Is Q Fever an emerging or re-emerging zoonosis?

Abstract

-Q fever is a zoonotic disease considered as emerging or re-emerging in many countries. It is caused by Coxiella burnetii, a bacterium developing spore-like forms that are highly resistant to the environment. The most common animal reservoirs are livestock and the main source of infection is by inhalation of contaminated aerosols. Although the culture process for Coxiella is laborious, advances on the knowledge of the life cycle of the bacterium have been made. New tools have been developed to (i) improve the diagnosis of Q fever in humans and animals, and especially animal shedders, (ii) perform epidemiological studies, and (iii) prevent the disease through the use of vaccines. This review summarizes the state of the knowledge on the bacteriology and clinical manifestations of Q fever as well as its diagnosis, epidemiology, treatment and prevention in order to understand what factors are responsible for its emergence or re-emergence. Coxiella burnetii / epidemiology / bacteriology / diagnostic / control

Association betweenCoxiella burnetii shedding in milkand subclinical mastitis in dairy cattle

“…Coxiella burnetii is an obligate intracellular zoonotic pathogen and the etiologic agent of Q fever in humans [1,[17][18][19]. Domestic ruminants (cattle, sheep, and goats) are described as the primary reservoir species for exposure of humans [1,[17][18][19].…”

“…Domestic ruminants (cattle, sheep, and goats) are described as the primary reservoir species for exposure of humans [1,[17][18][19]. In dairy cattle C. burnetii infections may be underrecognized [19,20] and there is incomplete understanding of infection dynamics and disease manifestations.…”

“…In the United States there are currently no approved C. burnetii are inconsistent [8,15,24]. In past studies, a major limitation may have been the reliance on serology to define C. burnetii infection status, as serology is poor indicator of active C. burnetii shedding in individual animals [1,5,6,9,18]. Classically, confirmation of active infection in cattle required isolation of the organism either by laboratory animal or cell culture inoculation [1,4,7,13,16], and currently few laboratories carry out isolation due to legal limitations, risk of human exposure, and lack of sensitivity of the technique [1,9,18].…”

“…In past studies, a major limitation may have been the reliance on serology to define C. burnetii infection status, as serology is poor indicator of active C. burnetii shedding in individual animals [1,5,6,9,18]. Classically, confirmation of active infection in cattle required isolation of the organism either by laboratory animal or cell culture inoculation [1,4,7,13,16], and currently few laboratories carry out isolation due to legal limitations, risk of human exposure, and lack of sensitivity of the technique [1,9,18]. A small number of recent studies have described PCR-based DNA detection to identify shedding of C. burnetii in ruminants, including dairy cattle with reproductive disorders [5,6,9,24].…”

“…While C. burnetii is shed for extended periods in the milk of dairy cattle, and has been shown to be immunogenic in dairy cattle, potential associations with clinical or subclinical mastitis have only rarely been examined [1,4,7,13,17,18]. In reviews of mastitis etiologies, most authors recognize the potential public health significance of C. burnetii excretion in milk without describing the organism as a cause of mastitis [10,22].…”