Occupational Exposure to Coxiella burnetii (Q fever) in the Agriculture and Food Sector ACDP/85/P8

2. Coxiella burnetii is the causative agent of Q fever (Annex 1). C. burnetii are obligate intracellular gram-negative bacteria, which replicate as large-cell variants in the phagolysosome of infected mammalian cells. The bacteria also exist as smallcell variants and small dense cells (SDC), the latter of which have a greater physical stability (related to heat, pressure and chemical agents) and are believed to be the persistant forms in the host and environment. The SDC variants are believed to survive extracellularly as infectious particles for ~150 days. C. burnetii has two antigenic states, which differ in the structure of their lipopolysaccharide (i.e. infectious phase I bacteria (complete LPS) and avirulent phase II bacteria (truncated LPS)).