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Silva AT, Dorn RC, Tomás LR, Santos LB, Skalinski LM, Pinho ST. Spatial analysis of Dengue through the reproduction numbers relating to socioeconomic features: Case studies on two Brazilian urban centers. Infect Dis Model 2024; 9:142-157. [PMID: 38268698 PMCID: PMC10805647 DOI: 10.1016/j.idm.2023.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 12/08/2023] [Accepted: 12/16/2023] [Indexed: 01/26/2024] Open
Abstract
The study of the propagation of infectious diseases in urban centers finds a close connection with their population's social characteristics and behavior. This work performs a spatial analysis of dengue cases in urban centers based on the basic reproduction numbers, R0, and incidence by planning areas (PAs), as well as their correlations with the Human Development Index (HDI) and the number of trips. We analyzed dengue epidemics in 2002 at two Brazilian urban centers, Belo Horizonte (BH) and Rio de Janeiro (RJ), using PAs as spatial units. Our results reveal heterogeneous spatial scenarios for both cities, with very weak correlations between R0 and both the number of trips and the HDI; in BH, the values of R0 show a less spatial heterogeneous pattern than in RJ. For BH, there are moderate correlations between incidence and both the number of trips and the HDI; meanwhile, they weakly correlate for RJ. Finally, the absence of strong correlations between the considered measures indicates that the transmission process should be treated considering the city as a whole.
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Affiliation(s)
- Ana T.C. Silva
- Departamento de Física, Universidade Estadual de Feira de Santana, Av. Transnordestina, s/n. Novo Horizonte, Feira de Santana, 44036-900, BA, Brazil
- Instituto de Física, Universidade Federal da Bahia, Rua Barão de Jeremoabo s/n, Campus Universitário de Ondina, Salvador, 40170-115, BA, Brazil
| | - Rejane C. Dorn
- Instituto de Física, Universidade Federal da Bahia, Rua Barão de Jeremoabo s/n, Campus Universitário de Ondina, Salvador, 40170-115, BA, Brazil
| | - Lívia R. Tomás
- Centro Nacional de Monitoramento e Alertas de Desastres Naturais (CEMADEN), Estrada Dr. Altino Bondensan, 500, São José dos Campos, 12247-016, SP, Brazil
| | - Leonardo B.L. Santos
- Centro Nacional de Monitoramento e Alertas de Desastres Naturais (CEMADEN), Estrada Dr. Altino Bondensan, 500, São José dos Campos, 12247-016, SP, Brazil
| | - Lacita M. Skalinski
- Universidade Estadual de Santa Cruz, Campus Soane Nazaré de Andrade, Rodovia Jorge Amado, Km 16, Salobrinho, Ilhéus, 45662-900, BA, Brazil
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, R. Basílio da Gama, s/n - Canela, Salvador, 40110-140, BA, Brazil
| | - Suani T.R. Pinho
- Instituto de Física, Universidade Federal da Bahia, Rua Barão de Jeremoabo s/n, Campus Universitário de Ondina, Salvador, 40170-115, BA, Brazil
- Instituto Nacional de Ciência e Tecnologia - Sistemas Complexos, Virtual Institution, Brazil
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Ferreira DTDO, Atanaka M, Martinez Espinosa M, Schuler-Faccini L, da Silva Caldeira A, da Silva JH, Vivi-Oliveira VK, de Castro da Paz R, do Nascimento VF, Terças-Trettel ACP. Recent dengue virus infection: epidemiological survey on risk factors associated with infection in a medium-sized city in Mato Grosso. SAO PAULO MED J 2022; 140:33-41. [PMID: 34852169 PMCID: PMC9623843 DOI: 10.1590/1516-3180.2020.0718.r1.18052021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 05/18/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Dengue is considered to be the most important arbovirus worldwide, with important complications that increase its lethality. In Brazil, an endemic country, the disease reaches significant incidence levels, with occurrences of serious cases and high costs of hospitalizations for its treatment. OBJECTIVE To analyze risk factors among individuals with recent histories of dengue infection in a medium-sized city in Mato Grosso. DESIGN AND SETTING Descriptive cross-sectional study, of epidemiological-survey type, conducted among the urban population of a city located in mid-northern Mato Grosso. METHODS A seroepidemiological survey using questionnaires and collection of biological material was conducted among 596 adults aged ≥ 18 years who had been selected through a cluster sampling process. Positive dengue cases were those with positive results from anti-dengue immunoassays (ELISA). Statistical analyses with descriptive and inferential techniques were used, with 95% confidence intervals and a 5% significance level. RESULTS The seroepidemiological profile of the study participants was predominantly female, with ages between 18 and 39 years, self-declared non-white race/color, not more than eight years of education and not living with a companion. Among the sanitary factors analyzed, the following were risk factors for dengue virus infection: no running water at home; no water supply from the public piped network; no waste from drains or toilets sent to the sewage network; endemic disease combat agents visiting the home; and presence of mosquito breeding sites at home. CONCLUSION Low schooling levels and previous dengue virus infection were associated with current dengue virus infection.
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Affiliation(s)
- Dandára Thaís de Oliveira Ferreira
- MSc. Nutritionist and Public Manager, Storage and Distribution Center for Medicines and Supplies of the Municipal Health Department, Várzea Grande (MT), Brazil.
| | - Marina Atanaka
- PhD. Nurse and Associate Professor IV, Postgraduate Program on Collective Health, Universidade Federal de Mato Grosso (UFMT), Cuiabá campus, Cuiabá (MT), Brazil.
| | - Mariano Martinez Espinosa
- PhD. Statistician and Associate Professor IV, Postgraduate Program on Collective Health, Universidade Federal de Mato Grosso (UFMT), Cuiabá campus, Cuiabá (MT), Brazil.
| | - Lavinia Schuler-Faccini
- MD, PhD. Full Professor, Department of Genetics, Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre (RS), Brazil.
| | | | - Juliana Herrero da Silva
- MSc. Nurse and Technical Manager, Municipal Epidemiological Surveillance Department, Tangará da Serra (MT), Brazil.
| | | | - Rayana de Castro da Paz
- Specialist. Pharmacist, Biochemist and Technical Consultant, General Coordination Office for Health Laboratories, Health Surveillance Department, Ministry of Health, Brasília (DF), Brazil.
| | - Vagner Ferreira do Nascimento
- PhD. Nurse and Adjunct Professor II, Universidade do Estado de Mato Grosso (UNEMAT), Tangará da Serra campus, Tangará da Serra (MT), Brazil.
| | - Ana Cláudia Pereira Terças-Trettel
- PhD. Nurse and Adjunct Professor, Universidade do Estado de Mato Grosso (UNEMAT), Tangará da Serra campus, Tangará da Serra (MT), Brazil; and Permanent Professor, Postgraduate Program on Collective Health, Universidade Federal de Mato Grosso (UFMT), Cuiabá campus, Cuiabá (MT), Brazil.
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Bezerra JMT, Sousa SCD, Tauil PL, Carneiro M, Barbosa DS. Entry of dengue virus serotypes and their geographic distribution in Brazilian federative units: a systematic review. REVISTA BRASILEIRA DE EPIDEMIOLOGIA 2021; 24:e210020. [PMID: 33825776 DOI: 10.1590/1980-549720210020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/09/2020] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To describe the entry of Dengue virus (DENV) serotypes in Brazil and its federative units. METHODS A systematic review of studies published between 1980 and 2018 in databases and in the gray literature was performed using descriptors related to the years of entry of the DENV serotypes. Additionally, experts and official sources of information (Brazilian Ministry of Health) were consulted. RESULTS From 100 publications selected for the systematic review, 26 addressed the entry of DENV serotypes in the North region of the country, 33 in the Northeast, 24 in the Southeast, 14 in the Central-West, and five in the South. DENV-1 and DENV-4 were introduced in the North region in 1981. DENV-2 was introduced in the Southeast in 1990. DENV-3 was introduced in the North in 1999. CONCLUSION The rapid expansion of dengue throughout the Brazilian territory was verified from the second half of the 1980s, with the gradual entry of the four serotypes, which resulted in the emergence of epidemics of arbovirus, which are currently verified in the country. Considering the epidemiology of the disease, more information should be disseminated and published in the wide-ranging scientific literature for a better understanding of the spread and circulation of DENV serotypes.
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Affiliation(s)
| | - Selma Costa de Sousa
- Department of Occupational Health Care, Universidade Federal de Minas Gerais - Belo Horizonte (MG), Brazil.,Laboratory of Epidemiology of Infectious and Parasitic Diseases, Department of Parasitology, Biological Sciences Institute, Universidade Federal de Minas Gerais - Belo Horizonte (MG), Brazil
| | - Pedro Luiz Tauil
- School of Medicine, Graduate Program in Tropical Medicine, Universidade de Brasília - Brasília (DF), Brazil
| | - Mariângela Carneiro
- Laboratory of Epidemiology of Infectious and Parasitic Diseases, Department of Parasitology, Biological Sciences Institute, Universidade Federal de Minas Gerais - Belo Horizonte (MG), Brazil.,Graduate Program in Health Sciences, Infectious Disease and Tropical Medicine, Universidade Federal de Minas Gerais - Belo Horizonte (MG), Brazil
| | - David Soeiro Barbosa
- Laboratory of Epidemiology of Infectious and Parasitic Diseases, Department of Parasitology, Biological Sciences Institute, Universidade Federal de Minas Gerais - Belo Horizonte (MG), Brazil
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Catenacci LS, Ferreira MS, Fernandes D, Padda H, Travassos-da-Rosa ES, Deem SL, Vasconcelos PFC, Martins LC. Individual, household and environmental factors associated with arboviruses in rural human populations, Brazil. Zoonoses Public Health 2021; 68:203-212. [PMID: 33538403 DOI: 10.1111/zph.12811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/01/2020] [Accepted: 01/18/2021] [Indexed: 11/27/2022]
Abstract
Landscape change is one of the foremost drivers of the emergence of infectious diseases. Exploring demographic, household and environmental conditions under which infectious diseases occur may inform strategies to prevent disease emergence in human populations. We collected blood samples from 523 humans and explore factors for arbovirus emergence in Bahia, Brazil. The overall arbovirus seroprevalence was 65.2%, with the genus Flavivirus most prevalent (64.4%). Based on monotypic reactions, the population had contact with five arbovirus: Dengue 3, Ilheus, Oropouche, Caraparu and Eastern equine encephalitis virus. To our knowledge, this is the first study reporting exposure to Oropouche, Caraparu and Eastern equine encephalitis virus in human populations in Bahia, Northeast of Brazil. The best model fit demonstrated that household and environmental variables were more predictive of the risk of arbovirus exposure than demographic variables. The presence of forest and free-living monkeys in the areas close to the communities had a protective effect for the human population (i.e. lower seroprevalence). The dilution effect is considered as one explanation for this finding. These results highlight the important ecological role of wildlife-friendly agriculture.
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Affiliation(s)
- Lilian S Catenacci
- Department of Veterinary Morphophysiology, Federal University of Piauí State, Teresina, Brazil.,Federal University of Para State- Post Graduate Program PPGSAAM, Castanhal, Brazil.,Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO, USA
| | - Milene S Ferreira
- Section of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute- Ministry of Health, Ananindeua, Brazil
| | - Debora Fernandes
- Section of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute- Ministry of Health, Ananindeua, Brazil
| | - Hannah Padda
- Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO, USA.,Washington University in St. Louis, St. Louis, MO, USA
| | | | - Sharon L Deem
- Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO, USA
| | - Pedro F C Vasconcelos
- Section of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute- Ministry of Health, Ananindeua, Brazil
| | - Livia C Martins
- Section of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute- Ministry of Health, Ananindeua, Brazil
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Barreto FKDA, Alencar CH, Araújo FMDC, Oliveira RDMAB, Cavalcante JW, Lemos DRQ, Farias LABG, Boriz ILF, Medeiros LQ, Melo MNP, Miyajima F, Siqueira AM, Freitas ARR, Cavalcanti LPDG. Seroprevalence, spatial dispersion and factors associated with flavivirus and chikungunha infection in a risk area: a population-based seroprevalence study in Brazil. BMC Infect Dis 2020; 20:881. [PMID: 33234110 PMCID: PMC7685300 DOI: 10.1186/s12879-020-05611-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/11/2020] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The State of Ceará, in Northeastern Brazil, suffers from a triple burden of arboviruses (dengue, Zika and chikungunya). We measured the seroprevalence of chikungunya, dengue and Zika and its associated factors in the population of Juazeiro do Norte, Southern Ceará State, Brazil. METHODS A cross-sectional study of analytical and spatial analysis was performed to estimate the seroprevalence of dengue, Zika and chikungunya, in the year 2018. Participants were tested for IgM and IgG against these three viruses. Those with IgM and/or IgG positive tests results were considered positive. Poisson regression was used to analyze the factors associated with positive cases, in the same way that the spatial analysis of positive cases was performed to verify whether the cases were grouped. RESULTS Of the 404 participants, 25.0% (103/404) were positive for CHIKV, 92.0% (373/404) for flavivirus (dengue or Zika) and of these, 37.9% (153/404) samples were classified as probable dengue infection. Of those who reported having had an arbovirus in the past, positive CHIKV cases had 58.7% arthralgia (PR = 4.31; 95% CI: 2.06-9.03; p = 0.000) mainly in the hands, ankles and feet. Age over 60 years had a positive association with cases of flavivirus (PR = 1.29; 95% CI: 1.09-1.54; p = 0.000). Fever, muscle pain, joint pain and skin rash were the most reported symptoms (46.1, 41.0, 38.3 and 28.41%, respectively). The positive cases of chikungunya and dengue or Zika were grouped in space and the city center was most affected area. CONCLUSIONS Four years after the introduction of CHIKV, where DENV has been in circulation for over 30 years, 1/4 of the population has already been exposed, showing the extent of the epidemic. The measured prevalence was much higher than that reported by local epidemiological surveillance.
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Affiliation(s)
| | - Carlos Henrique Alencar
- Programa de Pós-graduação em Saúde Coletiva, Universidade Federal do Ceará, Fortaleza, CE, Brazil
- Programa de Pós-graduação em Patologia, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | | | | | - John Washington Cavalcante
- Programa de Pós-graduação em Patologia, Universidade Federal do Ceará, Fortaleza, CE, Brazil
- Serviço de Verificação de Óbitos Dr Rocha Furtado, Secretaria de Saúde do Estado do Ceará, Fortaleza, CE, Brazil
| | | | - Luís Arthur Brasil Gadelha Farias
- Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
- Hospital São José de Doenças infecciosas, Fortaleza, CE, Brazil
| | - Isac Lucca Frota Boriz
- Programa de Pós-graduação em Saúde Coletiva, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - Leticia Queiroz Medeiros
- Programa de Pós-graduação em Saúde Coletiva, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | | | | | - André Machado Siqueira
- Fundação Oswaldo Cruz, Presidência da Fiocruz, Instituto de Pesquisa Clínica Evandro Chagas (INI/Fiocruz), Rio de Janeiro, Brazil
| | | | - Luciano Pamplona de Góes Cavalcanti
- Programa de Pós-graduação em Saúde Coletiva, Universidade Federal do Ceará, Fortaleza, CE, Brazil
- Programa de Pós-graduação em Patologia, Universidade Federal do Ceará, Fortaleza, CE, Brazil
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Cattarino L, Rodriguez-Barraquer I, Imai N, Cummings DAT, Ferguson NM. Mapping global variation in dengue transmission intensity. Sci Transl Med 2020; 12:12/528/eaax4144. [PMID: 31996463 DOI: 10.1126/scitranslmed.aax4144] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 09/12/2019] [Accepted: 01/02/2020] [Indexed: 12/28/2022]
Abstract
Intervention planning for dengue requires reliable estimates of dengue transmission intensity. However, current maps of dengue risk provide estimates of disease burden or the boundaries of endemicity rather than transmission intensity. We therefore developed a global high-resolution map of dengue transmission intensity by fitting environmentally driven geospatial models to geolocated force of infection estimates derived from cross-sectional serological surveys and routine case surveillance data. We assessed the impact of interventions on dengue transmission and disease using Wolbachia-infected mosquitoes and the Sanofi-Pasteur vaccine as specific examples. We predicted high transmission intensity in all continents straddling the tropics, with hot spots in South America (Colombia, Venezuela, and Brazil), Africa (western and central African countries), and Southeast Asia (Thailand, Indonesia, and the Philippines). We estimated that 105 [95% confidence interval (CI), 95 to 114] million dengue infections occur each year with 51 (95% CI, 32 to 66) million febrile disease cases. Our analysis suggests that transmission-blocking interventions such as Wolbachia, even at intermediate efficacy (50% transmission reduction), might reduce global annual disease incidence by up to 90%. The Sanofi-Pasteur vaccine, targeting only seropositive recipients, might reduce global annual disease incidence by 20 to 30%, with the greatest impact in high-transmission settings. The transmission intensity map presented here, and made available for download, may help further assessment of the impact of dengue control interventions and prioritization of global public health efforts.
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Affiliation(s)
- Lorenzo Cattarino
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, Norfolk Place, London W2 1PG, UK.
| | | | - Natsuko Imai
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, Norfolk Place, London W2 1PG, UK
| | - Derek A T Cummings
- Department of Biology and Emerging Pathogens Institute, University of Florida, P. O. Box 100009, Gainesville, FL 32610, USA
| | - Neil M Ferguson
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, Norfolk Place, London W2 1PG, UK
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Ogashawara I, Li L, Moreno‐Madriñán MJ. Spatial-Temporal Assessment of Environmental Factors Related to Dengue Outbreaks in São Paulo, Brazil. GEOHEALTH 2019; 3:202-217. [PMID: 32159042 PMCID: PMC7007072 DOI: 10.1029/2019gh000186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/19/2019] [Accepted: 07/09/2019] [Indexed: 05/06/2023]
Abstract
Dengue fever, a disease caused by a vector-borne flavivirus, is endemic to tropical countries, but its occurrence has been reported worldwide. This study aimed to understand important factors contributing to the spatial and temporal patterns of dengue occurrence in São Paulo, the largest municipality of Brazil. The temporal assessment of dengue occurrence covered the 2011-2016 time period and was based on climatological data, such as the El Niño indices and time series statistical tools such as the continuous wavelet transformation. The spatial assessment used Landsat 8 data for years 2014-2016 to estimate land surface temperature and normalized indices for vegetation, urban areas, and leaf water. Results from a cross correlation for the temporal analysis found a relationship between the sea surface temperature anomalies index and the number of reported dengue cases in São Paulo (r = 0.5) with a lag of +29 (weeks) between the climatic event and the response on the dengue incidence. This relationship, initially nonlinear, became linear after correcting for the lag period. For the spatial assessment, the linear stepwise regression model detected a low relationship between dengue incidence and minimum surface temperature (r = 0.357) and no relationship with other environmental parameters. The poor relationship might be due to confounding effects of socioeconomic factors as these seem to influence the spatial dynamics of dengue incidence. More testing is needed to validate these methods in other locations. Nevertheless, we presented possible tools to be used for the improvement of dengue control programs.
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Affiliation(s)
- I. Ogashawara
- Department of Earth SciencesIndiana University‐Purdue University at IndianapolisIndianapolisINUSA
| | - L. Li
- Department of Earth SciencesIndiana University‐Purdue University at IndianapolisIndianapolisINUSA
| | - M. J. Moreno‐Madriñán
- Department of Environmental Health, Fairbanks School of Public HealthIndiana University‐Purdue University at IndianapolisIndianapolisINUSA
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Chiaravalloti-Neto F, da Silva RA, Zini N, da Silva GCD, da Silva NS, Parra MCP, Dibo MR, Estofolete CF, Fávaro EA, Dutra KR, Mota MTO, Guimarães GF, Terzian ACB, Blangiardo M, Nogueira ML. Seroprevalence for dengue virus in a hyperendemic area and associated socioeconomic and demographic factors using a cross-sectional design and a geostatistical approach, state of São Paulo, Brazil. BMC Infect Dis 2019; 19:441. [PMID: 31109295 PMCID: PMC6528304 DOI: 10.1186/s12879-019-4074-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/09/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND São José do Rio Preto is one of the cities of the state of São Paulo, Brazil, that is hyperendemic for dengue, with the presence of the four dengue serotypes. OBJECTIVES to calculate dengue seroprevalence in a neighbourhood of São José do Rio Preto and identify if socioeconomic and demographic covariates are associated with dengue seropositivity. METHODS A cohort study to evaluate dengue seroprevalence and incidence and associated factors on people aged 10 years or older, was assembled in Vila Toninho neighbourhood, São José do Rio Preto. The participant enrolment occurred from October 2015 to March 2016 (the first wave of the cohort study), when blood samples were collected for serological test (ELISA IgG anti-DENV) and questionnaires were administrated on socio-demographic variables. We evaluated the data collected in this first wave using a cross-sectional design. We considered seropositive the participants that were positive in the serological test (seronegative otherwise). We modelled the seroprevalence with a logistic regression in a geostatistical approach. The Bayesian inference was made using integrated nested Laplace approximations (INLA) coupled with the Stochastic Partial Differential Equation method (SPDE). RESULTS We found 986 seropositive individuals for DENV in 1322 individuals surveyed in the study area in the first wave of the cohort study, corresponding to a seroprevalence of 74.6% (95%CI: 72.2-76.9). Between the population that said never had dengue fever, 68.4% (566/828) were dengue seropositive. Older people, non-white and living in a house (instead of in an apartment), were positively associated with dengue seropositivity. We adjusted for the other socioeconomic and demographic covariates, and accounted for residual spatial dependence between observations, which was found to present up to 800 m. CONCLUSIONS Only one in four people aged 10 years or older did not have contact with any of the serotypes of dengue virus in Vila Toninho neighbourhood in São José do Rio Preto. Age, race and type of house were associated with the occurrence of the disease. The use of INLA in a geostatistical approach in a Bayesian context allowed us to take into account the spatial dependence between the observations and identify the associated covariates to dengue seroprevalence.
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Affiliation(s)
- Francisco Chiaravalloti-Neto
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo (USP), Avenida Doutor Arnaldo 715, São Paulo, SP, 01246-904, Brazil.
| | - Rafael Alves da Silva
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Nathalia Zini
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Gislaine Celestino Dutra da Silva
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Natal Santos da Silva
- Laboratório de Modelagens Matemática e Estatística em Medicina, Faculdade de Medicina, União das Faculdades dos Grandes Lagos, Rua Doutor Eduardo Nielsen 960, São José do Rio Preto, SP, 15030-070, Brazil
| | - Maisa Carla Pereira Parra
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Margareth Regina Dibo
- Laboratório de Entomologia, Superintendência de Controle de Endemias, Rua Cardeal Arcoverde 2878, São Paulo, SP, 05408-003, Brazil
| | - Cassia Fernanda Estofolete
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Eliane Aparecida Fávaro
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Karina Rocha Dutra
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Manlio Tasso Oliveira Mota
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Georgia Freitas Guimarães
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Ana Carolina Bernardes Terzian
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
| | - Marta Blangiardo
- MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, Imperial College, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK
| | - Mauricio Lacerda Nogueira
- Laboratório de Pesquisas em Virologia, Departamento de Doenças Dermatológicas Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto (FAMERP), Avenida Brigadeiro Faria Lima, 5416, São José do Rio Preto, SP, 15090-000, Brazil
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Dias JDJ, Branco MDRFC, Queiroz RCDS, dos Santos AM, Moreira EPB, da Silva MDS. Analysis of dengue cases according to clinical severity, São Luís, Maranhão, Brazil. Rev Inst Med Trop Sao Paulo 2017; 59:e71. [PMID: 29116291 PMCID: PMC5679683 DOI: 10.1590/s1678-9946201759071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 08/29/2017] [Indexed: 11/22/2022] Open
Abstract
Severe dengue cases have increased in Brazil since 2001, with the first records in Maranhão dating back to 2002. The aim of this study was to determine the prevalence of severe dengue cases by age group and the possible risk factors. This was a study of secondary data on dengue in residents of São Luís, Maranhão, Brazil, using probable cases notified to the National Mandatory Reporting System (SINAN) from 2002 to 2011. The diagnosis and classification of dengue were based on the Brazilian Ministry of Health criteria: dengue fever (DF), dengue hemorrhagic fever (DHF) and dengue fever with complications (DWC). DHF and DWC were considered severe dengue, and DF was classified as non-severe dengue. A logistic regression analysis was performed with severe dengue as the outcome. During the study period, 1,229 cases of severe dengue were reported; of these, 812 in patients under the age of 15 (66%). Among the risk factors evaluated, age under 15 years old (OR = 3.10, 95% CI = 2.69-3.57, p-value = 0.001) was associated with severe dengue. The prevalence of severe dengue in children under the age of 15 was higher, and only this age group was associated with the occurrence of severe dengue.
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Affiliation(s)
- José de Jesus Dias
- Universidade Federal do Maranhão, Programa de Pós-Graduação em Saúde
Coletiva, São Luís, Maranhão, Brazil
| | - Maria dos Remédios Freitas Carvalho Branco
- Universidade Federal do Maranhão, Programa de Pós-Graduação em Saúde
Coletiva, São Luís, Maranhão, Brazil
- Universidade Federal do Maranhão, Programa de Pós-Graduação em Saúde e
Ambiente, São Luís, Maranhão, Brazil
| | | | - Alcione Miranda dos Santos
- Universidade Federal do Maranhão, Programa de Pós-Graduação em Saúde
Coletiva, São Luís, Maranhão, Brazil
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10
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Kikuti M, Cunha GM, Paploski IAD, Kasper AM, Silva MMO, Tavares AS, Cruz JS, Queiroz TL, Rodrigues MS, Santana PM, Lima HCAV, Calcagno J, Takahashi D, Gonçalves AHO, Araújo JMG, Gauthier K, Diuk-Wasser MA, Kitron U, Ko AI, Reis MG, Ribeiro GS. Spatial Distribution of Dengue in a Brazilian Urban Slum Setting: Role of Socioeconomic Gradient in Disease Risk. PLoS Negl Trop Dis 2015. [PMID: 26196686 PMCID: PMC4510880 DOI: 10.1371/journal.pntd.0003937] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background Few studies of dengue have shown group-level associations between demographic, socioeconomic, or geographic characteristics and the spatial distribution of dengue within small urban areas. This study aimed to examine whether specific characteristics of an urban slum community were associated with the risk of dengue disease. Methodology/Principal Findings From 01/2009 to 12/2010, we conducted enhanced, community-based surveillance in the only public emergency unit in a slum in Salvador, Brazil to identify acute febrile illness (AFI) patients with laboratory evidence of dengue infection. Patient households were geocoded within census tracts (CTs). Demographic, socioeconomic, and geographical data were obtained from the 2010 national census. Associations between CTs characteristics and the spatial risk of both dengue and non-dengue AFI were assessed by Poisson log-normal and conditional auto-regressive models (CAR). We identified 651 (22.0%) dengue cases among 2,962 AFI patients. Estimated risk of symptomatic dengue was 21.3 and 70.2 cases per 10,000 inhabitants in 2009 and 2010, respectively. All the four dengue serotypes were identified, but DENV2 predominated (DENV1: 8.1%; DENV2: 90.7%; DENV3: 0.4%; DENV4: 0.8%). Multivariable CAR regression analysis showed increased dengue risk in CTs with poorer inhabitants (RR: 1.02 for each percent increase in the frequency of families earning ≤1 times the minimum wage; 95% CI: 1.01-1.04), and decreased risk in CTs located farther from the health unit (RR: 0.87 for each 100 meter increase; 95% CI: 0.80-0.94). The same CTs characteristics were also associated with non-dengue AFI risk. Conclusions/Significance This study highlights the large burden of symptomatic dengue on individuals living in urban slums in Brazil. Lower neighborhood socioeconomic status was independently associated with increased risk of dengue, indicating that within slum communities with high levels of absolute poverty, factors associated with the social gradient influence dengue transmission. In addition, poor geographic access to health services may be a barrier to identifying both dengue and non-dengue AFI cases. Therefore, further spatial studies should account for this potential source of bias. Dengue is influenced by the environment; however, few studies have investigated the relationship between neighborhood characteristics and the spatial distribution of dengue within small urban areas. We examined whether specific characteristics of an urban slum community were associated with dengue risk. From January 2009 to December 2010, we conducted community-based surveillance in a slum in Salvador, Brazil to identify patients with acute febrile illness (AFI) and to test them for dengue. We identified 651 (22.0%) patients with laboratory evidence of dengue infection among 2,962 AFI patients. All the four dengue serotypes were detected, but DENV2 predominated (DENV1 8.1%; DENV2 90.7%; DENV3 0.4%; DENV4 0.8%). Estimated risk of symptomatic dengue was 21.3 and 70.2 cases per 10,000 inhabitants in 2009 and 2010, respectively. We found that neighborhood poverty level and proximity to the health center were associated with higher risk of detection of dengue and other AFI. This study highlights the large burden of dengue in poor urban slums of Brazil and indicates that socioeconomic development could potentially mitigate risk factors for both dengue and non-dengue AFI cases. In addition, we found that residential proximity to a health care facility was associated with improved case detection. Therefore, further studies on disease distribution should consider household proximity to health care facilities when assessing risk.
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Affiliation(s)
- Mariana Kikuti
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Geraldo M. Cunha
- Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Igor A. D. Paploski
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Amelia M. Kasper
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Monaise M. O. Silva
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Aline S. Tavares
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Jaqueline S. Cruz
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Tássia L. Queiroz
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Moreno S. Rodrigues
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Perla M. Santana
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Helena C. A. V. Lima
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Juan Calcagno
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Daniele Takahashi
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | | | - Josélio M. G. Araújo
- Departamento de Microbiologia e Parasitologia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Kristine Gauthier
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
| | - Maria A. Diuk-Wasser
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
| | - Uriel Kitron
- Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America
| | - Albert I. Ko
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
| | - Mitermayer G. Reis
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
- Faculdade de Medicina, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Guilherme S. Ribeiro
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil
- Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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11
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Branco MDRFC, Luna EJDA, Braga Júnior LL, Oliveira RVBD, Rios LTM, Silva MDSD, Medeiros MNL, Silva GF, Nina FCAF, Lima TJ, Brito JA, Oliveira ACCD, Pannuti CS. Risk factors associated with death in Brazilian children with severe dengue: a case-control study. Clinics (Sao Paulo) 2014; 69:55-60. [PMID: 24473560 PMCID: PMC3870309 DOI: 10.6061/clinics/2014(01)08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/19/2013] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE The purpose of this case-control study was to evaluate risk factors associated with death in children with severe dengue. METHODS The clinical condition of hospitalized patients with severe dengue who died (cases, n = 18) was compared with that of hospitalized patients with severe dengue who survived (controls, n = 77). The inclusion criteria for this study were age under 13 years; hospital admission in São Luis, northeastern Brazil; and laboratory-confirmed diagnosis of dengue. RESULTS Severe bleeding (hemoptysis), a defining criterion for dengue severity, was the factor most strongly associated with death in our study. We also found that epistaxis and persistent vomiting, both included as warning signs in the World Health Organization (WHO) classification of dengue, were strongly associated with death. No significant association was observed between any of the laboratory findings and death. CONCLUSIONS The finding that epistaxis and persistent vomiting were also associated with death in children with severe dengue was unexpected and deserves to be explored in future studies. Because intensive care units are often limited in resource-poor settings, any information that can help to distinguish patients with severe dengue with a higher risk to progress to death may be crucial.
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Affiliation(s)
| | - Expedito José de Albuquerque Luna
- Departamento de Moléstias Infecciosas e Parasitárias (LIMHC), Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo/SP, Brazil, Universidade de Sa˜o Paulo, Instituto de Medicina Tropical de Sa˜o Paulo, Departamento de Mole´ stias Infecciosas e Parasita´ rias (LIMHC), Sa˜o Paulo/SP, Brazil
| | - Leônidas Lopes Braga Júnior
- Hospital da Universidade Federal do Maranhão, São Luís/MA, Brazil, Hospital da Universidade Federal do Maranha˜o, Sa˜o Luı´s/MA, Brazil
| | | | - Lívia Teresa Moreira Rios
- Hospital da Universidade Federal do Maranhão, São Luís/MA, Brazil, Hospital da Universidade Federal do Maranha˜o, Sa˜o Luı´s/MA, Brazil
| | - Maria do Socorro da Silva
- Vigilância Epidemiológica Municipal de São Luís, São Luís/MA, Brazil, Vigilância Epidemiológica Municipal de São Luı´s, Sa˜o Luı´s/MA, Brazil
| | - Maria Nilza Lima Medeiros
- Vigilância Epidemiológica Municipal de São Luís, São Luís/MA, Brazil, Vigilância Epidemiológica Municipal de São Luı´s, Sa˜o Luı´s/MA, Brazil
| | - Gilnara Fontinelle Silva
- Departamento de Patologia, Universidade Federal do Maranhão, São Luís/MA, Brazil, Universidade Federal do Maranha˜ o, Departamento de Patologia, Sa˜o Luı´s/MA, Brazil
| | - Fernanda Campos Amaral Figueiredo Nina
- Departamento de Patologia, Universidade Federal do Maranhão, São Luís/MA, Brazil, Universidade Federal do Maranha˜ o, Departamento de Patologia, Sa˜o Luı´s/MA, Brazil
| | - Taliane Jardim Lima
- Departamento de Patologia, Universidade Federal do Maranhão, São Luís/MA, Brazil, Universidade Federal do Maranha˜ o, Departamento de Patologia, Sa˜o Luı´s/MA, Brazil
| | - Jayron Alves Brito
- Departamento de Patologia, Universidade Federal do Maranhão, São Luís/MA, Brazil, Universidade Federal do Maranha˜ o, Departamento de Patologia, Sa˜o Luı´s/MA, Brazil
| | - Avessandra Costa Cardoso de Oliveira
- Departamento de Patologia, Universidade Federal do Maranhão, São Luís/MA, Brazil, Universidade Federal do Maranha˜ o, Departamento de Patologia, Sa˜o Luı´s/MA, Brazil
| | - Claudio Sergio Pannuti
- Departamento de Moléstias Infecciosas e Parasitárias (LIMHC), Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo/SP, Brazil, Universidade de Sa˜o Paulo, Instituto de Medicina Tropical de Sa˜o Paulo, Departamento de Mole´ stias Infecciosas e Parasita´ rias (LIMHC), Sa˜o Paulo/SP, Brazil
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12
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Guerra-Silveira F, Abad-Franch F. Sex bias in infectious disease epidemiology: patterns and processes. PLoS One 2013; 8:e62390. [PMID: 23638062 PMCID: PMC3634762 DOI: 10.1371/journal.pone.0062390] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 03/25/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Infectious disease incidence is often male-biased. Two main hypotheses have been proposed to explain this observation. The physiological hypothesis (PH) emphasizes differences in sex hormones and genetic architecture, while the behavioral hypothesis (BH) stresses gender-related differences in exposure. Surprisingly, the population-level predictions of these hypotheses are yet to be thoroughly tested in humans. METHODS AND FINDINGS For ten major pathogens, we tested PH and BH predictions about incidence and exposure-prevalence patterns. Compulsory-notification records (Brazil, 2006-2009) were used to estimate age-stratified ♂:♀ incidence rate ratios for the general population and across selected sociological contrasts. Exposure-prevalence odds ratios were derived from 82 published surveys. We estimated summary effect-size measures using random-effects models; our analyses encompass ∼0.5 million cases of disease or exposure. We found that, after puberty, disease incidence is male-biased in cutaneous and visceral leishmaniasis, schistosomiasis, pulmonary tuberculosis, leptospirosis, meningococcal meningitis, and hepatitis A. Severe dengue is female-biased, and no clear pattern is evident for typhoid fever. In leprosy, milder tuberculoid forms are female-biased, whereas more severe lepromatous forms are male-biased. For most diseases, male bias emerges also during infancy, when behavior is unbiased but sex steroid levels transiently rise. Behavioral factors likely modulate male-female differences in some diseases (the leishmaniases, tuberculosis, leptospirosis, or schistosomiasis) and age classes; however, average exposure-prevalence is significantly sex-biased only for Schistosoma and Leptospira. CONCLUSIONS Our results closely match some key PH predictions and contradict some crucial BH predictions, suggesting that gender-specific behavior plays an overall secondary role in generating sex bias. Physiological differences, including the crosstalk between sex hormones and immune effectors, thus emerge as the main candidate drivers of gender differences in infectious disease susceptibility.
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Affiliation(s)
- Felipe Guerra-Silveira
- Instituto Leônidas e Maria Deane – Fiocruz Amazônia, Manaus, Amazonas, Brazil
- School of Medicine, Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil
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13
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Recombinant envelope protein-based enzyme immunoassay for IgG antibodies is comparable to neutralization tests for epidemiological studies of dengue infection. J Virol Methods 2013; 187:114-20. [DOI: 10.1016/j.jviromet.2012.09.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 11/20/2022]
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14
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Resendes APDC, Silveira NAPRD, Sabroza PC, Souza-Santos R. Determination of priority areas for dengue control actions. Rev Saude Publica 2011; 44:274-82. [PMID: 20339626 DOI: 10.1590/s0034-89102010000200007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 08/05/2009] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To identify areas at risk of dengue transmission by means of cluster analysis. METHODS A cluster analysis in which the primary analysis units were the 48 districts of the municipality of Niterói, Southeastern Brazil, was conducted. The districts were grouped into six strata according to sociodemographic conditions, using the k-means cluster analysis method. After defining the strata, the incidence of dengue was calculated for each stratum in relation to four different periods: 1998 - 2000; 2001; 2002; 2003 - 2006. RESULTS The analysis on the incidence showed that the rates for the last three study periods were greatest in the stratum 2.1, which had the worst sanitation infrastructure conditions and high population increases, and in stratum 3.1, which had the highest percentage of shantytowns. Stratum 1.2 presented the lowest incidence and the best sanitation and income indicators, along with small increases in population and a low proportion of shantytowns. The incidence rates in 2001 and 2002 were high in most strata except for stratum 1.2, which had the districts with the least heterogeneity in relation to the indicators used. In 2001, the strata presented high rates of incidence when group immunity had supposedly become established for serotype I, thus expressing the transmission strength of this agent. CONCLUSIONS The cluster analysis technique made it possible to recognize priority areas. It indicated areas where the dengue control and surveillance actions needed to be improved, along with structural improvements that influenced the living conditions and health of the municipality's population.
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15
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Marón GM, Clará AW, Diddle JW, Pleités EB, Miller L, Macdonald G, Adderson EE. Association between nutritional status and severity of dengue infection in children in El Salvador. Am J Trop Med Hyg 2010; 82:324-9. [PMID: 20134012 DOI: 10.4269/ajtmh.2010.09-0365] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Clinical observations and some studies suggest that dengue virus infection is more severe among children with better nutritional status. We examined the nutritional status of children in El Salvador and its relationship between this and the severity of dengue infection. Z-scores for weight-for-age, height-for-age, and body mass index (BMI)-for-age of children with dengue fever (66), dengue hemorrhagic fever (62), and healthy controls (74) were compared. There were no differences in weight-for-age or BMI-for-age Z-scores between the three groups. Children with dengue fever had a greater height-for-age than healthy controls but no significant differences in rates of stunting. There was no difference in height between children with dengue fever and dengue hemorrhagic fever. Excess nutrition does not appear to be a risk factor for severe forms of dengue infection in El Salvador, nor does malnutrition appear to be predictive of good outcomes.
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Affiliation(s)
- Gabriela M Marón
- St. Jude Children's Research Hospital, 262 DannyThomas Place, Memphis, TN 38105-3678, USA.
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16
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Costa CAD, Santos IGCD, Barbosa MDG. Detecção e tipagem de vírus dengue em Aedes aegypti (Diptera: Culicidae) na Cidade de Manaus, Estado do Amazonas. Rev Soc Bras Med Trop 2009; 42:677-81. [DOI: 10.1590/s0037-86822009000600013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 11/05/2009] [Indexed: 11/22/2022] Open
Abstract
O estudo teve por objetivo a detecção e tipagem do vírus dengue, nos vetores Aedes aegypti. Durante o período de dezembro de 2005 a dezembro de 2006, foram coletados 8.984 mosquitos, em 46 bairros da Cidade de Manaus abrangendo todas as zonas geográficas da cidade. Destes, 819 eram Aedes aegypti (414 fêmeas e 405 machos). As fêmeas de Aedes aegypti foram agrupadas em pools de 1 a 10 mosquitos totalizando 138 pools, sendo que 111 pools foram positivos para DENV 3. Porém, um pool mostrou-se positivo para dois sorotipos, DENV 1 e DENV 3. A prevalência de Aedes aegypti infectados com DENV 3, na Cidade de Manaus foi de 53%. Entretanto, a prevalência por zona foi de 70% no Centro-oeste, 60% no Sul, 53% no Oeste, 47% no Centro-Sul, 30% no Norte e 23% na zona Leste. O monitoramento da circulação viral em mosquitos com o uso da técnica da transcrição reversa-reação da polimerase em cadeia que permite o conhecimento prévio dos níveis de disseminação viral em determinadas áreas contribuindo para determinar os locais para aplicar as medidas de prevenção e controle.
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17
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Machado JP, Oliveira RMD, Souza-Santos R. [Spatial analysis of dengue occurrence and living conditions in Nova Iguaçu, Rio de Janeiro State, Brazil]. CAD SAUDE PUBLICA 2009; 25:1025-34. [PMID: 19488487 DOI: 10.1590/s0102-311x2009000500009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Accepted: 12/29/2008] [Indexed: 11/22/2022] Open
Abstract
The reemergence, spread, and persistence of dengue are currently challenging the Brazilian health system. Factors related to living conditions have been addressed to understand different health outcomes. This study examines the occurrence of dengue and its relationship to living conditions in the city of Nova Iguaçu, Rio de Janeiro State, from 1996 to 2004. Data on dengue occurrence were obtained from the Brazilian National Disease Notification System (SINAN). A composite indicator of socioeconomic and urban infrastructure variables was created to characterize the prevailing living conditions, using 2000 census data. Operations between layers were used to identify spatial associations between the composite indicator and dengue incidence by neighborhood. The results do not show a linear relationship between poor living conditions and disease occurrence, but the spatial patterns indicated greater susceptibility of areas with inequalities in living conditions and behind highway access routes. The results also suggest that such inequalities can influence the dengue time trend. Thus, models that consider the interaction between socioeconomic variables (and not only the quantification of social indicators) can be useful for dengue surveillance.
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Affiliation(s)
- Juliana Pires Machado
- Gerência de Produção e Análise de Informações, Agência Nacional de Saúde Suplementar, Rio de Janeiro, Brasil.
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18
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Teixeira MG, Costa MDCN, Barreto F, Barreto ML. Dengue: twenty-five years since reemergence in Brazil. CAD SAUDE PUBLICA 2009; 25 Suppl 1:S7-18. [DOI: 10.1590/s0102-311x2009001300002] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 07/03/2008] [Indexed: 11/21/2022] Open
Abstract
This article revisits the epidemiology of dengue in Brazil, 25 years after its reemergence in the country, discussing the main determinants and implications for its control. The authors emphasize the clinical and epidemiological peculiarities of this viral disease in Brazil, which leads the world in both the number of cases reported and risk of occurrence of the disease. The article presents the changes occurring in the dengue epidemiological pattern in recent years, like the sudden age shift in the incidence of dengue hemorrhagic fever, and discusses possible associated factors. The article focuses specifically on the epidemic in Rio de Janeiro in 2008, this episode's impact on the international community, and the fear that the disease could spread to Europe. The authors conclude that the current situation emphasizes the need for the international scientific community to renew its efforts to generate knowledge allowing improvement and progress in the development of new tools and strategies for dengue prevention.
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19
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Siqueira-Junior JB, Maciel IJ, Barcellos C, Souza WV, Carvalho MS, Nascimento NE, Oliveira RM, Morais-Neto O, Martelli CMT. Spatial point analysis based on dengue surveys at household level in central Brazil. BMC Public Health 2008; 8:361. [PMID: 18937868 PMCID: PMC2576465 DOI: 10.1186/1471-2458-8-361] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 10/20/2008] [Indexed: 12/03/2022] Open
Abstract
Background Dengue virus (DENV) affects nonimunne human populations in tropical and subtropical regions. In the Americas, dengue has drastically increased in the last two decades and Brazil is considered one of the most affected countries. The high frequency of asymptomatic infection makes difficult to estimate prevalence of infection using registered cases and to locate high risk intra-urban area at population level. The goal of this spatial point analysis was to identify potential high-risk intra-urban areas of dengue, using data collected at household level from surveys. Methods Two household surveys took place in the city of Goiania (~1.1 million population), Central Brazil in the year 2001 and 2002. First survey screened 1,586 asymptomatic individuals older than 5 years of age. Second survey 2,906 asymptomatic volunteers, same age-groups, were selected by multistage sampling (census tracts; blocks; households) using available digital maps. Sera from participants were tested by dengue virus-specific IgM/IgG by EIA. A Generalized Additive Model (GAM) was used to detect the spatial varying risk over the region. Initially without any fixed covariates, to depict the overall risk map, followed by a model including the main covariates and the year, where the resulting maps show the risk associated with living place, controlled for the individual risk factors. This method has the advantage to generate smoothed risk factors maps, adjusted by socio-demographic covariates. Results The prevalence of antibody against dengue infection was 37.3% (95%CI [35.5–39.1]) in the year 2002; 7.8% increase in one-year interval. The spatial variation in risk of dengue infection significantly changed when comparing 2001 with 2002, (ORadjusted = 1.35; p < 0.001), while controlling for potential confounders using GAM model. Also increasing age and low education levels were associated with dengue infection. Conclusion This study showed spatial heterogeneity in the risk areas of dengue when using a spatial multivariate approach in a short time interval. Data from household surveys pointed out that low prevalence areas in 2001 surveys shifted to high-risk area in consecutive year. This mapping of dengue risks should give insights for control interventions in urban areas.
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Affiliation(s)
- João B Siqueira-Junior
- Institute of Tropical Pathology and Public Health, Federal University of Goias, Department of Collective Health, Goias, Brazil.
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20
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Mondini A, Chiaravalloti Neto F. [Socioeconomic variables and dengue transmission]. Rev Saude Publica 2008; 41:923-30. [PMID: 18066463 DOI: 10.1590/s0034-89102007000600006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 06/18/2007] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To evaluate the relationship between risk of occurrence of dengue and socioeconomic level. METHODS All confirmed autochthonous cases of dengue between September 1990 and August 2002 were geocoded and grouped according to the urban census tracts of the municipality of São José do Rio Preto, Southeastern Brazil. A socioeconomic factor generated by principal component analysis was used to group census tracts into four socioeconomic levels. Incidence rates were calculated for each year and four-year period for each of the census sectors, considering the period from September of one year to August of the next. Thematic maps of sectors, grouped into each of the four socioeconomic levels and their respective disease incidences, are presented. RESULTS Principal component analysis generated a socioeconomic factor that accounted for 87% of total variation. This factor was associated with dengue incidence only for the 1994-95 period. CONCLUSIONS The lack of an association between risk of occurrence of dengue and socioeconomic levels in almost all years studied indicates that this issue deserves further study, and may vary depending on the settings found in each municipality. It will be important to determine the spatial relationship between dengue transmission and other variables, such as degree of immunity in the population, effectiveness of control measures, degree of infestation by the vector; and population habits and behaviors, among others.
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Affiliation(s)
- Adriano Mondini
- Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, SP, Brasil
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Mondini A, Chiaravalloti-Neto F. Spatial correlation of incidence of dengue with socioeconomic, demographic and environmental variables in a Brazilian city. THE SCIENCE OF THE TOTAL ENVIRONMENT 2008; 393:241-8. [PMID: 18262225 DOI: 10.1016/j.scitotenv.2008.01.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 01/03/2008] [Accepted: 01/04/2008] [Indexed: 05/13/2023]
Abstract
Dengue is endemic in most tropical countries. The reasons for its maintenance are related to several risk factors including socioeconomic factors. Urban space and time are also two important dimensions to describe the dynamics of an outbreak. The aim of this study was to evaluate the existence of a spatial correlation of the incidence of dengue and to identify variables that explain the spatial dependence in a medium-sized city of Brazil. We analyzed registered autochthonous dengue cases from September 1994 to August 2002 correlating them with socioeconomic, demographic and environmental variables using the Moran index. Our results indicate spatial dependence of the incidence of dengue and that socioeconomic factors were critical both at the beginning of the study and later on; other variables related to the organization of urban space were also involved in the occurrence of the disease. The use of spatial analysis tools is important to identify critical control areas with several variables intimately related to the modulation of the disease dynamics.
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Affiliation(s)
- Adriano Mondini
- Laboratório de Vetores. Faculdade de Medicina de São José do Rio Preto, São Pedro, São José do Rio Preto, SP, Brazil
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Lima VLCD, Rangel O, Andrade VR, Silveira NYJD, Oliveira SSD, Figueiredo LTM. [Dengue: sero-epidemiological survey and virological surveillance in Campinas, São Paulo, Brazil]. CAD SAUDE PUBLICA 2008; 23:669-80. [PMID: 17334580 DOI: 10.1590/s0102-311x2007000300025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Accepted: 07/03/2006] [Indexed: 11/21/2022] Open
Abstract
The epidemiology of dengue in the municipality of Campinas, São Paulo, Brazil, was studied in 1998 using a randomized sero-epidemiological survey. Epidemiological surveillance data from 1996-2003 were also analyzed, with an emphasis on virological surveillance. 1,260 individuals participated in the survey and had blood samples drawn by finger stick on filter paper. Blood samples were tested by EIA-ICC, an enzyme immunoassay using infected cells as antigen. Dengue antibody prevalence (14.79%) was lower than in other surveys in other States of Brazil, but higher than in two other serological surveys in São Paulo State. Dengue antibody prevalence was far higher than the reported case incidence during the 1996, 1997, and 1998 epidemics. Antibody prevalence and reported case incidence in different health districts were disproportional. The article concludes by recommending further research on the significance of transmission rates during epidemics and more intensive virological surveillance, especially in years with few reported cases.
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Gonçalves Neto VS, Monteiro SG, Gonçalves AG, Rebêlo JMM. Conhecimentos e atitudes da população sobre dengue no Município de São Luís, Maranhão, Brasil, 2004. CAD SAUDE PUBLICA 2006; 22:2191-200. [PMID: 16951891 DOI: 10.1590/s0102-311x2006001000025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Accepted: 03/10/2006] [Indexed: 11/21/2022] Open
Abstract
Trata-se de uma investigação amostral com 843 entrevistados, realizado no Município de São Luís, Maranhão, Brasil. Avaliou-se o conhecimento da população sobre dengue, assim como suas condições sócio-econômicas, sanitárias e ambientais. Verificaram-se criadouros potenciais em toda a área pesquisada. A mídia (TV, rádio etc.) foi o meio de comunicação mais importante como fonte de informação sobre a doença para a população. No entanto, observou-se uma lacuna entre o conhecimento e a prática de atitudes voltadas para evitar a proliferação do mosquito do dengue. Os resultados indicam que se deve buscar estratégias que visem a envolver a população de São Luís para uma participação mais efetiva para evitar a proliferação do vetor e, assim, ajudar no controle do dengue.
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Teixeira MDG, Costa MDCN, Barreto ML, Mota E. Dengue and dengue hemorrhagic fever epidemics in Brazil: what research is needed based on trends, surveillance, and control experiences? CAD SAUDE PUBLICA 2005; 21:1307-15. [PMID: 16158135 DOI: 10.1590/s0102-311x2005000500002] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dengue epidemics account annually for several million cases and deaths worldwide. The high endemic level of dengue fever and its hemorrhagic form correlates to extensive domiciliary infestation by Aedes aegypti and multiple viral serotype human infection. This study analyzed serial case reports registered in Brazil since 1981, describing incidence evolutionary patterns and spatial distribution. Epidemic waves followed the introduction of every serotype (DEN 1 to 3), and reduction in susceptible individuals possibly accounted for decreasing case frequency. An incremental expansion of affected areas and increasing occurrence of dengue fever and its hemorrhagic form with high case fatality were noted in recent years. In contrast, efforts based solely on chemical vector control have been insufficient. Moreover, some evidence demonstrates that educational measures do not permanently modify population habits. Thus, as long as a vaccine is not available, further dengue control depends on potential results from basic interdisciplinary research and intervention evaluation studies, integrating environmental changes, community participation and education, epidemiological and virological surveillance, and strategic technological innovations aimed to stop transmission.
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25
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Barcellos C, Pustai AK, Weber MA, Brito MRV. [Identification of places with potential transmission of dengue fever in Porto Alegre using Geographical Information Systems]. Rev Soc Bras Med Trop 2005; 38:246-50. [PMID: 15895177 DOI: 10.1590/s0037-86822005000300008] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The social-environmental conditions that promote the continuity of Aedes aegypti in urban areas and its capacity for dengue transmission have yet to be determined. The aim of this work was to locate dengue cases and vector presence, then to identify social-environmental factors that characterize these sites, through Geographical Information Systems (GIS), with a view to developing a dengue fever prevention model. The vector was mainly located in south and east areas of the city, with a broad dispersion, while most of the cases were located in the central region of the city. The sectors with cases present characteristics of high income. Otherwise, sectors with vector present a predominance of houses and good sanitation infrastructure. The difference between cases and vector spatial patterns ensured for 2002 an absence of dengue transmission in the city.
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Affiliation(s)
- Christovam Barcellos
- Departamento de Informações em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro, RJ.
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26
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Gonçalves Neto VS, Rebêlo JMM. [Epidemiological characteristics of dengue in the Municipality of São Luís, Maranhão, Brazil, 1997-2002]. CAD SAUDE PUBLICA 2004; 20:1424-31. [PMID: 15486688 DOI: 10.1590/s0102-311x2004000500039] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A total of 12,008 cases of dengue were reported from 1997 to 2002, with peaks in 1997 (35.8%) and 1998 (45.8%). The disease predominated in the 15-49-year age group (72.2%) and during the rainy season (83.3%), showing a positive correlation with the amount of rainfall (r = 0.84) and relative humidity (r = 0.76) and a negative correlation with temperature (r = -0.78). There was no significant difference (chi2 = 2.319; p > 0.05) in the number of cases in males (49%) and females (51%). Dengue was detected in all seven health districts: Tirirical (27%), Coroadinho (17%), Bequimao (16%), Cohab (14%), Itaqui-Bacanga (11%), Centro (8%), and Vila Esperanca (7%). The building infestation rate ranged from 1.01 to 7.15, and the Breteau index ranged from 1.10 to 8.18. The most frequent mosquito breeding sites were metal barrels or similar recipients (80.0%), followed by plant vases (4.7%), bottles, cans, and plastics (3.6%), tires (3.3%), water tanks (2.7%), and others (5.7%). In the case of Aedes aegypti, 134,631 positive water deposits were detected, with a predominance of type B (80.0%), followed by types C (4.7%), E (3.6%), and A (3.3%).
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Heukelbach J, de Oliveira FA, Kerr-Pontes LR, Feldmeier H. Risk factors associated with an outbreak of dengue fever in a favela in Fortaleza, north-east Brazil. Trop Med Int Health 2001; 6:635-42. [PMID: 11555429 DOI: 10.1046/j.1365-3156.2001.00762.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To increase the effectiveness of ongoing anti-dengue control measures, we conducted a case-control study in a favela in Fortaleza (north-east Brazil) during an outbreak of dengue fever. Cases were defined according to the national guidelines for dengue control as well as based on the detection of IgM-dengue antibodies, and 34 cases and 34 controls were investigated. Significant risk factors were: living in a street perpendicular to the beach on which the favela is situated (P < 0.0001), an interval > 30 days since the last visit of the vector control agent (P=0.001), receptacles in the garden or courtyard (P=0.001), plants with temporary water pools on the property, gutter to collect rainwater, uncovered water storage container (all P=0.02), and no waste collection (P=0.03). Socio-economic variables were not associated with dengue fever. The probable starting point of the epidemic was an uncovered water tank on the roof of the house adjacent to the index case. From there, the outbreak spread uphill parallel to the prevailing direction of the wind. Thus, the chronological and spatial evolution of the epidemic could have been forecast after the first cases had occurred. This example of investigative epidemiology in an operational setting shows that targeted intervention leading to increased effectiveness of control measures is possible.
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Affiliation(s)
- J Heukelbach
- School of Public Health at Ceará State, Fortaleza, Brazil.
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28
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Teixeira MG, Costa MC, Barreto ML, Barreto FR. [Epidemiology of dengue in Salvador-Bahia, 1995-1999]. Rev Soc Bras Med Trop 2001; 34:269-74. [PMID: 11460213 DOI: 10.1590/s0037-86822001000300007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Since 1981, Brazil has registered dengue epidemic and simultaneous circulation of the DEN-1 and DEN-2 serotypes in over 2,700 municipalities. In Salvador- Bahia, located in the Northeastern region of the Country, two epidemic outbreaks occurred in the years of 1995 and 1996, with further endemic spread of the disease. This study analyses the incidence of the virosis within this municipal area, from 1995 to 1999, considering, among other variables, its distribution in the Sanitary Districts and density of Aedes aegypti. Registers of notified cases and the city's Vectorial Control Program were used as data source. The incidence rate of notified cases of dengue in 1995 and 1996, which were 691.4 and 393.5 per 100,000 inhabitants, respectively, decreased to 65 per 100,000 inhabitants in 1998. In the poorer Sanitary Districts, this index reached figures of over 800 per 100,000 inhabitants. The Premise Index for Aedes aegypti reached 54.1% in one of the Districts. Bearing in mind the relevance of the re-emergence of dengue in the world, the authors discuss the possible factors which condition the virus introduction, its epidemiological presentation over the course of four years, and the effectiveness of the vectorial combat (eradication) program.
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Affiliation(s)
- M G Teixeira
- Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, BA.
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Vasconcelos PF, Mota K, Straatmann A, Santos-Torres S, da Rosa AP, Tavares Neto J. [A dengue epidemic in Ipupiara and Prado, Bahia. A seroepidemiologic survey]. Rev Soc Bras Med Trop 2000; 33:61-7. [PMID: 10881120 DOI: 10.1590/s0037-86822000000100009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Serologic studies in Brazil have indicated a 25% to 56% prevalence of dengue virus infections. However, these studies were carried out in populations of middle-sized and larger cities. The present study describes two epidemics of classic dengue fever in two small cities in the State of Bahia. The first occurred in 1987, in Ipupiara and was caused by dengue serotype-1 (DEN-1), the second occurred in 1995, in Prado and was caused by dengue serotype-2 (DEN-2). The laboratory diagnosis was made by the hemagglutination-inhibition test. 461 serum samples were collected in 1995 in Ipupiara (district of Chapada Diamantina) out of a population of 3,868 and 228 samples out of a total of 9,126 inhabitants of Prado (in the southernmost coastal region). The seropositivity of the samples was 11.9% (55/461) in Ipupiara and 17.5% (40/228) in Prado. These were no statistically significant differences as to age and sex between seropositive and seronegative individuals of the two cities studied. However, the seropositive cases in Ipupiara indicated a higher percentage (15.9% vs. 9.3%) of residency in or travel to other states of Brazil (p<0.03). Based on these data we estimate the occurrence of 460 and 1,597 cases of infection in Ipupiara and Prado, respectively. In conclusion, dengue virus infections in smaller cities probably have singular characteristics, since they exhibit a lesser prevalence of seropositivity caused by decreased breeding possibilities of Aedes aegypti.
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Affiliation(s)
- P F Vasconcelos
- Centro Colaborador da Organizacão Mundial de Saúde para Arbovirus, Serviço de Arbovírus, Instituto Evandro Chagas, Belém, PA
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