Signs and symptoms of virus

Typically, people infected with dengue virus are asymptomatic (80%) or only have mild symptoms such as an uncomplicated fever.Others have more severe illness (5%), and in a small proportion it is life-threatening. Theincubation period (time between exposure and onset of symptoms) ranges from 3–14 days, but most often it is 4–7 days. Therefore, travelers returning from endemic areas are unlikely to have dengue if fever or other symptoms start more than 14 days after arriving home. Children often experience symptoms similar to those of the common cold and gastroenteritis (vomiting and diarrhea),but are more susceptible to the severe complications.

[edit]Clinical course

The characteristic symptoms of dengue are sudden-onset fever, headache (typically located behind the eyes), muscle and joint pains, and a rash. The alternative name for dengue, "break-bone fever", comes from the associated muscle and joint pains. The course of infection is divided into three phases: febrile, critical, and recovery.

mucous membra

The febrile phase involves high fever, often over 40 °C (104 °F), and is associated with generalized pain and a headache; this usually lasts two to seven days. At this stage, a rash occurs in approximately 50–80% of those with symptoms. It occurs in the first or second day of symptoms as flushed skin, or later in the course of illness (days 4–7), as a measles-like rash. Some petechiae (small red spots that do not disappear when the skin is pressed, which are caused by broken capillaries) can appear at this point, as may some mild bleeding from the nes

of the mouth and nose. The fever itself is classically biphasic in nature, breaking and then returning for one or two days, although there is wide variation in how often this pattern actually happens.

 During this phase there may be significant fluid accumulation in the chest and abdominal cavity due to increased capillary permeability and leakage.

 During this phase, organ dysfunction and severe bleeding, typically from the gastrointestinal tract, may occur

 Shock (dengue shock syndrome) and hemorrhage (dengue hemorrhagic fever) occur in less than 5% of all cases of dengue

 however those who have previously been infected with other serotypes of dengue virus ("secondary infection") are at an increased risk.

The recovery phase occurs next, with resorption of the leaked fluid into the bloodstream. This usually lasts two to three days.The improvement is often striking, but there may be severe itching and a slow heart rate. During this stage, a fluid overload state may occur; if it affe

cts the brain, it may cause a reduced level of consciousness  .

[edit]Associated problems

Dengue can occasionally affect several other body systems, either in isolation or along with the classic dengue symptoms

 A decreased level of consciousness occurs in 0.5–6% of severe cases, which is attributable either to infection of the brain by the virus or indirectly as a result of impairment of vital organs, for example, the liver.

Other neurological disorders have been reported in the context of dengue, such as transverse myelitis and Guillain-Barré syndrome.

^]Infection of the heart and acute liver failure are among the rarer complications.