Epidemiological studies on dengue virus type 3 in Playa municipality, Havana, Cuba, 2001–2002

SummaryObjectivesRecognizing the uniqueness of secondary dengue virus (DENV)-1/3 dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) cases at an interval of 24 years, we sought to estimate DENV infections as well as the ratios between mild disease and DHF/DSS by DENV infection sequence in Playa District (Havana, Cuba) during the 2001–2002 outbreak of dengue virus type 3 (DENV-3).MethodsA retrospective seroepidemiological study was conducted in 2003 in Playa District. Blood samples were collected from a 1% random sample of residents and were studied for the prevalence of dengue neutralizing antibodies.ResultsDENV-3 was found to have infected 7.2% (95% confidence interval (95% CI) 6.0–8.4%) of susceptible individuals (the entire cohort), the majority of whom experienced silent infections. Virtually every individual who had a secondary infection in the sequence DENV-1 then DENV-3 became ill, with a ratio of severe to mild cases of 1:35 (95% CI 1:67–1:23). Secondary infections in the sequence DENV-2/3 were less pathogenic than DENV-1/3. Mild disease accompanying secondary DENV2/3 occurred at a ratio of 1:4.49 infections (95% CI 1:5.77–1:3.42) secondary infections.ConclusionsThe results obtained highlight the role of the infecting serotype and also the sequence of the viral infection in the clinical outcome of a dengue infection

Comparison of Rapid Centrifugation Assay with Conventional Tissue Culture Method for Isolation of Dengue 2 Virus in C6/36-HT Cells

A rapid centrifugation assay was compared with conventional tube cell culture for dengue virus isolation in both sera and autopsy samples from dengue and dengue hemorrhagic fever/dengue shock syndrome fatal cases. The rapid centrifugation assay allowed isolation of virus from 16.6% more samples than the conventional method, and it shortened the time for dengue virus detection. Finally, it allowed the isolation of dengue 2 virus in 42.8% of tissue samples from five fatal cases. Our results suggest that the rapid centrifugation assay may be useful for detection of dengue virus in clinical specimens

First Epidemic of Echovirus 16 Meningitis in Cuba

From April to September 2000, an epidemic of aseptic meningitis spread throughout Cuba, with 16,943 reported cases. Virologic studies identified echovirus 16 as the cause of this epidemic. This is the first reported isolate of echovirus 16 from patients with viral meningitis in Cuba

Deteccion de citomegalovirus mediante la tecnica de inmunoperoxidasa y aislamiento viral

En el presente estudio se comparó la técnica de inmunoperoxidasa para la detección de citomegalovirus (IPCMV) utilizando anticuerpos monoclonales que reconocen proteínas precoces virales con el método convencional de aislamiento viral en fibroblastos humanos. Un total de 150 muestras de orina fueron examinadas encontrando una sensibilidad de un 89.8% y una especificidad de 91.3% de la técnica de IPCMV comparada con el aislamiento viral. Una de las ventajas que presentó la IPCMV fue la rapidez con que fueron obtenidos los resultados (48 horas) mientras que el aislamiento viral fue como promedio 14 días.An Immunoperoxidase assay was applied to detect early antigens of Cytomegalovirus (CMV) in 150 urine samples from immunocompromised patients, using the commercial available monoclonal antibody against CMV El3. The detection of early antigen by IP (IPCMV) is compared to the conventional cell culture isolation regarding specificity and sensitivity in order to evaluate is usefulness in the diagnostic of CMV infections. The IPCMV showed a sensitivity of 89.8% and a specificity of 91.3% when compared to the isolation method. The great advantage of the IPCMV is based on the shorter time results are achieved, since 48-72 Hs can be enough to provide evidence of CMV infection, while in the isolation technique cytopatho-genic effect was present around 14 days after sample inoculation

Casos de poliomielitis paralítica asociada a la vacuna oral antipoliomielítica en Cuba (1963-2006) Cases of paralytic poliomyelitis associated with oral antipoliomielytis vaccine in Cuba (1963-2006)

OBJETIVO: divulgar los indicadores de poliomielitis paralítica asociada encontrados en 44 años en niños vacunados con oral antipoliomielítica, suministrada exclusivamente en campañas masivas de vacunación durante el período de 1963 a 2006 y reportar el riesgo de poliomielitis paralítica asociada a la vacuna con relación a diferentes aspectos epidemiológicos. MÉTODOS: se realizó un estudio retrospectivo en 596 casos de parálisis fláccida aguda en niños ingresados en hospitales pediátricos, basado en investigaciones virológicas y detección de diferentes variables epidemiológicas. RESULTADOS: de 113 pacientes estudiados se aislaron 120 agentes virales y 30 fueron identificados como poliovirus. Los datos clínicos y epidemiológicos en 596 casos de parálisis fláccida aguda permitieron categorizar a 20 niños afectados con poliomielitis paralítica asociada a la vacuna. Todos los casos se presentaron en niños menores de un año, vacunados con oral antipoliomielítica con estrategias de campañas masivas de vacunación exclusivamente y 19 fueron producidos por la primera dosis. El riesgo global en los niños vacunados con primera dosis de 1963 a 2006 fue 1 en 379 888 (7 217 866 dosis administradas/19 casos con poliomielitis paralítica asociada a la vacuna). Los casos de poliomielitis paralítica asociada a la vacuna se han presentado esporádicos o en un grupo de 8 casos en el período 1989-1992. El riesgo de primera dosis en casos esporádicos fue 1 en 612 864 y en el grupo de 1 en 84 670. El riesgo en casos agrupados es 7,2 veces mayor que los ocurridos en casos aislados. Particularmente en el año 1992, que coincidió con una epidemia de neuropatía epidémica, el riesgo fue de 1 en 52 140, lo que representó un incremento de 11,8 veces a lo ocurrido en casos esporádicos. Los niños de 4-7 meses de edad también tuvieron un riesgo mayor que fue 1 en 132 812. CONCLUSIONES: se identificaron aspectos epidemiológicos que incrementaron el riesgo de poliomielitis paralítica asociada a la vacuna, en los cuales coinciden aspectos de deficiencias nutricionales.AIM: to disseminate the indicators of associated paralytic poliomyelitis found during 44 years in children that received the oral antipoliomyelitis vaccine, which was only administered in massive vaccination campaigns from 1963 to 2006, and to report the risk of vaccine-associated paralytic poliomyelitis as regards different epidemiological aspects. METHODS: a retrospective study was undertaken in 596 cases of acute flaccid paralysis in children admitted in pediatric hospitals, based on virology researches, and on the detection of different epidemiological variables. RESULTS: 120 viral agents were isolated from 113 studied patients. 30 were identified as poliovirus. The clinical and epidemiological data from 596 cases of acute flaccid paralysis allowed to categorize 20 children affected with vaccine-associated paralytic poliomyelitis. All the cases were children under one that were exclusively administered the oral antipoliomyelitis vaccine through the strategy of the massive vaccination campaigns. 19 of them were caused by the first dose. Global risk in children vaccinated with the first dose from 1963-2006 was of one in 379 888 (7 217 866 doses administered/19 cases with vaccine-associated paralytic poliomyelitis). Cases of vaccine-associated paralytic poliomyelitis have been sporadic or in a group of 8 cases during 1989-1992. The risk of first dose in sporadic cases was of one in 612 864, and in the group of 1 in 84 670. The risk of grouped cases is 7.2 times higher than those occurred in isolated cases. Particularly, in 1992, coinciding with an outbreak of epidemic neuropathy, the risk was of one in 52 140, which represented an increase of 11.8 times compared with sporadic cases. Children aged 4-7 months old also had a higher risk of 1 in 132 812. CONCLUSIONS: there were identified epidemiological aspects that augmented the risk of vaccine-associated paralytic poliomyelitis, in which the aspects of nutritional deficiencies coincided

Analysis of respiratory syncytial virus in clinical samples by reverse transcriptase-polymerase chain reaction restriction mapping

The aim of this study was to develop a polymerase chain reaction (PCR) for the detection of respiratory syncytial virus (RSV) genomes. The primers were designed from published sequences and selected from conserved regions of the genome encoding for the N protein of subgroups A and B of RSV. PCR was applied to 20 specimens from children admitted to the respiratory ward of "William Soler" Pediatric Hospital in Havana City with a clinical diagnosis of bronchiolitis. The PCR was compared with viral isolation and with an indirect immunofluorescence technique that employs monoclonal antibodies of subgroups A and B. Of 20 nasopharyngeal exudates, 10 were found positive by the three assayed methods. In only two cases, samples that yielded positive RNA-PCR were found negative by indirect immunofluorescence and cell culture. Considering viral isolation as the "gold standard" technique, RNA-PCR had 100% sensitivity and 80% specificity. RNA-PCR is a specific and sensitive technique for the detection of the RSV genome. Technical advantages are discussed

Molecular evolution of coxsackievirus A24v in Cuba over 23-years, 1986–2009

Coxsackievirus A24 variant (CVA24v) is a major causative agent of acute hemorrhagic conjunctivitis outbreaks worldwide, yet the evolutionary and transmission dynamics of the virus remain unclear. To address this, we analyzed and compared the 3C and partial VP1 gene regions of CVA24v isolates obtained from five outbreaks in Cuba between 1986 and 2009 and strains isolated worldwide. Here we show that Cuban strains were homologous to those isolated in Africa, the Americas and Asia during the same time period. Two genotypes of CVA24v (GIII and GIV) were repeatedly introduced into Cuba and they arose about two years before the epidemic was detected. The two genotypes co-evolved with a population size that is stable over time. However, nucleotide substitution rates peaked during pandemics with 4.39 × 10−3 and 5.80 × 10−3 substitutions per site per year for the 3C and VP1 region, respectively. The phylogeographic analysis identified 25 and 19 viral transmission routes based on 3C and VP1 regions, respectively. Pandemic viruses usually originated in Asia, and both China and Brazil were the major hub for the global dispersal of the virus. Together, these data provide novel insight into the epidemiological dynamics of this virus and possibly other pandemic viruses