We all know that DENGUE is a serious problem during the rainy seasons in many countries. We also know the culprit who is the DEADLY AEDES MOSQUITOES. But, how many of us know that birds are the natural host of dengue. I know guys.. I think we should inoculated all these birds first! They are such a delicacy and a pest at the same time. Anyways, dengue as well as yellow fever and West Nile fever are flaviviruses which fall in the virus family Flaviviridae.
The Flaviviridae family consists of enveloped viruses and they have a single linear positive sense RNA genome. The complete genome is about 9500-12500 nucleotides long. Many species of Flaviviridae can replicate in both mammalian and insect cells. They also can survive for long periods in hosts by replicating in the host itself.
Many people have been victims of this dengue virus and it is believed that approximately 40% of the world’s population (about 2.5 billion people) is at risk for infection; either because they live in endemic areas or in regions where the mosquito vector is present. Statistics by World Health Organisation (WHO) show that the number of people infected each year range from 50 million to 100 million. It is worrying situation as a vaccine is not found yet.
Fatal dengue includes dengue fever (DF), dengue haemorrhagic fever (DHF), and dengue shock syndrome (DSS).
Dengue fever is a severe flu-like illness. Its symptoms include rash, very high fever (104 - 105 degrees Fahrenheit), severe headache, extreme muscle and joint pain, nausea, vomiting, and enlarged lymph nodes.
Dengue hemorrhagic fever is even more severe and a life-threatening disease which causes early symptoms that are very similar to those of dengue fever. They would be very high fever, headache, muscle and joint aches, malaise, decreased appetite, bleeding, hypotension and vomiting. After several days, the patient may undergo symptoms of irritability, restlessness, and excess perspiration. Further complications include liver enlargement and circulatory failure.
Dengue shock syndrome usually occurs after 2 to 6 days. Patients usually exhibit the symptoms of Dengue fever and Dengue haemorrhagic fever first. Later, they would suffer from sudden collapse, “clammy” extremities, decrease in pulse, and circumoral cyanosis (blueness around mouth). At this stage, mortality rate can reach as high as 30%.
There are four serotypes of dengue virus. Infection by a serotype provides future infections by the same serotype, but does not offer cross protection for infection from other serotypes. In fact, a second infection by a different serotype can cause a phenomenon known as “immune enhancement” which may lead to a more severe form of the disease from the second infection.
Control mesures would include putting up a mosquito screen, removing stagnant water and also spraying insecticides.
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The Flaviviridae family consists of enveloped viruses and they have a single linear positive sense RNA genome. The complete genome is about 9500-12500 nucleotides long. Many species of Flaviviridae can replicate in both mammalian and insect cells. They also can survive for long periods in hosts by replicating in the host itself.