Q fever is a zoonotic disease caused by Coxiella burnetii, an intracellular gamma-proteobacteria that occurs worldwide causing a broad spectrum of clinical manifestations ranging from asymptomatic to severe and fatal infections in humans. Although C. burnetii is ubiquitously distributed, magnitudes, and risks of infection are not homogeneous.1, 2, 3 In Latin America Q fever has been neglected in most countries and reports are inconstant and sparse, with cases described in Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Panama, El Salvador, Mexico, Peru, Trinidad, Uruguay and Venezuela.4 Interestingly, C. burnetii is among the major agents of community-acquired pneumonia in French Guiana, the country with the highest reported incidence rates of Q fever of the world.4, 5, 6, 7
In The Lancet Regional Health – Americas, Bailly et al.7 addressed an intriguing question, that despite its relatively high incidence of Q fever, the epidemiology in the Guianese territory remains unclear. In addition to suggesting wild animals from Amazon rainforest as the main source of human infections in the region, the authors also identified factors not usually associated with Q fever, such as living near the forest, presence of wild animals near the house and gardening.4, 5, 6 A distinct scenario of what is reported from the rest the world, where Q fever is related to livestock.1,3
Conducting a general population survey with over 2.697 individuals, combining ELISA and IFA tests, and using a serocatlytic models to assess the characteristics of Q fever in French Guiana, Bailly et al.7 demonstrated an overall seroprevalence of 9.6% (95% CI: 8.3–11.0), with atypical prevalence profile in the municipalities of Rémire and Matoury. The risk rate of Q fever exposure increased with proximity to a sheep farm, especially for those individuals living within 2–5 km. Although the role that wild animals play in the enzootic cycle of C. burnetii in French Guiana cannot be underestimated, the identification of proximity to livestock as an important risk factor in Guianese territory, consistent with other parts of the world, shows how the epidemiology of C. burnetii is highly complex and multifaceted.4,5
The hyperendemicity of Q fever in French Guiana, with an overall incidence of 223/100,000 (95% CrI: 189/100,000–258/100,000) is still more evident when compared with the absence of information about C. burnetii in most countries of Latin America, especially those on Amazonian region of the Guiana Shield.6, 7, 8 Since there is a great overlap between the geography, climate, health, richness in this region it is reasonable to assume that the lack of recognition of C. burnetii infection in many Latin American countries is not the prove of its nonexistence, but rather an absence of clinical suspicion and the lack of availability of specific tests, and few well-founded research and epidemiological surveillance.6,9
Q fever is still an invisible zoonosis in most countries making it difficult to fill the puzzle with only few pieces on the board. Despite the limitations inherent to the study design, also considering the lack of information regarding the estimation base used to define the sample size and the possibility of an inadequate interpretation of the serological results, due to cross-reaction (Bartonella and Legionella, for example), Bailly et al. point to the need for future studies that consider the interaction between the environment, humans, domestic and wild animals, requiring researchers, health professionals and police officers to implement One Health surveillance activities, paving the way for future research aiming an understand of the heterogeneous Q fever eco-epidemiological profiles in Latin America.6, 7, 8, 9, 10
In this sense, studies must be multidisciplinary, requiring an effective integration between surveillance activities in the field of human, animal and environmental health, in the context of One Health, investments in key components, such as laboratory and epidemiological experience, availability of diagnosis and awareness of professionals and veterinarians for a better understanding of Q fever. Investigation based on differential diagnostic, using molecular analysis and genetic characterization of agent in areas with reported cases of animals with reproductive disorders need to be encouraged, as this could provide robust and irrefutable information about the transmission dynamics in the different regions of the Latin America. In conclusion, only with a holistic approach will it be possible to provide the basis for understanding the dynamics of C burnetii infection in the human population and in domestic and wild animals, with a view to implementing strategies for the prevention and control of Q fever and coxiellosis in countries Latin Americans.
Contributors
Both the authors contributed equally to the article.
Declaration of interests
The authors declared no conflicts of interest.
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