Bundibugyo virus disease: transmission dynamics, infectiousness and viral persistence.

BVD is a severe filoviral haemorrhagic fever caused by the Bundibugyo virus (BDBV), for which outbreak-related evidence remains limited compared with that available for Zaire ebolavirus. This perspective summarizes current evidence on transmission dynamics, presymptomatic infectiousness, post-recovery viral persistence and the duration of infectiousness, distinguishing BDBV-specific data from evidence extrapolated from other ortho-Ebolaviruses. Available epidemiological data from the 2007-2008 outbreak in Uganda indicate that BDBV transmission occurs primarily through direct contact with the blood or body fluids of symptomatic or deceased individuals, with the handling of corpses representing a significant risk factor (adjusted odds ratio 3.83; 95% confidence interval 1.78-8.23). The average incubation period is 6.3 days, and prolonged chains of transmission were documented in household and healthcare settings. No documented human cases of pre-symptomatic transmission have been reported, however, the limited number of documented outbreaks precludes excluding this possibility, and experimental animal data support its biological plausibility. No BDBV-specific data are available regarding viral persistence and duration of infectiousness. Consequently, current recommendations rely largely on evidence derived from other orthoebolaviruses. Viral RNA may persist after recovery in immunoprivileged sites, particularly in semen, with rare but documented episodes of delayed transmission. The ongoing outbreak highlights the need for BDBV-specific studies to strengthen the evidence base underpinning public health recommendations.