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Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has spread globally. However, the contribution of community versus household transmission to the overall risk of infection remains unclear. Methods: Between November 2021 and March 2022, we conducted an active case-finding study in an urban informal settlement with biweekly visits across 1174 households with 3364 residents. Individuals displaying coronavirus disease 2019 (COVID-19)-related symptoms were identified, interviewed along with household contacts, and defined as index and secondary cases based on reverse-transcription polymerase chain reaction (RT-PCR) and symptom onset. Results: In 61 households, we detected a total of 94 RT-PCR-positive cases. Of 69 sequenced samples, 67 cases (97.1%) were attributed to the Omicron BA.1* variant. Among 35 of their households, the secondary attack rate was 50.0% (95% confidence interval [CI], 37.0%-63.0%). Women (relative risk [RR], 1.6 [95% CI, .9-2.7]), older individuals (median difference, 15 [95% CI, 2-21] years), and those reporting symptoms (RR, 1.73 [95% CI, 1.0-3.0]) had a significantly increased risk for SARS-CoV-2 secondary infection. Genomic analysis revealed substantial acquisition of viruses from the community even among households with other SARS-CoV-2 infections. After excluding community acquisition, we estimated a household secondary attack rate of 24.2% (95% CI, 11.9%-40.9%). Conclusions: These findings underscore the ongoing risk of community acquisition of SARS-CoV-2 among households with current infections. The observed high attack rate necessitates swift booster vaccination, rapid testing availability, and therapeutic options to mitigate the severe outcomes of COVID-19.
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To evaluate whether oral fluids (OF) and urine can serve as alternative, non-invasive samples to diagnose chikungunya virus (CHIKV) infection via RT-qPCR, we employed the same RNA extraction and RT-qPCR protocols on paired serum, OF and urine samples collected from 51 patients with chikungunya during the acute phase of the illness. Chikungunya patients were confirmed through RT-qPCR in acute-phase sera (N = 19), IgM seroconversion between acute- and convalescent-phase sera (N = 12), or IgM detection in acute-phase sera (N = 20). The controls included paired serum, OF and urine samples from patients with non-arbovirus acute febrile illness (N = 28) and RT-PCR-confirmed dengue (N = 16). Nine (47%) of the patients with positive RT-qPCR for CHIKV in sera and two (17%) of those with CHIKV infection confirmed solely via IgM seroconversion had OF positive for CHIKV in RT-qPCR. One (5%) patient with CHIKV infection confirmed via serum RT-qPCR was positive in the RT-qPCR performed on urine. None of the negative control group samples were positive. Although OF may serve as an alternative sample for diagnosing acute chikungunya in specific settings, a negative result cannot rule out an infection. Further research is needed to investigate whether OF and urine collected later in the disease course when serum becomes RT-qPCR-negative may be helpful in CHIKV diagnosis and surveillance, as well as to determine whether urine and OF pose any risk of CHIKV transmission.
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Fiebre Chikungunya , Virus Chikungunya , Dengue , Humanos , Virus Chikungunya/genética , ARN Viral/genética , Progresión de la Enfermedad , Inmunoglobulina M , Anticuerpos Antivirales , Dengue/epidemiologíaRESUMEN
BACKGROUND: The first chikungunya virus (CHIKV) outbreaks during the modern scientific era were identified in the Americas in 2013, reaching high attack rates in Caribbean countries. However, few cohort studies have been performed to characterize the initial dynamics of CHIKV transmission in the New World. METHODOLOGY/PRINCIPAL FINDINGS: To describe the dynamics of CHIKV transmission shortly after its introduction in Brazil, we performed semi-annual serosurveys in a long-term community-based cohort of 652 participants aged ≥5 years in Salvador, Brazil, between Feb-Apr/2014 and Nov/2016-Feb/2017. CHIKV infections were detected using an IgG ELISA. Cumulative seroprevalence and seroincidence were estimated and spatial aggregation of cases was investigated. The first CHIKV infections were identified between Feb-Apr/2015 and Aug-Nov/2015 (incidence: 10.7%) and continued to be detected at low incidence in subsequent surveys (1.7% from Aug-Nov/2015 to Mar-May/2016 and 1.2% from Mar-May/2016 to Nov/206-Feb/2017). The cumulative seroprevalence in the last survey reached 13.3%. It was higher among those aged 30-44 and 45-59 years (16.1% and 15.6%, respectively), compared to younger (12.4% and 11.7% in <15 and 15-29 years, respectively) or older (10.3% in ≥60 years) age groups, but the differences were not statistically significant. The cumulative seroprevalence was similar between men (14.7%) and women (12.5%). Yet, among those aged 15-29 years, men were more often infected than women (18.1% vs. 7.4%, respectively, P = 0.01), while for those aged 30-44, a non-significant opposite trend was observed (9.3% vs. 19.0%, respectively, P = 0.12). Three spatial clusters of cases were detected in the study site and an increased likelihood of CHIKV infection was detected among participants who resided with someone with CHIKV IgG antibodies. CONCLUSIONS/SIGNIFICANCE: Unlike observations in other settings, the initial spread of CHIKV in this large urban center was limited and focal in certain areas, leaving a high proportion of the population susceptible to further outbreaks. Additional investigations are needed to elucidate the factors driving CHIKV spread dynamics, including understanding differences with respect to dengue and Zika viruses, in order to guide prevention and control strategies for coping with future outbreaks.
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Fiebre Chikungunya , Virus Chikungunya , Infección por el Virus Zika , Virus Zika , Masculino , Humanos , Femenino , Estudios de Cohortes , Brasil/epidemiología , Estudios Seroepidemiológicos , Anticuerpos Antivirales , Inmunoglobulina GRESUMEN
Dried blood spot (DBS) sampling is a simple, fast, and minimally invasive blood collection method that is particularly useful for diagnostic or epidemiological studies in hard-to-reach populations. Nevertheless, the use of DBS in assays that have been optimized with gold-standard samples (serum or plasma) must be optimized to yield reliable results. Here, we describe the validation of DBS in a commercial assay to measure IgG against chikungunya virus (CHIKV IgG ELISA; Euroimmun, Lübeck, Germany). During a health survey of people experiencing homelessness in Salvador, Brazil, between September 2021 and February 2022, a subset (75/523; 14.3%) of the study participants had paired capillary (for DBS preparation) and venous (for serum separation) blood samples collected. A pilot optimization test was initially performed with 17 paired samples to compare the CHIKV IgG ELISA absorbance values between serum and three different dilutions of DBS. Based on the preliminary results, the best DBS dilution was selected for a final evaluation comparing paired serum and DBS samples from 58 participants. The sensitivity and specificity of the CHIKV ELISA of DBS compared to sera were 100% (95% C.I.: 85.8-100%) and 100% (95% C.I.: 93-100%), respectively. In the linear regression analysis, a coefficient of determination (R2) value of 0.98 indicated the excellent performance of DBS in predicting the serum levels of IgG CHIKV antibodies. Our findings suggest that DBS at an optimized dilution is reliable for investigating the prevalence of CHIKV IgG antibodies during population surveys in the commercial assay tested here.
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Virus Chikungunya , Humanos , Sensibilidad y Especificidad , Ensayo de Inmunoadsorción Enzimática/métodos , Anticuerpos Antivirales , Inmunoglobulina G , Pruebas con Sangre Seca/métodosRESUMEN
BACKGROUND: Chikungunya is associated with high morbidity and the natural history of symptomatic infection has been divided into three phases (acute, post-acute, and chronic) according to the duration of musculoskeletal symptoms. Although this classification has been designed to help guide therapeutic decisions, it does not encompass the complexity of the clinical expression of the disease and does not assist in the evaluation of the prognosis of severity nor chronic disease. Thus, the current challenge is to identify and diagnose musculoskeletal disorders and to provide the optimal treatment in order to prevent perpetuation or progression to a potentially destructive disease course. METHODS: The study is the first product of the Clinical and Applied Research Network in Chikungunya (REPLICK). This is a prospective, outpatient department-based, multicenter cohort study in Brazil. Four work packages were defined: i. Clinical research; ii) Translational Science - comprising immunology and virology streams; iii) Epidemiology and Economics; iv) Therapeutic Response and clinical trials design. Scheduled appointments on days 21 (D21) ± 7 after enrollment, D90 ± 15, D120 ± 30, D180 ± 30; D360 ± 30; D720 ± 60, and D1080 ± 60 days. On these visits a panel of blood tests are collected in addition to the clinical report forms to obtain data on socio-demographic, medical history, physical examination and questionnaires devoted to the evaluation of musculoskeletal manifestations and overall health are performed. Participants are asked to consent for their specimens to be maintained in a biobank. Aliquots of blood, serum, saliva, PAXgene, and when clinically indicated to be examined, synovial fluid, are stored at -80° C. The study protocol was submitted and approved to the National IRB and local IRB at each study site. DISCUSSION: Standardized and harmonized patient cohorts are needed to provide better estimates of chronic arthralgia development, the clinical spectra of acute and chronic disease and investigation of associated risk factors. This study is the largest evaluation of the long-term sequelae of individuals infected with CHIKV in the Brazilian population focusing on musculoskeletal manifestations, mental health, quality of life, and chronic pain. This information will both define disease burden and costs associated with CHIKV infection, and better inform therapeutic guidelines.
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Fiebre Chikungunya , Humanos , Fiebre Chikungunya/diagnóstico , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/terapia , Estudios de Cohortes , Estudios Prospectivos , Calidad de Vida , Enfermedad Crónica , Estudios Multicéntricos como AsuntoRESUMEN
The Americas, particularly Brazil, were greatly impacted by the widespread Zika virus (ZIKV) outbreak in 2015 and 2016. Efforts were made to implement genomic surveillance of ZIKV as part of the public health responses. The accuracy of spatiotemporal reconstructions of the epidemic spread relies on the unbiased sampling of the transmission process. In the early stages of the outbreak, we recruited patients exhibiting clinical symptoms of arbovirus-like infection from Salvador and Campo Formoso, Bahia, in Northeast Brazil. Between May 2015 and June 2016, we identified 21 cases of acute ZIKV infection and subsequently recovered 14 near full-length sequences using the amplicon tiling multiplex approach with nanopore sequencing. We performed a time-calibrated discrete phylogeographic analysis to trace the spread and migration history of the ZIKV. Our phylogenetic analysis supports a consistent relationship between ZIKV migration from Northeast to Southeast Brazil and its subsequent dissemination beyond Brazil. Additionally, our analysis provides insights into the migration of ZIKV from Brazil to Haiti and the role Brazil played in the spread of ZIKV to other countries, such as Singapore, the USA, and the Dominican Republic. The data generated by this study enhances our understanding of ZIKV dynamics and supports the existing knowledge, which can aid in future surveillance efforts against the virus.
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Infección por el Virus Zika , Virus Zika , Humanos , Virus Zika/genética , Brasil/epidemiología , Filogenia , Américas/epidemiologíaRESUMEN
BACKGROUND: Low-income urban communities in the tropics often lack sanitary infrastructure and are overcrowded, favoring Aedes aegypti proliferation and arboviral transmission. However, as Ae. aegypti density is not spatially homogeneous, understanding the role of specific environmental characteristics in determining vector distribution is critical for planning control interventions. The objectives of this study were to identify the main habitat types for Ae. Aegypti, assess their spatial densities to identify major hotspots of arbovirus transmission over time and investigate underlying factors in a low-income urban community in Salvador, Brazil. We also tested the field-collected mosquitoes for arboviruses. METHODS: A series of four entomological and socio-environmental surveys was conducted in a random sample of 149 households and their surroundings between September 2019 and April 2021. The surveys included searching for potential breeding sites (water-containing habitats) and for Ae. aegypti immatures in them, capturing adult mosquitoes and installing ovitraps. The spatial distribution of Ae. aegypti density indices were plotted using kernel density-ratio maps, and the spatial autocorrelation was assessed for each index. Visual differences on the spatial distribution of the Ae. aegypti hotspots were compared over time. The association of entomological findings with socio-ecological characteristics was examined. Pools of female Ae. aegypti were tested for dengue, Zika and chikungunya virus infection. RESULTS: Overall, 316 potential breeding sites were found within the study households and 186 in the surrounding public spaces. Of these, 18 (5.7%) and 7 (3.7%) harbored a total of 595 and 283 Ae. aegypti immatures, respectively. The most productive breeding sites were water storage containers within the households and puddles and waste materials in public areas. Potential breeding sites without cover, surrounded by vegetation and containing organic matter were significantly associated with the presence of immatures, as were households that had water storage containers. None of the entomological indices, whether based on immatures, eggs or adults, detected a consistent pattern of vector clustering in the same areas over time. All the mosquito pools were negative for the tested arboviruses. CONCLUSIONS: This low-income community displayed high diversity of Ae. aegypti habitats and a high degree of heterogeneity of vector abundance in both space and time, a scenario that likely reflects other low-income communities. Improving basic sanitation in low-income urban communities through the regular water supply, proper management of solid wastes and drainage may reduce water storage and the formation of puddles, minimizing opportunities for Ae. aegypti proliferation in such settings.
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Aedes , Fiebre Chikungunya , Virus Chikungunya , Dengue , Infección por el Virus Zika , Virus Zika , Animales , Femenino , Brasil/epidemiología , Mosquitos Vectores , Infección por el Virus Zika/epidemiología , AguaRESUMEN
Reliable and scalable seroepidemiology methods are needed to estimate SARS-CoV-2 incidence and monitor the dynamics of population-level immunity as the pandemic evolves. We aimed to evaluate the reliability of SARS-CoV-2 normalized ELISA optical density (nOD) at a single dilution compared to titers derived from serial dilutions. We conducted serial serosurveys within a community-based cohort in Salvador, Brazil. Anti-S IgG ELISA (Euroimmun AG) was performed with 5 serial 3-fold dilutions of paired sera from 54 participants. Changes in nOD reliably predicted increases and decreases in titers (98.1% agreement, κ = 95.8%). Fitting the relationship between nOD and interpolated titers to a log-log curve yields highly accurate predictions of titers (r2 = 0.995) and changes in titers (r2 = 0.975), using only 1 to 2 dilutions. This approach can significantly reduce the time, labor and resources needed for large-scale serosurveys to ascertain population-level changes in exposure and immunity.
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COVID-19 , SARS-CoV-2 , Humanos , Reproducibilidad de los Resultados , Estudios Seroepidemiológicos , Anticuerpos Antivirales , COVID-19/diagnóstico , Inmunoglobulina GRESUMEN
BACKGROUND: The structural environment of urban slums, including physical, demographic, and socioeconomic attributes, renders inhabitants more vulnerable to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. Yet, little is known about the specific determinants that contribute to high transmission within these communities. We therefore aimed to investigate SARS-CoV-2 seroprevalence in an urban slum in Brazil. METHODS AND FINDINGS: We performed a cross-sectional serosurvey of an established cohort of 2,041 urban slum residents from the city of Salvador, Brazil between November 2020 and February 2021, following the first Coronavirus Disease 2019 (COVID-19) pandemic wave in the country and during the onset of the second wave. The median age in this population was 29 years (interquartile range [IQR] 16 to 44); most participants reported their ethnicity as Black (51.5%) or Brown (41.7%), and 58.5% were female. The median size of participating households was 3 (IQR 2 to 4), with a median daily per capita income of 2.32 (IQR 0.33-5.15) US Dollars. The main outcome measure was presence of IgG against the SARS-CoV-2 spike protein. We implemented multilevel models with random intercepts for each household to estimate seroprevalence and associated risk factors, adjusting for the sensitivity and specificity of the assay, and the age and gender distribution of our study population. We identified high seroprevalence (47.9%, 95% confidence interval [CI] 44.2% to 52.1%), particularly among female residents (50.3% [95% CI 46.3% to 54.8%] versus 44.6% [95% CI 40.1% to 49.4%] among male residents, p < 0.01) and among children (54.4% [95% CI 49.6% to 59.3%] versus 45.4% [95% CI 41.5% to 49.7%] among adults, p < 0.01). Adults residing in households with children were more likely to be seropositive (48.6% [95% CI 44.8% to 52.3%] versus 40.7% [95% CI 37.2% to 44.3%], p < 0.01). Women who were unemployed and living below the poverty threshold (daily per capita household income <$1.25) were more likely to be seropositive compared to men with the same employment and income status (53.9% [95% CI 47.0% to 60.6%] versus 32.9% [95% CI 23.2% to 44.3%], p < 0.01). Participation in the study was voluntary, which may limit the generalizability of our findings. CONCLUSIONS: Prior to the peak of the second wave of the COVID-19 pandemic, cumulative incidence as assessed by serology approached 50% in a Brazilian urban slum population. In contrast to observations from industrialized countries, SARS-CoV-2 incidence was highest among children, as well as women living in extreme poverty. These findings emphasize the need for targeted interventions that provide safe environments for children and mitigate the structural risks posed by crowding and poverty for the most vulnerable residents of urban slum communities.
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COVID-19 , Adulto , Brasil/epidemiología , COVID-19/epidemiología , Niño , Estudios Transversales , Femenino , Humanos , Inmunoglobulina G , Masculino , Pandemias , Áreas de Pobreza , SARS-CoV-2 , Estudios Seroepidemiológicos , Glicoproteína de la Espiga del CoronavirusRESUMEN
We conducted enhanced acute febrile illness surveillance in an urban slum community in Salvador, Brazil. We found that rickettsial infection accounted for 3.5% of urgent care visits for acute fever. Our results suggest that rickettsiae might be an underrecognized, treatable cause of acute febrile illness in impoverished urban populations in Brazil.
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Infecciones por Rickettsia , Rickettsia , Anticuerpos Antibacterianos , Brasil/epidemiología , Fiebre/epidemiología , Humanos , Áreas de Pobreza , Infecciones por Rickettsia/diagnóstico , Infecciones por Rickettsia/epidemiologíaRESUMEN
Immunity with SARS-CoV-2 infection during the acute phase is not sufficiently well understood to differentiate mild from severe cases and identify prognostic markers. We evaluated the immune response profile using a total of 71 biomarkers in sera from patients with SARS-CoV-2 infection, confirmed by RT-PCR and controls. We correlated biological marker levels with negative control (C) asymptomatic (A), nonhospitalized (mild cases-M), and hospitalized (severe cases-S) groups. Among angiogenesis markers, we identified biomarkers that were more frequently elevated in severe cases when compared to the other groups (C, A, and M). Among cardiovascular diseases, there were biomarkers with differences between the groups, with D-dimer, GDF-15, and sICAM-1 higher in the S group. The levels of the biomarkers Myoglobin and P-Selectin were lower among patients in group M compared to those in groups S and A. Important differences in cytokines and chemokines according to the clinical course were identified. Severe cases presented altered levels when compared to group C. This study helps to characterize biological markers related to angiogenesis, growth factors, heart disease, and cytokine/chemokine production in individuals infected with SARS-CoV-2, offering prognostic signatures and a basis for understanding the biological factors in disease severity.
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COVID-19 , SARS-CoV-2 , Biomarcadores , Quimiocinas , Citocinas , Factor 15 de Diferenciación de Crecimiento , Humanos , Mioglobina , Selectina-PRESUMEN
BACKGROUND: Leptospirosis is an important public health problem affecting vulnerable urban slum populations in developing country settings. However, the complex interaction of meteorological factors driving the temporal trends of leptospirosis remain incompletely understood. METHODS AND FINDINGS: From March 1996-March 2010, we investigated the association between the weekly incidence of leptospirosis and meteorological anomalies in the city of Salvador, Brazil by using a dynamic generalized linear model that accounted for time lags, overall trend, and seasonal variation. Our model showed an increase of leptospirosis cases associated with higher than expected rainfall, lower than expected temperature and higher than expected humidity. There was a lag of one-to-two weeks between weekly values for significant meteorological variables and leptospirosis incidence. Independent of the season, a weekly cumulative rainfall anomaly of 20 mm increased the risk of leptospirosis by 12% compared to a week following the expected seasonal pattern. Finally, over the 14-year study period, the annual incidence of leptospirosis decreased significantly by a factor of 2.7 (8.3 versus 3.0 per 100,000 people), independently of variations in climate. CONCLUSIONS: Strategies to control leptospirosis should focus on avoiding contact with contaminated sources of Leptospira as well as on increasing awareness in the population and health professionals within the short time window after low-level or extreme high-level rainfall events. Increased leptospirosis incidence was restricted to one-to-two weeks after those events suggesting that infectious Leptospira survival may be limited to short time intervals.
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Leptospira , Leptospirosis , Clima , Humanos , Humedad , Incidencia , Leptospirosis/epidemiología , Conceptos MeteorológicosRESUMEN
Vaccination is a major strategy to prevent the coronavirus disease 2019 (COVID-19). However, information about factors associated with men and women intention to be vaccinated are scarce. To determine COVID-19 vaccine acceptance and identify factors associated vaccine hesitancy according to sex, we performed a cross-sectional population-based random survey in Salvador, Brazil between Nov/2020-Jan/2021. Participants were interviewed to obtain data on intention to receive and pay for a COVID-19 vaccine, as well as on demographics, comorbidities, influenza vaccination history, previous diagnosis of COVID-19, and exposures and perception of COVID-19 risk. Among 2,521 participants, 2,053 (81.4%) reported willingness to use a COVID-19 vaccine and 468 (18.6%) hesitated to take it. Among those intending to get vaccinated, 1,400 (68.2%) would pay for the vaccine if necessary. Sex-stratified multivariable analysis found that men who were working and who had comorbidities were less likely to hesitate about using the vaccine. Among women, higher educational level and high perception of COVID-19 risk were associated with less vaccine hesitancy. In both groups, reporting influenza vaccination in 2020 reduced the chance of COVID-19 vaccine hesitancy. COVID-19 vaccine campaigns targeting to reduce vaccine hesitancy are urgently needed. These campaigns should consider gender differences in order to be successful.
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Vacunas contra la COVID-19/administración & dosificación , COVID-19/prevención & control , SARS-CoV-2/patogenicidad , Vacilación a la Vacunación/psicología , Vacunación/psicología , Adulto , Anciano , Brasil/epidemiología , COVID-19/epidemiología , Estudios Transversales , Femenino , Humanos , Intención , Masculino , Persona de Mediana Edad , Análisis Multivariante , SARS-CoV-2/inmunología , Factores Sexuales , Vacunación/estadística & datos numéricos , Vacilación a la Vacunación/estadística & datos numéricosRESUMEN
In early 2019, following the 2015-2016 severe drought, the provinces of Sofala and Cabo Delgado, Mozambique, were hit by Cyclones Idai and Kenneth, respectively. These were the deadliest and most destructive cyclones in the country's history. Currently, these two provinces host tens of thousands of vulnerable households due to the climatic catastrophes and the massive influx of displaced people associated with violent terrorist attacks plaguing Cabo Delgado. The emergence of the COVID-19 pandemic added a new challenge to this already critical scenario, serving as a real test for Mozambique's public health preparedness. On the planetary level, Mozambique can be viewed as a 'canary in the coal mine', harbingering to the world the synergistic effects of co-occurring anthropogenic and natural disasters. Herein, we discuss how the COVID-19 pandemic has accentuated the need for an effective and comprehensive public health response in a country already deeply impacted by health problems associated with natural disasters and population displacement.
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COVID-19 , Tormentas Ciclónicas , Urgencias Médicas , Humanos , Mozambique/epidemiología , Pandemias , Salud Pública , SARS-CoV-2RESUMEN
Slum residents are more vulnerable to COVID-19 infection. Without a specific treatment, vaccination became the main strategy against COVID-19. In this study, we determined the rate and factors associated with the willingness to get vaccinated against COVID-19 among slum residents and their main reasons associated with the vaccine intention. The study was conducted in Pau da Lima, a slum community in Salvador Brazil. In total, 985 residents were interviewed. Among them 66.0% (650/985) were willing to get vaccinated, 26.1% (257/985) were hesitant to take the vaccine and 7.9% (78/285) were not sure. The main reasons cited for vaccine hesitancy or being unsure were concerns about vaccine efficacy and potential side effects. In contrast, the main reasons cited for wanting the vaccine were the high incidence of COVID-19 cases and participants' self-perception of their own health history. Multivariate analysis identified that COVID-19 vaccine hesitancy was associated with younger age and low social capital, summarized as low perceived importance of vaccination to protect one's family, friends and community. Slum residents have been less willing to vaccinate than the general population. Social capital presents a critical opportunity in the design of communication campaigns to increase COVID-19 vaccine acceptance in slum settings.
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OBJECTIVES: To investigate risk factors for persistent arthralgia in patients with chikungunya, and describe its impact on daily activities. METHODS: From September 2014 to July 2016, a surveillance study enrolled patients with acute febrile illness in Salvador, Brazil, and detected those with chikungunya virus infection using IgM enzyme-linked immunosorbent assay or reverse transcriptase polymerase chain reaction. Telephone follow-ups were performed to ascertain the progression of disease. RESULTS: Of 153 followed cases, 65 (42.5%) reported chronic arthralgia that lasted >3 months, and 47 (30.7%) were still symptomatic at the time of the interview (approximately 1.5 years after symptom onset). Limitations in daily activities and mental distress were reported by 93.8% and 61.5% of those with chronic arthralgia, respectively. Female sex [risk ratio (RR) 1.79, 95% confidence interval (CI) 1.95-2.69] and age (RR 1.02 for each 1-year increase, 95% CI 1.01-1.03) were independent risk factors for chronic arthralgia. Chronic arthralgia was not associated with co-infection with dengue virus (RR 0.97, 95% CI 0.48-1.94) or chikungunya viral load at diagnosis (median chikungunya virus RNA of 5.60 and 5.52 log10 copies/µL for those with and without chronic arthralgia, respectively; P = 0.75). CONCLUSIONS: These findings reinforce the high frequency of chronic chikungunya arthralgia, and highlight the substantial disability associated with the persistence of pain. Development of novel strategies to mitigate the transmission of chikungunya virus and to provide long-term medical assistance for patients with chikungunya are needed urgently.
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Artralgia/epidemiología , Fiebre Chikungunya/epidemiología , Virus Chikungunya/inmunología , Dolor Crónico/epidemiología , Adolescente , Adulto , Artralgia/etiología , Artralgia/virología , Brasil/epidemiología , Fiebre Chikungunya/complicaciones , Fiebre Chikungunya/virología , Virus Chikungunya/genética , Niño , Preescolar , Dolor Crónico/etiología , Dolor Crónico/virología , Estudios de Cohortes , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Factores de Riesgo , Adulto JovenRESUMEN
Domestic rats are the principal reservoir for urban leptospirosis. However, few studies have identified infestation markers in slums and evaluated their predictivity for leptospirosis risk. We compared households with leptospirosis cases in Salvador, Brazil between 2007 and 2009 and their neighbors using a case control design, surveying for rodent infestation signs and environmental characteristics. With the 2007-2008 data, a conditional logistic regression modeling identified the peridomiciliar presence of rodent burrows (OR, 3.30; 95% CI, 1.50-7.26), rat feces (2.86; 1.24-6.59), runs (2.57; 1.06-6.22), households bordering abandoned houses (2.48; 1.04-6.02), and unplastered walls (2.22; 1.02-6.02) as risk factors and developed a predictive score for leptospirosis. With an independent data set from 2009, a receiver operating characteristic (ROC) curve analysis evaluated the prediction score performance, with the area under the curve being 0.70 (95% CI, 0.64-0.76) for score development and 0.71 (0.65-0.79) for validation. Results indicate that high proportions of urban slum households are infested with R. norvegicus. The score performed well when identifying high-risk households within slums. These findings need confirmation in other urban centers, but suggest that community-based screening for rodent infestation can allow to target rodent and environmental control measures in populations at highest risk for leptospirosis.
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Leptospirosis/epidemiología , Ratas , Características de la Residencia/estadística & datos numéricos , Animales , Brasil/epidemiología , Estudios de Casos y Controles , Reservorios de Enfermedades , Humanos , Modelos Logísticos , Áreas de Pobreza , Factores de RiesgoRESUMEN
OBJECTIVE: We tested the hypothesis that Zika virus (ZIKV) immunity may protect against dengue virus (DENV) infection, disease severity or human amplification, based on analysis of epidemiological data from our long-term surveillance study (2009-2016) in the city of Salvador, Brazil, that indicated a substantial reduction in the frequency of laboratory-confirmed dengue cases following the Zika outbreak. To assess whether similar patterns were observed across the Americas, we did a broader explorative investigation of historical series (2004 to 2019) of suspected cases of dengue fever, covering 20 DENV-endemic South and Central American countries. METHODS: We used segmented linear regressions of single group interrupted time series (ITS) analysis to evaluate whether the Zika epidemic had a statistical effect on the trends of annual dengue incidence. RESULTS: We observed in our 16-year historical series that in all countries, the incidence of dengue exhibited periodic oscillations over time, with a general trend of statistically significant increase during the pre-Zika period overall and for 11 of the 20 countries. Following the peak of the first population exposure to ZIKV in the Americas, in 2016, the overall rate of reported dengue cases in 2017 and 2018 in the countries under study sharply dropped (P < 0.05) and was the lowest reported since 2005. Individually in each country, a statistically significant reduction in the annual dengue incidence beginning in 2016 or in 2017-2018 occurred in 13 of the 20 studied countries. However, in 2019, reports of suspected dengue cases increased across the Americas. In Brazil, Dominican Republic, Guatemala and Honduras, dengue incidence was >5 times higher in 2019 than in 2017 and 2018, and, in 2019, they had the greater dengue incidence than in all previous years throughout the historical series. CONCLUSIONS: The widespread decline in suspected dengue cases recorded in 2017 and 2018 lends further support to our previous epidemiological hypothesis of ZIKV-induced cross-species immunity to DENV. However, the cross-protection appears to be transient (around 2 years). Long-term, prospective follow-ups of dengue reports are needed to confirm (or refute) these findings, which could have significant public health implications, in particular regarding DENV vaccine development and application.
CONTEXTE: Nous avons émis l'hypothèse que l'immunité contre le virus Zika (ZIKV) pourrait protéger contre l'infection par le virus de la dengue (DENV), la sévérité de la maladie ou l'amplification humaine, sur la base de l'analyse des données épidémiologiques de notre étude de surveillance à long terme (2009-2016) dans la ville de Salvador, au Brésil, qui a indiqué une réduction substantielle de la fréquence des cas de dengue confirmés en laboratoire à la suite de l'épidémie de Zika. MÉTHODES: Pour évaluer si des tendances similaires ont été observées dans les Amériques, nous avons mené une enquête exploratoire plus large sur des séries historiques (2004 à 2019) de cas suspects de dengue, couvrant 20 pays d'Amérique du Sud et d'Amérique centrale endémiques pour DENV. Nous avons utilisé des régressions linéaires segmentées de l'analyse des séries chronologiques interrompues pour un seul groupe pour évaluer si l'épidémie de Zika avait un effet statistique sur les tendances de l'incidence annuelle de la dengue. RÉSULTATS: Nous avons observé dans notre série historique de 16 ans que dans tous les pays, l'incidence de la dengue présentait des oscillations périodiques au fil du temps, avec une tendance générale à une augmentation statistiquement significative pendant la période pré-Zika en général et pour 11 des 20 pays. Après le pic de la première exposition de la population au ZIKV dans les Amériques en 2016, le taux global des cas de dengue rapportés en 2017 et 2018 dans les pays étudiés a fortement diminué (p <0,05) et était le plus bas depuis 2005. Individuellement dans chaque pays, une réduction statistiquement significative de l'incidence annuelle de la dengue à partir de 2016 ou en 2017-2018 s'est produite dans 13 des 20 pays étudiés. Cependant, en 2019, les reports de cas suspects de dengue ont augmenté dans les Amériques. Dans des pays comme le Brésil, la République Dominicaine, le Guatemala et le Honduras, l'incidence de la dengue était >5 fois plus élevée en 2019 qu'en 2017 et 2018, et, en 2019, l'incidence de la dengue était plus élevée qu'au cours de toutes les années précédentes de la série historique. CONCLUSIONS: Le déclin généralisé des cas suspects de dengue enregistrés en 2017 et 2018 vient étayer notre hypothèse épidémiologique précédente de l'immunité inter-espèces induite par le ZIKV contre le DENV. Cependant, la protection croisée semble être transitoire (environ 2 ans). Des suivis prospectifs à long terme des reports sur la dengue sont nécessaires pour confirmer (ou réfuter) ces résultats, qui pourraient avoir des implications importantes pour la santé publique, en particulier en ce qui concerne le développement et l'application d'un vaccin DENV.
Asunto(s)
Dengue/epidemiología , Infección por el Virus Zika/epidemiología , América Central/epidemiología , Virus Chikungunya/inmunología , Dengue/complicaciones , Virus del Dengue , Epidemias , Humanos , Incidencia , Modelos Lineales , América del Sur/epidemiología , Virus Zika , Infección por el Virus Zika/etiologíaRESUMEN
While studying aseptic meningitis in Salvador, Brazil, we diagnosed anicteric leptospirosis in 1.7% (5/295) of patients hospitalized for aseptic meningitis. Leptospirosis-associated meningitis patients had lower mean cerebrospinal fluid cell counts and protein than other-cause aseptic meningitis (p<0.05). Clinicians must consider leptospirosis-associated meningitis in appropriate clinical-epidemiologic contexts.
Asunto(s)
Leptospirosis , Meningitis Aséptica , Meningitis , Brasil , Humanos , Leptospirosis/diagnóstico , Leptospirosis/epidemiología , Meningitis/diagnóstico , Meningitis/epidemiologíaRESUMEN
After a chikungunya outbreak in Salvador, Brazil, we performed a cross-sectional, community-based study of 1,776 inhabitants to determine chikungunya virus (CHIKV) seroprevalence, identify factors associated with exposure, and estimate the symptomatic infection rate. From November 2016 through February 2017, we collected sociodemographic and clinical data by interview and tested serum samples for CHIKV IgG. CHIKV seroprevalence was 11.8% (95% CI 9.8%-13.7%), and 15.3% of seropositive persons reported an episode of fever and arthralgia. Infections were independently and positively associated with residences served by unpaved streets, a presumptive clinical diagnosis of chikungunya, and recall of an episode of fever with arthralgia in 2015-2016. Our findings indicate that the chikungunya outbreak in Salvador may not have conferred sufficient herd immunity to preclude epidemics in the near future. The unusually low frequency of symptomatic disease points to a need for further longitudinal studies to better investigate these findings.