Molecular and phylogenetic analysis of influenza A H1N1 pandemic viruses in Cuba, May 2009 to August 2010.

The influenza A(H1N1)pdm09 virus was detected in Cuba in May 2009. The introduction of a new virus with increased transmissibility into a population makes surveillance of the pandemic strain to the molecular level necessary. The aim of the present study was the molecular and phylogenetic analysis of pandemic influenza A(H1N1)pdm09 strains that circulated in Cuba between May 2009 and August 2010.

[Molecular diagnosis of influenza A(H1N1) 2009 virus and other respiratory viruses during the first pandemic wave in Cuba].

Introduction: the first pandemic virus of the 21st century - the influenza A (H1N1)/2009 virus-appeared in Mexico in April 2009 after triple reassortment of influenza strains of avian, human and pig origin and from there, it was spread worldwide. With the purpose of facing up to this event, Cuba adopted antipandemic measures including the virology surveillance using all necessary actions.

Objectives: the detection and validation of the entry of the causative agent of pandemic into the country in a fast and timely way, in addition to the definition of involvement of other viruses in the etiology of acute respiratory infections.

[Severe acute respiratory infection in Cuban patients during the influenza A(H1N1) pandemic in Cuba, 2009].

Introduction: On April 2009, the Mexican health authorities reported increased hospitalization indexes caused by pneumonia with high mortality rates to the Pan-American Health Organization (PAHO). The National Epidemiological Surveillance System of Mexico noticed that this increase mainly occurred in the 20-40 year old population. A new type of swine influenza A (H1N1) virus was identified by laboratory studies as the etiological agent of the first pandemic of the 21st century.

[Cuban strategy for the molecular characterization of the pandemic influenza A virus (H1N1)].

Introduction: In April 2009, there was identified a variant of the A/H1N1 influenza virus of swine origin, and shortly after the first pandemic in XXI century was declared.

Objectives: To establish a nucleotide sequencing strategy for the differential diagnosis of the seasonal and pandemic influenza A viruses, and to obtain as much molecular information as possible about hemagglutinin and neuraminidase genes in patients with influenza-like illnesses, in those with severe respiratory infection and in patients who died.

Methods: Three sequencing strategies were designed and implemented, which also offered important information about the new virus in Cuba.

[Design and implementation of a molecular method for influenza A virus (H1N1) in Cuba].

Introduction: From March through April of 2009, Mexico notified outbreaks of respiratory illness, due to a new influenza virus of swine origin, which spread over rapidly via human-to-human transmission. The molecular methods currently in use were not suitable because the genome composition based on gene segments of swine, avian and human origin was quite different from the influenza A virus (H1N1) circulating at that time.

Objective: Based on the published sequences, a set of specific primers for the HA gene was designed to evaluate a new RT-PCR assay.

[Contribution of the National Influenza Laboratory to confront the 2009 pandemic influenza in Cuba].

Introduction: Acute respiratory infections are considered the most important causes of morbidity and mortality around the world. These infections became more significant when associated to epidemics and pandemic events caused by influenza virus. The need for global surveillance of influenza viruses was recognized as early as 1947 and led to the establishment of the World Health Organization (WHO) Global Influenza Surveillance Network (GISN).