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SAFETY IN THE LABATORY AND THE HANDLING

OF BIOHAZARDOUS SPECIMENS

n one hand, the theme of the talk presented by Dr Pyndiah, virologist at the Central Laboratory, is a matter of genuine interest and real concern for all health workers. This is the reason why pathologists, biochemists, principal medical laboratory technicians (PMLT) , senior medical laboratory technicians and medical laboratory technicians made it a must to attend this talk. On the other hand, with the emergence and re-emergence of infectious diseases, it is becoming more and more important that universal precautions should be observed when handling blood and other body fluids. In the Centre for Disease Control (CDC) prevention guidelines in 1988, it is published that under universal precautions , blood and other body fluids of all patients are considered potentially infectious for Human Immuno Deficiency virus (HIV), Hepatitis B virus (HBV), and other bloodborne pathogens.

De facto in the laboratory, infection may be caused by microorganisms entering the body through the skin, eyes, mouth, or respiratory tract. These microorganisms may be classified on the basis of hazard (Medical lab manual for tropical countries vol II) :

Risk Group 1 : The organisms in this group present a low risk to the individual laboratory worker and to the members of the community. They are unlikely to cause human disease.

Risk Group 2 : These oraganisms offer a moderate risk to the laboratory worker and a limited risk to members of the community. They can cause serious human disease but are not a serious hazard.

Risk Group 3:This group contains organisms that present a high risk to the laboratory worker but a low risk to the community should they escape from the laboratory. They do not ordinarily spread rapidly from one individual to another.

Risk Group 4 : The agents in this group offer a high risk to the laboratory worker and to the community. They can cause serious disease and are Readily transmitted from one individual to another.

This is why the World Health Organisation (WHO) recommends that the health authorities of each country should make a list of the

4 4 4 talk for the month of March

 

organisms and viruses in each risk group , as appropriate to local circumtances, so that suitable precautions may be applied. Thus laboratory (lab) can be classified into Basic lab, containment lab and maximum containment lab. In Mauritius, the laboratories can certainly be classified as basic labs as they work with organisms of risk groups 1 & 2.

A pamphlet containing the code of practice was distributed during the talk . Here it is said that the most important factor in the prevention of lab acquired infections is good technique. To this end, equipment such as safety cabinets are used in most labs so as to protect the laboratory worker from aerosols and airborne particles. There are three kinds of safety cabinet, classes 1, 2 and 3. The class 1 and class 2 cabinets are used in diagnostic and containment lab for work with risk group 3 organisms. Class 3 cabinets are used almost exclusively for risk group 4 agents.

Furthermore, all specimens, cultures and other materials that have been examined in a lab must be made non-infectious before being discarded or leaving the lab. This can be achieved by decontamination with chemical disinfectants, autoclaving and incineration.

Hence, one of the main theme of the talk was the control of selected infections transmitted among health care personnel and patients. In a special article "Guideline for infection control in health care personnel, 1998" published by CDC , it is stated that it is designed to provide methods for reducing the transmission of infections from patients to health care personnel and from personnel to patients. The prevention strategies addressed in this document include immunisations, for vaccine-preventable diseases, isolation precautions to prevent exposures to infectious agents, management of health care personnel exposure to infected persons,including post-exposure prophylaxis and work restrictions for exposed or infected health care personnel.

The infection control objectives usually include the following:

Consequently, it is evident that special attention should be paid to the design of a lab and the assignment of certain types of work to it as well as the conditions that are known to pose problems.These include:

Upon reading the above, anyone working in a local lab will agree that not all these conditions are met. To this end, in order to discuss some of these problems, a debate followed the talk. To the question put forward as to whether who would be responsible for the health and safety of the lab personnel,Dr Pyndiah answered that there is a real need for a health & safety officer in the lab for such a task. Also much concern was expressed by all those present relating to bloodborne pathogens and it was affirmed that here in Mauritius we do not deal with pathogens from risk group 3 and 4.

Since the workload of the various departments working with blood has been increasing year by year and thus providing greater exposure to infectious agents, the PMLTs and the biochemists asked whether the specimens of patients with HIV and HBV could have been labelled and identified as biohazardous specimens. To this question Dr Pyndiah said that all specimens should be considered as biohazardous. Also it is important to bear in mind that gloves should be changed as often as it deem necessary.

As expected, the inevitable question concerning the absence of a messroom at the Central Laboratory had to crop up in the debate. Everybody present expressed their disapproval of such a condition. On one hand, the lack of other important facilities gave way to much debate as for example, the lack of disinfectants and incinerators. On the other hand, much concern was expressed for the lack of training of the personnel for proper maintenance of equipment and handling of biohazardous substances including Quality Control (QC) solutions. Also there should be at least one eyewash facility per lab. Consequently, lab personnel should be aware that biosafety should prevail at all times.

Dr Pyndiah announced that the ministry has set up a prophylaxis unit at the Day Care Centre, Bouloux Area Health Centre, Cassis, where any personnel who has been exposed to HIV or any bloodborne pathogens can be treated. Also treatment should be given within four hours post-exposure for HIV. Any exposure should be related to the Consultant Pathology, Dr Pyndiah or head of department .

Finally, all those present agreed that the lab safety committee that existed some years back should be revived . Typically the duties of a safety / employee health committee usually include (occupational safety and health administration OSHA) :

Also Heads of departments should inculcate health and safety precautions to their staff i.e. both technical and non-technical (attendants) by way of refresher courses and regular quality circle meetings.

Rehana Jauhangeer