Experiments with mathematical models to simulate hepatitis A population dynamics under different levels of endemicity

Guimaraens, Mariana Alves de; Codeço, Cláudia Torres

doi:10.1590/s0102-311x2005000500026

Cited by 9 publications

(9 citation statements)

References 17 publications

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“…The purpose of the study was to evaluate the effectiveness of interventions by quantitatively assessing the impact of campaigns that were implemented among MSM in terms of reducing the incidence of hepatitis A infection. We also examined the transmission dynamics in Japan, referring to published evidence on the transmission dynamics of HAV in the past [35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Assessing countermeasures during a hepatitis A virus outbreak among men who have sex with men

Saito

Imamura

Nishiura

2021

Theor Biol Med Model

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Background A hepatitis A epidemic occurred among men who have sex with men (MSM) in Japan in 2017–2018. In this study, we employ a parsimonious mathematical model to epidemiologically investigate the dynamics of infection, aiming to evaluate the effectiveness of campaign-based interventions among MSM to raise awareness of the situation. Methods A mathematical model describing a mixture of human-to-human transmission and environmental transmission was fitted to surveillance data. Taking seasonally varying environmental transmission into account, we estimated the reproduction number of hepatitis A virus during the course of epidemic, and, especially, the abrupt decline in this reproduction number following campaign-based interventions. Results The reproduction number prior to the countermeasures ranged from 2.6 to 3.1 and then began to decrease following campaign-based interventions. After the first countermeasure, the reproduction number decreased, but the epidemic remained supercritical (i.e., Rt > 1). The value of Rt dropped well below one following the second countermeasure, which used web articles to widely disseminate information about the epidemic risk. Conclusions Although the effective reproduction number, Rt, changes because of both intrinsic and extrinsic factors, the timing of the examined countermeasures against hepatitis A in the MSM population was consistent with the abrupt declines observed in Rt. Even without vaccination, the epidemic was brought under control, and risky behaviors may have been changed by the increase in situation awareness reached through web articles.

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Section: Introductionmentioning

confidence: 99%

Assessing countermeasures during a hepatitis A virus outbreak among men who have sex with men

Saito

Imamura

Nishiura

2021

Theor Biol Med Model

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“…Lower values of turbidity did not influence disease transmission; for average values, the turbidity was positively associated; and for higher values turbidity was negatively related to disease transmission. The peaked Gaussian distribution shape dependence was attributed to different characteristics of the limnological environment, for example, increased untreated sewage discharge into the environment (Guimaraens & Codeço, 2005), contamination of waterbodies nearby, and particle sedimentation (James et al., 2013; UNESCO, 1982). Aside from the fact that untreated sewage is directly linked to virus dispersion and propagation of the disease (Guimaraens & Codeço, 2005), wastewater also influences the attenuation of light in the water column, increasing the turbidity of the water body (de Oliveira et al., 2018).…”

Section: Discussionmentioning

confidence: 99%

Associations Between Environmental and Sociodemographic Data and Hepatitis‐A Transmission in Pará State (Brazil)

2021

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Risk assessment and vulnerability analyses are common practices in epidemiology (Avanzi et al., 2018;Gullón et al., 2017; WHO, 2014). Evidence from around the world confirms that climate change can affect distribution and occurrence of diseases, a major concern for policy making and healthcare facilities (UN, 2007). The health of human populations is sensitive to shifts in weather patterns and other aspects of climate change (Smith et al., 2015). Weather events and climate change are important drivers of the Abstract Hepatitis-A is a waterborne infectious disease transmitted by the eponymous hepatitis-A virus (HAV). Due to the disease's sociodemographic and environmental characteristics, this study applied public census and remote sensing data to assess risk factors for hepatitis-A transmission. Municipalitylevel data were obtained for the state of Pará, Brazil. Generalized linear and nonlinear models were evaluated as alternative predictors for hepatitis-A transmission in Pará. The Histogram Gradient Boost (HGB) regression model was deemed the best choice (RMSE= 2.36, and higher 2 R = 0.95) among the tested models. Partial dependence analysis and permutation feature importance analysis were used to investigate the partial dependence and the relative importance values of the independent variables in the disease transmission prediction model. Results indicated a complex relationship between the disease transmission and the sociodemographic and environmental characteristics of the study area. Population size, lack of sanitation, urban clustering, year of notification, insufficient public vaccination programs, household proximity to open-air dumpsites and storm-drains, and lack of access to healthcare facilities and hospitals were sociodemographic parameters related to HAV transmission. Turbidity and precipitation were the environmental parameters closest related to disease transmission. Based on HGB model, a hepatitis-A risk map was built for Pará state. The obtained risk map can be thought of as an auxiliary tool for public health strategies. This study reinforces the need to incorporate remote sensing data in epidemiological modelling and surveillance plans for the development of early prevention strategies for hepatitis-A.

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“…For example, among other researchers, Yongsi and Ntetu [21] in Cameroon, and Pande et al [22] in Benin, found that the standard of living has a positive impact on diarrhea, lowering the number of cases of diarrhea. Furthermore, research done in Brazil has found hepatitis A seroprevalence to be higher in low-income populations [23,24,25]. This paper fills a gap in the literature on the macro-level relationships for waterborne diarrhea and hepatitis A in Jordan since its approach is different from previous analyses that are local or site-specific.…”

Section: Introductionmentioning

confidence: 94%

Assessment of Macro-Level Socioeconomic Factors That Impact Waterborne Diseases: The Case of Jordan

Polimeni

Almalki

Iorgulescu

et al. 2016

IJERPH

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The Hashemite Kingdom of Jordan is an example of a country that suffers from high water scarcity. Additionally, due to the economic drivers in the country, such as phosphate and potash extraction and pharmaceutical production, the little fresh water that remains is generally polluted. The infrastructure, often antiquated in urban areas and non-existent in rural areas, also contributes to poor water conditions and to the spread of waterborne diseases. This paper examines the socioeconomic factors that contribute to diarrhea and hepatitis A on a macro level in Jordan and discusses the public-policies that government officials could use to abate those problems. Ordinary least squares time series models are used to understand the macro-level variables that impact the incidence of these diseases in Jordan. Public health expenditure has a significant impact on reducing their incidence. Furthermore, investment in sanitation facilities in rural regions is likely to reduce the number of cases of hepatitis A. Perhaps the most surprising outcome is that importation of goods and services likely results in a decrease in cases of hepatitis A. However, income has little impact on the incidence of diarrhea and hepatitis A.

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Experiments with mathematical models to simulate hepatitis A population dynamics under different levels of endemicity

Cited by 9 publications

References 17 publications

Assessing countermeasures during a hepatitis A virus outbreak among men who have sex with men

Assessing countermeasures during a hepatitis A virus outbreak among men who have sex with men

Associations Between Environmental and Sociodemographic Data and Hepatitis‐A Transmission in Pará State (Brazil)

Assessment of Macro-Level Socioeconomic Factors That Impact Waterborne Diseases: The Case of Jordan

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