Infection Hazards of Human Cadavers
Cadavers may pose infection hazards to people who handle them, such as pathologists, nurses, mortuary attendants, embalmers, funeral directors and members of the emergency services. Viruses which poses particular risks include HIV, HBV, HCV, CJD, rabies, yellow fever and viral haemorrhagic fevers. The following practices are routinely carried out on cadavers;-
1. Bagging - the body is placed in a plastic bag. This is recommended for cadavers infected with the above high risk viral agents. A problem with bagging is that it speeds up decomposition since it slows down the cooling of the cadaver.
2. Viewing - the bereaved is allowed to see, touch and spend time with the body before disposal. This is not advised for high risk agents.
3. Embalming - chemical preservatives are injected into the body to slow the process of decay. Cosmetic work may be included. This is not advised for high risk agents although embalmers were thought to be at low risk due to the wearing of protective clothing and the use of formalin-based preservatives.
4. Hygienic preparation - the body is cleaned and tidied before viewing. Some ethnic groups requires this process to be carried out by close relatives. Again this is not advised for high risk agent.
In general, following COSHH (Control of Substances Hazardous to Health) precautions, especially the use of protective clothing will greatly reduce the risk of acquiring infection. Some additional precautions may be advisable for particular infections.
Hepatitis B and C;- HBV is extremely infectious and health care workers especially those in morbid anatomy are particularly at risk. Embalmers are also thought to be at risk from needle stick injuries. Therefore the bodies of those known to be infected with HBV should be handled only by workers wearing full protective clothing. Mortuary workers and embalmers should be vaccinated against HBV. HCV is transmitted by the same routes as HCV but probably less infectious. Therefore, the same precautions should be taken.
HIV;- HBV and HIV are transmitted by similar routes and thus the precautions for HBV such as full protective clothing should be adequate to prevent the transmission of HIV. To date, no embalmers or mortuary technicians had developed infection following documented exposure although a few may have acquired the infection occupationally. HIV survives for many days after death in tissues preserved under laboratory conditions.
CJD;- The agent that causes CJD has been shown to survive well in formalinised tissue. Exposure to sodium hypochlorite containing 20,000 ppm for 1 hour, or autoclaving at 134oC for at least 18 minutes are needed for decontamination. The Health and Safety Commission suggested recently that skulls of people who have died of CJD should only be opened inside a large plastic bag fitted over the head and neck of the cadaver.
Reduction of Risk
The Howie report (1978) presented a detailed code of practice for the prevention of infection in laboratories and necropsy rooms. There are detailed protocols for the layout, construction, ventilation and operation of necropsy rooms, Hands should be washed routinely after each procedure and the environment cleaned with a phenolic disinfectant daily. The instruments should be washed in a washer-disinfector, autoclaved or immersed in a phenolic disinfectant for 20 minutes. A phenolic disinfectant is preferred to hypochlorite because hypochlorite is corrosive and may damage surfaces and instruments.
At present, funeral directors are not given access to the death certificate and therefore they may not be alerted to potential infection hazards. Body bags are becoming more and more commonly used but they may be unpleasant to the relatives. All instruments used for embalming or preparing the body for the funeral should be cleaned and warm water and detergent and then disinfected by a phenolic disinfectant. Although an autoclave provides excellent decontamination, this is not justified by the existing levels of risk.
Role of Safety Officers