Uncovering hidden outbreaks: What syndromic surveillance revealed about arboviruses and respiratory illness in The Gambia

Introduction The emergence of H1N1 (Swine flu) virus in 2009 and severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) in 2019 demonstrated the need for effective surveillance for early detection of epidemic diseases. Through the Syndromic Sentinel Surveillance System (4S) for arboviruses and respiratory infections, we analyzed epidemiological data for arbovirus and respiratory infection surveillance to inform public health decisions. Methods Two sentinel surveillance sites; one rural and the other semi-urban, were identified based on epidemiological profile. Case definition were developed as; Severe Acute Respiratory Infection (SARI): “any person with acute onset of fever and cough”. Arboviruses; “Any person with fever and at least two of these signs: headaches, myalgia, arthralgia, rashes, retro-orbital pain, or hemorrhagic manifestation”. Nasopharyngeal samples were collected from SARI suspects and Blood for arboviruses. Both arbovirus and respiratory samples were tested using RT-PCR. Positive arbovirus samples were sent to a regional reference laboratory for confirmatory testing. Data collected through the Teranga platform were analyzed using Epi Info. The 7-1-7 approach was used to assess timeliness of detection, reporting, and response. Results A total of 620 samples were collected with a median age of 16 years (0 – 80 years). Of these, 33% (206/620) were respiratory. A total of 34 samples tested positive: 28 respiratory viruses; [39% (11/28) SARS-CoV2, 36% (10/28) Flu A, 21% (6/28) RSV] and 6 arboviruses [67% (4/6) Yellow Fever and 16% (1/6) for Chikungunya and Dengue respectively]. One patient was co-infected with Dengue, Yellow Fever, and Malaria. Timeliness indicators showed that 35% of confirmed cases were detected within 7 days, 98% were reported immediately, and 53% received response within 7 days. Conclusion The 4S has revealed the presence of epidemic-prone arboviruses and other respiratory viruses in The Gambia. Therefore, the Epidemiology and Disease Control Program should strengthen the 4S to ensure rapid detection and enhance response mechanisms.