Viral Haemorrhagic Fevers and Malaria Co-Infections Among Febrile Patients Seeking Health Care in Tanzania

Abstract Background: In recent years there have been reports of viral haemorrhagic fever (VHF) epidemics in Sub-Saharan Africa where malaria is endemic. VHF and malaria have overlapping clinical presentations making differential diagnosis a challenge. The objective of this study was to determine the prevalence of selected zoonotic VHFs and malaria co-infections among febrile patients seeking health care in Tanzania. Methods: This facility-based cross-section study was carried out in Buhigwe, Kalambo, Kyela, Kilindi, Kinondoni, Kondoa, Mvomero, and Ukerewe districts in Tanzania. The study involved febrile patients seeking health care from primary healthcare facilities. Blood samples were collected and tested for infections due to malaria, Crimean-Congo haemorrhagic fever (CCHF), Ebola virus disease (EVD), Marburg virus disease (MVD), Rift Valley fever (RVF) and yellow fever (YF). Malaria infections were tested using rapid diagnostics tests while exposure to VHFs was determined by screening for immunoglobulin M antibodies using commercial enzyme-linked immunosorbent assays. Results: A total of 308 participants (mean age=35±18.9 years) were involved in the study. Of these, 54 (17.5%) had malaria infection and 15 (4.8%) were positive for IgM antibodies against VHFs (RVF=8; CCHF=2; EBV=3; MBV=1; YF=1). Six (1.9%) individuals had both VHF (RVF=2; CCHF=1; EVD=2; MVD=1) and malaria infections. The highest co-infection prevalence (0.6%), was observed among individuals aged 46-60 years (p<0.05). District was significantly associated with co-infection (p<0.05) with the highest prevalence recorded in Buhigwe (1.2%) followed by Kinondoni (0.9%) districts. Headache (100%) and muscle, bone, back and joint pains (83.3%) were the most significant complaints among those infected with both VHFs and malaria (p=0.001). Conclusions: Co-infections of VHF and malaria are prevalent in Tanzania and affect more the older than the younger population. Since the overlapping symptoms in co-infected individuals may challenge accurate diagnosis, adequate laboratory diagnosis should be emphasized in the management of febrile illnesses.