A person infected by the dengue virus develops severe flu-like symptoms.
Dengue, influenza and chikungunya are serious viral infections that are usually accompanied by severe symptoms. And since the symptoms of all three are so similar, it can be quite difficult, if not impossible, to make a conclusive identification without laboratory testing, says Dr J. Anish Anand, consultant internal medicine, Apollo Hospitals.
DENGUE
Dengue is a mosquito-borne viral infection causing a severe flu-like illness, sometimes leading to severe complications. The dengue virus (DEN) comprises four distinct serotypes (DEN-1, DEN-2, DEN-3 and DEN-4) which belong to the genus Flavivirus, family Flaviviridae. Once infected, humans become the main carriers and multipliers of the virus, serving as a source of the virus for uninfected mosquitoes. The virus circulates in the blood of an infected person for 2-7 days, at approximately the same time that the person develops a fever. Patients who are already infected with the dengue virus can transmit the infection via Aedes mosquitoes after the first symptoms appear (during 4-5 days; maximum 12).
SYMPTOMS
A person infected by the dengue virus develops severe flu-like symptoms. Individuals should suspect dengue when a high fever (40°C/ 104°F) is accompanied by two of the following symptoms:
Symptoms usually last for 2-7 days, following an incubation period of 4-10 days after being bitten by an infected mosquito. Severe dengue is a potentially deadly complication due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding or organ impairment. The warning signs to look out for occur 3-7 days after the first symptoms in conjunction with a decrease in temperature (below 38°C/ 100°F).
Warning signs include:
The next 24-48 hours of the critical stage can be lethal, and proper medical care is needed to avoid complications and risk of death.
TREATMENT
PREVENTION AND CONTROL
CHIKUNGUNYA
Chikungunya is a viral disease transmitted to humans by infected mosquitoes. It causes fever and severe joint pain. Other symptoms include muscle pain, headache, nausea, fatigue and rash.
DIAGNOSIS
Several methods can be used for diagnosis. Serological tests, such as enzyme-linked immunosorbent assays (ELISA), may confirm the presence of IgM and IgG anti-chikungunya antibodies. IgM antibody levels are highest 3 to 5 weeks after the onset of the illness and persist for about two months. Samples collected during the first week after the onset of symptoms should be tested by both serological and virological methods (RT-PCR).
TREATMENT
There is no specific anti-viral drug treatment for chikungunya. Treatment is directed primarily at relieving the symptoms, including the joint pain using anti-pyretics, optimal analgesics and fluids. There is no commercial chikungunya vaccine.
PREVENTION AND CONTROL
INFLUENZA
Seasonal influenza is an acute respiratory infection caused by influenza viruses which circulate in all parts of the world. There are four types of seasonal influenza viruses - types A, B, C and D. Influenza A and B viruses circulate and cause seasonal epidemics of the disease.
SIGNS AND SYMPTOMS
DIAGNOSIS
Collection of appropriate respiratory samples and the application of a laboratory diagnostic test is required to establish a definitive diagnosis.
TREATMENT
PREVENTION AND CONTROL
How to differentiate between dengue, flu and chikungunya