Research Article: Evaluation of the sentinel surveillance system for influenza-like illnesses in the Greater Accra region, Ghana, 2018

Date Published: March 14, 2019

Publisher: Public Library of Science

Author(s): Francis Sena Nuvey, Elijah Paa Edu-Quansah, George Khumalo Kuma, John Eleeza, Ernest Kenu, Samuel Sackey, Donne Ameme, Mahamat Fayiz Abakar, Katharina Kreppel, Richard Bongo Ngandolo, Edwin Afari, Bassirou Bonfoh, Joel M. Schnur.

http://doi.org/10.1371/journal.pone.0213627

Abstract

Influenza-like Illness (ILI) is a medical diagnosis of possible influenza or another respiratory illness with a common set of symptoms. The deaths of four schoolchildren, during a pandemic influenza outbreak in December 2017 in Ghana, raised doubts about the ILI surveillance system’s performance. We evaluated the ILI surveillance system in the Greater Accra region, Ghana, to assess the system’s attributes and its performance on set objectives.

CDC guidelines were used to evaluate the data of the ILI surveillance system between 2013 and 2017. We interviewed the surveillance personnel on the system’s description and operation. Additionally, routinely entered ILI data from the National Influenza Center provided by the six sentinel sites in Accra was extracted. We sampled and reviewed 120 ILI case-investigation forms from these sites. Surveillance activities were examined on system’s performance indicators, each being scored on a scale of 1 to 3 (poorest to best performance).

All population and age groups were under ILI surveillance over the period evaluated. Overall, 2948 suspected case-patients, including 392 (13.3%) children under-five were reported, with 219 being positive for influenza virus (Predictive value positive = 7.4%). The predominant influenza subtype was H3N2, recorded in 90 (41.1%) of positive case-patients. The system only met two out of its four objectives. None of the six sentinel sites consistently met their annual 260 suspected case-detection quota. Samples reached the laboratory on average 48 hours after collection and results were disseminated within 7 days. Of 120 case-investigation forms sampled, 91 (76.3%) were completely filled in.

The ILI surveillance system in the Greater Accra region is only partially meeting its objectives. While it is found to be sensitive, representative and timely, the data quality was sub-optimal. We recommend the determination of thresholds for alert and outbreak detection and ensuring that sentinel sites meet their weekly case-detection targets.

Partial Text

Influenza-like illnesses (ILI), often also called acute respiratory infection or flu-like syndrome, are acute viral infections of the respiratory tract with similar signs and symptoms to influenza. ILI is a syndrome and affected persons may become infectious before, during or after the onset of symptoms. The pathogen can be transmitted both directly (by droplets) and indirectly through contact with contaminated fomites. Children, the elderly and pregnant women, as well as persons with chronic illnesses or immunosuppression are at the highest risk for morbidity and mortality from ILIs [1,2].

We described the attributes and effectiveness of the ILI sentinel surveillance system in the Greater Accra region (GAR) of Ghana using a descriptive cross-sectional survey. We extracted and evaluated routinely recorded ILI data between January 2013 and December 2017.

Influenza causes considerable morbidity and about 500,000 deaths per year globally. The disease is highly infectious with high pandemic potential. Therefore, worldwide surveillance systems to record Influenza-like illnesses (ILI) in real time and detect possible influenza outbreaks are essential to prevent and control epidemics. Ghana’s ILI surveillance system since its inception in 2007, aims to early detect changes in circulating influenza, identify vulnerable groups to influenza infection, determine influenza thresholds and detect antiviral resistance to influenza viruses. The late detection of a pandemic influenza outbreak in Ghana raised doubts about the ILI surveillance system’s performance.

In spite of the usefulness and fair performance of ILI surveillance in GAR on indicators evaluated, it is only partially meeting its set objectives. It is sensitive in detecting circulating influenza types, representative of the population under surveillance and timely. However, sentinel sites do not consistently meet annual case detection quotas. There is the need to address shortfalls in the system’s objectives as well as improving case detection at sentinel facilities. This would ensure that the successes chocked are not undermined, thereby preventing increasing morbidity and mortality related to influenza infections. Failure of the system to address these shortfalls would also affect Ghana’s contribution to the WHO Global Influenza Surveillance and Response System. Considering the zoonotic character of most influenza viruses, it is important that a One Health approach is adopted with influenza surveillance in Ghana. We propose strict adherence to case detection targets by individual sentinel sites and determination of alert thresholds for the system to allow for a more effective monitoring of influenza activity in the region for prompt public health actions.

 

Source:

http://doi.org/10.1371/journal.pone.0213627

 

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