Q fever in French Guiana: new trends

Effects of cattle on vector-borne disease risk to humans: A systematic review

Vector-borne pathogens (VBPs) causing vector-borne diseases (VBDs) can circulate among humans, domestic animals, and wildlife, with cattle in particular serving as an important source of exposure risk to humans. The close associations between humans and cattle can facilitate the transmission of numerous VBPs, impacting public health and economic security. Published studies demonstrate that cattle can influence human exposure risk positively, negatively, or have no effect. There is a critical need to synthesize the information in the scientific literature on this subject, in order to illuminate the various ecological mechanisms that can affect VBP exposure risk in humans. Therefore, the aim of this systematic review was to review the scientific literature, provide a synthesis of the possible effects of cattle on VBP risk to humans, and propose future directions for research. This study was performed according to the PRISMA 2020 extension guidelines for systematic review. After screening 470 peer-reviewed articles published between 1999-2019 using the databases Web of Science Core Collection, PubMed Central, CABI Global Health, and Google Scholar, and utilizing forward and backward search techniques, we identified 127 papers that met inclusion criteria. Results of the systematic review indicate that cattle can be beneficial or harmful to human health with respect to VBDs depending on vector and pathogen ecology and livestock management practices. Cattle can increase risk of exposure to infections spread by tsetse flies and ticks, followed by sandflies and mosquitoes, through a variety of mechanisms. However, cattle can have a protective effect when the vector prefers to feed on cattle instead of humans and when chemical control measures (e.g., acaricides/insecticides), semio-chemicals, and other integrated vector control measures are utilized in the community. We highlight that further research is needed to determine ways in which these mechanisms may be exploited to reduce VBD risk in humans.

Transmission dynamics of Q fever in French Guiana: A population-based cross-sectional study

Background

Q fever is a zoonosis caused by Coxiella burnetii which is among the major agents of community-acquired pneumonia in French Guiana. Despite its relatively high incidence, its epidemiology in French Guiana remains unclear, and all previous studies have considered transmission from livestock unlikely, suggesting that a wild reservoir is responsible for transmission.

Methods

A country-wide seroprevalence survey of 2697 participants from French Guiana was conducted. Serum samples were tested for phase II IgG antibodies by ELISA and indirect immunofluorescence assays (IFAs). Factors associated with Q fever were investigated, and a serocatalytic model was used to reconstruct the annual force of infection.

Findings

The overall weighted seroprevalence was estimated at 9.6% (95% confidence interval (CI): 8.2%-11.0%). The model revealed constant, low-level circulation across French Guiana, particularly affecting middle-aged males (odds ratio (OR): 3.0, 95% credible interval (CrI): 1.7-5.8) and individuals living close to sheep farms (OR: 4, 95% CrI: 1.5-12). The overall annual number of cases was estimated at 579 (95% CrI: 492-670). In the region around Cayenne, the main urban municipality, the high seroprevalence was explained by an outbreak that may have occurred between 1996 and 2003 and that infected 10% (95% CrI: 6.9%-14%) of the population and males and females alike.

Interpretation

This study reveals for the first time Q fever dynamics of transmission and the role of domestic livestock in transmission in French Guiana and highlights the urgent need to reinforce Q fever surveillance in livestocks of the entire Guianese territory.

Funding

This study was supported by the "European Regional Development Fund" under EPI-ARBO grant agreement (GY0008695), the "Regional Health Agency of French Guiana" and the "National Center of Spatial Studies". The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

High endemicity of Q fever in French Guiana: A cross sectional study (2007–2017)

Q fever (QF) is a zoonosis caused by Coxiella burnetii (Cb). French Guiana (FG) had a high incidence but no data have been published since 2006. The objective of this study was to update the incidence and epidemiological data on QF in FG. A retrospective study of all FG Q fever serodiagnosis between 2007 and 2017 was carried out. Among the 695 patients included, the M/F sex-ratio was 2.0 and the median age of 45.3 years (IQR 33.7–56.3). The annual QF incidence rate was 27.4 cases (95%CI: 7.1–47.7) per 100,000 inhabitants ranging from 5.2 in 2007 to 40.4 in 2010. Risk factors associated with Q fever compared to general population were male gender, being born in mainland France, an age between 30 to 59 years-old and a residence in Cayenne and surroundings. The incidence of QF in FG remains high and stable and the highest in the world.

We present here a study showing the exceptional nature of the incidence of Q fever in French Guiana. Indeed, this zoonosis due to the bacterium Coxiella burnetii, is a real public health problem in French Guiana, a French ultra-marine territory located in the North East of South America. The study found an endemic state with a stable incidence between 2010 and 2017 around 25–30 cases per 100,000 inhabitants per year. More than 90% of cases are concentrated in the territory’s capital, Cayenne, and its surroundings. The risk factors for Q fever are being male, being between 30 and 59 years old, which are risk factors found elsewhere, but also living in Cayenne and its surroundings and being born in mainland France or Europe.

Capybara and Brush Cutter Involvement in Q Fever Outbreak in Remote Area of Amazon Rain Forest, French Guiana, 2014

We investigated a Q fever outbreak that occurred in an isolated area of the Amazon Rain Forest in French Guiana in 2014. Capybara fecal samples were positive for Coxiella burnetii DNA. Being near brush cutters in use was associated with disease development. Capybaras are a putative reservoir for C. burnetii.

Human Q Fever on the Guiana Shield and Brazil: Recent Findings and Remaining Questions

Purpose of Review

In this review, we report on the state of knowledge about human Q fever in Brazil and on the Guiana Shield, an Amazonian region located in northeastern South America. There is a contrast between French Guiana, where the incidence of this disease is the highest in the world, and other countries where this disease is practically non-existent.

Recent Findings

Recent findings are essentially in French Guiana where a unique strain MST17 has been identified; it is probably more virulent than those usually found with a particularly marked pulmonary tropism, a mysterious animal reservoir, a geographical distribution that raises questions.

Summary

Q fever is a bacterial zoonosis due to Coxiella burnetii that has been reported worldwide. On the Guiana Shield, a region mostly covered by Amazonian forest, which encompasses the Venezuelan State of Bolivar, Guyana, Suriname, French Guiana, and the Brazilian State of Amapá, the situation is very heterogeneous. While French Guiana is the region reporting the highest incidence of this disease in the world, with a single infecting clone (MST 117) and a unique epidemiological cycle, it has hardly ever been reported in other countries in the region. This absence of cases raises many questions and is probably due to massive under-diagnosis. Studies should estimate comprehensively the true burden of this disease in the region.

Q fever epidemic in Cayenne, French Guiana, epidemiologically linked to three-toed sloth

A Q fever epidemic occurred in 2013 in a small military residential area in Cayenne, French Guiana. A retrospective cohort study was conducted to identify Q fever risk factors. Confirmed acute Q fever case was defined as positive serology (IgM ≥ 50 and phase II IgG ≥ 200) and/or positive qPCR on serum or blood. In addition, wild mammals were captured at the study site and tested by serology and real-time PCR performed on blood, vaginal swabs and ticks. The attack rate was 20 percent (11/54). All the cases were symptomatic with fever >38.5 °C and community-acquired pneumonia for four cases. Log binomial multivariate models identified two independent risk factors associated with Q fever: to clean the house (RRa = 7.5 CI95% [1.03-55.3]) and to carry a three-toed sloth in arms (RRa = 2.6 CI95% [1.1-5.8]). Eighteen marsupial individuals were captured, all PCRs were negative but 17% (3/18) had a positive serology. Another study conducted after the epidemic found only one (1/4) three-tooth sloth (Bradypus tridactylus) with feces highly infectious for C. burnetii MST17. The same strain C. burnetii genotype 17 has been laboratory- confirmed in this mammal and in human cases. These results support the implication of three-toed-sloth in this epidemic. Human contamination mainly occurs through inhalation of infectious aerosols as suggested by high relative risk associated with house cleaning activities and pulmonary forms of the disease, and through direct contact with three- toed-sloth. Positive serological results among marsupials confirm wildlife exposure and suggest a more complex sylvatic transmission cycle among wild mammals.

The contribution of genomics to the study of Q fever

Coxiella burnetii is the etiological agent of Q fever, a worldwide zoonosis that can result in large outbreaks. The birth of genomics and sequencing of C. burnetii strains has revolutionized many fields of study of this infection. Accurate genotyping methods and comparative genomic analysis have enabled description of the diversity of strains around the world and their link with pathogenicity. Genomics has also permitted the development of qPCR tools and axenic culture medium, facilitating the diagnosis of Q fever. Moreover, several pathophysiological mechanisms can now be predicted and therapeutic strategies can be determined thanks to in silico genome analysis. An extensive pan-genomic analysis will allow for a comprehensive view of the clonal diversity of C. burnetii and its link with virulence.

Q fever in French Guiana

Coxiella burnetii, the causative agent of Q fever, is present worldwide. Recent studies have shown that this bacterium is an emerging pathogen in French Guiana and has a high prevalence (24% of community-acquired pneumonia). In this review, we focus on the peculiar epidemiology of Q fever in French Guiana. We place it in the context of the epidemiology of the disease in the surrounding countries of South America. We also review the clinical features of Q fever in this region, which has severe initial presentation but low mortality rates. These characteristics seem to be linked to a unique genotype (genotype 17). Finally, we discuss the issue of the animal reservoir of C. burnetii in French Guiana, which is still unknown. Further studies are necessary to identify this reservoir. Identification of this reservoir will improve the understanding of the Q fever epidemic in French Guiana and will provide new tools to control this public health problem.

Comparison between emerging Q fever in French Guiana and endemic Q fever in Marseille, France

Q fever is an emergent disease in French Guiana. We compared the incidence clinical and serologic profiles between patients from Cayenne, French Guiana and Marseille in metropolitan France during a four-year period. The annual incidence of diagnosed acute Q fever was significantly higher in Cayenne (17.5/100,000) than in Marseille (1.9/100,000) (P = 0.0004), but not the annual incidence of endocarditis (1.29 versus 0.34/100,000). Most patients had fever (97%) and pneumonia (83%) in Cayenne versus 81% and 8% in Marseille (P < 0.0001 and P < 0.0001, respectively) but transaminitis was more common in patients from Marseille (54% versus 32%; P < 0.0001). The proportion of patients with cardiovascular infections was significantly lower in Cayenne (7%) than in Marseille (17%) (P = 0.017), although they showed a stronger immune response with higher levels of phase I IgG (P = 0.024). The differing epidemiology, clinical, and serologic responses of patients from Cayenne and Marseille suggest a different source of infection and a different strain of Coxiella burnetii.

Unique clone of Coxiella burnetii causing severe Q fever, French Guiana

Acute Q fever is an emergent and severe disease in French Guiana. We obtained 5 Coxiella burnetii isolates from samples of patients from Cayenne and found an epidemic clone circulating in Cayenne. This clone has caused pneumonia and endocarditis and seems to be more virulent than previously described strains.

Serologic detection of a rare case of Q fever in New York City having hepatic and unusual renal complications

We describe the case of a 46-year-old resident of New York City with a one-year history of frequent urination and 3 weeks of undulating fevers. He also had liver and bone marrow abnormalities where a non-culturable Gram-negative rod was identified. Q fever was suspected and confirmed based on highly elevated phase I and II serum IgM/IgG antibodies against Coxiella burnetii.