ABOUT DENGUE

Dengue is transmitted by the bite of an Aedes mosquito infected with any one of the four dengue viruses. It occurs in tropical and sub-tropical areas of the world. Symptoms appear 3—14 days after the infective bite. Dengue fever is a febrile illness that affects infants, young children and adults.
Symptoms range from a mild fever, to incapacitating high fever, with severe headache, pain behind the eyes, muscle and joint pain, and rash. There are no specific antiviral medicines for dengue. It is important to maintain hydration. Use of acetylsalicylic acid (e.g. aspirin) and non steroidal anti-inflammatory drugs (e.g. Ibuprofen) is not recommended.
Dengue haemorrhagic fever (fever, abdominal pain, vomiting, bleeding) is a potentially lethal complication, affecting mainly children. Early clinical diagnosis and careful clinical management by experienced physicians and nurses increase survival of patients.

By World Health Organization

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Under the auspicious of the Faculty of Medical Sciences of the University of Sri Jayewardenepura (USJ) has recently established a Centre for Dengue Research (CDR) at the Department of Microbiology. Hon. S.B. Dissanayake, the Minister of Higher Education has accepted the CDR proposal of the Faculty of Medical Sciences submitted by its Dean Prof. Mohan De Silva through the Vice Chancellor – USJ to the ministry. The Cabinet Memorandum dated 20th August, 2012, submitted by Hon. S.B. Dissanayake was approved by the Cabinet of Ministers at its meeting held on 28th August, 2012, granting a sum of Rs. 92.6 million to establish CDR and to continue its ongoing Dengue research projects, which are to be completed within the next 2-3 years. The ongoing CDR research projects include:


    1) Defining Correlates of a Protective Immune Response (Principal Investigator- Dr. Neelika Malavige, Department of Microbiology)
    2) Vector Biology of Aedes mosquitoes (Principal investigators - Dr. Neelika Malavige & Prof. B.G.D. Nissanka K. De Silva)
    3) Geospatial modeling of socio-ecological factors influencing dengue (Principle Investigator – Prof. Krishan Deheragoda, Department of Geography)
    4) To Establish a Dengue Surveillance System for a Period of 5 Years in 5 MOH Areas Around the University of Sri Jayewardenepura (Principle Investigators – Dr. Neelika Malavige, Prof. Krishan Deheragoda, Dr. Vathsala Jayasuriya)

Dr. Vathsala Jayasuriya, (Senior Lecturer, Department of Community Medicine) and Dr. Chandima Jeewandara (Probationary Lecturer, Dept of Family Medicine) will be the co-investigators for the projects NO.1 & 4. Dr. Chandima Jeewandara and Ms. Achala Kamaladasa are currently reading their Ph.D. Degrees on a part of the project No. 1 while Mr. H.M. Prabath Jayantha will read for the Ph.D. Degree in Geospatial modeling of socio-ecological factors influencing dengue under project no. 3.

These projects are done in collaboration with Prof. Graham Ogg, Nuffield Department of Clinical Medicine, University of Oxford, who will be advising CDR on the immunology component and Prof. Marilyn O’Hara Ruiz - College of Veterinary Medicine, Department of Pathobiology, University of Illinois, who will be advising on the GIS modeling component and Prof. Ng Mah Lee, National University of Singapore, will be advising the CDR on the virology component.Prof. B.G.D. Nissanka K. De Silva (Department: Zoology, Faculty of Physical and Life Sciences –USJ) is the principle investigator for another research project titled “Genetic structure of Aedes mosquito populations in Sri Lanka”, as an extension to CDR dengue research. Some of the above mentioned CDR dengue projects are partially funded by the National Sciences Foundation, Sri Lanka.

Background

Dengue viral infections are one of the most dangerous mosquito borne viral infections in the world. In the past fifty years, its incidence has increased 30-fold with significant outbreaks occurring in five of six WHO regions. Although the Sri Lankan population had been exposed to the virus for decades, severe forms of dengue infection (DHF/DSS) was rare. However, in recent years dengue has become the number one killer mosquito borne infection in Sri Lanka, and the number of cases of dengue appears to be rising each year due to its spatial expansion in unprecedented scale. According to the Health Ministry, Dengue fever has claimed 85 lives and 25,000 cases reported this year. The project is to be implemented within a period of two years.

Present Status & Justification

The Department of Microbiology of the University of Sri Jayewardenepura is the forefront of Dengue Research and four projects are under implementation with the collaboration of multidisciplinary research groups. Also in collaboration with a senior academic at the MRC Human Immunology Unit, University of Oxford this particular academic department has engaged in dengue research during the past few years and has produced over 10 publications in peer review international journals and have filed one International Patent. This technology enables to find out the number of past dengue viral infections a person has had, and also the dengue virus serotypes that were responsible for the past dengue infections. With this knowledge it is envisaged to determine the dynamics of dengue virus transmission in the community. Furthermore, this knowledge would help the researchers to understand the immune responses to the dengue virus in those who are infected with the virus but do not develop apparent infection. This knowledge will help them to define the levels of protection that are needed to prevent dengue, which is crucial for development of a dengue vaccine.

Dr. Neelika Malavige of the Department of Microbiology – USJ has been appointed as the Director of CDR. The CDR research projects have established an active collaboration with the University of Oxford - U.K., University of Illinois – USA and National University of Singapore for dengue research. These successes have achieved with very limited available funding, in the past few years. However, with the availability of direct funds from the Government of Sri Lanka for this national endevour, the CDR team of USJ researchers with the technical support from the said foreign partner universities, is confident in generating data for dengue vaccine development, vector control measures and preventing dengue transmission in the community. We expect CDR to be a centre of excellence for research and development on dengue, locally as well as internationally. It will enable to foster relevant and cutting edge research on Dengue in order to come up with a long lasting solution to this health issue which would not only benefit Sri Lanka, but the whole world.

Source:http://www.sjp.ac.lk/dengueresearch/index.htm

Dengue Fever Symptoms

Dengue Haemorrhagic Fever is a mosquito-borne viral infection endemic in the tropical and sub-tropical regions. The female Ae.aegypti (the most important vector) mosquito is semi-domesticated, preferring to lay its eggs in man-made water containers, resting indoors and feeding in the early morning or late afternoon. There are 4 serotypes of Dengue virus. Dengue usually occurs as epidemics in Sri Lanka following monsoon seasons.
According to data from epidemiology unit of Sri Lanka, the number of total cases recorded for year 2009 is 32713. Most affected district was Kandy. Colombo, Gampaha and Kaluthara districts which have been susceptible in the past have also recorded a high rate of infection and deaths.
Dengue virus; There are 4 serotypes of the single-stranded RNA virus (flaviviridae).
Patients become infected once bitten by mosquitos. The virus passes to lymph nodes and replicates which is followed by spread to the circulation and other tissues. It is thought that infection with a secondary serotype is what leads to severe haemorrhagic disease.
Disease varies in severity
- Incubation period is 2-7 days.
- All haemorrhagic fever syndromes begin with abrupt onset of fever (39.5–41ºC) and myalgia.
- Fever is often biphasic with two peaks.
- Fever is associated with frontal or retro-orbital headache lasting 1–7 days, accompanied by generalised macular, blanching rash.
- Initial rash usually fades after 1–2 days.
- Symptoms regress for a day or two then rash reappears in maculopapular, morbilliform pattern, sparing palms and soles of feet. Fever recurs but not as high. There may be desquamation.
- DF cases experience severe bony and myalgic pain in legs, joints and lower back which may last for weeks (hence breakbone fever).
- Nausea, vomiting, cutaneous hyperaesthesia, taste disturbance and anorexia are common.
- Abdominal pain may occur and if severe suggests DHF pattern.The signs of dengue fever/ Dengue haemorrhagic fever are- High fever, rash, hypotension and narrow pulse pressure, poor capillary refill.
- There may be hepatomegaly and lymphadenopathy.
- A tourniquet placed on an arm may induce petechiae in early DHF cases. DHF sufferers exhibit a bleeding tendency as evidenced by petechiae, purpura, epistaxis, gum bleeding, GI haemorrhage and menorrhagia. There may be pleural effusion, ascites and pericarditis due to plasma leakage.
- Petechiae are best visualised in the axillae.
- Flushing of head and neck.
- Tender muscles on palpation.
- Periorbital oedema and proteinuria may be present.
- Maculopathy and retinal haemorrhages may also occur.
- DSS pattern cases progress through DHF until profound shock due to severe hypotension is present.
- CNS involvement e.g. encephalopathy, coma, convulsions.

- Hepatic failure: Means failure of the liver
- Encephalopathy: Means damage to the brain causing fits, loss of consciousness and confusion- Myocarditis – Inflamation of heart muscles
- Disseminated intravascular coagulation - Damage to blood vessels and blood cells causing problematic bleeding and clottingDengue can cause death
- FBC - low platelets and high packed cell volume if haemoconcentrated. Usually white cell count will fall
- Infection may be confirmed by isolation of virus in serum and detection of IgM and IgG antibodies for Dengue by ELISA, monoclonal antibody or haemagglutination
- Molecular diagnostic methods such as reverse-transcriptase-PCR are increasingly being used.
- Chest X-ray may show pleural effusion.
- Bed rest
- Nutritious diet and lot of liquids, But avoid red and brown foods and drinks like coffee, chocolate, grapes etc as it may misinterpret vomiting as blood stained vomitus.
- Fever control with paracetamol, tepid sponging and fans. Aspirin should be avoided.
- Need to seek advice from a qualified medical practitioner if fever lasts for more than 2 days
- Hospital managemnt includes intravenous fluid resuscitation with close monitoring. Haemorrhage and shock will require Fresh Frozen Plasma, platelets and blood. Intensive management with inotropes of the shock syndrome may be required in severe DHF/DSS cases.
- Vaccines are being researched
- Anti-mosquito public health measures such as reducing breeding sites ( flower pots, fish tanks,tires, coconut shells, tins, water collecting plants, gutters which can collect water) and good sewage management
- Insecticides to destroy the larvae
- Mosquito nets can be used during day time as the Aedes mosquitoes is day-biting.
- Mosquita repellents
- There is a bacteria called Bacillus thuringiensis which destroy the mosquito larvea

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