RESUMEN
We challenge the notion that influenza B is milder than influenza A by finding similar clinical characteristics between hospitalized adult influenza-cases. Among patients treated with oseltamivir, length of stay and mortality did not differ by type of virus infection.
Asunto(s)
Virus de la Influenza A/aislamiento & purificación , Virus de la Influenza B/aislamiento & purificación , Gripe Humana/patología , Gripe Humana/virología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antivirales/uso terapéutico , Femenino , Humanos , Gripe Humana/mortalidad , Tiempo de Internación , Masculino , Persona de Mediana Edad , Oseltamivir/uso terapéutico , Análisis de Supervivencia , Adulto JovenRESUMEN
Schools are important amplification settings of influenza virus transmission. We demonstrated correlation of school absenteeism (due to any illness) with other influenza A (H1N1) activity surveillance data during the 2009 pandemic. We collected nonspecific illness student absenteeism data from August 17, 2009 through April 3, 2010 from 187 voluntarily participating South Dakota schools using weekly online surveys. Relative risks (RR) were calculated as the ratio of the probability of absenteeism during elevated weeks versus the probability of absenteeism during the baseline weeks (RR = 1.89). We used Pearson correlation to associate absenteeism with laboratory-confirmed influenza cases, influenza cases diagnosed by rapid tests, influenza-associated hospitalizations and deaths reported in South Dakota during the 2009 H1N1 pandemic period. School-absenteeism data correlated strongly with data from these other influenza surveillance sources.
Asunto(s)
Absentismo , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/epidemiología , Pandemias/estadística & datos numéricos , Estudiantes/estadística & datos numéricos , Adolescente , Niño , Preescolar , Brotes de Enfermedades/estadística & datos numéricos , Humanos , Vigilancia de la Población/métodos , Instituciones Académicas , South Dakota/epidemiologíaRESUMEN
BACKGROUND: After identifying a student with triple-reassortant swine influenza virus (SIV) infection and pig exposure at a livestock event, we investigated whether others were infected and if human-to-human transmission occurred. METHODS: We conducted a cohort study and serosurvey among persons exposed to (1) event pigs, (2) other pigs, (3) the index case, and (4) persons without pig or index case exposure. Confirmed cases had respiratory specimens positive for SIV within 2 weeks of the index case's illness. Probable and suspected cases had illness and (1) exposure to any pig or (2) contact with a confirmed case preceding illness. Probable cases were seropositive. Suspected cases did not give serum samples. RESULTS: Of 99 event pig-exposed students, 72 (73%) participated in the investigation, and 42 (42%) provided serum samples, of whom 17 (40%) were seropositive and 5 (12%) met case criteria. Of 9 students exposed to other pigs, 2 (22%) were seropositive. Of 8 index case-exposed persons and 10 without exposures, none were seropositive. Pig-exposed persons were more likely to be seropositive than persons without pig exposure (37% vs 0%, P < .01). CONCLUSIONS: We identified an outbreak of human SIV infection likely associated with a livestock event; there was no evidence of human-to-human transmission.