Classification and Virology
Filoviridae is a family of enveloped, negative-sense single-stranded RNA viruses known for causing severe viral haemorrhagic fevers in humans and non-human primates.
The family includes several genera, the most important being:
- Ebolavirus — includes Zaire, Sudan and Bundibugyo viruses;
- Marburgvirus — includes Marburg and Ravn viruses;
- other filoviruses with limited or no established human pathogenicity.
Filoviruses are characteristically filamentous or thread-like in shape, which gives the family its name.
Their genome encodes proteins involved in:
- viral replication;
- nucleocapsid formation;
- immune evasion;
- attachment and entry into host cells.
Reservoirs, Transmission and Disease
The best-supported natural reservoirs for important filoviruses are fruit bats, particularly for Marburg virus; bats are also strongly implicated in the ecology of ebolaviruses.
Human outbreaks usually begin through zoonotic spillover, followed by human-to-human transmission through:
- direct contact with blood or body fluids;
- contaminated medical equipment or surfaces;
- close care of infected patients;
- unsafe burial practices.
Major human diseases associated with the family include:
- Ebola Virus Disease (EVD);
- Marburg Virus Disease (MVD).
These illnesses can cause:
- high fever;
- severe weakness;
- vomiting and diarrhoea;
- vascular and coagulation abnormalities;
- multi-organ dysfunction;
- haemorrhage in some severe cases.
The incubation period for Ebola and Marburg disease is generally 2–21 days.
Public-Health Importance
Filoviridae is important in global health because outbreaks can have high case-fatality rates, spread rapidly through close-contact networks and place healthcare workers at significant risk.
Control depends on:
- rapid laboratory diagnosis, especially RT-PCR;
- case isolation;
- contact tracing;
- strict infection-prevention practices;
- safe and dignified burials;
- community engagement.
Vaccines and monoclonal-antibody treatments are available for Zaire ebolavirus, but protection is not universal across the entire Filoviridae family. This makes accurate identification of the virus essential during an outbreak.
Filoviruses are also a classic example of the One Health interface, where wildlife reservoirs, human behaviour, ecosystem disturbance and health-system preparedness jointly influence outbreak risk.
