Dengue Virus
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| Dengue Virus | ||||||
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Classification
Group: Group IV ((+)ssRNA)
Family: Flaviviridae
Genus: Flavivirus
Species: Dengue Virus
Description and significance:
The Dengue Virus, pronounced as [deng – gey or deng – gee] is a category-A pathogen and therefore is a serious threat to the human population globally. Category A pathogens are microbes that are hazardous to lab personnel and have the potential to cause serious epidemic disease. The Dengue Virus has four different serotypes, DEN-1, DEN-2, DEN-3 and DEN-4. These four serotypes are approximately 60-80% homologous but different enough to restrict cross immunity. This means that if a person is infected with one type of the four Dengue virus strains, they will build immunity to that specific serotype, but not for the other three. This lack of cross immunity is what poses a problem in the development of a vaccine for Dengue. The Dengue virus causes a less lethal condition known as Dengue Fever, which is also known as the breakbone fever. The Dengue virus causes a more lethal condition in some who are infected and that is known as the Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DHS).
The Dengue virus is currently believed to be the most common mosquito-borne disease in recent times and cause for increased international health concerns. The Dengue virus currently poses a risk to approximately 2.5 billion people of the worlds total population. In other words, almost one third of the world is at risk for this potentially deadly virus. The Dengue virus is transmitted amongst humans via its main vector, the Aedes aegypti mosquito. This virus is mostly found in countries along the equator and in countries with tropical and subtropical conditions because these are the conditions needed for this mosquito to thrive in. The mosquito acquires the disease from an infected individual and then carries it and passes it on to other individuals it feeds off of. Once an individual has been infected the virus then causes the person to come down with Dengue Fever. Dengue fever is a febrile disease and has Flu like symptoms accompanied by a rash and severe aches and pains. Headaches are extremely common and stronger than normal. Joint pain is also very common. Dengue Fever will usually subside in approximately five to ten days. Dengue Hemorrhagic Fever is the more serious complication caused by the Dengue Virus. Dengue Hemorrhagic Fever has an incubation period that is similar to Dengue Fever (approximately 3-5 days) but unless treated with a combination of corticosteroids, proper hydration and physician supervision, DHF will be mortal for the individual. Dengue Hemorrhagic Fever causes the blood vessels to become excessively permeable accompanied by thrombocytopenia and abnormal hemostasis.
Natural Host:
When was your organism discovered?
An encyclopedia of disease symptoms and remedies from the Chin Dynasty contains the earliest possible records of the Dengue virus. The encyclopedia was originally written around 265 to 420 and was formally edited in 610 A.D. under the Tang Dynasty and then again in 992 A.D. under the Northern Sung Dynasty. The disease that the Chinese were talking about was called “water poison” and was thought to be somehow connected with flying insects that were associated with the water.
Dr. Benjamin Rush discovered, identified and documented the first case of Dengue Fever back in 1779. Dr. Rush is the person responsible for calling it the “breakbone” fever. During the timeframe of 1779-1780 the first of multiple Dengue Fever reports were recorded across Asia, Africa and North America. Dengue Fever was a known disease in North America back in that time but in more modern times, outbreaks of Dengue has not been too significant. The only recorded occurences of Dengue via the Aegypti mosquito has only been recorded six times since 1975 in the state of Texas. (Need to cite)
How and where it was isolated:
In more recent times, cases of Dengue have been isolated from Pakistan to the Americas. The first ever Dengue viruses were isolated from soldiers who fell sick in Calcutta, India, New Guinea and Hawaii. The viruses from India, Hawaii and one strain from New Guinea were Antigenically similar, whereas three other strains from New Guinea appeared to be different. They were called Dengue 1 (DEN-1) and Dengue 2 (DEN2) and designated as prototype viruses (DEN-1, Hawaii and DEN-2, New Guinea-C). Two more serotypes - Dengue 3 (DEN-3) and Dengue 4 (DEN-4) were subsequently isolated from patients with a hemorrhagic disease during an epidemic in Manila in 1956.
Genome structure:
Interesting Features:
How does this organism cause disease?
What makes it biologically interesting?
Its application to Biotechnology... its medical importance... major research findings made with it... what's cool about myxoma virus as an organism:
Current Research:
References:
http://cmr.asm.org/cgi/content/full/11/3/480?view=long&pmid=9665979
http://pathport.vbi.vt.edu/pathinfo/pathogens/Dengue1.html
http://www.flickr.com/photos/ajc1/1437910835/
http://www.ihcworld.com/royellis/ABCSafe/glossary/category-a-pathogens.htm
http://www.stanford.edu/group/virus/flavi/2000/dengue.htm
http://www.who.int/csr/disease/dengue/en/