DENGUE IN ENGLISH

                                               

                                          DENGUE IN ENGLISH

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DENGUE-

Dengue is a viral disease caused by infection with dengue virus (an arbovirus) and transmitted to man by infected aedes mosquito.

           Dengue fever (DF) and its severe forms dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS) have become major international public health concerns. Dengue is endemic in more than 100 countries. In India, the risk of dengue has shown an increase in recent years due to rapid urbanization, lifestyle changes and deficient water management

CAUSATIVE AGENT-

           The dengue is caused by a virus Which is form genus flavivirus.  based on antigenic and biological characteristics, here are four virus serotypes which are designated as DENV-1, DENV-2, DENV-3 and DENV-4. All four serotypes are equally responsible for epidemics of dengue fever (with or without DHF) with varying degree of severity.

MODE  OF  TRANSMISSION –

           VECTOR TRANSMISSION:

           Dengue is transmitted by the bite of aedes aegypti and aedes albopictus mosquitoes. The Aedes mosquito becomes infective by feeding on a patient from the day before onset to the 5th day of illness. After an extrinsic incubation period of 8 to 10 days, the mosquito becomes infective, and is able to transmit the infection. Once the mosquito becomes infective, it remains so for life.

           The population of Aedes aegypti fluctuates with rainfall and water storage. Its life span is influenced by temperature and humidity, survives best between 16°C-30°C and a relative humidity of 60-80 per cent. It breeds even in the containers in and around the houses. The mosquito is recognized by white markings on it’s body

SIGN AND S YMPTOMS-

           Dengue virus infection may be asymptomatic or may have following symptoms-

           Fever with our without maculopapular rash.

           Chills and high fever,

           Intense headache,

           Muscle and joint pains.

           Retro-orbital pain, particularly on eye movements or eye pressure and photophobia develops. Other common symptoms include extreme weakness, anorexia, constipation, altered taste sensation, colicky pain and abdominal tenderness, pain in inguinal region, sore throat and general depression. Fever is usually between 39°C and 40°C.

           Fever lasts for about 5 days, rarely more than 7 days after which recovery is usually complete.

           Complications-

           1. Dengue haemorrhagic fever

           Dengue haemorrhagic fever (DHF) is a severe form of dengue fever.

           DHF have three stage-

           1.Febrile phase-  In this stage there is high fever accompanied by facial flushing and headache. Anorexia, vomiting, epigastric discomfort, tenderness at the right costal margin and generalized abdominal pain are common. Occasionally, the temperature may be 40°C to 41°C and febrile convulsions may occur particularly in infants.

           2. Critical phase-  this phase starts usually on third dasy of illness. There is an increase in capillary permeability. The period of clinically significant plasma leakage usually lasts 24-48  hours. The degree of plasma leakage varies. Pleural effusion mostly on right side. and ascites may be clinically detectable depending on the degree of plasma leakage and the volume of fluid therapy. Severe haemorrhage may occur into internal organs.

           3. Recovery phase-  if the patient is able to survive the critical phase than recovery phase may start. A gradual reabsorption of extravascular compartment fluid takes place. General well-being improves, appetite returns, gastrointestinal symptoms improves, blood pressure stabilizes and diuresis occurs. Some patients  may experience generalized pruritus and bradycardia.

           2. Dengue shock syndrome

           Dengue shock syndrome (DSS) is a very severe form of dengue. In DSS plasma leakage that may lead to shock along with severe bleeding and severe organ impairment. The patient may have hypoxia and acidosis, can lead to multiple organ failure and death may occur.

DIAGNOSTIC INVESTIGATIONS-

           1. RTPCR-  The dengue virus consists of RNA, that can be detected by reverse transcriptase polymerase chain reaction (RT -PCR) from blood sample of the patient.

           2. ELISA - ELISA and dot blot assays directed against the envelop/membrane (EM) antigens and nonstructural protein 1 (NSl) can be detected in both patients with primary and secondary dengue infection

           3. Rapid diagnostic test (RDT)- A number of commercial rapid format serological test-kits for anti-dengue IgM and IgG antibodies have become available in the market. These kits provide result only in 15 minutes.

           4. Platelet count- blood platelet count is also important in determinging the severity of disease and need for platlet transfusion.

TREATMENT-

           Treatment depends upon the severity of dengue. For normal dengue fever only symptomatic treatment is needed along with adequate hydration. Encourage intake of oral rehydration solution (ORS), fruit juice and other fluids containing electrolytes and sugar to replace losses from fever and vomiting. Paracetamol is given to control the fever.

           For DHF and DSS the patient should be admitted in the hospital. Close observation is must to detect shock at early stage. Fever and dehydration management should be continue paracetamol, ORS and other oral fluids. IV fluid may be administered if the patient is vomiting persistently or refusing to feed. Plasma expanders or Blood / platelet transfusion may be given as per need.

PREVENTION-

Ø  Health education regarding prevention and control of dengue is very important step to prevent it.

Ø  Control of mosquitos is another very important measure to prevent malaria.

Ø  Insecticide-treated mosquito nets (ITNs) are the most universally useful measure for the prevention of dengue

Ø  Control of larval stages by elimination of mosquito breeding sites, for example by filling and draining the water collection site.

Ø  The use of larvivorous fish especially Gambusia is well known in mosquito control

Ø  General cleanliness is also helpful in eliminating breeding places of aedes mosquito.

Ø  Isolation of patient and preventing him from mosquito bite until fever subsites also help in preventing further transmission of dengue.

Ø  Vector control also involves the application of pesticides in the form of fog or mist using special equipment. The ultra-low-volume method of pesticide dispersion by air or by ground equipment has proved to be effective.

Ø  Wear long sleeved clothing and long trousers when going out to protect ourselves from mosquito bite.

Ø  Apply mosquito repellent cream to exposed skin.

Ø  Use screens/net over doors and windows; if no screens are available, close windows and doors at night.

Ø  Use anti mosquito coil or electric mosquito killer to reduce number of vector.