Ebola is the common term for Ebola Virus Disease (EVD) - a lethal viral haemorrhagic fever (VHF) currently seen mainly in Sub-Saharan Africa. In March 2014, the World Health Organization (WHO) was notified of an outbreak of Ebola in Guinea and by August, it had declared the epidemic a: “public health emergency of international concern”.
The current epidemic has already killed over 5,000 people - more than all previous epidemics combined, has spread mainly in West Africa, in Liberia, Guinea and Sierra Leone and is of serious concern because of death rates of up to 70 per cent. Although most common in the resource-poor world, with continually increasing global travel, Ebola is appearing or may appear in most countries.
Ebola is characterised by various features:
- The five known strains of the virus are RNA viruses (filoviruses) whose survival is dependent on an animal natural reservoir, mainly fruit bats and nonhuman primates, eaten by humans as “bush meat”.
- Humans can be infected when they care for, slaughter or eat infected animals such as “bush meat”, or by contact with infected hosts or their urine, faeces, saliva, or other body excretions.
- Humans can become infected when they care for infected humans whether alive or dead, or indirectly, through contact with contaminated objects.
- Humans, if infected, have the virus in tissues, bodily fluids including saliva, and in all body orifices.
- Outbreaks of Ebola are not new, and have occurred sporadically and irregularly mainly in Africa, for decades. The first cases of Ebola recognised were in 1976 between Sudan (now Republic of South Sudan) and Zaire (now Democratic Republic of the Congo) and named Ebola after a river in north-western Zaire.
- The current Ebola virus has spread from its endemic sub-Saharan habitat by travellers to USA, Europe and the antipodes.
- Transmission is most likely in later stages of disease.
- Ebola first appears to disable the dendritic cells of immune system and then the vascular system via a cytokine storm, culminating in 30 per cent by shock and death.
- Few vaccines, or effective drug treatments yet exist.
Clinical features
The incubation of up to 21 days can be followed by non-specific manifestations which include fever, fatigue, myalgia, and malaise. Patients may bleed because of liver damage, disseminated intravascular coagulopathy (DIC), and bone marrow dysfunction. They may show signs of bleeding in the skin, in internal organs, or from the mouth or other orifices. Patients may then develop shock, delirium, seizures and coma.
Management
No reliable curative treatment is yet available. Patients mostly must rely on supportive therapy. Treatment with convalescent-phase plasma or antivirals (such as brincidofovir), has been used with success in some patients. Vaccines are in development.
Prevention efforts concentrate on avoiding contact with patients with acute infection. The viruses are readily destroyed by washing hands with soap and water. Barrier nursing or infection control techniques include isolating infected individuals and wearing protective clothing. Other infection control recommendations include proper use, disinfection, and disposal of contaminated instruments and equipment. Environmental decontamination is typically
accomplished with phenolics or hypochlorite (such as bleach). Ebola in Senegal and Nigeria has been largely contained with these measures.
The Centres for Disease Control and Prevention (CDC) in the USA has developed guidelines, entitled Infection Control for Viral Haemorrhagic Fevers in the African Health Care Setting (available at www.cdc.gov/vhf/abroad/vhf-manual.html).
Ebola in oral healthcare
Human-to-human transmission is possible through direct contact with the blood, secretions, tissues or other bodily
fluids, including saliva, from infected people. Infections in healthcare settings have been due to healthcare workers treating patients with suspected or confirmed Ebola, when infection control precautions were not strictly practised.
Transmission through the air has not been documented, nor have there been any reports of transmission through saliva contamination. A lethal viral infection via needlestick exposure has been reported. Oral healthcare workers have not reportedly been infected but may run the risk of acquiring Ebola if meticulous infection control measures
are not always routinely followed. Accurate history including travel history, careful patient examination and the regular careful use of standard/universal infection control measures are probably adequate to minimise any infection risk. Elective dental care may best be deferred for three weeks.
Interested e-readers are referred to the URL www.cdc.gov/vhf/ebola/pdf/checklist-patients-evaluated-us-evd.pdf