Clinical and molecular characteristics of influenza outbreak in two military bases in Tumbes, Perú 2007

Abstract

Objective. To describe an Influenza outbreak in two military bases in Tumbes, department located in northern Peru. Material and methods. In patients within 5 days of symptoms the Ministry of Health case definition of Influenza-like illness was used. Nasal swabs were taken for Rapid Influenza Test (RIT) and throat swab for viral isolation, three cell lines (MDCK, VERO, LLCMK2) were used. For Influenza B genotypification we made a partial sequencing of hemaglutinine region of 898 pair bases, having 2007 vaccine strain B/Florida/4/2006 as a model. For Influenza A genotypification we analysed 958 pair bases, having 2007 vaccine strain A/Brisbane/10/2007 (H3N2) as a model. Results. We took 124 samples, 20 from military base (MB) # 1 and 104 from MB # 2. RIT promptly identified 41 positive cases: Flu B: 27, Flu A: 02, Flu: 12, with 62% of sensibility and specificity 100%. Finally, 66 cases were confirmed by virus isolation, 54 Flu B and 12 Flu A. Genotypification showed that isolates were genetically similar to Influenza B/Texas/4/2006 (n=34) and A/Texas/91/2007 (H3N2) (n=7). Most common symptoms found were fever, headache, malaise, cough, sore throat, myalgias and rinorrheae. Control strategies consisted to identify probable cases and to isolate them in a special room and to wear facemasks. Conclusions. We confirmed 66 cases by cellular culture. Isolates were genetically similar to Influenza B/Texas/4/2006 and A/Texas/91/2007 (H3N2).