Prevalence of non-influenza respiratory viruses in acute respiratory infection cases in Mexico

Fernandes-Matano, Larissa; Monroy-Muñoz, Irma Eloísa; Angeles-Martínez, Javier; Sarquiz-Martinez, Brenda; Palomec-Nava, Iliana Donají; Pardavé-Alejandre, Hector Daniel; Santos Coy-Arechavaleta, Andrea; Santacruz-Tinoco, Clara Esperanza; González-Ibarra, Joaquín; González-Bonilla, Cesar Raúl; Muñoz-Medina, José Esteban

Approximately 27 million ARI cases occur annually in Mexico [14] . These cases can be caused by a large variety of aetiological agents. However, the main purpose of epidemiological surveillance in the country is to detect the antigenic variations of influenza that are presented each season, which determine the changes in the vaccine composition. In 2013, the Instituto de Diagnóstico y Referencia Epidemiológicos (InDRE; Institute of Epidemiological Diagnosis and Reference) implemented a differential diagnosis of influenza that included 14 other respiratory viruses [15] . Due to this, at this moment Mexico does not have enough epidemiological information about the great diversity of viruses causing Acute Respiratory Infection. This lack of information, makes physicians search only for influenza, it is therefore the most requested confirmatory test in the laboratory during the whole year, even when we are out of influenza season (season comprises from October to May), leading to useless negative influenza results in most of the cases, without identifying the real causal agent of ARI in Mexico. This problem have direct implications for each patient, as the clinician does not know the causal agent, the patient does not receive the suitable treatment. It also has implications that affect the whole society, because the ignorance of the circulation patterns and incidence of other respiratory viruses limit preventive actions by health institutions. According to data from the Secretary of Health, approximately 80% of the samples from patients with ARIs that are received for confirmation of influenza virus infection outside of flu season are negative for the different strains of this virus and remain without a defined aetiology. Therefore, the objective of this study was to determine the viral aetiology of these infections and to analyse the behaviour of non-influenza respiratory viruses in the Mexican population.