Author: Pamela Sinywimaanzi
Citation Style For This Article: Sinywimaanzi P. Surveillance for respiratory infections in Macha, Zambia. The Health Press Zambia Bull. 2020; 4(4); pp 32
Respiratory infections, including influenza viruses and respiratory syncytial virus (RSV), are well-established causes of global morbidity and mortality. While southern Africa experiences among the highest mortality rates from respiratory infections, the burden and epidemiology of the viral disease in rural areas is poorly understood.
We established a hospital-based surveillance program for influenza viruses and RSV in Macha, Zambia in 2018. Outpatients and inpatients presenting with influenza-like illness (ILI) were enrolled in the study. At enrollment, a questionnaire was administered and samples were collected and tested for influenza and RSV using the GeneXpert Xpress Flu/RSV assay at Macha Research Trust and other viruses using the BioFire FilmArray EZ panel at Johns Hopkins University. Participants were prospectively followed to assess the clinical course. In May 2020, testing for SARS-CoV-2 was incorporated into the surveillance program.
30,111 outpatients were screened between December 2018 and May 2020, and 16.1% presented with ILI. 723 outpatients with ILI were enrolled in the study. 553 inpatients admitted for a respiratory illness were screened for ILI and 137 were enrolled in the study. In the first year of surveillance (December 2018 to December 2019), influenza viruses and RSV were detected in 18% (13% influenza A and 5% influenza B) and 11% of participants with ILI, respectively. Of the influenza A viruses, 29% were H1N1 and 67% were H3N2. Influenza (Jul-Sep 2019) and RSV (Jan-Apr 2019) prevalence peaks were temporally distinct. Additional viruses detected among participants with ILI in the first year included rhinovirus (26%), coronavirus (6%, not SARS-CoV-2), adenovirus (3%), parainfluenza (2%), and metapneumovirus (1%). Overall, 6% of participants were infected with multiple respiratory pathogens. In the second year of surveillance (December 2019 to May 2020), no cases of influenza or RSV have been detected. Results of SARS-CoV-2 testing will be reported.
This rural population in southern Zambia bears a sizeable burden of viral respiratory infections and severe respiratory disease. The prevalence and seasonal presentation of these infections in rural areas differ from that previously reported in urban areas.