What is Considered a Level 4 Disease?

Diseases that have high fatality rates and have no known treatments are considered level 4 diseases. An example of a level 4 disease is Ebola virus, a disease that causes headache, muscle pain, fever, impaired liver and kidney function, and in some cases, death. Since last year, Ebola virus has infected over 18,000 people, according to the World Health Organization (WHO). Of those 18,000 people, only 50% have survived.

Understanding the 4 Levels of Disease

The Center for Disease Control (CDC) considers infectious diseases to be biohazards and has developed a 4-level system to help prevent the transmission of infectious diseases. These 4 levels are known as biohazard levels.

How is a disease’s biohazard level determined?

Each biohazard level signifies how detrimental a disease is to human health — the higher the biohazard level, the more serious the disease. Other factors include a microbe’s stability, concentration, route of transmission, and origin. By separating biological hazards into 4 levels, lab technicians are better able to identify specific features of microorganisms and determine the safest way to handle them.

What are some examples of each biohazard level?

Biohazard level 1 – Agents that do not typically cause disease in healthy adults.

  • An example of a level 1 disease would be bacillus subtilis.

Biohazard level 2 – Agents that can cause severe illness in healthy adults through direct contact with infected material.

  • Examples of level 2 diseases include HIV, salmonella, and hepatitis B.

Biohazard level 3 – Human pathogens that can become airborne and cause serious diseases.

  • An Example of a level 3 disease would be tuberculosis.

Biohazard level 4 – Human pathogens that cause fatal diseases for which there are no treatments.

  • Examples of a level 4 disease include Ebola virus, Marburg virus, and Hantavirus.

Communicable Disease Decontamination Services

Transmission of Level 4 Diseases

Most commonly, level 4 diseases are transmitted to humans through direct contact with urine, fecal matter, or saliva from infected rodents. Ebola virus, for instance, is believed to have originated from the fruit bats of the Pteropodidae family, and was introduced into the human population through close contact with blood and body fluids of the infected bats. Human-to-human transmission occurs when broken skin becomes exposed to blood, semen, breast milk, or other body fluids of an infected person.

Control and Prevention

When in doubt, turn to a professional. Aftermath has been an industry leader in bioremediation since 1996. To protect our technicians and our clients, we treat every scene as if it contains a life threatening infection and use the same cleanup techniques that health care and food preparation facilities use to eradicate disease and restore safety. At Aftermath, we believe that no one should have to compromise personal health or safety. Contact us to learn more.