Coxiella burnetii, A Neglected Infectious Bacterium of Global Distribution

Coxiella burnetii is an obligate intracellular bacterium of worldwide distribution, which results in a highly infectious zoonotic disease known as Q fever or coxiellosis in a wide range scale of hosts including domestic and wild ruminants, birds, murine animals, and arthropods as well as humans. Among domestic ruminants, cattle, sheep and goats are the major reservoirs for the pathogen; and frequently, human outbreaks of Q fever are related to domestic animals. Under farm conditions, C. burnetii is extremely resistant to environmental conditions, and this ability to withstand harsh conditions explains its potential capability to cause severe disease in human and to be deemed as one of the biological terrorist agent. Uterus and mammary glands are the primary sites of infection, particularly in chronic phase, and the shedding of C. burnetii to environment occurs mainly by birth products during parturition, milk, urine, faeces, semen, and inhalation. In recent years, C. burnetii appears to be endemic in several countries worldwide resulting in severe economic losses in animals and extensive health impacts in human. Therefore, further investigations in the field of human and different animals are highly recommended to providing additional recent information about the extension of C. burnetii, and the role of the pathogen in different infections in both domestic and wild animals and humans to develop new active schedules for control and preventing its spreading.