Know all about Dengue and Chikungunya and how to prevent it

Chikungunya and Dengue have created havoc in the capital city of Delhi and certain other parts of the country. The death toll from the two vector-borne diseases has been climbing every day even as the number of affected people crossed 2,800. It has been reported that according to the National Vector Borne Disease Control Programme (NVBDCP), the number of chikungunya cases in Delhi had spiked to over 2000 till September 11 as fever clinics in the city continue to be swamped with patients.

The World Health Organisation has said that in recent years, globalisation of travel and trade, unplanned urbanisation and environmental challenges including climate change has had a “significant” impact on transmission of vector-borne diseases.

However, the key to averting such an adverse outcome is timely diagnosis and appropriate monitoring along with supportive care.

Let me begin with the basics about dengue and chikungunya…….the culprit for both is the Aedes aegypti mosquito and hence a person can be infected with both diseases simultaneously by its bite. Viruses are the cause of both problems, which enter the mosquito when it bites a human suffering from dengue or chikungunya.

The most likely time for this mosquito to bite is 2 hrs after sunrise and 2 hrs before sunset but, probability of a bite occurring is anytime during daylight hours. So it’s active during the time when most of us are also likely to be outdoors.

Chikungunya begins with sudden onset of high fever, ranging from 101 to 105 degree Fahrenheit accompanied by severe pain in joints. Other symptoms like chills, headache, fatigue, abdominal pain, nausea, vomiting, diarrhea, reduced appetite and conjunctivitis can also be seen. Rash occurs typically on day 2 or 3 when the fever has subsided along with itching.

The Complete Blood Count (CBC) may show reduction in the total White cell count and platelet count, though neither are severe nor life threatening. IgM (Immunoglobulin M) antibody against Chikungunya can be detected in blood after 5 days till months after onset of symptoms. Joint pains and stiffness can last for weeks or months and can be distressing.

Treatment involves paracetamol to control fever, although NSAIDS (Non-Steroidal Anti Inflammatory Drugs like Brufen and diclofenac) may be needed to reduce fever and joint pains as paracetamol may not suffice. Ice compress on the joints can reduce pain. Ensuring water intake of at least 3 liters/day for adults is a must to counter the dehydration resulting from high fever. Antihistamines reduce the rash and itching. Extreme joint pains get relieved by oral steroids.

Dengue is equally dangerous and spreading. According to New Johns Hopkins Bloomberg School of Public Health’s research finds that the Dengue virus is the most rapidly spreading virus transmitted by mosquitoes and is a major source of illness in the tropics and subtropics, infecting as many as 400 million people annually.

Dengue symptoms are no different from Chikungunya. Both have similar onset with high grade fever (102 to 105 degree fahrenheit), headaches especially behind the eyes, back pain, muscle & joint pains, weakness. Rash can also occur. Cold and cough, vomiting and diarrhoea may accompany other symptoms. The diagnosis can be done through blood tests like Dengue NS1 which comes positive during first 3 days of fever & Dengue IgM which is detected from 5^th to 7^th day from onset of fever.

Treatment of uncomplicated dengue is same as chikungunya. Hospitalization is a must in worsened abdominal pain & vomiting, significant fall in blood pressure, breathlessness and platelet count going lower than 30,000. Platelet transfusions may be needed along with fluid infusion.

There are no antiviral medicines yet for dengue and chikungunya. Prevention of mosquito bites is the easiest way of avoiding these diseases, wearing full length shirts & trousers helps, applying mosquito repellent & using mosquito nets goes a long way in avoiding bites.

The Aedes aegypti mosquito breeds in stagnant fresh water which is avoidable by disposing used plastic bottles & discarded tyres properly. Pooling in plant trays and coolers also needs to be prevented. Also one should cover water containers that can be mosquito breeding grounds.