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

Abstract

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.

Methods: as a result of the lab surveillance, from the 38th to the 42nd epidemiological weeks (September and October, 2009), 1 063 respiratory clinical samples were processed (nasopharyngeal exudates, bronchial aspirates and lung necropsy samples). The highest number of confirmed cases caused by the new virus was detected in this period that represented the first pandemic wave in Cuba. Diagnosis was based on molecular diagnosis algorithm.

Results: out of the 1063 samples, 597 (56.0 %) were positive. The pandemic influenza A (H1N1) virus was the most commonly detected etiological agent in 306 suspected cases (51 %) followed by influenza A (H3N2) virus in 228 cases (38 %). Other respiratory viruses were diagnosed in 63 clinical samples (11 %). The pandemic virus was confirmed in 50 pregnant women. Rhinoviruses were identified more frequently in those samples from patients with clinical diagnosis of bronchial pneumonia and broncholitis. Morbidity increased during this period; 225 825 medical consultations were notified due to acute respiratory infections mid-October 2009.

Conclusions: the molecular diagnosis algorithm proved to be sensitive, specific and effective to assure the systematic virological surveillance in our country during the pandemic phase.