Relación genética del virus dengue 1 aislado en Cuba durante la epidemia de 1977 / Genetic relationship of dengue virus 1 isolated in Cuba, 1977

Introducción: el dengue es una enfermedad aguda causada por cuatro serotipos del virus del dengue (DENV-1 al 4) y transmitida al hombre por el mosquito Aedes aegypti. En Cuba, la primera epidemia de dengue con confirmación de laboratorio ocurrió en 1977, identificándose al DENV-1 como agente causal. Se plantea que el virus se dispersó en varios países de Latinoamérica y el Caribe partir de su introducción en Jamaica en 1977. Objetivos: explicar la caracterización molecular y determinar la relación genética del DENV-1 aislado en Cuba, 1977. Métodos: a partir de un aislamiento de DENV-1 obtenido en Cuba en el año 1977 conservado en el Banco de Cepas del Laboratorio Nacional de Referencia de Arbovirus (Instituto de Medicina Tropical Pedro Kourí) se realizó la amplificación y secuenciación nucleotídica del gen de la envoltura con cebadores específicos. A partir de la secuencia obtenida se construyó un árbol filogenético de Máxima Verosimilitud, utilizando secuencias de cepas de DENV-1 circulantes a nivel mundial. Resultados: el aislamiento de DENV-1 correspondiente a la epidemia cubana de 1977, se agrupó dentro del genotipo I, relacionándose genéticamente con la cepa de Referencia Hawaii/1943. Es significativo que, el resto de los aislamientos de Latinoamérica de ese mismo período pertenecen al genotipo V, reconocido como el genotipo Americano/Africano. Conclusiones: los resultados del presente trabajo indican que durante la epidemia cubana de 1977 circuló una cepa de DENV-1 del genotipo I, lo que constituye la primera evidencia sobre la presencia de este genotipo en la región de Latinoamérica y el Caribe. No obstante, este hallazgo no descarta la posibilidad de una co-circulación de los genotipos I y V(AU)

Introduction: dengue is an acute disease caused by four dengue virus serotypes (DENV-1 to -4) and transmitted to humans by Aedes aegypti mosquitoes. The first laboratory confirmed dengue epidemic in Cuba occurred in 1977, with DENV-1 as the causative agent. It has been stated that the virus spread to several Latin American and Caribbean countries after being introduced in Jamaica in 1977. Objectives: perform a molecular characterization and determine the genetic relationship of DENV-1 isolated in Cuba in 1997. Methods: Based on a DENV-1 isolate obtained in Cuba in the year 1997 and preserved at the Strain Bank of the National Arbovirus Reference Laboratory (Pedro Kouri Tropical Medicine Institute), nucleotide amplification and sequencing was performed of the envelope gene using specific primers. Starting from the sequence obtained, a maximum likelihood phylogenetic tree was developed using sequences of DENV-1 strains circulating worldwide. Results: the DENV-1 isolate corresponding to the Cuban 1977 epidemic was classed as genotype I and genetically related to the reference strain Hawaii 1943. It is noteworthy that the remaining Latin American isolates from that period belong to genotype V, recognized as the American/African genotype. Conclusions: results show that a DENV-1 strain of genotype I circulated during the Cuban 1977 epidemic. This is the first evidence of the presence of this genotype in the Latin American and Caribbean region. However, this finding does not rule out the possibility of co-circulation of genotypes I and V1(AU)

First Isolation of Dengue Virus from the 2010 Epidemic in Nepal

Dengue is an emerging disease in Nepal and was first observed as an outbreak in nine lowland districts in 2006. In 2010, however, a large epidemic of dengue occurred with 4,529 suspected and 917 serologically-confirmed cases and five deaths reported in government hospitals in Nepal. The collection of demographic information was performed along with an entomological survey and clinical evaluation of the patients. A total of 280 serum samples were collected from suspected dengue patients. These samples were subjected to routine laboratory investigations and IgM-capture ELISA for dengue serological identification, and 160 acute serum samples were used for virus isolation, RT-PCR, sequencing and phylogenetic analysis. The results showed that affected patients were predominately adults, and that 10% of the cases were classified as dengue haemorrhagic fever/ dengue shock syndrome. The genetic characterization of dengue viruses isolated from patients in four major outbreak areas of Nepal suggests that the DENV-1 strain was responsible for the 2010 epidemic. Entomological studies identified <i>Aedes aegypti</i> in all epidemic areas. All viruses belonged to a monophyletic single clade which is phylogenetically close to Indian viruses. The dengue epidemic started in the lowlands and expanded to the highland areas. To our knowledge, this is the first dengue isolation and genetic characterization reported from Nepal.