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DENGUE FEVER FACT SHEET

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DENGUE FEVER FACT SHEET

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									                           DENGUE                                       FEVER                         FACT                           SHEET

DENGUE FEVER
Dengue fever is a relatively common problem that periodically reaches epidemic                 The most useful laboratory test in suspected DHF is the estimation of
proportions, usually every 4-5 years. Dengue occurs due to infection by a FLAVIVIRUS,          thrombocytes (platelets) which will be very low. In contrast to uncomplicated
which is transmitted by the bite of the Aedes aegypti mosquito. It is very rarely fatal in     dengue fever the white cell count is more often high in patients with DHF.
healthy and fit individuals. The patient is often left debilitated and requires considerable
convalescence. Dengue is not transmitted from person to person.                                PREVENTIVE MEASURES AGAINST MOSQUITOS
Recurrent infections with Dengue fever, especially when they are from different strains of     All varieties of mosquitoes breed in or near water that is stagnant or slow moving.
the Flavivirus, are associated with a higher risk of complications, in particular Dengue       The importance of mosquitoes in transmission of disease makes adequate control
Haemorrhagic shock syndrome (covered later in this bulletin).                                  of mosquito-breeding sites very important, especially those close to human
                                                                                               habitation.
                                                                                               Personal protective measures can greatly reduce the risk of being bitten.
                                                                                               1.    The use of mosquito deterrents in bedrooms is effective to reduce the
                                                                                                     number of mosquitoes in the room, but it does not prevent mosquito bites
                                                                                                     all together. The chemical deterrent is released through an electronically
                                                                                                     heated impregnated pad or gel, and its effectiveness depends largely on the
                                                                                                     size and ventilation of the room.
                                                                                               2.    Correct use of mosquito nets (essential if accommodation is not air-
                                                                                                     conditioned). For added protection for up to 3 months or longer, mosquito
                                                                                                     nets can be soaked in 1 % solution of PERMETHRIN (or other repellent /
                                                                                                     insecticide). If resident in a dengue or malaria affected areas, curtains can
                                                                                                     be treated in a similar manner. Windows can be closed with fine insect
SYMPTOMS                                                                                             screens, which may or may not be treated with PERMETHRIN, to keep
Following an incubation period of 2 - 14 days (usually 4 - 8), the onset of symptoms is              mosquito away from bedrooms.
usually abrupt with chills, headache, backache, weakness and pain behind the eyes. The         3.    Use of mosquito coils and "knockdown spray" (containing pyrethoids) -
joint and back pains can be very bad indeed; hence the older name 'backbone fever'. The              spray insecticide in cool dark places where mosquitoes lurk. After spraying
temperature rapidly rises, often to 40°C (104°F), and there is a low heart rate (compared            do not enter the room and keep all doors and windows closed.
to the other causes of high fever). The blood pressure is often also low.                      4.    Avoid use of dark coloured clothing, perfumes and colognes as all these
                                                                                                     attract mosquitoes, especially at night.
                                                                                               5.    Use of an effective mosquito repellent on exposed skin and clothing if you
                                                                                                     are sitting outside. DEET (diethylmethylbenzamide) is still an effective safe
                                                                 The rash is                         component of good repellents. The actual concentration of DEET varies
                                                                 made up of                          widely between different manufacturers, and can be as high as 90% (too
                                                                 small red                           high for safety). Choose a repellent with between 30-45% DEET and take
                                                                 dots                                the following precautions against adverse reactions:
                                                                                                          a. apply sparingly and only to exposed skin
                                                                                                          b. never apply high concentrations to skin (use those for clothing)
                                                                                                          c. do not inhale / swallow repellent or get in eyes or mucous
                                                                                                              membranes
                                                                                                          d. do not apply to hands that may touch eyes or mouth
After 2 - 4 days, a temporary improvement can occur with a sudden drop in temperature                     e. do not apply to wounds, rashes, or abrasions
and subjective improvement, usually for 24 hours until there is a second rapid                            f. wash repellent off after coming indoors to stay
temperature rise, and the appearance of a characteristic rash on the trunk, limbs, palms                  g. if skin starts to burn, wash repellent off and seek medical advice
and soles especially. The skin in these areas turns bright red (the rash is usually a series   6.    DEET-based repellents should last for up to 4 hours.
of dots) and may peel. (This second phase of fever does not always occur). Thereafter
there is slow improvement. An attack produces immunity for a year or more, but only to         DESTROY MOSQUITOES AND THEIR LARVAE (YOUNG).
the one of the four FLAVIVIRUS strains responsible.                                            •   Clear the neighbourhood of ponds & pits.
                                                                                               •   Cover all water containers and any objects that can trap rain water (tires,
CONFIRMING THE DIAGNOSIS                                                                           pots, rubbish piles)
There are no immediate useful tests for diagnosing dengue fever. The white blood cell          •   Filling or drain areas of stagnant water except for swimming pools and
count is often low unlike in bacterial causes of fever. The dengue antibody test can give          ornamental pools if they are aerated by a pump or fountain or similar.
both false positive and false negative results, especially in the first week of the disease.   •   Use of mosquito larvicides (ABATE) or mosquito larvae-eating fish in waters
The diagnosis will, in a large proportion of cases, be based on clinical presentation and a        that cannot be drained.
characteristic drop of platelets in the blood.
                                                                                               •   Installation of mosquito screens on doors and windows and mosquito nets on
Convalescence can take weeks, and bed rest and fever lowering medications are required.            beds.
Do not use Asprin.                                                                             •   Change water in flower pots once a week and wash them thoroughly. Do not
                                                                                                   let plants stand in trays containing water. Scrub trays weekly to get rid of any
DENGUE HAEMORRHAGIC FEVER (DHF)                                                                    mosquito eggs.
A rare complication of dengue fever, dengue haemorrhagic fever, can occur, most often in       •   Cover all water containers and eliminate objects that can trap rainwater. This
small children and elderly adults. This can sometimes be a serious illness. If DHF occurs          includes areas underneath elevated walkways and accommodations.
it will usually do so by day 3-5 of the fever.                                                 •   Avoid the uncontrolled use of residual and space insecticides, and the use of
                                                                                                   toxic materials.
It has been suggested that DHF is more likely if the patient has previously had an attack
of dengue within the last calendar year, and that the occurrence of DHF relates to this        •   Fogging is effective to kill mosquitoes but does not kill larvae. Fogging will not
previous exposure. The relationship between DHF and previous dengue infection is not               stop mosquitoes entering your premises, however, it may deter them from
this clear-cut, however previous exposure does raise the incidence of subsequent DHF, in           establishing breeding grounds at premises where fogging is performed.
particular when this involves different strains of the virus.
                                                                                                 Do not allow indiscriminate use of insecticides unless possible risks of their use
SYMPTOMS OF DHF                                                                                are clearly understood. Know what you are doing and / or what chemical is being
Uncontrolled bleeding distinguishes this from uncomplicated dengue fever. Bleeding can                                                used.
occur from the gums, nose, intestine, or under the skin as bruises or spots of blood
especially under a tourniquet - this test should be employed if there is any suspicion. The                                                                     Dr. Uwe Stocker,
liver is often enlarged.                                                                                                                                         Medical Advisor
Patients can have rapid onset of marked drowsiness, lethargy or restlessness or the                                                                   International SOS, Jakarta
presence of shock as manifested by a rapid and weak pulse, low blood pressure and cold
clammy skin. Such patients should be immediately referred to a good hospital for further       Should you wish to arrange a briefing on Dengue Fever for your
management. DHF shock can be a mortal illness and requires rapid and careful in-               company employees and/or families, please contact the Sales and
hospital management with replacement of fluid, electrolytes, plasma and sometimes fresh        Marketing department at International SOS on (21) 750 5973
blood / platelet transfusions.                                                                 (Jakarta) or (361) 710 505 (Bali) to arrange a quotation.

                                                                                               The briefing can be provided in Bahasa Indonesia or English.

								
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