Page updated 30 April 2007
Transmission of VHF Infection to Healthcare Workers
Before the virus was discovered, there were episodes of transmission to hospital staff of Lassa fever both in Africa and New York. Marburg and Ebola viruses may also be transmitted within hospitals in Africa to health care workers. It is thought that nosocomial transmission may occur particularly where needles are not properly sterilised between patients, and where there is a high density of infected patients, some of whom may have pulmonary disease. Transmission of Ebola and Marburg virus may occur through sexual intercourse. In one episode this occurred months after recovery from infection and Marburg virus was found to persist in the semen.
Apart from one laboratory accident where a laboratory technician injected himself with Ebola virus, there has been no documented transmission of any VHF by casual contact in the UK.
A nursing sister caught Ebola virus from a patient in the isolation unit in Johannesburg. One member of the ICU staff caring for an infected student in Germany seroconverted for Lassa fever but was entirely asymptomatic. Despite these observations, the evidence suggests that transmission of these viruses does not occur frequently through casual contact1.
The greatest potential risk to staff is by NEEDLESTICK INJURY from a patient (donor) with VHF or contamination of open cuts by infectious blood or secretions. Marburg virus was transmitted to a nurse and doctor who attempted resuscitation of a profusely bleeding patient in Nairobi. However, many other carer contacts did not catch the disease. Therefore the routes of transmission other than by percutaneous inoculation (e.g. the respiratory route) are simply not known. Airborne spread has been documented in non-human primates. The risk of transmission probably increases in the terminal stages of the illness when there is a high viraemia with overt bleeding. Note that all viruses are shed in secretions for long periods after recovery from infection.
 |
 |