2013, Number 1
Outbreak of Influenza “A” H1N1 and the sensitivity and specificity of a rapid test
Gómez VC, Munguía RM, Lara SG, Ortiz GF, Aldana CO
Full text
Language: Spanish
References: 15
Page: 26-31
PDF size: 337.09 Kb.
ABSTRACT
background. In April 2009, in Mexico, there was one of the largest outbreaks of influenza caused by a variant of Influenza A (H1N1 subtype).material and method. Due to an unusual behavior of acute respiratory illness ARI, from July 1st to the 23rd, the epidemiological research in the Rural Medical Unit Praxedis Guerrero Km 18, located in the northern region of Veracruz IMSS-Oportunidades Program, by reviewing daily consultation sheet were identified cases of ARI and to identify influenza-like illness (ILI). The objective was to mitigate the transmission of ARI caused by Influenza A H1N1, and to describe the outbreak and determine the sensitivity and specificity of the rapid test for Influenza QuickVue Influenza A+B.
By chart review investigated the clinical manifestations of disease were used rapid test for the qualitative detection and differentiation of t ypes A and B from paired nasopharyngeal samples, this allowed the testing of sensitivity and specificity.
results. During the study period, we identified 179 cases of ARI. The average age of patients was 23.5 years (range 5 months to 78 years). 58% of cases (n 104) were female and 42% (n 75) male. The overall attack rate was 5%. Of total respiratory infections, 46 cases were consistent with the operational definition for ILI representing 25.6% of the IRA. Of these, 34 met the criteria for test sensitivity and specificity. 26 were positive with the rapid, qualitative influenza “A “, and 24 were confirmed by RT-PCR. The sensitivity was 83.3% (95% CI 64.1 to 93.3) and the specificity, was only 40% (95% CI 16.6 to 68.7).
Information, Education and Communication (IEC) strategies were worked. Under this scheme 3,292 people received information.
discussion. Regarding rapid tests for influenza, there are several studies. Some highlight its low sensitivity and specificity compared with direct immunofluorescence, viral culture and RT-PCR. Further evaluations are needed on the usefulness of the rapid test.
REFERENCES