Background: Acute respiratory tract infections are the most common reason for consulting with general practitioners in all age groups. These infections can be caused by several pathogens, and the clinical presentation of patients with different viral infections can be very similar, making diagnosis difficult. Influenza is not an eradicable disease; prevention and control are the only realistic goals. Surveillance can help in planning and evaluating disease prevention and control programs, and can improve capacity to control annual epidemics as well as the next influenza pandemic. In Cuba, particularly, influenza virus infection and its complications constitutes the fourth cause of death within all the causes of mortality and the first cause of mortality between the infectious diseases. Method: At the end of September/2006 an alert of acute respiratory infection (ARI) increase was reported by health authorities in one internal school, located in the peripheral municipality of Havana city. Nasopharyngeal swabs were taken in viral transport media and delivered to the National Reference Respiratory Viruses Laboratory. A Multiplex nested RT-PCR was employed. This multiplex is able to detect RSVA, RSVB, Adenovirus and Influenza A, Influenza B and Influenza C viruses and was previously described by Coiras et. al in 2003. Results: 51% of patients clinically diagnosed as influenza-like illness in this outbreak, Influenza C virus was detected. Viral dual infections were detected in two cases. In no case was the illness of greater severity. Conclusion: Surveillance is an important component of influenza control. With the implementation of molecular tools at National Influenza Centre and the National reference laboratory of respiratory viruses, undertaken an effective monitoring the circulation of respiratory viruses in our country.

Background: Influenza epidemics are caused by rapid evolution of the viral genome and continue to play a significant role in the annual frequency of mortality and morbidity as a result of respiratory tract infection. World Health Organization created more than 50 years ago the World Influenza Surveillance System, which has contributed to the knowledge and the understanding of the epidemiology of these viruses. However, it still is necessary to improve and strengthen the surveillance and control of this disease all over the world. Method: During the 2005–2006 influenza season, the totality of respiratory samples were analyzed using two multiplex RT nested-RCP multiplex for the detection of 14 respiratory virus and an third RT nested PCR assay (L gen) was used for detection of hMPV. Recently, we introduce two RT nested-RCP for the typing and subtyping of hemagglutinin and neuraminidase of influenza A virus, including the subtype A (H5N1). Results: Virological surveillance highlighted the predominant circulation of B viruses (32% of isolates) in Cuba, in contrast to many other countries in Europe and North America where AH3N2 viruses were isolated most frequently, and in contrast to the infrequent isolation of B viruses in Cuba during the previous years. Influenza A(H1N1) viruses were not identified. However, the surveillance through serum pair studies showed a predominant positively to influenza A (H3N2) and the circulation studies using monoserum of health population (children and adults) showed very low titles to Influenza A (H1N1). Three viruses influenza B were characterized by direct sequencing of haemagglutinin (HA1). Preliminary phylogenetic analysis indicated that the totality of the B viruses belonged to the B/Victoria/2/87-lineage. Conclusion: With the implementation of new advanced techniques in the NCI of Cuba, we will be able to undertake an effective monitoring of the circulation of influenza virus in our country and will keep the national health authorities alert and the WHO about the strains circulating in the country.

Background: Vaccine campaigns against flu in Cuba increased for those groups at risk of developing complications, such as persons with chronic heart or lung diseases, including asthmatics. Several statements justify the study of asthmatic persons with the objective of reducing morbidity, mortality, exacerbations of asthma and the use of antibiotics. Humoral response of a group of asthmatic persons, generated by the commercial vaccine Agrippal S1 (Biocine s.p.a., Siena, Italy), was evaluated for the influenza virus during the 2000–2001 season. The efficacy and effectiveness of the influenza vaccine to prevent clinical flu infection and exacerbations in a population with asthma (one vaccine dose) was studied. Materials and methods: The study was carried out during the 2000–2001 season, with Agrippal S1 (Chiron Vaccines), containing the influenza strains (formula recommended by WHO for this season). In all, 45 patients received one dose. The sera were measured before vaccination and 1 month after by hemagglutination test (IH). Statistical analysis was made using the Student's test. Results: The IH test demonstrated the capacity of the vaccine to stimulate the production of antihemagglutinin antibody levels. The positive cases for the subtypes H3N2 and H1N1 were 57.8% before vaccination and 95.6% and 84.4% after vaccination; and, for type B, 4.4% before and 44.4% after vaccination. There was an increment in the GMT subtype, AH3N2, from 11.7 to 39.4; AH1N1 from 14.9 to 76.2 and type B from 5.2 to 9.7. The family doctor did not report any cases of acute flu or asthma crisis during the year after vaccination, reduction of the morbidity, hospitalizations due to pneumonia and reduction of antibiotic use. Conclusions: The vaccination (one dose) achieved satisfactory levels of antibodies for the strains H3N2 and H1N1. These were low for type B. The real results of the vaccination were very effective. There were neither acute cases of flu nor exacerbations of asthma after vaccination during the following year. The study concluded that the inactivated influenza vaccine is safe to administer to adults and children with asthma, including those with severe asthma.In Cuba, influenza vaccination rates increased, demonstrating the convenience of annual vaccination in high-risk groups.