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Background: Viral haemorrhagic fevers (VHFs) are a group of zoonotic diseases caused by several distinct groups of viruses from the families Flaviviridae, Phenuiviridae, Arenaviridae, and Filoviridae. Despite the widespread occurrence of VHFs, the true burden in Sub-Saharan African countries is still not sufficiently known. Objective: To determine the seroprevalence of selected zoonotic viral haemorrhagic fevers (VHFs) and their associated risk factors in Tanzania. Methods: Blood samples were collected from consenting outpatients and community members in eight districts selected from five ecological zones of Tanzania. Serum was harvested and tested for the presence of immunoglobulin G (IgG) and M (IgM) antibodies against Crimean-Congo haemorrhagic fever (CCHF), Ebola virus disease (EVD), Marburg virus disease (MVD), Rift Valley fever (RVF), and Yellow fever (YF). Results: The presence of IgM and IgG antibodies against to CCHF, EVD, MVD, RVF, and YF was detected in 64 of 500 (12.8%) samples. The prevalence of IgM and IgG antibodies to CCHF, EVD, MVD, RFV and YF was 2.0%, 3.4%, 1.2%, 4.8%, and 1.4%, respectively. Contact with wild animals (OR = 1.2, CI = 1.3-1.6) and keeping goats (OR = 1.3, CI = 1.5-1.9) were significantly associated with RVF while contact with bats (OR = 1.2, CI = 1.1-1.5) was associated with MVD. Conclusion: The findings of this study provide evidence of exposure to CCHF, EVD, MVD, RVF and YF in Tanzania. Since most of these VHFs occur without apparent clinical form of the disease, these findings call for the need to strengthen the surveillance system and management of febrile illnesses in Tanzania. [ABSTRACT FROM AUTHOR]

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. Objective: 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-sectional 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 populations. [ABSTRACT FROM AUTHOR]

Purpose: Yellow fever (YF) is a major public health concern particularly in Africa and South America. This study aimed to detect YF in human and mosquito samples to understand transmission dynamics in the Tanzania-Uganda and Tanzania-Kenya cross-border areas., Methods: Blood samples were collected from 9 months and older individuals for serological testing while mosquitoes were captured and tested for YF virus RNA. Logistic regression models were used to predict seroprevalence and associated risk factors., Results: The overall YF seroprevalence was 12.5% with higher rates in older individuals (7.0%) and females (IgG 4.4%, IgM 6.0%). Notably, YF virus RNA was detected in three out of 46 pools of 192 mosquitoes. The odds of testing positive for YF IgG were lower among those with primary education compared with college education (AOR = 0.27, CI: 0.08-0.88) and increased with being female (AOR = 4.7, CI: 1.5-14.7), traveling to YF endemic areas (AOR = 5.2, CI: 1.35-44.75), exposure to Aedes mosquitoes (AOR = 3.7, CI: 1.27-10.84), experiencing muscle pain (AOR = 4.5, CI: 1.08-18.78), and exhibiting bruising (AOR = 13.5, CI: 1.23-145.72)., Conclusion: Despite not experiencing YF outbreaks, Tanzania shows evidence of YF exposure in studied borders highlighting the need to strengthen cross border-surveillance, vector control, vaccination and further research to evaluate country overall YF risks., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)