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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.
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BACKGROUND: While Latin America has been heavily affected by the pandemic, only a few seroprevalence studies have been conducted there during the first epidemic wave in the first half of 2020. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional survey was performed between 15 July 2020 and 23 July 2020 among individuals who visited 4 medical laboratories or 5 health centers for routine screening or clinical management, with the exception of symptomatic suggestive cases of covid-19. Samples were screened for the presence of anti-SARS-CoV-2 IgG directed against domain S1 of the SARS-CoV-2 spike protein using the anti-SARS-CoV-2 enzyme-linked immunosorbent assay (ELISA) from Euroimmun. CONCLUSIONS/SIGNIFICANCE: The overall seroprevalence was 15.4% [9.3%-24.4%] among 480 participants, ranging from 4.0% to 25.5% across the different municipalities. The seroprevalence did not differ according to gender (p = 0.19) or age (p = 0.51). Among SARS-CoV-2 positive individuals, we found that 24.6% [11.5%-45.2%] reported symptoms consistent with COVID-19. Our findings revealed high levels of infection across the territory but a low number of resulting deaths, which can be explained by French Guiana's young population structure.
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Anticorpos Antivirais/sangue , COVID-19/epidemiologia , Imunoglobulina G/sangue , SARS-CoV-2/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Estudos Transversais , Guiana Francesa/epidemiologia , Humanos , Lactente , Pessoa de Meia-Idade , Estudos Soroepidemiológicos , Adulto JovemRESUMO
Serological surveys are essential to quantify immunity in a population but serological cross-reactivity often impairs estimates of the seroprevalence. Here, we show that modeling helps addressing this key challenge by considering the important cross-reactivity between Chikungunya (CHIKV) and O'nyong-nyong virus (ONNV) as a case study. We develop a statistical model to assess the epidemiology of these viruses in Mali. We additionally calibrate the model with paired virus neutralization titers in the French West Indies, a region with known CHIKV circulation but no ONNV. In Mali, the model estimate of ONNV and CHIKV prevalence is 30% and 13%, respectively, versus 27% and 2% in non-adjusted estimates. While a CHIKV infection induces an ONNV response in 80% of cases, an ONNV infection leads to a cross-reactive CHIKV response in only 22% of cases. Our study shows the importance of conducting serological assays on multiple cross-reactive pathogens to estimate levels of virus circulation.
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Algoritmos , Febre de Chikungunya/imunologia , Vírus Chikungunya/imunologia , Reações Cruzadas/imunologia , Modelos Estatísticos , Vírus O'nyong-nyong/imunologia , Febre de Chikungunya/diagnóstico , Febre de Chikungunya/epidemiologia , Vírus Chikungunya/fisiologia , Humanos , Mali/epidemiologia , Martinica/epidemiologia , Vírus O'nyong-nyong/fisiologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estudos SoroepidemiológicosRESUMO
Despite the health, social and economic impact of arboviruses in French Guiana, very little is known about the extent to which infection burden is shared between individuals. We conducted a large multiplexed serological survey among 2697 individuals from June to October 2017. All serum samples were tested for IgG antibodies against DENV, CHIKV, ZIKV and MAYV using a recombinant antigen-based microsphere immunoassay with a subset further evaluated through anti-ZIKV microneutralization tests. The overall DENV seroprevalence was estimated at 73.1% (70.6-75.4) in the whole territory with estimations by serotype at 68.9% for DENV-1, 38.8% for DENV-2, 42.3% for DENV-3, and 56.1% for DENV-4. The overall seroprevalence of CHIKV, ZIKV and MAYV antibodies was 20.3% (17.7-23.1), 23.3% (20.9-25.9) and 3.3% (2.7-4.1), respectively. We provide a consistent overview of the burden of emerging arboviruses in French Guiana, with useful findings for risk mapping, future prevention and control programs. The majority of the population remains susceptible to CHIKV and ZIKV, which could potentially facilitate the risk of further re-emergences. Our results underscore the need to strengthen MAYV surveillance in order to rapidly detect any substantial changes in MAYV circulation patterns.
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Anticorpos Antivirais/sangue , Infecções por Arbovirus/epidemiologia , Infecções por Arbovirus/imunologia , Arbovírus/genética , Arbovírus/imunologia , Adolescente , Adulto , Idoso , Infecções por Arbovirus/classificação , Arbovírus/classificação , Arbovírus/patogenicidade , Criança , Pré-Escolar , Efeitos Psicossociais da Doença , Estudos Transversais , Demografia , Feminino , Guiana Francesa/epidemiologia , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Soroepidemiológicos , Adulto JovemRESUMO
While general lockdowns have proven effective to control SARS-CoV-2 epidemics, they come with enormous costs for society. It is therefore essential to identify control strategies with lower social and economic impact. Here, we report and evaluate the control strategy implemented during a large SARS-CoV-2 epidemic in June-July 2020 in French Guiana that relied on curfews, targeted lockdowns, and other measures. We find that the combination of these interventions coincided with a reduction in the basic reproduction number of SARS-CoV-2 from 1.7 to 1.1, which was sufficient to avoid hospital saturation. We estimate that thanks to the young demographics, the risk of hospitalisation following infection was 0.3 times that of metropolitan France and that about 20% of the population was infected by July. Our model projections are consistent with a recent seroprevalence study. The study showcases how mathematical modelling can be used to support healthcare planning in a context of high uncertainty.
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COVID-19/prevenção & controle , COVID-19/transmissão , Pandemias , Quarentena/métodos , SARS-CoV-2 , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Número Básico de Reprodução/prevenção & controle , Número Básico de Reprodução/estatística & dados numéricos , COVID-19/epidemiologia , Criança , Pré-Escolar , Feminino , Guiana Francesa/epidemiologia , Hospitalização/estatística & dados numéricos , Hospitalização/tendências , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Pandemias/prevenção & controle , Pandemias/estatística & dados numéricos , Quarentena/estatística & dados numéricos , Quarentena/tendências , Adulto JovemRESUMO
Characterizing the circulation of Mayaro virus (MAYV), an emerging arbovirus threat, is essential for risk assessment but challenging due to cross-reactivity with other alphaviruses such as chikungunya virus (CHIKV). Here, we develop an analytical framework to jointly assess MAYV epidemiology and the extent of cross-reactivity with CHIKV from serological data collected throughout French Guiana (N = 2697). We find strong evidence of an important sylvatic cycle for MAYV with most infections occurring near the natural reservoir in rural areas and in individuals more likely to go to the forest (i.e., adult males) and with seroprevalences of up to 18% in some areas. These findings highlight the need to strengthen MAYV surveillance in the region and showcase how modeling can improve interpretation of cross-reacting assays.
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Infecções por Alphavirus/epidemiologia , Arbovírus/isolamento & purificação , Vírus Chikungunya/imunologia , Doenças Transmissíveis Emergentes/epidemiologia , Monitoramento Epidemiológico , Adolescente , Adulto , Infecções por Alphavirus/sangue , Infecções por Alphavirus/imunologia , Infecções por Alphavirus/virologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Arbovírus/imunologia , Criança , Pré-Escolar , Doenças Transmissíveis Emergentes/sangue , Doenças Transmissíveis Emergentes/imunologia , Doenças Transmissíveis Emergentes/virologia , Reações Cruzadas/imunologia , Estudos Transversais , Feminino , Guiana Francesa/epidemiologia , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Lactente , Masculino , Pessoa de Meia-Idade , Saúde da População Rural/estatística & dados numéricos , Estudos Soroepidemiológicos , Adulto JovemRESUMO
BACKGROUND: Since the identification of Zika virus (ZIKV) in Brazil in May 2015, the virus has spread throughout the Americas. However, ZIKV burden in the general population in affected countries remains unknown. METHODS: We conducted a general population survey in the different communities of French Guiana through individual interviews and serologic survey during June-October 2017. All serum samples were tested for anti-ZIKV immunoglobulin G antibodies using a recombinant antigen-based SGERPAxMap microsphere immunoassay, and some of them were further evaluated through anti-ZIKV microneutralization tests. RESULTS: The overall seroprevalence was estimated at 23.3% (95% confidence interval [CI], 20.9%-25.9%) among 2697 participants, varying from 0% to 45.6% according to municipalities. ZIKV circulated in a large majority of French Guiana but not in the most isolated forest areas. The proportion of reported symptomatic Zika infection was estimated at 25.5% (95% CI, 20.3%-31.4%) in individuals who tested positive for ZIKV. CONCLUSIONS: This study described a large-scale representative ZIKV seroprevalence study in South America from the recent 2015-2016 Zika epidemic. Our findings reveal that the majority of the population remains susceptible to ZIKV, which could potentially allow future reintroductions of the virus.
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Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologia , Zika virus , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Doenças Transmissíveis Emergentes/diagnóstico , Doenças Transmissíveis Emergentes/imunologia , Estudos Transversais , Feminino , Guiana Francesa/epidemiologia , Geografia Médica , Humanos , Masculino , Pessoa de Meia-Idade , Vigilância da População , Estudos Soroepidemiológicos , Testes Sorológicos , Adulto Jovem , Zika virus/imunologia , Infecção por Zika virus/diagnóstico , Infecção por Zika virus/imunologiaRESUMO
Dengue continues to be the most important vector-borne viral disease globally and in Brazil, where more than 1.4 million cases and over 500 deaths were reported in 2016. Mosquito control programmes and other interventions have not stopped the alarming trend of increasingly large epidemics in the past few years. Here, we analyzed monthly dengue cases reported in Brazil between 2001 and 2016 to better characterise the key drivers of dengue epidemics. Spatio-temporal analysis revealed recurring travelling waves of disease occurrence. Using wavelet methods, we characterised the average seasonal pattern of dengue in Brazil, which starts in the western states of Acre and Rondônia, then travels eastward to the coast before reaching the northeast of the country. Only two states in the north of Brazil (Roraima and Amapá) did not follow the countrywide pattern and had inconsistent timing of dengue epidemics throughout the study period. We also explored epidemic synchrony and timing of annual dengue cycles in Brazilian regions. Using gravity style models combined with climate factors, we showed that both human mobility and vector ecology contribute to spatial patterns of dengue occurrence. This study offers a characterization of the spatial dynamics of dengue in Brazil and its drivers, which could inform intervention strategies against dengue and other arboviruses.
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Dengue/epidemiologia , Epidemias , Estações do Ano , Viagem , Brasil/epidemiologia , Humanos , Modelos Lineares , Controle de Mosquitos , Periodicidade , Análise Espaço-TemporalRESUMO
Since 2015, Zika virus (ZIKV) has caused large epidemics in the Americas. Households are natural targets for control interventions, but quantification of the contribution of household transmission to overall spread is needed to guide policy. We developed a modeling framework to evaluate this contribution and key epidemic features of the ZIKV epidemic in Martinique in 2015-2016 from the joint analysis of a household transmission study (n = 68 households), a study among symptomatic pregnant women (n = 281), and seroprevalence surveys of blood donors (n = 457). We estimated that the probability of mosquito-mediated within-household transmission (from an infected member to a susceptible one) was 21% (95% credible interval (CrI): 5, 51), and the overall probability of infection from outside the household (i.e., in the community) was 39% (95% CrI: 27, 50). Overall, 50% (95% CrI: 43, 58) of the population was infected, with 22% (95% CrI: 5, 46) of infections acquired in households and 40% (95% CrI: 23, 56) being asymptomatic. The probability of presenting with Zika-like symptoms due to another cause was 16% (95% CrI: 10, 23). This study characterized the contribution of household transmission in ZIKV epidemics, demonstrating the benefits of integrating multiple data sets to gain more insight into epidemic dynamics.