does dengue infection provides lifelong immunity?

Answer 1

Dengue (DF) and dengue hemorrhagic fever (DHF) are caused by one of four closely related, but antigenically distinct, virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4), of the genus Flavivirus. Infection with one of these serotypes provides immunity to only that serotype for life, so persons living in a dengue-endemic area can have more than one dengue infection during their lifetime. DF and DHF are primarily diseases of tropical and sub tropical areas, and the four different dengue serotypes are maintained in a cycle that involves humans and the Aedes mosquito.
Please see the webpages for more details on Dengue fever.

Answer 2

It does not, at most it provides yearlong immunity if any at all, and there are 4 strains of the virus. Getting ill from 1 of the strains makes you immune to that specific one but you can still get the others. Also, once you've had classic dengue, you're chances of developing hemorragic dengue are greatly increased.

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Check this out for more info: http://healthlink.mcw.edu/article/954993538.html

Answer 3

Supposed to be, but there are right now three species of Dengue. So if you had the first one, then you still have two more to go.

Answer 4

Dengue and Dengue Haemorrhagic Fever (DHF)
Dengue is a mosquito-borne infection. It is an infectious viral disease associated with fever and eruptions. Dengue is found in tropical and subtropical regions around the world, predominately in urban and peri-urban areas. Dengue haemorrhagic fever (DHF) which is a potentially lethal complication was first recognized during the 1950s. Dengue has today become a leading cause of childhood mortality in several Asian countries. There are four distinct, but closely related, viruses that cause dengue. Recovery from infection by one provides lifelong immunity against that virus but confers only partial and transient protection against subsequent infection by the other three.

Epidemiology
The global prevalence of dengue has grown dramatically in recent decades. The disease is now endemic in more than 100 countries. Before 1970 only nine countries had experienced DHF epidemics. But by 1955 this number grew by more than fourfold. 2500 million people (i.e. about two fifths of the world's population) are now at risk from dengue.

It is estimated that there may be 50 million cases of dengue infection worldwide every year. This is greater than double the number of dengue cases recorded in the same region in 1995. Not only is the number of cases increasing as the disease is spreading to new areas, but explosive outbreaks are occurring.

During epidemics of dengue, attack rates among susceptible are often 40 - 50%, but may reach 80 - 90%. An estimated 500,000 cases of DHF require hospitalization each year. A large proportion of these is children and roughly 5% of them die. Without proper treatment, DHF case fatality rates can exceed 20%.

With modern intensive supportive therapy, this can be reduced to less than 1%. The spread of dengue is attributed to expanding geographic distribution of the four dengue viruses and of their mosquito vectors, the most important of which is the predominantly urban species Aedes aegypti.

A rapid rise in urban populations is bringing ever greater numbers of people into contact with this vector, especially in areas which are favorable for mosquito breeding e.g., where household water storage is common and where solid waste disposal services are inadequate.

Dengue fever has been known in India for a very long time. There have been periodic outbreaks of the disease. An explosive out break of DHF occurred in Delhi in october 1996 with 7247 cases and 297 deaths.

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Transmission
Dengue viruses are transmitted to humans through the bites of infective female Aedes mosquitoes. When the mosquitoes feed on the blood of the infected person, they acquire the virus.

Once infective, a mosquito is capable of transmitting the virus to susceptible individuals for the rest of its life, during probing and blood feeding. Infected female mosquitoes may also transmit the virus to the next generation of mosquitoes by transovarian transmission i.e. via its eggs.

Humans are the main amplifying host of the virus, although studies have shown that in some parts of the world monkeys may become infected. These monkeys can serve as a source of virus for uninfected mosquitoes. The virus circulates in the blood of infected humans for 2-7 days, at approximately the same time as they have fever.

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Clinical picture
Dengue fever is a severe, flu-like illness that affects infants, young children and adults but rarely causes death. The clinical features of dengue fever vary according to the age of the patient. Infants and young children may have a nonspecific febrile illness with rash. Older children and adults may have either a mild febrile illness or the classical disease.

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Classical Dengue Fever
Sudden onset with chills and high fever, intense headache, muscle and joint pains, which prevent all movement, characterize the disease. Within 24 hours retro-orbital pain (pain at the back of the eye), particularly on eye movements or eye pressure and photophobia develops.

Other common symptoms include extreme weakness, loss of appetite, constipation, altered taste, colicky pain, dragging pain in the inguinal region, sore throat and general depression. Fever is usually between 39-40 deg. C. Fever is followed by a phase of remission lasting a few hours to a few days after which it reappears.

The skin eruptions usually appear either during the remission or on the reappearance of fever. The rash starts on the body and then spreads to the limbs and rarely to the face. Fever lasts for 5-7 days after which usually complete recovery occurs. Convalescence is prolonged.

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Dengue Haemorrhagic Fever (DHF)
DHF is a sever form of Dengue fever, caused by infection with more than one type of dengue virus. The disease is much more common in children below 15 years as compared to adults.

The onset is abrupt with high fever accompanied by facial flushing and headache. Loss of appetite, vomiting, abdominal pain and discomfort are common. Patient has a bleeding tendency and spontaneous bleeding into the skin may be apparent.

In sever cases there may be a collapse of the circulatory system characterized by a week and rapid pulse, fall in blood pressure and a cold and clammy skin. If diagnosed and treated early, death rate can be lower than 5%; otherwise it can be upto 30%.

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Treatment
There is no specific treatment for dengue fever. However, careful clinical management by experienced physicians and nurses frequently save the lives of DHF patients.

With appropriate intensive supportive therapy, mortality may be reduced to less than 1%. Bed rest is advisable during the febrile phase. Using antipyretics and cold sponging reduces fever. Aspirin is usually avoided, especially in areas where DHF is prevalent as it may cause bleeding.

Maintenance of the circulating fluid volume is the central feature of DHF case management.

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Prevention

* Vaccine development for dengue and DHF is difficult because any of four different viruses may cause disease. Moreover, protection against only one or two dengue viruses could actually increase the risk of more serious disease. However, progress is gradually being made in the development of vaccines that may protect against all four dengue viruses.
* To combat the vector mosquitoes as preventive measure is the only method of controlling or preventing dengue and DHF. In Asia and the Americas, Aedes aegypti breeds primarily in containers like earthenware jars, metal drums and concrete cisterns used for domestic water storage.

Answer 5

yes