Which of these describe a method in which a bloodborne pathogen may be transmitted?

Modes of transmission

Bloodborne pathogens such as HBV and HIV can be transmitted through contact with infected human blood and other potentially infectious body fluids, such as:

Semen

Vaginal secretions

Cerebrospinal fluid

Synovial fluid

Pleural fluid

Peritoneal fluid

Amniotic fluid

Saliva (in dental procedures)

Any body fluid that is visibly contaminated with blood.

It is important to know the ways exposure and transmission are most likely to occur in your particular situation, whether it be providing first aid or medical assistance, handling blood samples in the laboratory, cleaning up blood from a hallway, or restraining an unruly person.

HBV and HIV are most commonly transmitted through:

Sexual contact

Sharing of hypodermic needles

From mothers to their babies at/before birth

Accidental puncture from contaminated needles, broken glass, or other sharps

Contact between broken or damaged skin and infected body fluids

Contact between mucous membranes and infected body fluids

In most work or laboratory situations, transmission is most likely to occur because of accidental puncture from contaminated needles, broken glass, or other sharps; contact between broken or damaged skin and infected body fluids; or contact between mucous membranes and infected body fluids. For example, if someone infected with HBV cut his or her finger on a piece of glass and then you cut yourself on the now infected piece of glass, it is possible that you could contract the disease. Anytime there is blood-to-blood contact with infected blood or body fluids, there is a slight potential for transmission.

Unbroken skin forms an impervious barrier against bloodborne pathogens. However, infected blood can enter your system through:

Open sores

Cuts

Abrasions

Acne

Any sort of damaged or broken skin such as sunburn or blisters

Bloodborne pathogens may also be transmitted through the mucous membranes of the:

Eyes

Nose

Mouth

For example, a splash of contaminated blood to your eye, nose, or mouth could result in transmission.

Bloodborne Pathogens

OSHA defines a bloodborne pathogen as a microorganism present in human blood that can cause disease in humans. This definition necessarily includes microorganisms that are also present in biological products of human blood or its constituent materials. In the forensic science laboratory, the most serious risk of exposure to bloodborne pathogens comes from evidentiary materials contaminated with the blood of victims and suspects shed as a result of the crimes being investigated. For example, among the bloodiest of items typically submitted to a crime laboratory are firearms used during the commission of suicides. The safety of laboratory employees in cases like this rely significantly on the competence of crime scene technicians who collect and package the evidence. Wet blood is considerably more dangerous than blood residues that have been dried in a controlled environment. Unfortunately, by the time evidence reaches the front door of the laboratory, the extent to which the health and safety risks have been mitigated is generally unknown to the laboratory staff. Therefore, the best approach to protecting employees from diseases caused by bloodborne pathogens is to assume that every item of evidence is potentially dangerous.

Although bloodborne pathogens come in a wide variety, those generally considered the most serious in terms of contractibility and morbidity are:

Human immunodeficiency virus/AIDS

Hepatitis B

Hepatitis C

Human Immunodeficiency Virus (HIV) is the virus that causes the Acquired Immunodeficiency Syndrome, or AIDS. According to the Centers for Disease Control, HIV appeared in the United States in the mid to late 1970s. At that time, the virus quickly progressed into AIDS for which there is still no cure. Fortunately, private and public funding leading to significant medical advancements have enabled doctors to prevent HIV from becoming AIDS. This is not to say that HIV is curable. It is not. Those infected with HIV can remain infected for the remainder of their lives. But thanks to the treatments that are available, particularly with the benefit of early detection, HIV patients can now live with their infections without any adverse impact on longevity.

Hepatitis is a dangerous inflammation of the liver caused by one of multiple possible strains of the hepatitis virus. Each strain has its own designation: A, B, and C. Hepatitis A is primarily transmitted through oral exposure of contaminated fecal matter. There is no cure for hepatitis A; however, the disease usually runs its course over several weeks or months before clearing up on its own. Hepatitis B (HBV) and C (HCV) are both bloodborne pathogens having more serious consequences for infected patients including lifelong chronic liver problems that can lead to permanent liver damage from cirrhosis and liver cancer, sometimes resulting in death.

HBV infection can be prevented in the workplace by offering employees the opportunity to receive or decline the HBV vaccination. The HBV vaccine is usually administered in a series of three intramuscular injections over a period of approximately 6 months. The vaccine is safe with few side effects; those most likely to occur are soreness at the injection site (approximately 25% of patients) and/or a moderate fever (approximately 1 in 15 patients). Currently, there is no vaccine for HCV.

Hepatitis Foundation International located in Silver Spring, Maryland, estimates that 4.4 million Americans are living with chronic hepatitis, with approximately 80,000 new infections occurring each year. More troublesome, however, is the fact that most victims are unaware that they are infected. Similarly, among those who know of their infection, most do not know what actually caused it.

The strategy adopted by organizations to reduce the risk of exposure to bloodborne pathogens or illnesses caused by exposure is called an exposure control plan. In 2003, OSHA published a useful document titled Model Plans and Programs for the OSHA Bloodborne Pathogens and Hazard Communications Standards (OSHA 3186-06R 2003). According to OSHA, exposure control plans should include the following:

Determination of employee exposure

Universal precautions

Engineering and work practice controls

Personal protective equipment

Housekeeping

Hepatitis B vaccination

Postexposure evaluation and follow-up

Communication of hazards to employees and training

Recordkeeping

Procedures for evaluating circumstances surrounding exposure incidents

The creation, adoption, and enforcement of a forensic science laboratory's exposure control plan requires careful consideration by human resource management specialists. Persons responsible for the management of the plan must be adequately qualified. They must also be able to cater their plans to the risks associated with working in the forensic science laboratory environment. If, for example, the laboratory is part of a police agency, it is not sufficient to administer a plan designed for police officers. Execution of the exposure control plan must be respectful of the risks unique to the forensic laboratory sciences. Ensuring that the right people are managing the right plan is a key factor in eliminating or minimizing exposures to bloodborne pathogens.

Oversight in the United States

In the United States, working with primary human tissues requires compliance with Occupational Safety and Health Administration’s (OSHA’s) Bloodborne Pathogens Standard.15 Bloodborne pathogens are defined as infectious microorganisms present in blood that can cause disease in humans and other potentially infectious materials (OPIM) (ie, tissues or tumors). These pathogens include, but are not limited to, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus. Workers exposed to bloodborne pathogens are at risk for serious or life-threatening illnesses (refer to Chapter 8 for details on the pathogens that could be associated with PDX tumors). An overview of the regulatory requirements is outlined in Fig. 1.2 and detailed in the following discussion.

The Bloodborne Pathogens Standard require several actions on the part of the employer. These include:

Establishing an exposure control plan,

Updating the plan annually to reflect changes in tasks, procedures, and positions that affect occupational exposure, and also technological changes that eliminate or reduce occupational exposure,

Implementing the use of universal precautions (treating all human blood and OPIM as if known to be infectious for bloodborne pathogens),

Identifying and using engineering controls,

Identifying and ensuring the use of work practice controls,

Providing personal protective equipment (PPE), such as gloves, gowns, eye protection, and masks; employers must clean, repair, and replace this equipment as needed,

Making available hepatitis B vaccinations to all workers with occupational exposure,

Making available postexposure evaluation and follow-up to any occupationally exposed worker who experiences an exposure incident,

Using labels and signs to communicate hazards,

Providing information and training to workers, and

Maintaining worker medical and training records.

The employer also must maintain a sharps injury log, unless it is exempt under Part 1904—Recording and Reporting Occupational Injuries and Illnesses, in Title 29 of the Code of Federal Regulations. Persons conducting research with potentially infectious materials should have a thorough understanding of these regulations and their own institution’s policies.

The Biosafety in Microbiological and Biomedical Laboratories, 5th Edition, classifies human primary tissues as requiring Biosafety Level 2 precautions.16 This means that the tissues require standard microbiological practices (including prohibiting the practice of mouth pipetting), special practices (training and awareness of hazards), safety equipment [primary barriers, such as biosafety cabinets (BSCs), and PPE—gloves, laboratory coats, safety glasses, and closed toe shores], and laboratory facilities (eyewash and handwashing sink). It is very important to clarify all of these requirements up front and ensure that all the precautions are put into place well in advance of the tissue evaluation. Ensuring compliance with these standards requires coordination between the institution’s health and safety personnel, facilities personnel, and with the veterinary and animal care staff when animal studies are conducted.

Infection Control

Exposure to bloodborne pathogens (human immunodeficiency virus, hepatitis B virus, tuberculosis) may result from the initial handling of cell samples, from the preparation of both gynecologic and nongynecologic cell samples, from a lack of special handling in disposing of the specimen, and from not decontaminating the workspace used in the preparation of the cell sample. Body fluids—including pleural, peritoneal, pericardial, synovial, and respiratory tract specimens; cerebrospinal, salivary, and vaginal secretions; and potentially any body fluid visibly contaminated with blood—require special handling. Each and every specimen should be handled as though it were infectious. One may not learn of the infectious nature of the specimen until cytologic preparations have been completed.

A laboratory plan for occupational exposure to bloodborne pathogens and a chemical hygiene plan are required by the Occupational Safety and Health Administration.3 Employees at risk of exposure to hepatitis B virus must be offered vaccination within 10 days of assignment. An employee who chooses not to be vaccinated must sign a waiver.

A training program must be in place for all new employees and periodically renewed for all employees throughout their employment in the cytopathology laboratory. Employees are classified according to their potential risk of exposure. However, there are always instances when employees at low risk may unintentionally place themselves at greater risk. Vigilance on the part of each staff member is essential in order to maintain a safe workplace for all.

Creating a delineated workspace that requires workers to wear protective equipment may be helpful. Protective equipment such as gloves, masks, and disposable gowns are to be used by those preparing cell samples.

Color-coded disposal waste containers may also help remind workers of the difference between biohazardous waste material and other waste material and may prevent housekeeping personnel from being contaminated. Biohazardous materials must be sealed in containers by laboratory personnel.

Laboratory policy should state standards such as “specimens with needles attached are not accepted by the laboratory.” This rule alone will protect all the individuals who handle the specimen.

One of the most difficult tasks is to maintain the cooperation of each laboratory worker to comply with the protective procedures on a daily basis. Some workers inevitably believe themselves to be impervious to infectious hazards, and they may be responsible for contaminating the workplace and their coworkers.

Epidemiology

Exposure to bloodborne pathogens via parenteral or mucosal contact remains a major hazard for HCP, especially those performing invasive procedures. Although more than 30 diseases have been transmitted to HCP by sharps injuries or mucosal exposure,286 the agents of greatest concern are HBV, hepatitis C virus, and HIV.27–30,287–289 Seroprevalence surveys conducted before the availability of the HBV vaccine in 1981 showed that HCP had prevalence rates of past or present HBV infection threefold to fivefold higher than the general U.S. population.290–293 The risk of infection was related to both the extent and the duration of blood contact. The CDC predicted that, in 1989, an estimated 12,000 American HCP would become infected with HBV, which would result in 250 deaths.294 With a decreasing incidence of hepatitis B, the CDC estimated that, in 1994, 1012 HCP became infected with HBV because of occupational exposures, leading to approximately 22 deaths.295 In a more recent analysis, Mahoney and colleagues reported in 1997 that HBV infection among HCP declined from 17,000 in 1983 to 400 in 1995.296 The 95% decline in incidence observed among HCP was 1.5-fold greater than the reduction in incidence in the general U.S. population. The decline among HCP was because of the use of HBV vaccine, institution of universal (now standard) precautions, and other preventive measures such as needleless devices. Hepatitis B acquisition remains a concern for unimmunized HCP because the virus is environmentally stable and has been transmitted by other routes than percutaneous injury, including paper cuts, human bites, and mucosal contamination with blood.

4.6 OSHA BBP: Protection of Employees from Exposure to Bloodborne Pathogens

1.

Under the BBP standard, any entity where employee(s) may have exposure to BBP must have a written exposure control plan (CFR §1910.1030, c), and this plan must be made accessible to employees [18]. The concept of universal precautions (i.e., treating all blood, body fluids, and in some cases, cultures, as infectious) is critical to compliance with the BBP standard.

In addition to development of an exposure control plan and adherence to universal precautions, engineering, and work practices controls must be implemented to eliminate or minimize employee exposures (CFR §1910.1030, d, (2)) [18]. Proper handwashing facilities, enforcement of proper handwashing practices following removal of gloves or other PPE, and provision of antiseptic hand sanitizers when handwashing facilities are not immediately available are required. Use of sharps in conjunction with BBPs is a high-risk activity, and the BBP standard details proper sharps handling and disposal practices (including use of approved sharps disposal containers) and prohibition of bending, recapping, or removal of contaminated sharps (unless part of a procedure specific-requirement or if no feasible alternative is available) [18]. Basic good laboratory practices, such as prohibiting mouth pipetting, eating, drinking, smoking, applying cosmetics, or handling contact lenses in work areas, storage of food and drink outside of work areas, and performing laboratory procedures carefully to minimize splashing, spraying, or generation of aerosol droplets of pathogens are also required. Laboratories where work with BBP is performed and potentially contaminated equipment and containers are used for transport of BBP must be appropriately signed and labeled [18].

PPE use is mandated whenever engineering and work practice controls cannot eliminate the risk of exposure to personnel [18]. Minimum PPE requirements include gloves, gowns or laboratory coats, face shields or masks, and eye protection, as well as mouthpieces, resuscitation bags, or pocket masks or other ventilation devices. The BBP standard also requires employers to ensure that proper PPE is used by employees [18].

Universal Precautions

The Occupational Safety and Health Administration issued regulations regarding occupational exposure to BBPs in December 1991. Those occupations at risk for exposure to BBPs include law enforcement, emergency response, and forensic laboratory personnel (Title 29 CFR, 1910.1030).

Fundamental to the BBP Standard is the primary concept for infection control called Universal Precautions. These measures require employees to treat all human blood, body fluids, or other potentially infectious materials as if they are infected with diseases such as hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). The following protective measures should be taken to avoid direct contact with these potentially infectious materials (Title 29 CFR, 1991):

Use barrier protection such as disposable gloves, coveralls, and shoe covers when handling potentially infectious materials. Gloves should be worn, especially if there are cuts, scratches, or other breaks in the skin.

Change gloves when torn, punctured, or when their ability to function as a barrier is compromised.

Wear appropriate eye and face protection to protect against splashes, sprays, and spatters of infectious materials. Similar precautions should be followed when collecting dried bloodstains.

Place contaminated sharps in appropriate closable, leak-proof, puncture-resistant containers when transported or discarded. Label the containers with a BIOHAZARD warning label. Do not bend, recap, remove, or otherwise handle contaminated needles or other sharps.

Prohibit eating, drinking, smoking, or applying cosmetics where human blood, body fluids or other potentially infectious materials are present.

Wash hands after removing gloves or other personal protective equipment (PPE). Remove gloves and other PPE in a manner that will not result in the contamination of unprotected skin or clothing.

Decontaminate equipment after use with a solution of household bleach diluted 1:10, 70% isopropyl alcohol, or other disinfectant. Noncorrosive disinfectants are commercially available. Allow sufficient contact time to complete disinfection.

In addition to Universal Precautions, prudent work practices and proper packaging serve to reduce or eliminate exposure to potentially infectious materials. Packaging examples include puncture-resistant containers used for storage and disposal of sharps.

Safety at the Scene

Preserving the evidence at the scene is not the only thing that needs to be taken care of: A crime scene is one of the most hazardous locations a CSI can go (Figure 5.3.2). Chemical, biological, and physical threats abound. The list of threats is extensive, from explosives to blood to firearms. Considering most of the (criminal) activities are over with and the CSI probably does not have full knowledge of the events, it can be easy to happen upon a hazardous situation or material. Terrorist scenes multiply these dangers because of the prospect of explosives manufacture or use of chemical or biological agents.

The increase in bloodborne pathogens (AIDS and hepatitis, for example) and other pathogens that may be encountered at crime scenes (like the Hanta virus) has made law enforcement and CSIs more aware of personal protection when responding to crime scenes. Although the risk of infection to CSIs is exceedingly low, precautions are typically mandated by individual agencies’ protocols. Additionally, federal laws or regulations from one of several health agencies may be applicable to crime scene personnel.

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Safety

11 How is the transmission of pathogens such as HIV and hepatitis prevented?

To prevent transmission of blood-borne pathogens such as HIV, hepatitis B, or hepatitis C, the following specific measures should be followed:

Pre-event—dressing of all open wounds with occlusive dressings

Use of gloves, disinfectants, bleach, and antiseptics for washing/cleaning surfaces and clothing

Receptacles for contaminated clothing, bandages, dressing, and needles; must be available on the side of the field of play and in the dressing rooms

Removal of players from play if active bleeding is present

Control of bleeding, covering of wound with occlusive dressing, and change of blood-stained clothing before return to play

Wearing adequate, appropriate protective equipment by players

Athlete education and empowerment with responsibility to report wounds

Caregiver precautions including using and changing of gloves between contacts

Covering of minor cuts and abrasions while on the field

Airway devices available for use in case of life-threatening emergencies

Contaminated areas (eg, mats) wiped down immediately and disinfected with bleach; area should be dry before being reused

Post-event—wounds should be reviewed and redressed

Soiled clothing and towels should be washed separately

All personnel involved in coaching and support of a team should be trained in basic first-aid*

Strategies to Control HBV Transmission in Dialysis Units

To prevent transmission of blood-borne pathogen agents in general health care settings, “universal precautions” have been recommended by the CDC. These procedures are now referred to as “standard precautions” and include (1) hand washing after touching blood and other potentially infectious material, (2) wearing of gloves when touching blood or other potentially infectious material, and (3) use of gowns and face shields when exposure to blood or body fluids has been anticipated.

In addition to these “standard precautions,” there are routine hemodialysis unit precautions that are unique to the hemodialysis setting and are more stringent than the “universal precautions.” The infection control practices specific to the hemodialysis environment recommend that glove use is necessary whenever patients or hemodialysis equipment is touched, and that there should be no sharing of supplies, instruments, or medications between HD patients, including ancillary supply equipment (trays, blood pressure cuffs, clamps, scissors, and other nondisposable items). Further, the hemodialysis center precautions specify the separation of clean areas (used for handwashing and handling and storage of medications) from contaminated areas (handling blood samples and hemodialysis equipment after use), cleaning and disinfection of nondisposable items, machines and environmental surface between uses. In addition, other precautions to prevent HBV acquisition in the hemodialysis environment are needed: monthly serologic testing for hepatitis B surface antigen (HBsAg) of all susceptible patients, prompt review of results, physical separation of HBsAg-positive from susceptible patients and cohorting of separate dialysis staff, instruments, supplies, and hemodialysis machines to patients with HBsAg positivity.