Correlation between HIV and HCV in Brazilian prisoners: evidence for parenteral transmission inside prison

OBJETIVO: É um fato correntemente aceito que as condições de confinamento aumentam o risco de algumas infecções relacionadas às práticas sexuais e/ou ao uso de drogas injetáveis. Realizou-se estudo para estimar a densidade de incidência da infecção pelo HIV na população prisional com aplicação de técnicas matemáticas. MÉTODOS: Foram entrevistados em São Paulo, SP, 631 prisioneiros da maior prisão da América do Sul, que abrigava aproximadamente 4.900 presos na ocasião do estudo. Foi colhido sangue da população entrevistada, analisado o risco para a infecção pelo HIV e realizados testes sorológicos para HIV, HCV e sífilis. Técnicas matemáticas foram usadas para se estimar a densidade de incidência do HIV relacionada ao tempo de encarceramento. RESULTADOS: As prevalências gerais encontradas foram: HIV -- 16%; HCV -- 34%; sífilis -- 18%. Os principais fatores associados à infecção pelo HIV foram a soropositividade ao HCV (OR=10,49) e a confissão do uso de drogas injetáveis (OR=3,36). A análise matemática mostrou que o risco de adquirir a infecção pelo HIV aumenta com o tempo de detenção, atingindo o máximo por volta de 3 anos de aprisionamento. CONCLUSÕES: A correlação entre a soroprevalência do HIV e do HCV e os resultados da análise matemática sugerem que a transmissão do HIV nestsa população se dá preferencialmente pela via parenteral e que seu risco aumenta com o tempo de encarceramento.OBJECTIVE: It is an accepted fact that confinement conditions increase the risk of some infections related to sexual and/or injecting drugs practices. Mathematical techniques were applied to estimate time-dependent incidence densities of HIV infection among inmates. METHODS: A total of 631 prisoners from a Brazilian prison with 4,900 inmates at that time were interviewed and their blood drawn. Risky behavior for HIV infection was analyzed, and serological tests for HIV, hepatitis C and syphilis were performed, intended as surrogates for parenteral and sexual HIV transmission, respectively. Mathematical techniques were used to estimate the incidence density ratio, as related to the time of imprisonment. RESULTS: Prevalence were: HIV -- 16%; HCV -- 34%; and syphilis -- 18%. The main risk behaviors related to HIV infection were HCV prevalence (OR=10.49) and the acknowledged use of injecting drugs (OR=3.36). Incidence density ratio derivation showed that the risk of acquiring HIV infection increases with the time of imprisonment, peaking around three years after incarceration. CONCLUSIONS: The correlation between HIV and HCV seroprevalence and the results of the mathematical analysis suggest that HIV transmission in this population is predominantly due to parenteral exposure by injecting drug, and that it increases with time of imprisonment

Correlation between HIV and HCV in Brazilian prisoners: evidence for parenteral transmission inside prison

OBJETIVO: É um fato correntemente aceito que as condições de confinamento aumentam o risco de algumas infecções relacionadas às práticas sexuais e/ou ao uso de drogas injetáveis. Realizou-se estudo para estimar a densidade de incidência da infecção pelo HIV na população prisional com aplicação de técnicas matemáticas. MÉTODOS: Foram entrevistados em São Paulo, SP, 631 prisioneiros da maior prisão da América do Sul, que abrigava aproximadamente 4.900 presos na ocasião do estudo. Foi colhido sangue da população entrevistada, analisado o risco para a infecção pelo HIV e realizados testes sorológicos para HIV, HCV e sífilis. Técnicas matemáticas foram usadas para se estimar a densidade de incidência do HIV relacionada ao tempo de encarceramento. RESULTADOS: As prevalências gerais encontradas foram: HIV -- 16%; HCV -- 34%; sífilis -- 18%. Os principais fatores associados à infecção pelo HIV foram a soropositividade ao HCV (OR=10,49) e a confissão do uso de drogas injetáveis (OR=3,36). A análise matemática mostrou que o risco de adquirir a infecção pelo HIV aumenta com o tempo de detenção, atingindo o máximo por volta de 3 anos de aprisionamento. CONCLUSÕES: A correlação entre a soroprevalência do HIV e do HCV e os resultados da análise matemática sugerem que a transmissão do HIV nestsa população se dá preferencialmente pela via parenteral e que seu risco aumenta com o tempo de encarceramento.OBJECTIVE: It is an accepted fact that confinement conditions increase the risk of some infections related to sexual and/or injecting drugs practices. Mathematical techniques were applied to estimate time-dependent incidence densities of HIV infection among inmates. METHODS: A total of 631 prisoners from a Brazilian prison with 4,900 inmates at that time were interviewed and their blood drawn. Risky behavior for HIV infection was analyzed, and serological tests for HIV, hepatitis C and syphilis were performed, intended as surrogates for parenteral and sexual HIV transmission, respectively. Mathematical techniques were used to estimate the incidence density ratio, as related to the time of imprisonment. RESULTS: Prevalence were: HIV -- 16%; HCV -- 34%; and syphilis -- 18%. The main risk behaviors related to HIV infection were HCV prevalence (OR=10.49) and the acknowledged use of injecting drugs (OR=3.36). Incidence density ratio derivation showed that the risk of acquiring HIV infection increases with the time of imprisonment, peaking around three years after incarceration. CONCLUSIONS: The correlation between HIV and HCV seroprevalence and the results of the mathematical analysis suggest that HIV transmission in this population is predominantly due to parenteral exposure by injecting drug, and that it increases with time of imprisonment

Modeling the risk of malaria for travelers to areas with stable malaria transmission

BACKGROUND: Malaria is an important threat to travelers visiting endemic regions. The risk of acquiring malaria is complex and a number of factors including transmission intensity, duration of exposure, season of the year and use of chemoprophylaxis have to be taken into account estimating risk. MATERIALS AND METHODS: A mathematical model was developed to estimate the risk of non-immune individual acquiring falciparum malaria when traveling to the Amazon region of Brazil. The risk of malaria infection to travelers was calculated as a function of duration of exposure and season of arrival. RESULTS: The results suggest significant variation of risk for non-immune travelers depending on arrival season, duration of the visit and transmission intensity. The calculated risk for visitors staying longer than 4 months during peak transmission was 0.5% per visit. CONCLUSIONS: Risk estimates based on mathematical modeling based on accurate data can be a valuable tool in assessing risk/benefits and cost/benefits when deciding on the value of interventions for travelers to malaria endemic regions

Age and regional differences in clinical presentation and risk of hospitalization for dengue in Brazil, 2000-2014

OBJECTIVES: Dengue cases range from asymptomatic to severe, eventually leading to hospitalization and death. Timely and appropriate management is critical to reduce morbidity. Since 1980, dengue has spread throughout Brazil, affecting an increasing number of individuals. This paper describes age and regional differences in dengue’s clinical presentation and associated risk of hospitalization based on more than 5 million cases reported to the Brazilian Ministry of Health from 2000-2014. METHODS: We performed a retrospective analysis of ∼5,450,000 dengue cases, relating clinical manifestations and the risk of hospitalization to age, gender, previous infection by dengue, dengue virus serotype, years of formal education, delay to first attendance and the occurrence of dengue during outbreaks and in different Brazilian regions. RESULTS: Complicated forms of dengue occurred more frequently among those younger than 10 years (3.12% vs 1.92%) and those with dengue virus 2 infection (7.65% vs 2.42%), with a delay to first attendance >2 days (3.18% vs 0.82%) and with ≤4 years of formal education (2.02% vs 1.46%). The risk of hospitalization was higher among those aged 6-10 years old (OR 4.57; 95% CI 1.43-29.96) and those who were infected by dengue virus 2 (OR 6.36; 95% CI 2.52-16.06), who lived in the Northeast region (OR 1.38; 95% CI 1.11-2.10) and who delayed first attendance by >5 days (composite OR 3.15; 95% CI 1.33-8.9). CONCLUSIONS: In Brazil, the occurrence of severe dengue and related hospitalization is associated with being younger than 10 years old, being infected by dengue virus 2 or 3, living in the Northeast region (the poorest and the second most populated) and delaying first attendance for more than 2 days

Short-term economic impact of the Zika virus outbreak

Summary Zika virus (ZIKV) is mainly transmitted by mosquitoes bites. However, transmission by sexual contacts has been reported in 11 non endemic countries. The rapid spread of ZIKV in Latin American and Caribbean Countries (LCR), person-to-person transmission and perceived risk on people’s well being can affect the emerging economies of LCR which historically dependent on truism. Here we present an analysis on economic outputs for assessing the current impact of ZIKV on markets. Our analysis show an unexpected resilience of LCR markets to international alerts. This positive response represents an opportunity to scale-up interventions for preventing the further spreading of the ZIKV epidemic

Optimal Timing of Insecticide Fogging to Minimize Dengue Cases: Modeling Dengue Transmission among Various Seasonalities and Transmission Intensities

Dengue virus infection is a serious infectious disease transmitted by Aedes mosquitoes in the tropics and sub-tropics. Disease control often involves the use of insecticide fogging against mosquito vectors. However, the effectiveness of this method for reducing dengue cases, in addition to appropriate application procedures, is still debated. The previous mathematical simulation study reported that insecticide fogging reduces dengue cases most effectively when applied soon after the epidemic peak; however, the model did not take into account seasonality and population immunity, which strongly affect the epidemic pattern of dengue infection. Considering these important factors, we used a mathematical simulation model to explore the most effective time for insecticide fogging and to evaluate its impact on reducing dengue cases. Simulations were conducted with various lengths of the wet season and population immunity levels. We found that insecticide fogging substantially reduces dengue cases if conducted at an appropriate time. In contrast to the previously suggested application time during the peak of disease prevalence, the optimal timing is relatively early: between the beginning of the dengue season and the prevalence peak

Risk factors for hepatitis C virus infection among blood donors in southern Brazil: a case-control study

BACKGROUND: In Brazil, it is estimated that between 2.5 and 4.9% of the general population present anti-hepatitis C virus (HCV) antibodies, which corresponds to as many as 3.9 to 7.6 million chronic carriers. Chronic liver disease is associated with HCV infection in 20% to 58% of the Brazilian patients. The objective of this case-control study was to investigate the risk factors for presence of anti-HCV antibody in blood donors in southern Brazil. METHODS: One hundred and seventy eight blood donors with two positive ELISA results for anti-HCV were cases, and 356 controls tested negative. A standardized questionnaire was used to collect data concerning demographic and socioeconomic aspects, history of previous hepatitis infection, social and sexual behaviors, and number of donations. Variables were grouped into sets of hierarchical categories. Cases and controls were compared using logistic regression, odds ratios, and 95% confidence intervals. The statistical significance of the associations was assessed through likelihood ratio tests based on a P value < 0.05. RESULTS: The prevalence of anti-HCV among blood donors was 1.1%. Most of the donors were white and males. In the multivariate analysis, independent predictors of anti-HCV positivity were: intravenous drug use, blood transfusion >10 years earlier, having had two to four sexually transmitted diseases, incarceration, tattooing, sex with a hepatitis B or C virus carrier or with intravenous drug users. CONCLUSION: Intravenous drug use, blood transfusion, and tattooing were the main risk factors for anti-HCV positivity among blood donors from southern Brazil, but sexual HCV transmission should also be considered

Modeling Transmission Dynamics and Control of Vector-Borne Neglected Tropical Diseases

Neglected tropical diseases affect more than one billion people worldwide. The populations most impacted by such diseases are typically the most resource-limited. Mathematical modeling of disease transmission and cost-effectiveness analyses can play a central role in maximizing the utility of limited resources for neglected tropical diseases. We review the contributions that mathematical modeling has made to optimizing intervention strategies of vector-borne neglected diseases. We propose directions forward in the modeling of these diseases, including integrating new knowledge of vector and pathogen ecology, incorporating evolutionary responses to interventions, and expanding the scope of sensitivity analysis in order to achieve robust results

Imaginal Discs – A New Source of Chromosomes for Genome Mapping of the Yellow Fever Mosquito Aedes aegypti

Dengue fever is an emerging health threat to as much as half of the human population around the world. No vaccines or drug treatments are currently available. Thus, disease prevention is largely based on efforts to control its major mosquito vector Ae. aegypti. Novel vector control strategies, such as population replacement with pathogen-incompetent transgenic mosquitoes, rely on detailed knowledge of the genome organization for the mosquito. However, the current genome assembly of Ae. aegypti is highly fragmented and requires additional physical mapping onto chromosomes. The absence of readable polytene chromosomes makes genome mapping for this mosquito extremely challenging. In this study, we discovered and investigated a new source of chromosomes useful for the cytogenetic analysis in Ae. aegypti – mitotic chromosomes from imaginal discs of 4th instar larvae. Using natural banding patterns of these chromosomes, we developed a new band-based approach for physical mapping of DNA probes to the precise chromosomal positions. Further application of this approach for genome mapping will greatly enhance the utility of the existing draft genome sequence assembly for Ae. aegypti and thereby facilitate application of advanced genome technologies for investigating and developing novel genetic control strategies for dengue transmission