An examination of exposure and risk factors for viral, bacterial and parasitic diseases among febrile patients: A surveillance project in Kilombero, Tanzania

Introduction: The objective of this cross-sectional study was to employ quantitative and qualitative approaches to the characterization of fever syndrome in Kilombero, Tanzania. Methods: To identify the various etiologic agents potentiating fever syndrome, I conducted an exploratory diagnostic investigation, using two syndromic TaqMan Array Card (TAC) assays, which allowed for the surveying of 56 different microbial agents present in both blood and naso/oro-pharyngeal (NP/OP) specimens among patients presenting to clinical settings with acute febrile illness (AFI) in Kilombero, Tanzania. I collected demographic and clinical data in order to statistically establish epidemiologic risk for infection. Correlates were evaluated using agent-specific filtered multivariate logistic regression. Furthermore, I conducted a qualitative assessment of health beliefs and patient perspectives of febrile illness, based upon in-depth, physician-patient interviews, informed by the Health Belief Model (HBM). Interviews were audio recorded, translated into English and transcribed. Transcripts were coded using NVivo Version 11.1, and thematic content was analyzed by two separate researchers. Results: From 15 September 2014- 13 September 2015, 1,107 febrile patients were enrolled. AFI TAC and respiratory TAC were performed on 880 whole blood specimens and 391 NP/OP specimens, respectively. Of the 56 agents surveyed, Plasmodium was found to be the most common microbe detected. We detected a total of 434 detections among seven different bloodstream agents, including: Plasmodium (399; 47%), Leptospira (22; 3%), Bartonella (4;1%), Salmonella enterica (4; 1%), Coxiella burnetti (2; 1%), Rickettsia (2; 1%), and West Nile virus (1; 1%). Respiratory TAC detected nucleic acid for 24 different microbial agents, including 12 viruses and 12 bacteria. The most prevalent agents detected, included: Haemophilus influenzae (258; 67%), Streptococcus pneumoniae (213; 55%), Moraxella catarrhalis (152; 39%), Staphylococcus aureus (141; 37%), Pseudomonas aeruginosa (137; 36%), Human Rhinovirus (98; 25%), Influenza A (91; 24%), Klebsiella pneumoniae (55; 14%), Enterovirus (57; 15%) and Group A Streptococcus (46; 12%). Agent-specific multivariate regression demonstrated several statistically significant factors to be considered, particularly age and symptomatic presentation. Finally, a total of 18 febrile patients participated in the semistructured interview, which yielded substantial discrepancy among diagnostic determination of febrile illness from the standpoint of the patient, the clinician, and laboratory testing with overall concurrence of 11.1%. The overwhelming majority (72.2%) of respondents cited malaria as the greatest health hazard facing the community. Conclusions: Outputs of this research have developed a critical baseline of disease prevalence in this area and suggest a great diversity in the variety of viral, bacterial and parasitic pathogens present among febrile patients in Kilombero, Tanzania. The novelty of this study is proven in our use of highly sensitive multi-pathogen molecular diagnostics. My qualitative assessment of health beliefs and patient perceptions of febrile illness highlights important gaps in patient awareness of fever etiologies, and underscores the potential utility of patient-based participatory research to inform disease control programming. In summary, these findings contribute to the important, yet limited, base of knowledge characterizing both actual and perceived risk of febrile illness in a malaria endemic setting of sub-Saharan Africa.