ISSN: 1391 - 0531
Sunday, October 29, 2006
Vol. 41 - No 22
Plus

On the threshold of chikungunya

By Kumudini Hettiarachchi

It masquerades as dengue but the good news is that it is not as deadly as some strains of dengue such as the haemorrhagic kind.

As chikungunya spreads in South Asia, including southern India, Consultant Epidemiologist Dr. Ananda Amarasinghe was quick to reassure Sri Lankans that this viral disease had not been detected yet in our country.

"There are only suspected cases," he said adding that the Epidemiology Unit was attempting to put in place facilities to enable the detection of chikungunya.

Aedes aegypti is the vector which transmits both dengue and chikungunya

From February to October 10, 2006, the WHO Regional Office for South-East Asia has reported that 151 Indian districts in eight states have been affected by this viral fever. The affected areas are Kerala, Tamilnadu (in close proximity to Sri Lanka and with a constant flow of displaced, back and forth), Andhra Pradesh, Andaman & Nicobar Islands, Karnataka, Maharashtra, Gujarat, Madhya Pradesh and Delhi. More than 1.25 million suspected cases have been reported from India.

Both chikungunya and dengue viruses are transmitted to humans by the bites of infected mosquitoes, says Dr. Amaras-inghe, adding that Aedes aegypti is the vector which transmits both diseases. "Chikungunya is not transmitted from person to person.

“If the symptoms of a fever patient are similar to those of dengue, but the blood tests for the virus/antibody come negative, then doctors should look into the possibility of the patient having contracted chikungunya. Sometimes the patient may not even have a temperature, only a patchy red rash on the body and hands and legs and joint pains, mainly of the wrists, knees, ankles or small joints."

Stressing that the elimination of mosquito breeding sites would prevent both chikungunya and dengue, he says this mosquito breeds close to human habitation and multiplies in collections of stagnant water, mostly in artificial containers.

Tyres put on roofs to keep the roofing sheets down, blocked gutters or drainage, bird-baths, coconut shells, yoghurt or any plastic containers, vases and ponds without fish could be its breeding areas.

His message to the people is clear - Get rid of mosquitoes and their breeding grounds and you can prevent not only chikungunya but also dengue.

The fact fileThe fact file

Here is a fact sheet provided by the Epidemiology Unit.

What is chikungunya fever?

Chikungunya fever is a viral disease transmitted to humans by the bite of infected mosquitoes. Chikungunya virus (CHIKV) was first isolated from the blood of a febrile patient in Tanzania in 1953.

Transmission is thought to occur mainly between mosquitoes and monkeys.

What type of illness does chikungunya virus cause?

CHIKV infection can cause a debilitating illness, most often characterized by fever, headache, fatigue, nausea, vomiting, muscle pain, rash and joint pain. The term 'chikungunya' is Swahili for 'that which bends up'.

The incubation period (time from infection to illness) can be 2-12 days, but is usually 3-7 days. "Silent" CHIKV infections (infections without illness) do occur; but how commonly this happens is not yet known.

Acute chikungunya fever typically lasts a few days to a couple of weeks, but as with dengue, some patients have prolonged fatigue lasting several weeks.

Some patients have also reported incapacitating joint pain or arthritis which may last for weeks or months.

No deaths, neuroinvasive cases or haemorrhagic cases related to CHIKV infection have been conclusively documented in scientific literature.

CHIKV infection (whether clinical or silent) is thought to confer life-long immunity

How is chikungunya virus infection treated?

No vaccine or specific antiviral treatment for chikungunya fever is available. Treatment is symptomatic.

What can people do to prevent becoming infected with chikungunya virus?

The best way to avoid CHIKV infection is to prevent mosquito-bites.

Prevention tips are:

  • Have secure screens on windows and doors to keep mosquitoes out.
  • Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets and barrels.
    Change the water in pet dishes and replace the water in bird baths weekly.
    Drill holes in tyre swings so water drains out.
  • Wear long sleeves and pants.
  • Additionally, a person with chikungunya fever or dengue should limit their exposure to mosquito bites to avoid further spreading the infection. The person should stay indoors or under a mosquito net.
 
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Copyright 2006 Wijeya Newspapers Ltd.Colombo. Sri Lanka.