Friday, February 20, 2015

Ebola: The Standards

This section highlights OSHA standards, preambles to final rules, and directives (instructions for compliance officers) that may be applicable in the event of possible worker exposure to the Ebola virus.

OSHA’s Bloodborne Pathogens standard (29 CFR 1910.1030) covers exposure to Ebola virus. Ebola is among the subset of contact-transmissible diseases to which the Bloodborne Pathogens standard applies, as it is transmitted by blood or other potentially infectious materials as defined in the standard.

In situations where workers may be exposed to bioaerosols containing Ebola virus, employers must also follow OSHA’s Respiratory Protection standard (29 CFR 1910.134).

Other elements of infection control for Ebola, including a number of precautions for contact-transmissible diseases, are covered under OSHA’s Personal Protective Equipment (PPE) standard (29 CFR 1910.132) and Section 5(a)(1) of the Occupational Safety and Health (OSH) Act of 1970, often referred to as the General Duty Clause. Section 5(a)(1) requires employers to "furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees." This section may be used to address hazards for which there are no specific standards (e.g., occupational exposure to Ebola virus).

Under the Bloodborne Pathogens standard, and the PPE and other standards, OSHA has the ability to require employers to fully protect healthcare and other workers who may be exposed to Ebola virus. The best way to determine appropriate protections for workers exposed to Ebola is to consult the CDC guidance, which includes recommendations for PPE and infection control practices from CDC's Ebola web page.

Employers also must protect their workers from exposure to chemicals used for cleaning and disinfection. Employers would likely need to comply with provisions from a combination of OSHA standards and CDC guidance in order to implement a comprehensive worker protection program.

Paragraph 11(c) of the OSH Act prohibits employers from retaliating against workers for raising concerns about safety and health conditions. OSHA encourages workers who suffer such discrimination to submit a complaint to OSHA. Such complaints must be filed within 30 days.

Depending on the specific work task, setting, and exposure to biological or chemical agents, additional OSHA standards, including the following, may also apply:

General Industry (29 CFR 1910)
Preambles to final rules
Directives
Memoranda of Understanding
Additional guidance is available on the Control and Prevention and Additional Information tabs.

Tuesday, February 17, 2015

Ebola: Medical Information

The most common routes of transmission of Ebola viruses are:
  • Contact of the eyes or other mucous membranes with blood or body fluids of a person or animal with Ebola Hemorrhagic Fever (EHF),
  • Contact with contaminated equipment or other objects; and
  • Ingestion of infectious blood or body fluids.
Ebola virus is believed to be viable outside of the body for several days. An evaluation of the persistence of certain Category A select agents in the environment suggests that viruses of the family Filoviridae, of which Ebola viruses are members, may remain stable for 4-5 days in dried blood.2

Though transmission through inhalation of airborne virus is not currently a primary concern during naturally-occurring outbreaks, it may be possible for Ebola virus to be aerosolized under certain conditions. CDC has provided guidance for healthcare workers who must perform aerosol-generating procedures on patients known to have or suspected of having EHF. Pathogenicity (i.e., how the virus acts on the body to cause disease) and symptoms are typically the same regardless of the initial route of infection with Ebola virus
In all settings, avoid using compressed air or water when cleaning surfaces, as it might cause droplets containing infectious material to become airborne (i.e., create a bioaerosol).1

Symptoms of Ebola typically appear within 2-21 days (8-10 days is most common) following infection, and the illness runs its course within 14-21 days of symptom onset. The table below describes the natural history of Ebola:
Exposure Incubation Symptom Onset Illness Recovery or Death
- Exposure to Ebola virus through contact with infectious blood or body fluids, contaminated environmental surfaces, or an infected individual or animal.
- In some instances, exposure may be due to aerosolized viral particles.
- Exposed individuals are not contagious.
- Virus multiplies within the body before symptoms develop.
- Individuals become contagious when symptoms appear.
- Initial symptoms of EHF may include fever, fatigue, muscle pain, headache, and sore throat.
- Symptoms appear similar to other viral illnesses.
- Illness progresses to include nausea, vomiting, diarrhea, impaired organ function, and blood count changes.
- Some cases experience a rash and internal and/or external bleeding (e.g., from skin, eyes, or gums).
- The bodies of individuals who die from EHF remain infectious after death, and must be handled accordingly during death care.
- Individuals who recover from EHF generally are no longer contagious.
Day 0
2-21 days
14-21 days
Up to 49 days
As the infection progresses, patients often experience a rash and severe bleeding as the blood loses its ability to coagulate and blood vessel membranes become more permeable. Lymphocyte counts drop and neutrophils spike. Ebola patients ultimately die from diffuse bleeding and shock.
Medical Management and Countermeasures
There is currently no treatment, antiviral therapy, or approved vaccine for EHF or Ebola virus. Supportive hospital care for patients with EHF (like other viral hemorrhagic fevers) includes fluid and blood replacement, maintaining stable blood pressure, and treating other comorbidities (i.e., other injuries or infections) as appropriate.

Individuals who may have come into contact with Ebola virus may be quarantined at the discretion of public health officials. Isolate suspected and confirmed cases of EHF to prevent transmission of the disease to other individuals. Suspected and confirmed cases of Ebola should be isolated to prevent transmission of the disease to other individuals. If possible, isolating suspected cases separately from confirmed cases also may help prevent transmission.

Healthcare providers have a variety of tools at their disposal to test for Ebola virus infection and diagnose EHF, including blood tests that can detect antibodies to the Ebola virus or the RNA of the virus itself. Cell culture and electron microscopy are also used to identify Ebola virus.

The U.S. Department of Homeland Security has identified EHF as a high-priority threat. The U.S. Department of Health and Human Services is prioritizing the development of vaccines and other medical countermeasures for EHF and Ebola virus accordingly.3 The National Institutes of Health (NIH) has had some success with experimental vaccines in non-human primate models. Ongoing research into recombinant adenoviruses, recombinant vesicular stomatitis viruses (VSVs), and other recombinant vaccine products is underway, but human trials are still needed to demonstrate safety and efficacy.4 Research efforts continue in a number of nations to develop an effective vaccine and other medical countermeasures, such as antibody serum, to prevent or treat EHF and related diseases.