Rosmari Rodríguez

Fatal dengue hemorrhagic fever in Cuba, 1997

OBJECTIVES After more than 15 years without dengue activity, a dengue II epidemic was reported in Cuba in 1997. Three thousand and twelve serologically confirmed cases were reported, with 205 dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) cases and 12 fatalities. This report presents the clinical, serologic, and virologic findings in the 12 fatal DHF/DSS cases. METHODS Serum and necropsy samples were studied by viral isolation in C636 cell line and polymerase chain reaction. Serum samples were tested by IgM capture enzyme-linked immunoassay (ELISA) and ELISA inhibition method (EIM). RESULTS All 12 cases were classified as DHF/DSS according to the Pan American Health Organization Guidelines for Control and Prevention of Dengue and Dengue Hemorrhagic Fever in the Americas. All patients were older than 15 years. Women were more frequently affected. The symptoms and signs presented by these patients were similar to those previously described in DHF/DSS cases. Clinical deterioration occurred on average at day 3.75. Abdominal pain and persistent vomiting were the earliest and most frequent warning signs. Dengue infection was confirmed in all cases. IgM antibodies were detected in 11 of 12 cases, all of them with a secondary infection. Dengue II virus was detected by viral isolation in 12 samples and by polymerase chain reaction in 17. Virus or RNA was detected in various tissues, including kidney, heart, lung, and brain. CONCLUSION The clinical, pathologic, and laboratory features of 12 cases of fatal dengue hemorrhagic fever were reviewed. The results obtained demonstrate that adults with a primary dengue infection are at risk of developing the severe disease (DHF) if they are infected with a different serotype.

Dengue 3 Epidemic, Havana, 2001

In June 2001, dengue transmission was detected in Havana, Cuba; 12,889 cases were reported. Dengue 3, the etiologic agent of the epidemic, caused the dengue hemorrhagic fever only in adults, with 78 cases and 3 deaths. After intensive vector control efforts, no new cases have been detected.

Primary and Secondary Infections of Macaca fascicularis Monkeys with Asian and American Genotypes of Dengue Virus 2

ABSTRACT The goal of this study was to compare the immune response and the protection capacity induced by the dengue virus 2 (DENV-2) American and Asian genotypes in Macaca fascicularis monkeys. Animals were infected with American or Asian DENV-2 strains and challenged 1 year later with a DENV-2 Asian genotype strain. The viremia and monkey antibody levels were similar for the different strains after primary and secondary infection; however, the functionality of the antibody response was different. A limited viral replication was demonstrated after the secondary infection in all the monkeys. No virus was isolated in tissue culture, while reverse transcription-PCR showed a late positive reaction in four of five challenged monkeys. The immunoglobulin M response pattern and the detection of antibodies to specific proteins by Western blotting supported the protection data. Despite the demonstration of the protective effect after homologous challenge, a strong anamnestic antibody response was observed.

Reacción en cadena de la polimerasa para la detección rápida y determinación del serotipo de virus del dengue en muestras clínicas

El trabajo que aqui se presenta describe las ventajas de usar la reaccion en cadena de la polimerasa con transcriptasa inversa (RCP-TI) para detectar e identificar con rapidez virus del dengue en muestras clinicas. Se sometieron directamente a RCP-TI 27 muestras obtenidas de pacientes con fiebre de dengue y fiebre hemorragica de dengue durante epidemias en Colombia, Nicaragua y Panama. El ADN de cadena doble obtenido con la RCP-TI se identifico mediante una segunda amplificacion (RCP de anidacion) utilizando cebadores especificos para cada tipo de virus, aislamiento virico e inmunofluorescencia indirecta (IFI) y con electroinmunoensayo enzimatico detector de anticuerpos IgM contra el virus del dengue. El genoma virico amplificado se detecto e identifico en un maximo de 8 horas. Los parametros calculados para hacer el diagnostico por RCP-TI, usando el aislamiento virico y la IFI como estandar de oro, fueron una sensibilidad de 100%; una especificidad de 78%; un valor predictivo positivo de 69% y un valor predictivo negativo de 100%. Cabe notar que dos de los especimenes que dieron resultados positivos a la prueba de RCP-TI anidada y negativos al aislamiento virico mostraron anticuerpos especificos de tipo IgM. Los resultados de la RCP-TI en general mostraron una estrecha concordancia con los del aislamiento virico, lo cual sugiere que la RCP es un procedimiento que facilita enormemente el diagnostico rapido y temprano del dengue.

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

OBJECTIVES Recognizing 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). METHODS A 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. RESULTS DENV-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. CONCLUSIONS The 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.

Study of biologic attributes of cuban dengue 2 virus after serial passage in primary dog kidney cells

OBJECTIVE The serial passage of dengue viruses in primary dog kidney (PDK) cells has resulted in selection of attenuated viruses. However, the molecular changes responsible for loss of virulence are not well characterized. This article describes the isolation and biologic attributes of one dengue 2 virulent strain as a first step to allow the study of determinants of virulence at the molecular level. METHODS A15 dengue 2 Cuban strain was isolated from the viremic plasma of a patient with uncomplicated dengue fever during the 1981 epidemic. This was then subjected to serial passage in PDK cells. Viruses resulting from several PDK passages were compared to the parent strain for plaque size and temperature sensitivity, neurovirulence in newborn mice, and cytopathogenic effects on LLC-MK(2) and C6/36-HT cell lines. RESULTS A15 dengue 2 Cuban strain was successfully propagated in PDK cells. Primary dog kidney 52 to 53 viruses exhibited several biologic attributes, such as small plaques, temperature sensitivity, reduced mouse neurovirulence, and cytopathic effect in permissive cell lines. CONCLUSIONS These results represent the first step to allow attenuation of this strain of dengue 2 virus.

Early hepatitis C virus changes and sustained response in patients with chronic hepatitis C treated with peginterferon α‐2b and ribavirin

Abstract: Background: Interferon‐based therapy induces changes in viral dynamics in chronic hepatitis C (CHC) patients.