Dengue Fever Videos!

Click here to watch our homemade Video Describing the Biology Behind Dengue Fever!

Want to watch more Videos about Dengue? 

News Video Network, (Accessed February 22, 2013) http://www.youtube.com/watch?v=8RG4rZlrStI
How People in India are coping with the current crisis of Dengue 

Potential Solutions to Dengue

Michigan State University, (Accessed February 22, 2013) http://www.youtube.com/watch?v=aM2-QqEWzEM
This video shows an innovative solution to Dengue, that actually takes the disease from its Mosquitto carriers 

NDTV, (Accessed February 22, 2012) http://www.youtube.com/watch?v=4QaE_o38fWg
A potential solution to dengue, which keeps mosquitoes from continuing to breed. 

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What is dengue fever?

Dengue fever, also known as “breakbone” fever, is an infectious, tropical disease, resulting from the dengue virus transferred through mosquitoes (Wikipedia, Dengue Fever). There are four different types of dengue fever. Like most viruses, infection with one type will result in immunity from that specific type, but only a temporary immunity from the other three. Infection with a second type of dengue increases the likelihood of further complications (ibid). 

                                                   

   Sharevdo (Date Accessed: February 22, 2013) http://sharevdo.com/?p=60

Wikipedia. (2012) Dengue Fever. Wikipedia Free Encyclopedia. (Accessed February 2, 2013) http://en.wikipedia.org/wiki/Dengue_fever

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What are the symptoms of dengue fever?

Symptoms of dengue fever include a sudden high fever, severe headaches, pain behind the eyes, severe joint and muscle pain, nausea, vomiting, skin rash, and mild bleeding such as nosebleeds, gum bleeding, and easily bruising. Some mild symptoms can often be confused with the flu. Symptoms are generally less serious in younger children, and are more severe among older children and adults. The more serious cases may develop into what is known as “dengue hemorrhagic fever.” This is likely to result in bleeding and dangerously low blood pressure, which can lead to death (Webmd 2011).

                              Wikipedia (Date Accessed: February 22, 2013) http://en.wikipedia.org/wiki/File:Dengue_fever_symptoms.svg

WebMD. Dengue Fever. WebMD. (February 21, 2012.) webmd.com 

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How has dengue developed?

Although epidemics of a dengue like virus occurred before the 18th century, the accepted earliest occurrences were three epidemics in Cairo, modern day Jakarta, modern day Indonesia, and Philadelphia (Encyclopedia Britannica 2013).  The vector of mosquitoes most likely traveled to these port cities via ship (ibid). This illustrates the effect of globalization on the spread of disease. Slave trade allowed for dengue carrying mosquitoes to reach foreign regions (Basnyat 2012). Cases of Dengue fever are most often seen in tropical urban regions, for example in the Philippines, India, sub Saharan Africa, and in Latin America (CDC 2013c). The Figure above shows the spread of dengue throughout recent decades. This illustrates how Dengue fever has grown endemic in more regions over the years, meaning that there are a greater number of regions in which people are exposed to Dengue. 

      Medscape (Date Accessed: February 22, 2013 http://www.medscape.com/content/2003/00/45/89/458942/458942_fig.html

Basnyat, B. (2012) Dengue fever Nepali Times. (Date Accessed: February 10, 2013.)  http://nepalitimes.com/news.php?id=19301

Britannica Online Encyclopedia. Dengue (disease). (Date Accessed: February 10, 2013.) http://www.britannica.com/EBchecked/topic/157664/dengue

CDC. (2012c) Freifeld, C., and Brownstein, J. (2013) DengueMap. HealthMap.  (Date Accessed: February 19, 2013.) http://www.healthmap.org/dengue/index.php

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Who is currently affected by dengue?

Today, Dengue fever is in the range of 2.5 billion, meaning, 40% of the world’s population lives in areas where they run risk of catching dengue (CDC 2010b). That risk decreases or increases depending on where you live or what you are exposed to (ibid). Still to this day about 50 to 100 million infections occur annually (ibid). There have been around 22,000 deaths recorded per year. Dengue fever is still very much alive and haunting (ibid).

University of Delaware (Date Accessed: February 22, 2013) http://udel.edu/~sgolwala/Epidemiology.html

CDC. (2012b) Epidemiology. CDC.gov. Center for Disease Control. (Date Accessed: February 14, 2013.) http://www.cdc.gov/Dengue/epidemiology/index.html

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What is the biology behind dengue?

In order to understand how dengue fever propagates, one must first understand the life of the mosquitos that most often transmit the disease to people (CDC 2010a). The two types of mosquitoes that are known to harbor dengue fever virus are Aedes aegypti and Aedes albopictus (CDC 2010d).  As with all species of mosquito, aegypti and albopictus thrive in tropical environments and need stagnant water to reproduce. Female mosquitoes will lay eggs above the waterline on the inside surface of a container, and when the water level rises, the eggs are submerged under the water and will hatch, beginning the transformation from larva to pupa to adult (CDC 2009e). Mosquito eggs have been proven to be resilient to drying out, remaining viable for months without water (CDC 2010f). 

                          Boston College (Date Accessed: February 22, 2013) http://www.bc.edu/schools/cas/biology/research/infect/dengue.html

The question which follows is this: how is the mosquito itself inoculated with dengue fever virus? Ironically, it is an infected human that gives the mosquito the virus. There is a five-day period during infection when the host’s blood has a particularly high count of the dengue fever virus, and it is during this time that a mosquito may feed on the infected host’s blood and become infected itself (CDC 2010b). Having entered the mosquito, the virus then must incubate within the mosquito for one or two weeks before becoming transmittable (CDC 2010b).  The mosquito, whose lifespan may range from a few days to a few weeks, may very well die before it is able to transmit the disease to a human, which is why the chances of contracting the disease is low in areas of infrequent interaction between host and vector (i.e. southern U.S.) (CDC 2010b).  Conveniently enough for the mosquitos, humans are a source of both bloodmeals and habitat. Any open body of stagnant water, from rainwater collected in old tyres or flowerpots to the contents of damaged septic tanks, presents an opportunity for mosquitoes to lay eggs (CDC 2009f).  Mosquitos are very good at being parasites, because they capitalize on only on their hosts but also on the byproducts of their hosts’ activities.

CDC. (2012a) Entomology and Ecology. CDC.gov. Center for Disease Control. (Date Accessed: February 14, 2013.)http://www.cdc.gov/Dengue/entomologyEcology/index.html

CDC. (2012b) Epidemiology. CDC.gov. Center for Disease Control. (Date Accessed: February 14, 2013.)http://www.cdc.gov/Dengue/epidemiology/index.html

CDC. (2012d) Frequently Asked Questions. CDC.gov. Center for Disease Control. (Date Accessed: February 14, 2013.)http://www.cdc.gov/dengue/fAQFacts/index.html

CDC. (2012e) Mosquito Life-Cycle. CDC.gov. Center for Disease Control. (Date Accessed: February 14, 2013.)http://www.cdc.gov/dengue/entomologyEcology/m_lifecycle.html

CDC. (2012f) Mosquitoes’ Main Aquatic Habitats. CDC.gov. Center for Disease Control. (Date Accessed: February 14, 2013.)http://www.cdc.gov/dengue/entomologyEcology/m_habitats.html

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How do urbanization and globalization affect dengue?

The mosquitoes most likely to spread dengue , the Aedes aegypti or the Aedes albopictus mosquito, breed in areas with standing water. Urbanization inevitably creates an ideal environment for mosquitoes to breed in. Construction of buildings and the daily activities of the people who live in the buildings interfere with water’s ability to drain from the environment (Gubler 2011).

MissYunia (Date Accessed: February 22, 2013) http://missyunia.blogspot.com/2012/07/urbanization.html

The picture below shows recent increases in dengue due to trends in urbanization and globalization

WHO (Date Accessed: February 22, 2013) http://www.who.int/csr/disease/dengue/impact/en/

Urbanization has had the greatest impact on the propagation of dengue fever throughout the world. Rapid urbanization as seen in the past few decades in regions in India, the Phillipines, and South America, has caused difficulties in maintaining proper sanitation and infrastructure. The past few decades has also seen a marked increase in the incidence of dengue fever in those regions (see figure one). Inadequate housing, poor waste management systems, and high population density all increase the likelihood that mosquitoes--and dengue fever--will thrive in those areas. Nonetheless, urban environments bring people closer together and therefore make it easier for a mosquito first, to become infected, and second, to feed on and therefore infect multiple people. 

Figure One: Shows cases of dengue fever in green. Fever appears to be controlled by advances in technology and medicine, but spreads out of control as rapid urbanization occurs.

NCBI (Date Accessed: February 22, 2013) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3317603/bin/tmh-2011-S05-g003.jpg

Population density has long been thought to contribute to the spread of the disease.  The concept of urbanization implies a higher population density. Urban environments have had dengue problems, which could be linked to having a higher population density and poorer areas with inadequate water storage. But, a recent study suggests that rural areas might have a higher risk of dengue outbreaks (Science Daily 2011).  Lack of piped water in rural environments means mosquitoes have access to breeding grounds (PLOS 2011).

Figure Two: Map A shows the documented strains of dengue fever in 1970 then in 2011. Increase in population density and air travel has spread dengue fever.

NCBI (Date Accessed: February 22, 2013) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3317603/bin/tmh-2011-S05-g008.jpg

Globalization and travel are synonymous with urbanization, and both contribute to the spread of dengue fever on an international level. Air travel can transport infected hosts, whether human or mosquito, from point A on one side of the planet to point B on the other side of the planet, which is very convenient for introducing disease to new populations. In addition, urbanization and travel bring large numbers of people in close proximity to mosquito populations and to each other, which enables the dengue virus to undergo constant mutation as it is passed from host to host. We can see the effects of air travel and crowding on disease mutation and propagation in figure two, which displays the different types of dengue fever present on the planet in 1970 then in 2011 (Gubler 2011).

WRSC (Date Accessed: February 22, 2013) http://www.wrsc.org/attach_image/global-warming-and-insect-desease

Because of increased urbanization and global warming, the number of mosquitoes is predicted to vastly increase, thus increasing the amount of dengue worldwide. The map above shows predictions, making it clear that other solutions must be found before the disease spreads so rapidly. 

Berg, NB. (2009) Dengue Fever Increased by Rapid Urbanization. Planetizen. (Accessed February 9, 2013)http://www.planetizen.com/node/40439

Gubler, GJD. (2011) Dengue, Urbanization and Globalization: The Unholy Trinity of the 21^st Century. National Center for Bio Technology Information. US National Library of Medicine National Institutes of Health. (Accessed February 13, 2013)http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3317603/ 

NCBI (2012) Urban Environmental Health Hazards and Health Equity. National Center for Biotechnology Advancement. (Accessed February 13, 2013) http://www.ncbi.nlm.nih.gov/ 

Rajadhyaksha, M. (2011) Population density not key to devolopment. (Date Accessed: February 21,2013.)http://articles.timesofindia.indiatimes.com/2011-10-03/mumbai/30238017_1_density-world-population-population-data-sheet

ScienceDaily (2011) Rural Areas at Higher Risk of Dengue Fever Than Cities. ScienceDaily. (Date Accessed: February 21, 2013) http://www.sciencedaily.com/releases/2011/08/110830193842.htm 

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