and B possess an unusual side chain with an exocyclic double bond on the δ-lactone system, whereas nicansteroidins C and D have an uncommon cycloperoxide functionality in ring A as distinct structural motifs. Their biological evaluation as inhibitors of human immunodeficiency virus type 1 replication revealed that two compounds from this series, 7 and 13, displayed strong inhibition of HIV-1 replication with IC50 values lower than 2 µM. Moreover, cellular mechanism experiments showed that the main target of these compounds in the HIV replication cycle is viral transcription. This study is the first report of withanolide-type steroids as HIV inhibitors and provides insight into their potential as candidates for further preclinical studies.
Assuntos
Fármacos Anti-HIV/farmacologia , HIV-1/efeitos dos fármacos , Physalis/química , Replicação Viral/efeitos dos fármacos , Vitanolídeos/farmacologia , Linhagem Celular , El Salvador , HIV-1/fisiologia , Humanos , Estrutura Molecular , Componentes Aéreos da Planta/químicaRESUMO
Cross-reactivity within flavivirus antibody assays, produced by shared epitopes in the envelope proteins, can complicate the serological diagnosis of Zika virus (ZIKAV) infection. We assessed the utility of the plaque reduction neutralization test (PRNT) to confirm recent ZIKAV infections and rule out misleading positive immunoglobulin M (IgM) results in areas with various levels of past dengue virus (DENV) infection incidence. We reviewed PRNT results of sera collected for diagnosis of ZIKAV infection from 1 January through 31 August 2016 with positive ZIKAV IgM results, and ZIKAV and DENV PRNTs were performed. PRNT result interpretations included ZIKAV, unspecified flavivirus, DENV infection, or negative. For this analysis, ZIKAV IgM was considered false positive for samples interpreted as a DENV infection or negative. In U.S. states, 208 (27%) of 759 IgM-positive results were confirmed to be ZIKAV compared to 11 (21%) of 52 in the U.S. Virgin Islands (USVI), 15 (15%) of 103 in American Samoa, and 13 (11%) of 123 in Puerto Rico. In American Samoa and Puerto Rico, more than 80% of IgM-positive results were unspecified flavivirus infections. The false-positivity rate was 27% in U.S. states, 18% in the USVI, 2% in American Samoa, and 6% in Puerto Rico. In U.S. states, the PRNT provided a virus-specific diagnosis or ruled out infection in the majority of IgM-positive samples. Almost a third of ZIKAV IgM-positive results were not confirmed; therefore, providers and patients must understand that IgM results are preliminary. In territories with historically higher rates of DENV transmission, the PRNT usually could not differentiate between ZIKAV and DENV infections.
Assuntos
Anticorpos Antivirais/sangue , Vírus da Dengue/imunologia , Dengue/epidemiologia , Imunoglobulina M/sangue , Infecção por Zika virus/diagnóstico , Zika virus/imunologia , Samoa Americana/epidemiologia , Reações Cruzadas , Reações Falso-Positivas , Feminino , Flavivirus/imunologia , Humanos , Incidência , Masculino , Testes de Neutralização , Porto Rico/epidemiologia , Estados Unidos/epidemiologia , Ilhas Virgens Americanas/epidemiologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologiaRESUMO
BACKGROUND: Anti-dengue virus (DENV) immunoglobulin M (IgM) seroconversion has been the reference standard for dengue diagnosis. However, paired specimens are rarely obtained, and the interval for this testing negates its usefulness in guiding clinical case management. The presence of DENV viremia and appearance of IgM during the febrile phase of dengue provides the framework for dengue laboratory diagnosis by using a single serum specimen. METHODS: Archived paired serum specimens (n = 1234) from patients with laboratory-confirmed dengue from 2005 through 2011 were used to determine the diagnostic performance of real-time reverse transcription polymerase chain reaction (RT-PCR), for detection of DENV serotypes 1-4, and enzyme-linked immunosorbent assays (ELISAs), for detection of DENV nonstructural protein 1 (NS1) antigen and anti-DENV IgM. RESULTS: During 1-3 days after illness onset, real-time RT-PCR and NS1 antigen testing detected 82%-69% and 90%-84% of cases, respectively, as viremia levels declined, while anti-DENV IgM ELISA detected 5%-41% of cases as antibody appeared. Over the 10-day period of the febrile phase of dengue, the cumulative effect of using these 3 types of tests in a diagnostic algorithm confirmed ≥90% of dengue cases. CONCLUSIONS: The use of molecular or NS1 antigen tests to detect DENV and one to detect anti-DENV IgM in a single serum specimen collected during the first 10 days of illness accurately identified ≥90% of dengue primary and secondary cases.
Assuntos
Anticorpos Antivirais/sangue , Vírus da Dengue/isolamento & purificação , Dengue/diagnóstico , Testes Diagnósticos de Rotina/métodos , Ensaio de Imunoadsorção Enzimática/métodos , Imunoglobulina M/sangue , Técnicas de Diagnóstico Molecular/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , Reação em Cadeia da Polimerase em Tempo Real/métodos , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/imunologia , Adulto JovemRESUMO
As a part of our investigation into new anti-HIV agents, we report herein the isolation, structure elucidation, and biological activity of six new (1-6) and 20 known (7-26) pentacyclic lupane-type triterpenoids from the stem of Cassine xylocarpa and root bark of Maytenus cuzcoina. Their stereostructures were elucidated on the basis of spectroscopic and spectrometric methods, including 1D and 2D NMR techniques. To gain a more complete understanding of the structural requirements for anti-HIV activity, derivatives 27-48 were prepared by chemical modification of the main secondary metabolites. Sixteen compounds from this series displayed inhibitory effects of human immunodeficiency virus type 1 replication with IC50 values in the micromolar range, highlighting compounds 12, 38, and 42 (IC50 4.08, 4.18, and 1.70 µM, respectively) as the most promising anti-HIV agents.
Assuntos
Fármacos Anti-HIV/isolamento & purificação , Fármacos Anti-HIV/farmacologia , Celastraceae/química , Maytenus/química , Triterpenos/isolamento & purificação , Triterpenos/farmacologia , Fármacos Anti-HIV/química , Antineoplásicos Fitogênicos/química , HIV-1/efeitos dos fármacos , Humanos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peru , Casca de Planta/química , Caules de Planta/química , Relação Estrutura-Atividade , Triterpenos/químicaRESUMO
Dengue is a potentially fatal acute febrile illness caused by the mosquito-borne dengue viruses (DENV-1 to -4). To estimate DENV seroincidence in school-aged children, a 1-year prospective cohort study was conducted in Patillas, Puerto Rico; 10- to 18-year-olds (N = 345) were randomly selected from 13 public schools. At enrollment, 49.8% of the entire cohort had DENV immunoglobulin G (IgG) anti-DENV antibodies, and there were individuals with neutralizing antibodies specific to each of the four DENV. The mean age of participants with incident DENV infection was 13.4 years. The 1-year seroincidence rate was 5.6%, and 61.1% of infections were inapparent. Having IgG anti-DENV at enrollment was associated with seroincidence (risk ratio = 6.8). Acute febrile illnesses during the study period were captured by a fever diary and an enhanced and passive surveillance system in the municipios of Patillas and Guayama. In summary, at enrollment, nearly one-half of the participants had a prior DENV infection, with the highest incidence in the 10- to 11-year-olds, of which most were inapparent infections, and symptomatic infections were considered mild.
Assuntos
Vírus da Dengue , Dengue/epidemiologia , Adolescente , Anticorpos Antivirais/sangue , Criança , Dengue/sangue , Dengue/virologia , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Porto Rico/epidemiologia , Estudos SoroepidemiológicosRESUMO
In October 2012, the Haitian Ministry of Health and the US CDC were notified of 25 recent dengue cases, confirmed by rapid diagnostic tests (RDTs), among non-governmental organization (NGO) workers. We conducted a serosurvey among NGO workers in Léogane and Port-au-Prince to determine the extent of and risk factors for dengue virus infection. Of the total 776 staff from targeted NGOs in Léogane and Port-au-Prince, 173 (22%; 52 expatriates and 121 Haitians) participated. Anti-dengue virus (DENV) IgM antibody was detected in 8 (15%) expatriates and 9 (7%) Haitians, and DENV non-structural protein 1 in one expatriate. Anti-DENV IgG antibody was detected in 162 (94%) participants (79% of expatriates; 100% of Haitians), and confirmed by microneutralization testing as DENV-specific in 17/34 (50%) expatriates and 42/42 (100%) Haitians. Of 254 pupae collected from 68 containers, 65% were Aedes aegypti; 27% were Ae. albopictus. Few NGO workers reported undertaking mosquito-avoidance action. Our findings underscore the risk of dengue in expatriate workers in Haiti and Haitians themselves.
Assuntos
Dengue/epidemiologia , Adulto , Aedes , Idoso , Animais , Anticorpos Antivirais/sangue , Dengue/etiologia , Dengue/transmissão , Vírus da Dengue/imunologia , Feminino , Haiti/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fatores de TempoRESUMO
In June of 2007, West Nile virus (WNV) was detected in sentinel chickens and blood donors in Puerto Rico, where dengue virus (DENV) is hyperendemic. Enhanced human surveillance for acute febrile illness (AFI) began in eastern Puerto Rico on July 1, 2007. Healthcare providers submitted specimens from AFI cases for WNV and DENV virology and serology testing. Over 6 months, 385 specimens were received from 282 cases; 115 (41%) specimens were DENV laboratory-positive, 86 (31%) specimens were laboratory-indeterminate, and 32 (11%) specimens were laboratory-negative for WNV and DENV. One WNV infection was detected by anti-WNV immunoglobulin M (IgM) antibody and confirmed by a plaque reduction neutralization test. DENV and WNV infections could not be differentiated in 27 cases (10%). During a period of active WNV transmission, enhanced human surveillance identified one case of symptomatic WNV infection. Improved diagnostic methods are needed to allow differentiation of WNV and DENV in dengue-endemic regions.
Assuntos
Anticorpos Antivirais/sangue , Dengue/epidemiologia , Doenças Endêmicas , Vigilância de Evento Sentinela , Febre do Nilo Ocidental/diagnóstico , Vírus do Nilo Ocidental/imunologia , Adulto , Dengue/diagnóstico , Vírus da Dengue/genética , Vírus da Dengue/imunologia , Feminino , Humanos , Masculino , Testes de Neutralização , Porto Rico/epidemiologia , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/virologia , Adulto JovemRESUMO
A commercial anti-dengue virus (anti-DENV) indirect IgG enzyme-linked immunosorbent assay (ELISA) for serological diagnosis was evaluated for its utility in determining previous DENV exposure in U.S. travelers. The Boston Area Travel Medicine Network clinics used Focus Diagnostics anti-DENV IgG ELISA to measure anti-DENV IgG antibodies in 591 pretravel specimens from U.S. residents who had traveled to countries where dengue is endemic. When using the manufacturer's index cutoff value for this ELISA, false-positive results were observed that overestimated the perceived past DENV exposure in U.S. travelers. Validation of 121 of these anti-DENV IgG results by plaque reduction neutralization test (PRNT) was used for receiver operating characteristic (ROC) curve optimization of the index cutoff value from 1 to 3.0, improving the specificity of the anti-DENV IgG ELISA from 24% to 95.7%. Additionally, previous vaccination with yellow fever virus contributed to 52.8% of the false-positive rate in the anti-DENV IgG ELISA results. Optimization of the cutoff value of the anti-DENV IgG ELISA provided better interpretation and confidence in the results and eliminated the need for confirmation by PRNT. The travel history of U.S. travelers was also useful for categorizing these travelers into groups for analysis of previous DENV exposure.
Assuntos
Anticorpos Antivirais/sangue , Dengue/diagnóstico , Imunoglobulina G/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Boston , Criança , Dengue/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Curva ROC , Sensibilidade e Especificidade , Testes Sorológicos/métodos , Viagem , Ensaio de Placa Viral , Adulto JovemRESUMO
A laboratory testing algorithm was evaluated to confirm West Nile virus (WNV) infection in human serum following the introduction of the virus in Puerto Rico in 2007. This testing algorithm used two standard diagnostic assays, the IgM antibody capture enzyme-linked immunosorbent assay (MAC ELISA) and real-time reverse transcriptase PCR (RT-PCR), along with two nonconventional assays, the nonstructural protein 1 (NS1) ELISA and a 90%-plaque-reduction neutralization test (PRNT(90)) with IgG depletion for dengue virus (DENV) and WNV. A total of 2,321 serum samples from suspected WNV human cases were submitted for testing. Approximately one-third (867, 37%) were cross-reactive for DENV and WNV by MAC ELISA and had negative RT-PCR results for both viruses. Of a subset of 43 samples tested, 31 (72%) of these cases were identified as positive for DENV in the PRNT(90) with IgG depletion and 8 (19%) were positive in the DENV NS1 antigen ELISA. These two assays combined differentiated 36 (84%) of the samples that could not be diagnosed using the standard diagnostic testing methods.