1. Introduction

Dengue is a viral infection endemic to tropical regions, which is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. It usually presents a cyclic behavior with peaks separated by

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

3–5 years [1–3]. Even though this illness has been present for many years in tropical countries, the main prevention strategy is controlling the vector that carries the infection. Nowadays, vector control and prevention programs are the only strategies in the hands of public officials to handle and reduce dengue incidence.

compares different healthcare interventions estimating the economic costs and health gains (usually measured as Disability-Adjusted Life Years) of each intervention and hence identifies strategies with the potential of yielding the greatest health improvement for the least resources used [12]. The aforesaid type of analysis consists of two main elements, the burden estimation in the status quo scenario or current condition and the estimation in the intervention scenario. From this perspective, the analysis conducted in this chapter presents the burden estimation in

The Burden of Dengue Illness and Its Economics Costs in the Americas: A Review on the Most Affected Countries

http://dx.doi.org/10.5772/intechopen.79887

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As well as Latin-American and Caribbean countries, Asian countries have also been affected by dengue. Epidemiological studies conducted for Myanmar show that DALYs per million of inhabitants lost ranged between 90 and 97 in the 1990s [13], while in Thailand, the burden was estimated at 427 DALYs per million in the early 2000s. The latter allow us to have a frame of reference about the burden of dengue. Due to the increasing number of cases in Americas and Asia [14–16] and the economic cost that society must borne to treat (medical and out-of-pocket costs) and control the disease (prevention and promotion, surveillance and control activities), dengue continues to be a public health priority, especially in the regions previously mentioned. This chapter aims to present a recent picture of the treatment costs, generated by the disease and borne by the healthcare system and households, and its burden on the public health in

The following sections contain: the explanation of the criteria used to select the group of countries for which the total economic cost and burden of the disease were calculated (Countries selection); the methodology used for estimating the DALY and the total economic cost, as well as the necessary adjustment in the cost figures (Materials and methods); the main results for the year 2015 (Results) and finally a brief discussion on the current levels of incidence of dengue as a comparison between 2015 and 2017 in terms of total costs and burden. By estimating the burden for 2015, which corresponds to the year with the highest number of reported dengue cases, according to PAHO, we can estimate the impact that dengue has on public health and health expenditure in an epidemic year. In contrast, having the results for 2017 not only shows a more recent level of the burden but also serve as a comparison of the disease's impact between epidemic and inter-epidemic years. It is worth noting that even though the figures used in this chapter correspond to official figures collected by PAHO, underreport in the information health systems is an element that could hide the real burden1

To select the countries reviewed, we consider two main elements. The total number of dengue cases in each country according to Pan American Health Organization (PAHO) reports and the availability of information regarding total and average economic costs (per patient). Additionally,

Although it is challenging to estimate a robust level for underreport, attempts have been made. In Brazil the underreport expansion factor for total dengue cases have been estimated in 1.6, while in Nicaragua this estimation goes as high as 28. Additionally, the estimation for the underreport factor specific for severe dengue cases ranges from 1.4 to 3 [20].

.

relevant countries for each one of the main territories of the Americas.

the status quo scenario.

2. Countries selection

1

In the 1970s, because of the vector control campaign against yellow fever, dengue was close to be eliminated, but then it showed a reinvasion that has been present to this day [4]. The constant presence of the illness (and the mosquitoes) is related with the suboptimal conditions of trash collection, piped water supplies and uncontrolled urban development [5]. Another possible cause is climate change [6]. Warming temperatures have expanded the endemic territories of the A. aegypti and A. albopictus mosquitoes allowing them to be present in larger areas [7], which added to the low efficacy of vector control strategies and create the perfect scenario for the number of dengue cases to rise. Unfortunately, the programs aimed to control the mosquito population have low success rates which are reflected in the consistent high number of dengue cases in the last decade.

In recent years, there has been enough interest from the pharmaceutical industry to develop a dengue vaccine that could act as a preventive strategy against the infection [8–10]. Nevertheless, most dengue vaccine strategies are still in their final stages before implementation [11].

Figure 1 shows the evolution of the reported dengue cases in the Americas for the period 2010– 2017, from which it can be observed a drastic decline in the year 2017 after 2 years of high levels of dengue cases. Particularly, 2015 corresponds to the year with the highest number of cases in the region, which suggest it was an epidemic year. Given the cyclic behavior of the disease, the year 2017 could be interpreted as an interepidemic year.

The World Health Organization (WHO) recommends conducting an economic analysis for infectious disease to estimate the cost borne by the society, especially in low- and middleincome countries. These studies provide information to the governments that help them design policies and allocate public resources that achieve a positive impact on public health. The most common and recommended type of analysis is the cost-effectiveness analysis (CEA), which

Figure 1. Evolution of reported dengue cases in the Americas (2010–2017). Source: PAHO.

compares different healthcare interventions estimating the economic costs and health gains (usually measured as Disability-Adjusted Life Years) of each intervention and hence identifies strategies with the potential of yielding the greatest health improvement for the least resources used [12]. The aforesaid type of analysis consists of two main elements, the burden estimation in the status quo scenario or current condition and the estimation in the intervention scenario. From this perspective, the analysis conducted in this chapter presents the burden estimation in the status quo scenario.

As well as Latin-American and Caribbean countries, Asian countries have also been affected by dengue. Epidemiological studies conducted for Myanmar show that DALYs per million of inhabitants lost ranged between 90 and 97 in the 1990s [13], while in Thailand, the burden was estimated at 427 DALYs per million in the early 2000s. The latter allow us to have a frame of reference about the burden of dengue. Due to the increasing number of cases in Americas and Asia [14–16] and the economic cost that society must borne to treat (medical and out-of-pocket costs) and control the disease (prevention and promotion, surveillance and control activities), dengue continues to be a public health priority, especially in the regions previously mentioned. This chapter aims to present a recent picture of the treatment costs, generated by the disease and borne by the healthcare system and households, and its burden on the public health in relevant countries for each one of the main territories of the Americas.

The following sections contain: the explanation of the criteria used to select the group of countries for which the total economic cost and burden of the disease were calculated (Countries selection); the methodology used for estimating the DALY and the total economic cost, as well as the necessary adjustment in the cost figures (Materials and methods); the main results for the year 2015 (Results) and finally a brief discussion on the current levels of incidence of dengue as a comparison between 2015 and 2017 in terms of total costs and burden. By estimating the burden for 2015, which corresponds to the year with the highest number of reported dengue cases, according to PAHO, we can estimate the impact that dengue has on public health and health expenditure in an epidemic year. In contrast, having the results for 2017 not only shows a more recent level of the burden but also serve as a comparison of the disease's impact between epidemic and inter-epidemic years. It is worth noting that even though the figures used in this chapter correspond to official figures collected by PAHO, underreport in the information health systems is an element that could hide the real burden1 .
