Most Deadly Viruses – BioSafety Level 4

Last week I promised a look at the most deadly viruses after commenting on the Hantavirus outbreak. The latest news on that is a 3rd death and warnings that it might be a worldwide outbreak (

This week we’ll look at viruses considered most deadly, most infectious and have no cure. What researchers call “Biosafety Level 4” – viruses that cause hemorrhagic fevers and smallpox, and the Marburg, Ebola and Lassa viruses. Researchers and policy makers have a delimma: how to study these dangerous viruses to find a cure when they are so contagious and so deadly? It reminds me of a few of the movies that I’ve seen ads for in the past few years (like Outbreak). We don’t want to let these viruses loose! They put up special laboratories with specific layout and rules:

  • Positive Pressure suits (look like space suits or HazMat suits), with it’s own air supply
  • Special storage cabinets
  • Showers, vacuum, ultraviolet light room at each entrance and exit
  • Airlock – a room like a hallway, where only 1 set of doors can open at a time.
  • Restricted access – we don’t want to have these as biological weapons!
  • Air and water decontamination

There are only 15 Biosafety Level 4 (BSL-4) labortatories in the U.S., as of 2007. 9 of which are federal labs.

So what are these bugs?

  • Hemorrhagic fevers – All of these have headache and fever. Patients bleed out, or their blood coagulates everywhere. Some are spread by rodents or ticks.
  • Marburg virus
  • Ebola virus
  • Lassa virus
  • Smallpox

I remember in my studies that Hantavirus was considered a Biosafety Level 4 organism, but maybe it’s moved as I can’t find it now as such.

On a side note, there’s also a “Biosafety Level 5” in NASA for stuff that come from outer-space – we don’t want to spread any “out-of-this-world” bugs loose on Earth, would we!


If you want to study dieseases like these, start with microbiology! Work in infectious disease labs even while in college. Get your masters or Ph.D. Start working in these labs and work your way up! It’s a speciality, and people who work in these labs are experts – and they have to be!


Look in my favorite non-citable source, Wikipeida –



  1. We talk about Ebola virus and the outbreak in Summer 2014 in Post 126.

  2. From yesterday – The head of the bioterrorism lab involved in potentially exposing dozens of workers at the Centers for Disease Control and Prevention to deadly anthrax bacteria has resigned. Michael Farrell, who headed the Bioterrorism Rapid Response and Advanced Technology (BRRAT) Laboratory, submitted his resignation Tuesday, CDC spokesman Tom Skinner told CNN.

  3. Also take a look at Post 123 (search for Post 123) – we talk about the CDC closing some of their BSL 4 labs because they weren’t following protocol…

  4. […] BSL4 Post is probably the most popular one I have, and CDC’s BioLevel 2-3-4 laboratories have been […]

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