Sentinel Surveillance for Influenza among Severe Acute Respiratory Infection and Acute Febrile Illness Inpatients at Three Hospitals in Ghana.

Jones AH1, Ampofo W2, Akuffo R3, Doman B3, Duplessis C4, Amankwa JA5, Sarpong C5, Sagoe K6, Agbenohevi P7, Puplampu N4, Armah G8, Koram KA8,Nyarko EO9, Bel-Nono S9, Dueger E10.

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Abstract

BACKGROUND:

Influenza epidemiology in Africa is generally not well understood. Using syndrome definitions to screen patients for laboratory confirmation of infection is an established means to effectively conduct influenza surveillance.

METHODS:

To compare influenza-related epidemiologic data, from October 2010 through March 2013, we enrolled hospitalized severe acute respiratory infection (SARI; fever with respiratory symptoms) and acute febrile illness (AFI; fever without respiratory or other localizing symptoms) patients from three referral hospitals in Ghana. Demographic and epidemiologic data were obtained from enrolled patients after which nasopharyngeal and oropharyngeal swabs were collected, and processed by molecular methods for the presence of influenza viruses.

RESULTS:

Of 730 SARI patients, 59 (8%) were influenza positive; of 543 AFI patients, 34 (6%) were positive for influenza. Both SARI and AFI surveillance yielded influenza A(H3N2) (3% versus 1%), A(H1N1)pdm09 (2% versus 1%), and influenza B (3% versus 4%) in similar proportions. Data from both syndromes show year-round influenza transmission but with increased caseloads associated with the rainy seasons.

CONCLUSIONS:

Since an appreciable percentage of influenza cases (37%) presented without defined respiratory symptoms, and thus met the AFI but not the SARI definition, it is important to consider broader screening criteria (i.e. AFI) to identify all laboratory-confirmed influenza. The identified influenza transmission seasonality has important implications for the timing of related public health interventions. This article is protected by copyright. All rights reserved.