Biocontainment in the context of "U.S. Army Biological Warfare Laboratories"

Biosecurity refers to measures aimed at preventing the introduction or spread of harmful organisms (e.g. viruses, bacteria, plants, animals etc.) intentionally or unintentionally outside their native range or within new environments. In agriculture, these measures are aimed at protecting food crops and livestock from pests, invasive species, and other organisms not conducive to the welfare of the human population. The term includes biological threats to people, including those from pandemic diseases and bioterrorism. The definition has sometimes been broadened to embrace other concepts, and it is used for different purposes in different contexts.

The COVID-19 pandemic is a recent example of a threat for which biosecurity measures have been needed in all countries of the world.

Rickettsia typhi is a small, aerobic, obligate intracellular, rod shaped gram negative bacterium. It belongs to the typhus group of the Rickettsia genus, along with R. prowazekii. R. typhi has an uncertain history, as it may have long gone shadowed by epidemic typhus (R. prowazekii). This bacterium is recognized as a biocontainment level 2/3 organism. R. typhi is a flea-borne disease that is best known to be the causative agent for the disease murine typhus, which is an endemic typhus in humans that is distributed worldwide. As with all rickettsial organisms, R. typhi is a zoonotic agent that causes the disease murine typhus, displaying non-specific mild symptoms of fevers, headaches, pains and rashes. There are two cycles of R. typhi transmission from animal reservoirs containing R. typhi to humans: a classic rat-flea-rat cycle that is most well studied and common, and a secondary periodomestic cycle that could involve cats, dogs, opossums, sheep, and their fleas.

R. typhi was once one of the most prevalent causes of rickettsial diseases worldwide, but has since experienced a drop in case reports with the implementation of pest control programs. The microorganism is concentrated in warmer climate and coastal ports where there is an abundance of rats and their fleas, which are the preferred hosts for the pathogen. R. typhi  is transmitted between competent flea and mammalian hosts through flea bites and contact with infected feces and tissues.

A biosafety level (BSL), or pathogen/protection level, is a set of biocontainment precautions required to isolate dangerous biological agents in an enclosed laboratory facility. The levels of containment range from the lowest biosafety level 1 (BSL-1) to the highest at level 4 (BSL-4). In the United States, the Centers for Disease Control and Prevention (CDC) have specified these levels in a publication referred to as Biosafety in Microbiological and Biomedical Laboratories (BMBL). In the European Union (EU), the same biosafety levels are defined in a directive. In Canada the four levels are known as Containment Levels. Facilities with these designations are also sometimes given as P1 through P4 (for pathogen or protection level), as in the term P3 laboratory.

At the lowest level of biosafety, precautions may consist of regular hand-washing and minimal protective equipment. At higher biosafety levels, precautions may include airflow systems, multiple containment rooms, sealed containers, positive pressure personnel suits, established protocols for all procedures, extensive personnel training, and high levels of security to control access to the facility. Health Canada reports that world-wide until 1999 there were recorded over 5,000 cases of accidental laboratory infections and 190 deaths.