Q Fever in French Guiana: Tip of the Iceberg or Epidemiological Exception?

Abstract

Q fever is a cosmopolitan zoonosis caused by an intracellular bacterium, Coxiella burnetii. Since its discovery in 1935 in Australia, its presence has been reported almost worldwide in animals and humans [1]. In most developed countries, this infection has been widely described, and its life cycle, exposure factors, and clinical and biological pictures are well known. The incidence of Q fever is generally quite low, and most of the cases are diagnosed during short outbreaks related to direct or indirect contact of humans with cattle, sheep, or goats, which are the main reservoirs. In developing countries, information on endemicity is generally scarce and limited to seroprevalence studies in exposed populations or case reports. This presumably reflects misdiagnosis, rather than lower incidence. The diagnosis of acute Q fever mostly relies on the elevation of anti-C. burnetii antibodies by 15 to 21 days after the onset of the symptoms, detected by Immunofluorescence Assay, which is the gold standard for C. burnetii detection. However, these diagnostic techniques are often not available in tropical areas and, apparently, in numerous Latin American settings. Indeed, an exhaustive review of the literature in English, French, Spanish, and Portuguese showed that publications on Q fever in Latin America are scarce despite the worldwide presence of the disease (Table 1). Seven countries have never reported any cases of Q fever according to the available literature (Belize, Costa Rica, Guatemala, Guyana, Honduras, Paraguay, Suriname); three haven't reported any since 1990, but some older studies do exist (Bolivia, Pan-ama, Venezuela); seven countries reported one or two publications since 1990 (Argentina, Chile, Ecuador, El Salvador, Peru, Trinidad, Uruguay); and Colombia, Mexico, and Brazil published several publications, including mostly case reports of chronic Q fever, one case of acute Q fever, several seroprevalence studies in exposed populations, and some studies based on an acute febrile or acute respiratory syndrome approach. Recently, Q fever was confirmed in patients and animals in parts of the Brazilian Atlantic Forest. Thus, there are no publications on Q fever in the Amazon region except in French Guiana and Ecuador.