Assignment 11: Key Determinants

Problem Definition: There has been an increasing incidence of both classic dengue and dengue hemorrhagic fever among the adult population in Venezuela during the last two decades.


Key Determinants:


Biological:

• Individual Factors: Age, Gender, Genetic Background and Underlying Diseases: 

The host’s immune response, determined by individual factors like age, gender, genetic background and underlying diseases, plays a role in the clinical expression of DF/DHF. In Venezuela the incidence of DF has been the highest among 10 to 14 year old children, peaking in 2007 (570/100,000) On the other side, DHF highest incidence rates were observed among infants, peaking again in 2007 (62.9/100,000).

• Introduction of New and More Complex Secondary Vectors:

The number of countries with more than one viral stereotype circulating has steadily increased, favoring the occurrence of more cases of secondary infection and consequently and increase in the risk of DHF. Also, a potential additional risk is the introduction in the region of Ae. albopictus, an efficient dengue vector in Southeast Asia. Unlike Ae. aegypti, Ae. albopictus is not obligatorily anthropophilic and sometimes displaces the former from its habitat. This vector has been detected in several Latin American countries (Mexico, Honduras, Guatemala, Nicaragua, Panama, Cuba, Dominican Republic, Trinidad & Tobago, Brazil, and Bolivia); but thus far its presence has not been associated unequivocally with the increase in dengue transmission.


Social and Cultural:

• Mosquito Control is Virtually Non-Existing in the Society:

Mosquito control measures are practically non-existent in the society. In regular endemic periods, people do not take primary preventions to avoid the mosquito bite in the first place, such as using mosquito nets or lighting up citronella candles at home. Emphasis over the past 25 years has been placed on ultra-low-volume space sprays of insecticide for adult mosquito control, but this has been shown to be ineffective in controlling Ae. aegypti.

• Increased in Air Tavel

The increased travel of people by jet airplane favors the movement of dengue virus between endemic areas and other areas free of disease due to people's arrival during the disease incubation period (viremic period can be long and virus can be detected in blood from two days before initial symptoms until eight days after) and subsequent risk of infection of local mosquitoes and development of epidemics. An illustration of the increased human air travel is seen in the great number of Latin American airlines that emerged in this period of time and the increasing number of flights towards tropical areas.

Environmental:

• Population Growth

In the last 20 years, the urban population in Venezuela has more than doubled, and as a consequence, the incorporation of more land for food production and the negative impact of haphazard deforestation have created the conditions for the emergence of vector-borne diseases like dengue.

• Inadequate and Unplanned Urbanization:

The constant migrations from rural to urban areas have resulted in large, crowded human populations living in urban centres in substandard housing with inadequate water, sewer and waste management systems, creating ideal conditions for increased transmission of mosquito-borne infectious diseases.

• Trash Accumulation and Poor Urban Sanitation

The main urban centers, especially the city of Caracas, lack the appropriate urban sanitation infrastructures and the accumulation of trash is growing problem. Most of the consumer goods are packaged in non-biodegradable plastic or cellophane materials, which are discarded into the environment where they collect rain-water and provide ideal larval habitats for the vector mosquito.

• Global Warming

Increasing incidence of dengue in the Region might be be related to climatic changes that favor larval habitats for the mosquito vector, like increases in the amount of rainfall, higher sea-surface temperature, and increases in weekly minimum temperature. Although the association between climatic changes and the explosion of dengue in the Americas remains controversial; in April 2007, the Intergovernmental Panel on Climate Change concluded that global warming and climate change would cause an upsurge in dengue and other tropical diseases.


Economic:

• Decreased Access to Healthcare

Complications in cases of classic dengue that lead to an increasing incidence of DHF are related to the misdiagnosis and mistreatment of the disease when the first symptoms appear. This is the most common in low socio-economic status classes that have a more limited access to healthcare.

Political:

• Deterioration of the Public Health Infrastructure

The public health infrastructure required to deal with epidemic vector- borne infectious diseases has deteriorated during the past 20 years. Limited financial and human resources, and competing priorities for those resources, have resulted in a ‘crisis mentality’ among public health officials. The emphasis has thus been on implementing emergency control measures in response to epidemics rather than on developing programmes to prevent epidemic transmission. This approach has been particularly detrimental to dengue prevention and control because surveillance in Venezuela is very poor; the passive surveillance systems relied on to detect increased transmission are dependent upon reports by local physicians, who often have a low index of suspicion and do not consider dengue in their differential diagnosis of dengue-like illness. As a result, the epidemic has often reached or passed peak transmission before it is detected and emergency control measures are implemented too late to have any impact on the course of the epidemic.


References:
Javier Torres and Julio Castro; El Impacto Económico y Sanitario del dengue en América Latina http://www.scielosp.org/pdf/csp/v23s1/04.pdf


Duane J. Gubler; Epidemic Dengue/Dengue Hemorrhagic Fever: A Global Public Health Problem in the 21st Century; http://203.90.70.117/PDS_DOCS/B0776.pdf


José Luis San Martin; The Epidemiology of Dengue in the Americas Over the Last Three Decades: A Worrisome Reality; http://new.paho.org/hq/dmdocuments/2010/Jan%202010%20AJTMH%20Dengue%20BZ%20GD%20AB%20OS%20JSL%20OB%20MGG.pdf

Assignment 10: Data and magnitude Measurement

Since I couldn’t find enough data, I’ve decided to change my problem definition.

New Problem Definition: The rising incidence and prevalence of dengue in Latin America during the last two decades.

Dengue incidence and prevalence are rising in endemic areas of the tropical and subtropical regions. On the basis of mathematical model estimates, approximately 50 million infections occur each year. In the past, the burden of the disease has fallen on countries in South-East Asia and the Western Pacific regions, but a dramatic increase of cases has been reported in the Latin America during the last decade.

The World Health Organization (WHO), and its regional body in the Americas, the Pan American Health Organization (PAHO), keeps the dengue infection records for the 35 nations and 9 sub-regions of the territory. They carry an active surveillance through which they measure the number of cases reported on each country during each epidemiological week.

The total classic dengue fever cases reported in the Region were 1,033,417 (16.4/100,000) during the 80s, 2,725,405 (35.9/100,000) during the 90s, and 4,759,007 (71.5/100,000) during 2000–7. Similarly, the number of dengue hemorrhagic fever (DHF) cases increased over time from 13,398 (0.2/100,000) during the 80s, to 58,419 (0.8/100,000) during the 90s, to 111,724 (1.7/100,000) during 2000–7. The DHF cases as a percentage of total dengue cases also increased from 1.3% to 2.1% to 2.4%. Epidemic cycles were observed every 3–5 years with an increased frequency of DHF cases and fatalities caused by dengue during epidemic years. From 1980 through1987, 242 deaths were reported (1.8% of all DHF cases) compared with 1,391 deaths during 2000–7 (1.2% of all DHF cases).

The number of countries with an average incidence greater than 100/100,000 increased from 5 during the 80s to 7 during the 90s, and then to 15 during 2000–7. During the 27-year study period, Brazil reported the majority of dengue cases (54.5%) and Venezuela reported the highest number of DHF cases (35.1%) during the same period. In general, reported cases of both forms of dengue increased over time in all of the countries of the region, with the exception of those in the Hispanic Caribbean.

These data constitutes a direct indicator for the rising incidence and prevalence of dengue in the Region. I couldn’t find any indirect indicators for measuring dengue prevalence and incidence, but this is pretty strong data (even though it does not consider all the number of cases which are not reporter to the local public health institutions), but they do represent the general tendency considered for this study.

Sources:

Martín, José Luis: The Epidemiology of Dengue in the Americas Over the Last Three Decades: A Worrisome Reality; http://new.paho.org/hq/dmdocuments/2010/Jan%202010%20AJTMH%20Dengue%20BZ%20GD%20AB%20OS%20JSL%20OB%20MGG.pdf

World Health Organization, Dengue Alerts, http://new.paho.org/hq/index.php?option=com_moreinfo&moduleid=1011&Itemid=363

World Health Organization, Descripción de la situación epidemiologica actual del dengue en las Amèricas; http://new.paho.org/hq/index.php?option=com_content&task=view&id=4494&Itemid=2481

Assignment 9: Dengue Fever as a Public Health Problem

Dengue fever is a virus-caused disease that has been one of the most important resurgent tropical diseases in Latin America for the last two decades, where countries have experienced marked increases in the incidence of both classic dengue and dengue hemorrhagic fever.

The virus is spread by mosquitoes, specially by the mosquito Aedes aegypti, commonly known as patas blancas, because of the white markings on its legs. Its clinical diagnosis is relatively ambiguous, and lab tests are required in order to be sure that a case is dengue, because its initial symptoms are very similar to those of a common cold (fever, headache, fatigue, joints and muscles aches). This tends to lead to complications as people mis-diagnose the disease for common cold and take aspirin to treat it. Aspirin has anticoagulant effects that can increase the bleeding so that the classic dengue fever becomes an hemorrhagic fever that cannot be treated with regular antibiotics.

I want to do my research paper on how can public health institutions work to prevent the high incidence of dengue and develop/communicate more efficient and accessible diagnosis/treatment strategies for classical dengue fever, as to reduce the incidence of dengue hemorrhagic fever. As a background information, it will be necessary to study the major risk factors for the occurrence of dengue in the region and local societal/economical factors pertinent for the design of a preventive, diagnostic and treatment strategy for the localized region.

I'd like to frame this problem in my hometown, Caracas, during the last twenty years, because it is a problem that I have seen growing during my whole life. A lot of the people in my inner circle of friends and family have had dengue at some point of their lives, and I clearly remember the 2005 epidemic, when my mom wouldn't let us leave the house without mosquito repellent, Citronella candles where more coveted than gold and relatives where continuously looking for O- blood donors that could help for the treatment of those who had the hemorrhagic fever.

So, for the problem definition, it would be something around: The growing incidence of dengue hemorrhagic fever in Caracas during 1990-2010 as a consequence of the lack of an effective preventive, diagnostic and treatment structure for the classical dengue fever.

Assignment 8: On Human Rights

Human Rights are defined as the undeniable fundamental rights to which a person is entitled simply because of being human. For this reason, Human Rights are universal, applicable everywhere and to everyone. They are conceived in the Universal Declaration of Human Rights, which every nation has signed in order to make sure that local and international laws, as well as public policy, agree with these principles.

As dignified human beings, one of these fundamental rights is the right to an appropriate standard of living and health. This right not only assures the wellbeing of the people, in terms of guaranteeing conditions that can satisfy the most basic needs, like food, clothing, housing, and social services; but it also assures the wellbeing of the society in a macro-level, as these conditions allow the individuals to carry on better lives that allow them to be more productive in the society.

In this sense, the right to health is considered a fundamental right entitled under Article 25 of this declaration. It is a fundamental and universal right because health is a critical determinant for the kind of life we can carry on, and ultimately, the access to healthcare defines if we whether live or die. This article has a second clause that entitles pregnant women and children, of all social, economical and cultural backgrounds, require special care and assistance because they are vulnerable individuals that require specialized care and attention. Pregnant women have limited physical capacities and need to care for themselves and the child in their womb, and children aren't just capable of taking care of themselves, which is why they have the right to get this special care that sets hem aside from men.

In the Editorial that we read on maternal mortality and human rights we can see how progress in reducing maternal mortality has been slow across the nations in the last ten years, especially in developing and unstable countries were the material and human resources are limited and the State lacks an appropriate health infrastructure that can attend everyone equally, promptly and effectively.

In a case in Brazil, a woman died because her local health agency mis-diagnosed the symptoms and failed to deliver adequate obstetric care; and the case was brought up to the Committee on the Elimination of Discrimination against Women, alleging that the State had failed in providing this woman with appropriate care. As a result, the Committee established that governments have a human rights obligation to guarantee women of all racial and economic backgrounds timely and non-discriminatory access to appropriate maternal health services. In the case of countries outsourcing services to private health-care institutions, these states remain directly responsible for these institutions, so that they must regulate and monitor them in order to make sure that they are fairly providing the services that all sectors of the society deserve as a right.