Severe Acute Respiratory Surveillance (SARI) Surveillance, Louisiana 2013-2014

BACKGROUND:  Influenza Surveillance in Louisiana is conducted by the Infectious Disease Epidemiology Section (ID Epi) using a three pronged voluntary approach: 1) outpatient influenza-like illness (ILI) surveillance, 2) rapid test data reporting, and 3) active virologic surveillance. Influenza is not a reportable disease in Louisiana. Influenza-associated mortality is reportable but ID Epi rarely receives reports of persons >18 years of age in whom influenza is suspected as the cause of death. Severe acute respiratory illness (SARI) surveillance, monitoring persons with more severe illness, is a main component of international surveillance but is not uniformly monitored each state domestically. CDC does conduct hospitalization surveillance through the 10 Emerging Infections Program (EIP) states and three additional states but Louisiana is not part of this program. SARI surveillance was implemented in Louisiana during the 2013-2014 influenza season after ID Epi began receiving inquiries from hospital regarding acute respiratory distress syndrome (ARDS) due to influenza in November 2013.

METHODS:  A SARI case was identified as a person hospitalized with pneumonia or ARDS suspected to be caused by influenza. Demographic, medical history, clinical, and outcome information was collected on all reported SARI cases. Analysis was conducted using Microsoft Access 2010, Epi Info 7 and WINPEPI version 11.41.

RESULTS:  Of the 212 SARI cases, 181 (85%) had at least one underlying medical condition, 54 (24.7%) had two conditions, 43 (20.3%) had three conditions, and 25 (11.8%) reported four or more. The most common four underlying conditions were: obesity (43.4%), chronic cardiac conditions (39.6%), diabetes (29.7%), and chronic pulmonary conditions (29.6%). While obesity was the most reported underlying condition, it was three times more likely to be reported by cases less than 65 years old rather than those >65.

CONCLUSIONS:  Continuation of SARI data collection in future seasons will allow comparisons regarding severity, populations affected, and identify risk factors most commonly associated with severe illness. Reporting of SARI cases also increased influenza-associated mortality reporting to ID Epi. Though all influenza-associated mortality is reportable in Louisiana, adult mortality was reported rarely prior to the 2013-2014 influenza season.