PCR investigation of infections in patients consulting at a healthcare centre over a four-year period during the Grand Magal of Touba

Background: Respiratory and gastrointestinal symptoms and febrile illness are the most common complaints among ill pilgrims attending the Grand Magal of Touba (GMT) in Senegal. Methods: Patients presenting with respiratory or gastrointestinal symptoms or febrile systemic illnesses were recruited between 2018 and 2021 at a healthcare centre close to Touba. Respiratory, gastrointestinal and blood samples were tested for potential pathogens using qPCR. Results: 538 patients were included. 45.5% of these were female, with a median age of 17 years. Of the 326 samples collected from patients with a cough, 62.8% tested positive for at least one virus, including influenza viruses (33.1%). A high positivity rate of bacterial carriage was observed for Haemophilus influenzae (72.7%), Streptococcus pneumoniae (51.2%) and Moraxella catarrhalis (46.0%). Of the 95 samples collected from patients with diarrhoea, 71.3% were positive, with high rates of bacterial carriage, ranging from 4.2% for Tropheryma whipplei to 45.3% for Entero-pathogenic Escherichia coli. Of the 141 blood samples collected from patients with fever, 31.9% were positive including Plasmodium falciparum (21.3%), Borrelia sp. (5.7%) and dengue virus (5.0%). Conclusion: This study provides insight into the aetiology of most common infections at the GMT on which to base therapeutic options.