Dengue Fever

Was having a discussion with a friend on the symptoms of Dengue fever. And not to my surprise, none of us know much about dengue. Is ignorant really a bliss?! =p

Friend's a bit unwell and just a couple of days ago, Dengue cases in Singapore have reached 'epidemic' levels. 381 cases were reported between June 24 and 30, above the 'epidemic threshold' of 378 cases per week. (See Channelnewsasia for more details on the cases in Singapore.)

Notes on Dengue:
1) Vector - Aedes Aegypti. They prefer to rest indoors and feed on humans during daylight hours.

2) There are currently four strains of dengue virus being identified. After disease, specific immunity is produced to the infecting strain of dengue virus, however, infection with the other strains of dengue virus is still possible. Studies show that infection with and subsequent immunization from one dengue serotype actually increases the odds of developing dengue hemorrhagic fever during infection with a second serotype. Same goes with Co-infection with one of the other dengue virus.
p/s: I guess I'll have to be extra careful now.

2) Dengue fever usually starts suddenly with a high fever, rash, severe headache, pain behind the eyes, and muscle and joint pain. Nausea, vomiting, loss of appetite, and diarrhea are common too.

3) A rash usually appears 3 to 4 days after the start of the fever. The illness can last up to 10 days, but complete recovery can take as long as a month. Older children and adults are usually sicker than young children.

4) Most dengue infections result in relatively mild illness, but some can progress to dengue hemorrhagic fever. With dengue hemorrhagic fever, the blood vessels start to leak and cause bleeding from the nose, mouth, and gums. Bruising can be a sign of bleeding inside the body. Without prompt treatment, the blood vessels can collapse, causing shock (dengue shock syndrome).

5) Mechanism --For Hemorrhagic Variant. The hemorrhagic dengue variant seems to be able to replicate in the human body only in macrophages. It is possible that the virus-antibody interactions actually help hemorrhagic viral replication by promoting cell infection. This is via specific macrophage receptors--the Fc portion of the antibody molecule, or possibly via a protease-sensitive receptor. Apparently, the antibodies attach to the virus's outer envelope, then signal the larger macrophages. When a macrophage responds to the antibody signal and arrives on the viral scene, it engulfs the virus. However, the virus then takes control of the macrophage and replicates inside the macrophage instead of being destroyed by it. The virus is then carried throughout the body via the macrophage transports. Physical reactions triggered by this involvement of the immune system include fevers from 104-107 F, convulsions, shock, and death. Read here for more information.

6) Diagnosis is made by blood test for the presence of the virus or antibodies, or by serologic testing. Lab results may indicate that fibrinogen and clotting factors V, VII, IX, and X are reduced.

Have been a bit paranoid lately too especially when got bitten by the mosquitoes. I can see that I'm goin through the transition from 'whatever' attitude to 'be alert with what's goin on'. Is it an 'age' thingy? Hmm.

Anyways, to be aware of things is better than not. =)