Monday, October 20, 2014

Ebola and the Challenges Facing the Medical Community

An article in the American College of Physicians' Annals of Internal Medicine gives us an idea of how challenging it will be for medical facilities to care for Ebola patients in North America.

Let's get a bit of background first.  Scientists have developed the Biohazard Safety Level protocols to assist medical professionals and researchers who are working with hazardous materials.  There are four biohazard levels, BSL-1, BSL-2, BSL-3 and BSL-4 as shown on this diagram:

Here is a summary of each level:

BSL-1If you work in a lab that is designated a BSL-1, the microbes there are not known to consistently cause disease in healthy adults and present minimal potential hazard to laboratorians and the environment. An example of a microbe that is typically worked with at a BSL-1 is a nonpathogenic strain of E. coli.

Personal Protective Equipment (PPE) includes lab coats, gloves and eye protection.

Facilities must have a sink for hand washing and have doors to separate the working space from the rest of the facility.

BSL-2:  BSL-2 builds upon BSL-1. If you work in a lab that is designated a BSL-2, the microbes there pose moderate hazards to laboratorians and the environment. The microbes are typically indigenous and associated with diseases of varying severity. An example of a microbe that is typically worked with at a BSL-2 laboratory is Staphylococcus aureus.

PPE: includes lab coats, gloves and eye protection (i.e. face shields) as needed.

Facilities must have self-closing doors and a sink and eyewash must be readily available.  Procedures are performed within a biological safety cabinet and an autoclave or other decontamination method is used to ensure proper disposal of waste.

BSL-3: BSL-3 builds upon the containment requirements of BSL-2. If you work in a lab that is designated BSL-3, the microbes there can be either indigenous or exotic, and they can cause serious or potentially lethal disease through respiratory transmission. Respiratory transmission is the inhalation route of exposure. One example of a microbe that is typically worked with in a BSL-3 laboratory is Mycobacterium tuberculosis, the bacteria that causes tuberculosis.

PPE: May include respirators and the aforementioned equipment including full body coverage.  Personnel are under medical surveillance and may receive immunization for the microbes that they work with.

Facilities must have controlled and restricted access and have hands-free sinks and eyewash equipment.  Exhaust air cannot be recirculated and air must be drawn into the laboratory from clean areas and exhausted outwards.  Entrance to the lab is through two sets of self-closing and locking doors.

BSL-4: BSL-4 builds upon the containment requirements of BSL-3 and is the highest level of biological safety. There are a small number of BSL-4 labs in the United States and around the world. The microbes in a BSL-4 lab are dangerous and exotic, posing a high risk of aerosol-transmitted infections. Infections caused by these microbes are frequently fatal and without treatment or vaccines. Two examples of microbes worked with in a BSL-4 laboratory include Ebola and Marburg viruses.

PPE: If a Class III biological safety cabinet is not available, laboratory personnel must wear a full body, air-supplied positive pressure suit as shown in this picture:

You can readily see how this type of PPE would not be widely available in most hospitals and medical centers around the world.  Clothing must be changed before entering and personnel must shower upon exiting.  All materials must be decontaminated before exiting the facility.

Facilities must be in a separate building or in an isolated or restricted zone of the building.  The laboratory has a dedicated supply of air, vacuum lines and decontamination systems.

You'll note that scientists working with Ebola require a BSL-4 level facility.

Here is a chart summarizing of all four biohazard levels:

 If you want to see all of the details of what protocols are required for each of the Biohazard Safety Hazard levels, here is a link to the Centres for Disease Controls (CDC)Laboratory Biosafety Level Criteria document.

Now, back to the subject of this posting.  The authors noted that the CDC has developed a hospital preparedness checklist for hospitals dealing with Ebola.  The CDC believes that Ebola patients can be cared for in a conventional medical facility by using barrier methods and that high-level containment care (HLCC) such as that offered at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) is not necessary (it has since been decommissioned).  Currently, there are four facilities in the United States that offer a higher level of containment than a conventional hospital isolation room:

1.) Emory University Hospital in Atlanta, Georgia

2.) University of Nebraska Medical Centre in Omaha, Nebraska

3.) St. Patrick's Hospital in Missoula, Montana

4.) National Institutes of Health Clinical Centre in Bethesda, Maryland

The authors state that staff in conventional medical centres are learning that dealing with patients infected with an Ebola virus presents significant challenges.  It is impossible to rule out human error such as needlesticks or cuts from sharps.  Hospitals must be prepared for the following:

1.) Provide a means of triaging potential Ebola patients safely since these patients can present themselves to the facility unannounced.

2.) Entry and movement of Ebola patients through the facility.

3.) A location for the safe donning and removal of personal protective equipment.

4.) Handling of laboratory specimens.

5.) Disposal of all waste associated with Ebola patients.

6.) Cleaning up of spills and bodily waste materials.

The authors emphasize that there is a significant increase in the risk of infection when taking off potential contaminated personal protective equipment and that there is no room for error.

The authors recommend that, since it will be very difficult and prohibitively expensive to maintain a nationwide state of high alert for a long period to time, a network of regional referral centers that are tied to BSL-4 laboratories should be developed.  Patients that present with Ebola would be transferred to these major medical centres that have the ability to provide BSL-4 security as well as the day-to-day care that Ebola patients require without interfering with their normal operations.

As we can see, the complexity of handling and managing patients with Ebola would be well beyond the scope of most of the hospitals in the United States, Canada and the remainder of the developed world let alone the medical facilities in the world's developing nations.  With outbreaks of deadly disease being relatively rare in our lifetimes, while practice may make perfect, there has been very little opportunity for the vast majority of the medical community to practice the skills necessary to keep a deadly virus from spreading.

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