DENGUE FEVER Transmission of Dengue Viruses The Virus The Vector

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1 DENGUE FEVER Dengue Fever is still a major problem in tropic area. Mostly people get confused and sometimes they didn t know if they have dengue or it is other kind of fever. Identifying the signs and symptoms is really helping us to diagnose, not only rely on laboratory examination. Talking about dengue, we should know about this term, Dengue Fever, Dengue Haemorrhage Fever and Dengue Shock Syndrome. Dengue Fever (DF) is an acute febrile viral diseases frequently presenting with headaches, bone or joint and muscular pains, rash and leucopenia as symptoms. Dengue Haemorrhagic Fever (DHF) is characterized by four major clinical manifestations: high fever, haemorrhagic phenomena, often with enlarged of internal organ like liver and spleen and in severe case, circulatory failure. Such patient may develop hypovolaemic shock resulting from plasma leakage. This is called Dengue Shock Syndrome (DSS) and can be fatal. Transmission of Dengue Viruses Dengue viruses are transmitted to human through the bite of infected Aedes mosquitos, principally Aedes aegypti, and are therefore considered to be arbovirus (arthropod-borne virus). Once infected, mosquitos remain infected for life, transmitting the virus to susceptible individual during probing and feeding. The virus circulate in the blood of infected humans at approximately the time that they have fever, and uninfected mosquito may acquire the virus if ther feed on an individual when he or she is viraemic (have a high concentration of virus in blood). The virus then develops in the mosquitos for a period of 8-10 days before it can be transmitted to other humans during subsequent probing or feeding. The Virus Dengue virus belongs to the family Flaviviridae. The four serotypes of dengue virus (DEN-1, DEN-2, DEN-3 and DEN-4) can only be distinguished by serological methods. Infection in human by one serotype produces life-long immunity against re-infection by that same serotype, but only temporary and partial protection against the other serotype. The Vector Ae. Aegypti is tropical and subtropical species of mosquito found around the globe, and this type of mosquito do not survive the winter. The distribution of Ae. Aegypti is also limited by

2 altitude. It is usually not found above 1000m. Dengue outbreak is also having been attributed to Ae. Albopictus, Ae. Polynensis and several species of the Ae. Scutellaris complex. When the mosquito lying eggs, the eggs can withstand long periods of desiccation, sometimes for more than a year. The Host In human, each of the four dengue virus serotype has been associated with DF and DHF. Dengue shock syndrome occurs with higher frequency in two immunologically defined groups: children who have experienced a previous dengue infection, and infants with waning levels of maternal dengue antibody. The acute phase of infection, following an incubation of 3-14 days, last about 5-7 days and is followed by an immune response. Two main problem is an increased vascular permeability that gives rise to loss of plasma from the vascular compartment (this results in haemoconcentration, low pulse pressure and sign of shock) and disorder in haemostasis involving vascular changes, thrombocytopenia and coagulopathy. Platelet not only decrease in number but in their function and those incease chance of bleeding. Symptoms and Sign Dengue infection may be asymptomatic or may lead to Undifferentiated Fever, Dengue Fever (DF), and Dengue Haemorrhagic Fever (DHF) ( including Dengue Shock Syndrome (DSS)). The clinical feature of DF frequently depend on the age of the patient. Infants and young children may have an undifferentiated febrile disease, often with rash on skin. Older children and adults may have either a mild febrile syndrome or the classic incapacitating disease with two peak (saddle-backed), severe headache, pain behind eyeball, muscle and bone or joint pains, nausea and vomiting also rash. Dengue Fever may be accompanied by bleeding complications, such as epistaxis, gingival bleeding, gastrointestinal bleeding, haematuria and menorrhagia. Typical cases of DHF are characterized by four major clinical manifestations: high fever, haemorrhagic phenomena, enlarged of internal organ like liver and spleen and circulatory failure. Moderate to marked thrombocytopenia with concurrent haemoconcentration is distinctive clinical laboratory finding of DHF. Children with DHF commonly present with sudden rice in temperature (> 39 o C) accompanied by facial flush and other non-specific constitutional symptoms resembling DF, such as anorexia, vomiting, headache, muscle or bone or joint pain, sore throat, injected pharynx and conjuctival injection. The most common haemorrhagic phenomenon is a positive tourniquet test, easy bruishing and

3 bleeding such as nose bleeding and gum bleeding. There is enlargement of liver that we can palpate 2-4cm bellow the lowest rib. So, when someone has infected by dengue virus it can manifest into Dengue Fever or Dengue Haemorrhage Fever that can give the similar symptom and sign but in Dengue Haemorrhage Fever there is plasma Leakage as manifest by elevated haematocrit (the haemoconcentration) a serous effusion or hypoproteinemia. Please see picture bellow. Focus to the fever, classic type of DF and DHF is two peak (saddle-backed) of fever. Patient can have fever until the third day and the next three days there is rapid fall in temperature is often accompanied by sign of circulatory disturbance like sweat, restless, cool extremities and show some change in pulse rate and blood pressure. Beside than dengue fever, there is other diseases that give you similar symptoms and sign. This is some of the comparation.

4 Laboratory Examination Complete Blood Count (CBC) and ELISA test to determine IgM or IgG specific for dengue virus are the two of laboratory examination that can help us. It is simple and we can do it in almost local / public hospital. In CBC you can look into the trombocyte count and hematocrit. The decreased of thrombocyt (thrombocytopenia) bellow per mm 3 usually found between the third and eight day of illness in DF also in DHF case. Elevated of haematocrit which is indicated plasma leakage is always present in DHF cases but not in DF. Increase in the haematocrit of 20% or more considered to be definitive evidence of increase vascular permeability and plasma leakage. ELISA test to determined the IgM and IgG is check in the seventh until the tenth day of illness to get the better result. From this examination we can prove that the case was cause by dengue virus and determined that the case is primary infection or secondary infection. In acute primary infection of dengue virus, only the IgM that would increase, but in the acute secondary infection (wich is means you already have dengue infection more than once) both of IgM and IgG will increase.

5 Case Definition of Dengue Fever Probable Acute febril illness with two or more of : headache, pain behind eye ball, muscle ache, joint paint, rash, bleeding of gum or nose, decreasing of white blood cell And supportive serology ( IgM or IgG ) or occurrence at the same location and time as other confirmed cases of dengue fever Confirmed A case confirmed by laboratory criteria : isolation of the dengue virus from serum or autopsy sample or antigen positive for dengue virus, or detection of dengue virus genomic Case Definition for Dengue Haemorrhagic Fever: The following must all be present Fever, or history of acute fever, lasting 2 7 days, occasionally biphasic (saddlle back) type Haemorrhagic tendencies: can be positive tourniquet test Skin rash, mucosal bleeding, bloody vomit or black stool Thrombocutopenia ( cell per mm3 oe less Evidence of plasma leakage due to increased vascular permeability: Incresed haematocrit more then 20% above average for age, sex and Population A drop in the haematocrit following volume replacement treatment equal to or greater than 20% of baseline Sign of plasma leakage such as fluid and hipoprotemia

6 Treatment of Dengue Fever The dengue patient can be treated at home or at the hospital. It is depend on the condition of the patient. Dengue is a viral, so no point to give antibiotic for dengue patient except there is other infection accompanied this disease, like Typhoid Fever. The lost of fluid can be happen by the leakage of plasma, and also the high fever, anorexia, and vomit which is cause dehydration. So the most important therapy of dengue infection is replacement of fluid lost. This replacement can be by oral route if the patient can eat and drink, or by intravenous fluid. The electrolyte solution is the best option. The intravenous fluid therapy can be given in aggressive way if the patient is having shock. Other treatment is symptomatic. During the acute febrile phase, there is some risk of seizures, so antipyretic can be given if the temperature is greater than 39 o C. The paracetamol is the only recommended medicine. Salicylates should be avoid since they can cause bleeding and acidosis. Patient should be closely observed for sign of shock, during the critical phase which is the transition from the febril to afebrile phase (after the third day). So If the doctor decide you can be treated at home just remember to : - drink a lot electrolyte fluid - eat soft meal (especially if you had a history of gastrointestinal bleeding) - continue medicine that the doctor give to you - Stop doing exercise or working. It will worsening the dehydration and sometimes you can faint because of that. - Do the blood examination (CBC) every day to see if you have any bad thrombocytopenia that increasing your risk for having internal bleeding or haemoconcentration that make increasing your chance to have a shock.

7 If you treated at hospital, there are doctors and nurses that look after you and make sure you get all the medicine. The only one you can do is follow that medication, and tell them as soon as possible if you have this following symptom like: - Diarrhea - Stomach ache/cramp - Your stomach is getting bigger. - Black stool - Vomit with the black clod - Hard to breath of chest pain - Swelling on your feet - Severe headache - And anything else you feel weird and that never happen to you before Dengue Fever is a viral infection. The virus will be died by self mostly in the first week of illness. But until the virus die, your body need to survive to fight the sign that might be appear. After you cured from this disease, it still need a time for recovery phase. You might be fell dizzy until one or two weeks. It is really important to keep drink an electrolyte fluid and the vitamin to fasten your recovery phase. Prevention There is no prevention for dengue infection if you already bite with the mosquitos that have the virus inside their bodies. Your only fight is to increase your body immune system by taking a lot of food containing vitamins, antioxidant and plenty of rest. But the problem is we re not aware when we got bite. Some time we didn t feel itchy after the mosquito bite at all. The other ways it to prevent the bites by wearing the proper clothes and some bug spray. Other option is to reduce the population of the mosquito. In Indonesia we know the 3M Program, Menguras, Menutup dan Mengubur or 3C in English, which is mean CLEAN the bath up minimum twice a week with brush to prevent the mosquito lying eggs there, CLOSE all the water container, And Bury the tins so it will not become the place to mosquito to lying eggs ( in our situation COLLECT and recycling it ). Remember, the A. aegypti feed during the day time, especially indoor. So if you are at home in the morning, trying to look up in to the room, there is possibility of the mosquito is stay behind the curtain, the hanging clothes and other water container such us vas, rubbish bin and other place at home.