From the reported caseadmin / January 25, 2019
From the reported case, the transmission of infected happens between patient to health care workers in the blood bank laboratory. The first step doing a biological risk assessment identifies the hazardous agents and perform an initial assessment of risk.
Transmission of these viruses can be happening during the transfusion of blood, equipment in the laboratory not sterilized properly and it also can happen when the lab technologist is accidental punctures with a contaminated instrument to himself. By comparing on several factor, it is clearly that HBV has highest risk of transmission than HIV. Transmission of bloodborne infection can only happen when there is a sufficient dose of the infectious agent can pass through the skin or mucous membrane of the susceptible host. The diagram below shows a few modes of transmitting HIV and HBV however in this case we focused more to occupational exposure.
Next, transmission of the bloodborne pathogen depends on the mechanism and the effect of dose volume and concentration from the infectious source. Direct injection is the most efficient mechanism to infect the lab technologist. There are many documented sources on the occurrence of post-transfusion HBV and HIV (1-5). In the modern world, the development in diagnosis of antibody or vaccine to against HBV and HIV increase gradually year to year. Hence, in the most developed country and developing country, the number of transmission for these two viruses has been inclined. It is difficult to determine exact concentration or volume of blood which can give a significant risk assessment to the lab technologist. Eastern Europe has proved even a small amount of infected blood in contaminated needles and syringes can spread the HIV rapidly through intravenous drug-using communities and the nosocomial (6-9). In outbreaks of hepatitis the automatic fingerstick has been incriminated, even though in process of exchange between patients (10,11); apparently, the undisposed parts of the device contaminated the lancets been infected small amount of HBV blood during use. A Jet injector that delivers blood-contaminated fluids through the skin result of percutaneous exposures to pathogens from any blood-contaminated sharp object (12). Transmission of HIV and HBV has been documented through contact of infectious materials with mucous membranes or nonintact skin, although percutaneous inoculation may deliver a greater dose of infectious pathogens. The concentration of pathogen may vary greatly and is dependent primarily on the infectious characteristics of the pathogens concerned, although the mechanism of exposure will largely determine the volume of infectious blood introduced.
Besides that, we have to know the characteristic of infectious a pathogen. Infectious of HBV is greater than HIV from the available evidence. This can be statement can be supported a range of percentage of individuals needlestick injuries from patients positive HBV around 7-30% whereas the individual infected with positive HIV is only less than 0.5%. Relative infectivity of HBV is higher than HIV when we relate these two viruses with biological viral concentration. One ml of HBV blood circulates titers more than 108 of infection, but the infectious of HIV blood only circulates around 10-103 of infectious dose for one ml.
The resistance of pathogen against the body defenses and the viability of pathogen in a specific environment is another characteristic that can influence the infectivity. For example, HBV can remain viable for at least a week in dried blood, HIV appears to be less resistant. The ability of a virus such as HIV to mutate and evade immune responses are other crucial factors that influence infectivity.
Secondly, we need to identify procedure of handling of hazards in the laboratory. The lab technologist should keep in mind that every time they are processing blood, they must have to be very careful and considered that the blood has been infected with a dangerous pathogen which is could harm them if they are not following the procedures in the laboratory.
Every laboratory supervised by a supervisor must implement the institutional policies to control access to the laboratory. Lab technologist mush washes their hand every time handling the potentially hazardous materials before leaving the laboratory. The mechanical pipetting device should be used instead of mouth pipetting in order to prevent the transmission of the pathogen through the mouth. Development and implementation of policies for handling of sharp equipment safely such as needles, scalpels, broken glassware, and pipettes must be done. Also, during the practical, supervision on engineering and work practice control in the laboratory to reduce the risk of the hazard and prevent the injury happen. In the minimizing the occurrence of splashes blood in the laboratory, all procedure must be performed correctly.
Next, in the laboratory should have a safety equipment which acts as the primary barrier and personal protective equipment. Primarily, BSC and all other personal protective equipment are properly maintained whenever the procedures in the laboratory involve with potential hazardous that consists of high concentration or large volumes of infectious agents. This process must be done in the open laboratory using sealed rotor heads or centrifuge safety cups. The lab technologist while working with hazardous materials should wear the protective laboratory uniforms designated specifically for the processing of blood. Handling the hazardous materials outside the BSC or containment device the lab technologist should wear eyes and face protection to avoid anticipated blood splashes. All the eye and face protection must be disposed correctly or if to reuse the equipment must go through the sterilization process first. Lastly, gloves are used to protect the hand from exposure to hazardous materials.
Thirdly, we need to determine the biosafety level and the selection of additional precautions for this case. Generally, biosafety level (BSL) has four level. However, the HBV and HIV are from the type of biosafety level two. We use the BSC 2 since HBV and HIV are BSL II type A1. The diagram below shows a schematic of a Class II A1 BSC. It has an internal fan. The function of this fan is to draw outside cabinet through the front opening then it goes into the front intake grill. Before air flows over to workplace surface, the air must go through HEPA filter first. This is because to make sure half of the of the air split goes through the front exhaust and another half through rear exhaust grill. Splitting of air will capture the splashes of blood generated that will provide the highest protection. Lastly, the air then escapes through the rear plenum into space between the exhaust and supply at the top of the cabinet.
There is some additional precaution could be implemented in the blood lab. During the transportation of the blood, the lab technologist should place all specimen of blood in a well-constructed container with a secure lid. This action can prevent the leakage happen. After completion of blood specimen process, the gloves must be changed and wash the hands. A decontaminated with a proper chemical germicide is used to clean up spill of blood on the laboratory work surfaces after completion work activities. Under universal precautions, usage of needles and syringes should be limited to situations in which there is no alternative, and the recommendations for preventing injuries with needles outlined should be followed. Lastly, lab technologist should obey the institutional policies for disposal of infective waste, they should decontaminate every contaminated material used in the laboratory before processing or placed in bags and disposed.
The last step of control measures is reviewed the risk assessment. In this process, a biosafety professional and experts in the field has been sent to the laboratory or companies to review risk assessment and risk management practices. Usually, the period of this risk assessment is once every three years. However, risk assessment can conduct whenever there are any significant changes to the workplace processes or design, new machinery, substances or procedures are introduced and when there is an incident as a result of hazard exposure. The main reason for periodic review is to improve when their incident happens and prevent it happen in future.
A source or situation that has the potential to bring damage, harm or adverse health effects to humans and other living organisms are refers to Hazards. Hazards can be grouped based on their nature which are radiation hazards, physical hazards, ergonomic hazards, physiological hazards, environmental hazards, hazardous substances and last but no least is biological hazards.
Refer to the cases had reported about the lab technologist had HIV-positive and Hepatitis B, it shows that these cases are related to biological hazards which organisms produced organic matter (metabolic products) that are harmful to humans. The existence of HIV-positive and Hepatitis B diseases is caused by microorganisms such as bacteria, fungi, viruses and parasitic organisms. In general, there are three major of routes of entry for these microorganisms into our body, which are through the respiratory system, transmission through contact with body fluids of the infected or contact with contaminated objects.
Viruses essentially consist of nucleic acid and a protein coat. A host cell required by virion known as a virus particle in order to replicate. A virus enters a human cell and hijacks it, within the human anatomy using the cell to replicate. In many cases the immune system detects the presence of the virus and takes action leaving us with the symptoms of a common cold or influenza. But for HIV-positive viruses will permanent and irreversible damage to cells in human body. However, not all microorganisms bring harm to human, such as yeast is used in making breads and also some microorganisms live on every part of our body. They obtain nourishment from secretions, causes human body can be prevented from diseases.
In other hand, poor health, disability, disease or death are the factor that effect health and wellbeing some individual, are known as risk factors. A risk factor is a condition, or behaviour that increases the probability of getting a disease or injury. Underweight, unsafe sex, high blood pressure, tobacco and alcohol consumption, and unsafe water, sanitation and hygiene are some example of more important risk factors. A type of risk factors can be categorised generally into a following group which are Behavioural, Physiological, Demographic, Environmental and Genetic.
Behavioural risk factor usually relates to human take an “action” by themselves. They willing to change their lifestyle or behavioural choices by smoking tobacco, drinking too much alcohol, physical inactivity, unprotected sex that cause of someone getting HIV diseases and many others negative habit. Other than that, individual’s body or biology are related to Physiological risk factors. Human body may have influenced by a combination of lifestyle, genetic and another factor. Some examples include being overweight or obese, high blood pressure, and high blood cholesterol. The third one is Demographic risk factors which refer to the overall population. Age, gender and population subgroups, such as population or religion are the examples. Access to clean water and sanitation, risks in the workplace, air pollution and social settings are the examples included about the Environmental risk factors which relate to social, economic and cultural as well as physical, chemical and biological factors. Risk factors of genetic are based on individual’s genes. The interaction between the genes of the individual and environmental factors are cause someone getting diseases, such as asthma and diabetes.
Biological monitoring and health surveillance is the control measures which will be used to protect the employees from the exposure to biological agents and hazards in the workplace. Biological monitoring refers to the analysis of fluids obtained from the human body such as breath analysis, urine analysis and blood samples from employees in an organization. While health surveillance refers to the process of monitoring the health of an employee and includes biological monitoring due to occupational exposure. It systematically designed procedure that enables early detection of symptoms of work-related illnesses among employees.
Biological monitoring can be divided into two parts which are monitoring of exposure and monitoring of effect. It is mandatory for organizations that deal with hazardous chemicals to conduct health risk assessments at the workplace according to Malaysian Occupational Safety and Health (Use of Standards of Exposure of Chemicals Hazardous to Health). As a result, employees of such organization are required to undergo periodic health check-ups to know the current health status, possible methods of absorption and formulate the preventive actions.
The first parts of biological monitoring is biomarker of exposure which refer to the chemicals or its metabolite or the product of an interaction between a chemical and some target molecule or cell that is measured in a compartment in an organism. On the other hand, the other part is biomarker of effect which refers to a measurable biochemical, physiological, behavioural or other alteration in an organism that depending on magnitude, can be recognized as associated with an established or possible health impairment or disease.
Biomarker of exposure allow the evaluation of exposure to a particular chemical while the biomarkers of effect are usually used to examine changes in the biochemistry or physiology of a person. For example, blood and urine are regular body substances used in biological monitoring. While the common hazardous found in body fluids are heavy metals such as lead, cadmium and cobalt. Biological monitoring offers several advantages such as determining the exposure over period of time, exposure due to the mobility of an employee in the workplace, absorption location and quantity of a substance absorbed by the employee.
Next, biological monitoring with assessing exposure risk is to identify all hazardous materials in the workplace, from the walls, ventilation and carpets to toxic and hazardous materials. The most common route of exposure is through the respiratory system via inhalation. The rate and amount of hazardous materials taken up by the body depend on the following factors which are size and nature of the hazardous material, condition of local atmosphere, rate of breathing, personal hygiene, and fitness level.
Biological monitoring programmer be developed and conducted by a team of specialists comprising health and safety professionals, occupational physicians, chemist, toxicologists or environmentalists. The process of biological monitoring programmed are begin with risk assessment where identify all potential routes of exposure. Next process is review toxicology which identify all possible health effect and others. Furthermore, is consult with OSH committee and safety and health representatives where the committee are discuss on the safety factors, action levels, procedures when action levels are reached and policy and reporting processes. After all the process of biological monitoring are done, so the programmed can be implement.
Upon the completion of biological monitoring activities, the results obtained are compared against the Biological Exposure Index (BEI). The BEI contains reference values intended as guidelines for the evaluation of potential health hazards in the practice of industrial hygiene (ACGIH, 1996). Some of the criteria studied are systematic absorption and disposition, size of the exposed population, existence of a threshold limit value, availability of human toxiokinetic data and availability of chemical methods.
As for the health surveillance at workplace refers to activities which involve the collection of information on the health condition of employees. Early detection of adverse diseases can protect employees, providing indication of control measures, suggesting further appropriate actions and raising awareness among employees on the importance of following standards procedures. Health surveillance is often conducted by companies dealing with materials such as hazardous chemicals, hazardous biological agents, noise and irradiation.
To ensure the successful implementation of health surveillance, the following four steps serve as a guide in establishing / designing a health surveillance programmed at the workplace. Firstly, determine the aim of the health surveillance programmed the management determine the aim of the health surveillance programmed and who will be participants of this programmed. Next, engage employees where employees need to be informed about the aim objectives of the health surveillance programmed and how it will conduct such as the procedures of the self-checks, and biological monitoring. Thirdly the frequency and length of the health surveillance programmed where it should be allowed to continue as long as employees are exposed to the risk. Next is acting on the results where the information obtained from a health surveillance should be assesses by the person in charge. The information obtained can provide an indicator for the implementation of health risk control programmed and enable the formulation of further education, risk and health-related programmed.
Next is sampling strategies and collection of biological substances where the selection of an appropriate sampling strategy depends on the time taken for a substance to lose half of its activity similar to the half-life used in radioactive substances. In the sampling strategy, it is important to determine whether to collect samples from the whole population or from a selected few. The analysis of urine and blood samples should be conducted by qualified laboratories in accordance with available standard procedures. For example, in the collection of blood samples, these must be taken by phlebotomists or nurses, using the standard blood collection and storage procedures adopted by the Ministry of Health Malaysia.
The health records of any health surveillance programmed should be kept securely and be highly confidential, such record should include important elements such as name, gender, date of birth, age, address of residence, date of commencement of present job, historical records of jobs that include exposure to hazards, concluding remarks of the heath surveillance programmed, dates and name of person who conducted this programmed.
Thus, once a particular health surveillance programmed has commenced, it is important that the view of the participants be taken into consideration before any other programmed commences. Also, consultation with health and OSH practitioners will also aid in developing new procedure, policies, and actions. Moreover, in some organization, job rotation is required in order to limit single employee exposure to hazardous substances. While, from the management’s perspective, regular maintenance of the ventilation system, machineries and equipment is essential as well.
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