The Prevention and Control of Dengue Fever in Urban Areas

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MUNICIPALITY OF PIRIPIRI MUNICIPAL HEALTH SECRETARIAT HEALTH EVIDENCE TEAM

SUMMARY OF EVIDENCE # 01/2011 (Final text from July 7th, 2011) Health Evidence Team of the Piripiri Municipal Health Secretariat (MHS): Almiro Mendes da Costa Neto (Nurse at Piripiri MHS); Carliane Maria de Araújo Souza (Nurse at Piripiri MHS); Ciro Maciel Nunes Ibiapina (Nurse at Piripiri MHS); Denise Paiva Ximenes (Nurse at Piripiri MHS); Evaldo Sales Leal (Nurse at Piripiri MHS); Francisca das Chagas Sheyla Almeida Gomes (Nurse at Piripiri MHS); Francisco Machado da Fonseca Júnior (Dental Surgeon at Piripiri MHS); Marcílio Oliveira Melo (Dental Surgeon at Piripiri MHS); Maria Erinelda de Araújo Souza (Nurse at Piripiri MHS); Michell Lucilane dos Santos Holanda (Nurse at Piripiri MHS); and Yluska Myrna Meneses Brandão e Mendes (Nurse at Piripiri MHS).

Coordination: Jorge Otávio Maia Barreto (MSc, Municipal Health Secretary of Piripiri, PI) THEME: The Prevention and Control of Dengue Fever in Urban Areas PROBLEM: What are the most effective options for the prevention and control of dengue in urban areas?

1 KEY MESSAGES PROBLEM: Dengue is one of the main public health issues in the world. The World Health Organization (WHO) estimates that between 50 and 100 million people are infected annually in over 100 countries on all continents except Europe. Around 550,000 of those affected require hospitalization, and 20,000 die from the disease. The control of this typically urban disease is extremely complex, as it involves sectors outside health, such as city infrastructure, and the transportation of people and cargo, among others.

(Brazil 2010).

Dengue fever is characterized as an acute infectious fever disease, the course of which can be mild or serious, with symptoms varying from none to hemorrhage, shock, and death. It is transmitted primarily by the mosquito Aedes aegypti, and its incidence follows a seasonal pattern which coincides with periods of greater rain and higher environmental temperatures, with 70% of cases falling within the rainy season (in Brazil, from January to May). Dengue fever is more common in urban areas, where natural or man-made mosquito breeding grounds are more abundant. However, the disease can occur in any location where there is a susceptible human population, a vector presence, and where the virus in introduced (Brazil 2010).

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MUNICIPALITY OF PIRIPIRI MUNICIPAL HEALTH SECRETARIAT HEALTH EVIDENCE TEAM

The report from the Notifiable Disease Database (Sistema de Informação de Agravos Notificáveis, SINAN) shows that over the last four years in the state of Piauí, dengue has probably become more visible due to increased reporting. In this state, the greatest incidence of the disease occurred in 2007, when there were 9,806 reported cases. In the years 2008, 2009, and 2010, 2,442, 4,125, and 7,092 cases were reported, respectively. Based on this data, the annual increase of dengue in the state is cause for concern.

Within Piripiri Municipality, epidemiological awareness bulletins show an increase in reported cases for the years 2010 and 2011, with 133 reports and 75 confirmations in 2010 and more than 800 reports and almost 450 confirmations in 2011. Though the dengue outbreak has had a high rate of infection, most cases were of the classic form. Up to June 2011, there had been only six hospitalizations due to complications of the disease.

In general, the expansion of dengue as an endemic disease in the municipality of Piripiri has followed the same pattern as in the rest of the Americas and Brazil, in that the unplanned growth of urban centers is one of the central factor that enable environments that are favorable to the spread of dengue.

Dengue is currently one of the most frequently reported illnesses in Brazil, and the local situation in Piripiri is no different, leading to an increase in resources aimed at the prevention and control of dengue. This requires the creation of local decision-making programs to combat the problem, a process which must be based on the best scientific evidence available.

Given this evidence, the question is: what are the most effective options for the prevention and control of dengue, especially in municipal urban spaces?

This summary of evidence presents options for tackling the problem based on the best available evidence, which it evaluates and contextualizes it in order to discuss benefits and potential risks, costs, the perceptions of affected subjects, barriers, and the implications of implementation, with the aim of making an informed contribution to the management decisions of the local public health system regarding the prevention and control of dengue.

OPTIONS Option 1: Use of chemical products/biological agents to control the dengue vector in both its mature and larval forms.

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Option 2: Promotion of health education on a community level, in conjunction with healthcare workers, so as to identify and properly manage dengue cases early on, and to control vector breeding sites.

Option 3: Continuous monitoring of intersectoral relationships developed for the prevention and control of dengue.

Search Strategy The search strategy for systematic reviews with a focus on the problem in question used the Online Health Library (Biblioteca Virtual em Saúde, http://regional.bvsalud.org). The key terms used were: “dengue,” “control of dengue,” “dengue/prevention and control,” “the economy and dengue,” “the fight against dengue,” and searches of PubMed using with the following MeSH descriptors: “dengue epidemiology,” “dengue,” and “dengue systematic review”. Other references were also used to contextualize the problem, especially publications on dengue control available on the Brazilian Ministry of Health website. The Municipal Dengue Contingency Plan of the Municipality of Piripiri, PI was also used.

CONSIDERATIONS REGARDING THESE OPTIONS Option 1: Studies suggest that efforts to mobilize members of the community are essential to the sustainability of vector control methods when chemical and biological methods are used. The biological methods of vector control include the use of predatory organisms (fish and turtles) and bacteria.

Chemical control through the use of insecticides is effective at reducing the mosquito population, and furthermore, results can be seen and felt immediately.

Option 2: Educational actions at the community level and the training of healthcare professionals in care for dengue patients are pillars of the Brazilian Dengue Control Program (Programa Nacional de Controle da Dengue, PNCD) run by Brazil’s Ministry of Health. The inadequate use of available diagnostic technologies could be leading to a delay in the acknowledgement of an epidemic situation, thus causing an increase in public spending and, indirectly, a decrease in the quality of care. Another concern is in regard to the quality of care of patients with severe forms of dengue.

Option 3: Many of the main factors that determine dengue incidence rates are independent of the healthcare sector. Since dengue is a disease transmitted by a vector the reproduction of which depends on a certain set of environmental conditions, communication between the public and private sectors involved in the processes that lead to these conditions is important, so that they are also engaged in the decision-making process regarding disease-control.

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2 CONTEXT AND PRIORS In Brazil, dengue first emerged in the mid-19th century and since then has afflicted the country in a continuous and endemic form, alternating with periods of epidemics, usually associated with the emergence of a new, previously undiscovered virus.

During the 1990s, there was significant increase in the incidence of dengue as a result of the spread of Aedes aegypti throughout the country, especially in big cities. The presence of the vector, together with population mobility, led to the dissemination of serotypes 1 and 2 in 20 of the country’s 27 states. Between 1990 and 2000, various epidemics were recorded throughout Brazil, especially in large urban centers of the country’s southeastern and northeastern regions, which accounted for the majority of the reported cases.

The highest incidence of the disease was observed in 2002, when nearly 697,000 cases were confirmed, reflecting the introduction of serotype 3. In the first semester of 2004, 23 of the country’s 27 states already presented simultaneous circulation of viral dengue serotypes 1, 2, and 3.

Young adults are the group that has been most affected by the disease since its introduction into the country; however, as of 2006, due to the recirculation of serotypes that have already been controlled, there was an increase in some states in the number of serious hospital cases among children, especially in the northeast. In 2008, new epidemics occurred in various states, marking the worst dengue-related year in Brazil in terms of total hospitalizations and deaths. These epidemics were characterized by a pattern of serious cases in children, who represented more than 50% of hospitalized cases in municipalities with larger populations. Even in municipalities with smaller populations, more than 25% of hospitalized dengue patients were children, which is evidence that the entire country has been similarly affected by the alterations in the profile of the disease.

The municipality of Piripiri, Piauí, has presented varying report rates in the last ten years, with most cases of the disease being in its classic form. However, some cases reported hemorrhagic complications. The determining factors for the spread of dengue in the Americas in general and Brazil in particular are similar, in that they are related to the economic growth models that have been implemented, and which are characterized by the disorderly growth of urban centers.

Some 80% of Brazil’s population is concentrated in urban areas. In the municipality of Piripiri, 65% of residents are urban. Certain important elements are missing from the urban infrastructure, such as regular and continuous water supply and the systematic collection of solid waste. Significant environmental factors are also present, such as climate conditions which favor the reproduction of the dengue-causing mosquito.

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3 DESCRIPTION OF THE PROBLEM Dengue is one of the world’s main public health problems. The WHO estimates that 2.5 billion people (2/5 of the world’s population) are at risk of contracting dengue. Dengue is an acute infectious fever disease of viral etiology, the manifestations of which range from no symptoms to severe hemorrhagic cases, which can lead to death.

The current epidemiological status of dengue in Brazil is characterized by the widespread distribution of Aedes aegypti in all regions and the complex dispersion dynamic of the virus it carries, namely the simultaneous circulation of four viral serotypes (DENV1, DENV2, DENV3, and DENV4).

The Brazilian Dengue Control Program has determined that, given the current infrastructure of the municipalities and states in epidemic crises, certain minimal and necessary conditions must be taken into account if the following actions are to be implemented: epidemiological and environmental surveillance, vector-fighting, and the training of human resources, as well as the provision of equipment, transportation, a low-complexity care network, laboratory support, and social mobilization committees. .

The building infestation index and Breteau index, which show the proportion of buildings that tested positive for the presence of dengue-transmitting mosquito larvae and the quantity of deposits where these larvae were found, respectively, have varied over the years in the municipality of Piripiri, especially in urban areas.

In 2009, the building infestation index and Breteau index levels were both at 1.71%; in 2010 they were both at 1.47%; and in 2011, up until the second round of surveys, they had reached 1.87% and 1.9%, respectively. When analyzing these values, it is noticeable that there has been an increase in these past three years, and that in all years considered, the indices indicated an on-alert situation. According to Brazil’s Ministry of Health, satisfactory levels are classified as under 1%, on-alert levels from 1 to 3.9%, and outbreak levels at over 3.9%.

The current dengue situation in the municipality of Piripiri shows that up until epidemiological week #24 of 2011, 884 suspected cases of dengue had been reported, of which 506 were confirmed. Some 487 of these cases (55.09%) were confirmed by laboratory criteria and 19 (3.75%) by clinical-epidemiological criteria.

Some 343 (38.80%) had been ruled out at the moment of this summary, and 35 cases (2.36%) were awaiting laboratory analysis.

If we consider the number and mortality levels of cases of Hemorrhagic Dengue Fever (HDF) and the possibility of epidemics occurring in the rainy seasons, we are presented with a scenario that urgently requires vector-eradicating actions to be put forward, which leads to the need for dengue prevention

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strategies based on the best available evidence.

Dengue vector control involves the use of chemical and biological agents, continuous education of the professionals involved, and the participation of the community in the decision-making process for the elaboration and implementation of strategies.

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MUNICIPALITY OF PIRIPIRI MUNICIPAL HEALTH SECRETARIAT HEALTH EVIDENCE TEAM

4 DESCRIPTIONS OF OPTIONS Option 1: Use of chemical products/biological agents to control the dengue vector in both its mature and larval form.

Use of chemical products and biological agents as strategies to combat and control dengue on a municipal level, in accordance with locoregional realities.

Category of Findings

Summary of most relevant findings

Benefits

A recent high-quality systematic review concluded that there is evidence that community-based programs, either in isolation or in combination with other control measures (chemical larvicides, biological agents), can increase the effectiveness of dengue control programs (Heintze 2007).

Potential damages

A review revealed many disadvantages to the spraying of insecticides, including generalized chemical resistance by the vector (Ballenger 2009). Another recent review also showed that their effectiveness in controlling the vector is also limited, since larvicides have low coverage in relation to the large number of reproduction sites present in any urban setting (Gómez-Dantés 2009).

Costs or cost/benefit in comparison with the current situation

A systematic review indicated that biological methods need intensive maintenance and a high turnover of containment organisms with frequent use (Ballenger 2009).

Uncertainties related to benefits, potential damages and risks that imply the need for monitoring and evaluation if the option is chosen

One systematic review showed that special attention should be given to the issue of the sustainability of dengue vector control strategies, which should be maintained and controlled through a variety of interested parties at an accessible cost (Heintze 2007).

A systematic review geared toward the evaluation of chemical and biological products and educational programs for dengue prevention concluded that there is little evidence to support the effectiveness of mosquito-reducing programs, due to the lack of congruent indices (Ballenger 2009).

Another up-to-date and high-quality review showed that biological interventions should be adapted to local situations and should take into account cultural practices related to the storing of water and to the social acceptability of maintaining live organisms in recipients used to store drinking water (Erlanger 2008).

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Main features of the option (if already implemented/tested elsewhere )

One systematic review discussed five clinical controlled trials of biological interventions which resulted in the reduction of mosquito larva by 96.3%, the use of chemical sprays resulted in an average reduction of 27.2%, and five studies on educational interventions resulted in an average reduction of 41.6% (Ballenger 2009).

Another systematic review including 11 studies showed that there was a reduction in indices of larvae, or a reduction in seroconversion or the dengue incidence, showing statistically significant effects on the entomological index (Heintze 2007).

One review states that there is increasing reluctance on behalf of residents to accept the How the social subjects involved in the use of larvicides in drinking water because of their cost, the increase in non essential option perceive it in terms of its water holding containers in the environment, and in the frequency of residences being blocked during the day. This led to infrequent applications and inadequate coverage effectiveness which affected long-term suppression of the mosquito (Gómez-Dantés 2009).

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Option 2: Promotion of health education on a community level, in conjunction with healthcare workers, so as to identify and properly manage dengue cases early on, and to control vector breeding sites.

Training geared toward professionals involved in the identification and clinical management of dengue cases as a strategy to control the disease.

Category of Findings

Summary of most relevant findings

Benefits

One recent and high-quality systematic review showed that dengue control through educational interventions in the community, in isolation or in combination with other means, can increase the effectiveness of these programs (Heintze 2007).

Another recent high-quality systematic review involving five studies focusing on behavioral and educational interventions showed that there was an average reduction of 41.6% in entomological levels (Ballenger 2009).

Potential Damages

No potential damages related to this option were reported.

Costs or cost/benefit in comparison with the current situation

A recent high-quality study revealed that when resources allow, dengue control activities should be undertaken in combination with educational programs as a way of increasing the awareness of good practices for those involved (Erlanger 2008).

Uncertainties related to benefits, potential damages and risks that imply the need for monitoring and evaluation if the option is chosen

A systematic review highlighted the need for operational norms, a combination of interventions, the development and application of monitoring tools, and evaluation and training oriented toward the effectiveness of dengue control services (Horstick 2008).

Other studies state that it cannot be known if a specific dengue control strategy is more effective than another in the reduction of vectors when the exposed population is at a critical point with regard to the impact of dengue transmission (Erlanger 2008).

Main features of the option (if already implemented/tested elsewhere )

One recent high quality study indicates that dengue control activities are largely carried out by the community, more specifically by family members, and that to do so effectively they need education, preferably encompassing different aspects of behavior (Heintze 2007).

How the social subjects involved in the option perceive it in terms of its effectiveness

One review demonstrated that community-based control, in combination with chemical and biological control, led to a significant reduction in entomological levels (Heintze 2007).

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MUNICIPALITY OF PIRIPIRI MUNICIPAL HEALTH SECRETARIAT HEALTH EVIDENCE TEAM

Option 3: Continuous monitoring of intersectoral relationships developed for the prevention and control of dengue.

Intersectoral relationships include the articulation of ideas and the consolidation of partnerships between different actors from the public and private sectors in the fight against dengue. The monitoring of these relationships predicts the strengthening of dengue control.

Category of findings

Summary of most relevant findings

Benefits

One review concluded that the sustained control of dengue requires partnerships between the public sector, civil society, non-profits, and the private sector, and interactions between politicians, healthcare workers, administrators, engineers, urban planners, and environmental groups, in order to strengthen intersectoral structures (Gómez-Dantés 2009).

Potential damages

Studies dealing with potential damages were not found.

Costs or cost/benefit in comparison with the current situation

In one systematic review, the authors concluded that special attention should be given to the issue of the sustainability of dengue vector control strategies, and that control should be jointly maintained by a variety of interested parties (intersectorial partnerships) in a sound cost/benefit relationship (Heintze 2007).

Uncertainties related to benefits, potential damages and risks that imply the need for monitoring and evaluation if the option is chosen

Community interventions geared toward modifying population behavior in activities such as the reduction, cleaning, and protection of recipients for holding water were able to reduce entomological levels of the Aedes aegypti mosquito; however, this effect would be smaller with the isolated use of biological or chemical agents (Erlanger 2008).

Main features of the option (if already implemented/tested elsewhere )

One recent high-quality review showed that the effects of integrated vector control strategies are more likely to be sustainable when they are community-based, as opposed to being executed by specialized teams in a vertical manner, as they aim to change behavior and induce social mobilization (Erlanger 2008).

How the social subjects involved in the option perceive it in terms of its effectiveness

No studies were found which described how the social subjects involved in the option perceived it. However, it is believed that intersectoral involvement in the fight against dengue is to be sought after if these actions are to be effective.

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5 CONSIDERATIONS REGARDING THE IMPLEMENTATION OF OPTIONS Potential barriers to the implementation of options Option 1: Use of chemical/biological agents to control the dengue vector in both its mature and larval forms.

Use of chemical products, biological agents, and education as strategies to combat and control dengue on a municipal level, in accordance with locoregional realities.

Level Patient/Individual

Barriers The community must be made aware of the conscious use of chemical and biological methods, as well as educational interventions, to combat and control dengue.

Healthcare Workers

Contact between the community and healthcare professionals should be promoted to help clarify the chemical, biological, and educational methods use to combat dengue, so that these are implemented in the community.

Organization

An intervention plan for the implementation and maintenance of the systematic use of chemical, biological, and educational resources must be created.

Periodically, community events should be organized in order to promote and disseminate the use of chemical, biological, and educational methods to combat dengue.

Structural barriers must not be so relevant as to hinder the implementation of this option.

During periods of low transmission, most individuals as well as government agencies lose interest in mosquito control, and as consequence, the vector among the population increases.

System

Financing should be considered an important barrier to the implementation of the option, as resources that contribute to combating dengue, such as the acquisition and maintenance of biological methods, are often expensive.

Option 2: Promotion of health education on a community level, in conjunction with healthcare workers, so as to identify and properly manage dengue cases early on, and to control of vector breeding sites.

Health education on a community level and the training of professionals involved in dengue control services as a strategy to combat the disease.

Level Patient/Individual

Barriers Qualified, integrated attention to individuals must be guaranteed in an opportune fashion.

Healthcare Workers

Continuous, integrated training for healthcare professionals regarding the combat and control of dengue must be encouraged.

Healthcare professionals must be made aware of the importance of participating in training to combat and control dengue.

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Organization

Regular courses should be organized to focus professionals on the main issues related to dengue control.

Professionals involved in caring for patients with dengue should be encouraged to participate in training courses.

Feedback systems should be developed to deal with requests from professionals relating to the management of dengue control.

System

Financing should be ensured by those engaged in the constant training of professionals involved in dengue control services.

Success depends more on political commitment and organizational capacity than on the availability of resources.

There is room for improvement in the promotion of healthcare worker involvement and in empowering them to influence actions inside the community.

Option 3: Continuous monitoring of intersectoral relationships developed for the prevention and control of dengue.

Intersectorial relationships include the articulation of ideas and the consolidation of partnerships between different actors from the public and private sectors in the fight against dengue. The monitoring of these relationships predicts the strengthening of dengue control mechanisms.

Level Patient/Individual

Barriers A new relationship based on local sanitation structures should be proposed, as well as the organization of the community and the roles of different community leaders.

Healthcare Workers

Healthcare workers should promote intersectoral relationships in their area of work.

Organization

The community should be encouraged to play a role in combating dengue, and resources and financing from different government agencies and municipal healthcare bodies should be integrated.

System

There are difficulties regarding the integration and incorporation of sectors such as epidemiological surveillance, community participation, environmental management, basic public services, and the educational system.

A change in behavior should be proposed through the mobilization of networks and social organizations, as well as the implementation of public policies geared toward intersectoral action to combat and prevent dengue.

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6 ANNEX Annex 1: Summary of the Systematic Reviews Identified and Evaluated

Option Component

Use of chemical products, biological agents, and educational interventions in the community to combat dengue

Full training of healthcare professionals in the control of dengue

Permanent monitoring of intersectoral relationships to combat dengue

Focus of Systematic Review

Main Findings

Last year of Proportion of Quality search of studies study focused (AMSTAR) on problem included in the RS

The scope of community-based programs in dengue control (Heintze 2007).

The control of community-based programs in isolation or in combination with other control activities could increase the efficiency of dengue control programs.

6/11

11/11

2006

The functioning of vector control services (Horstick 2008).

Levels of permanent staff, capacity, management and organization, financing, and community participation were insufficient in the battle against dengue.

7/11

24/24

2007

The evaluation of the effectiveness of chemical and biological products and educational programs in the prevention of dengue and in the reduction of entomological indicators (Ballenger 2009).

Due to insufficient studies and the lack of congruent entomological indices, there is little evidence to support the effectiveness of mosquito reduction programs.

6/11

21/21

2008

The functioning of vector control services (Horstick 2008).

The need for operational norms, a combination of interventions, the development and application of monitoring tools, and the evaluation and training geared toward the efficiency of dengue control services (Horstick 2008).

7/11

24/24

2007

The scope of community-based dengue control programs (Heintze 2007).

Special attention needs to be given to the sustainability of dengue vector control strategies, and control strategies need to be maintained through a variety of interested parties (intersectoral partnerships), within a sound cost/benefit ratio (Heintze 2007).

6/11

11/11

2006

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7 REFERENCES Systematic Reviews Ballenger-Browning; Elder JP. Multi-modal Aedes aegypti mosquito reduction interventions and dengue fever prevention. Trop Med Int Health. 2009 Dec; 14 (12): 1542–51. Epub 2009 Sep 24.

T. E. Erlanger; J. Keiser and J. Utzinger. Effect of dengue vector control interventions on entomological parameters in developing countries: a systematic review and meta-analysis. Medical and Veterinary Entomology (2008) 22, 203–221.

Heintze C, V Garrido M, Kroeger A. What do community-based dengue control programmes achieve: a systematic review of published evaluations. Transactions of the Royal Society of Tropical Medicine and Hygiene (2007) 101, 317–325.

Horstick O, Runge-Ranzinger S, Nathan MB, Kroeger A. Dengue vector-control services: how do they work?

A systematic literature review and country case studies. Royal Society of Tropical Medicine and Hygiene (2009).

Other References BRAZIL. Ministry of Health. Executive Secretariat. Sub-secretariat of Planning and Budgeting System for the Planning of the Unified Health System: A collective construction: National Health Plan (PNS) 2088/2009– 2011.Brasília: Ministry of Health, 2010.

Gómez-Dantés H., Willoquet JR. Dengue in the Americas: challenges for prevention and control. Journal of Public Health. 2009; 25 Suppl 1: S19–31.