Valdar's Blog

Chikungunya virus (CHIKV) is an arbovirus, of the genus, Alphavirus, that is transmitted to humans by virus-carrying Aedes mosquitoes.[1] There have been recent outbreaks of CHIKV associated with severe morbidity. CHIKV causes an illness with symptoms similar to dengue fever. CHIKV manifests itself with a prolonged arthralgic disease that affects the joints of the extremities. The acute febrile phase of the illness lasts only two to five days. The pain associated with CHIKV infection of the joints persists for weeks or months.

Signs and symptoms

The incubation period of Chikungunya disease is from two to four days. Symptoms of the disease include a fever up to 39 °C (102.2 °F), a petechial or maculopapular rash of the trunk and occasionally the limbs, and arthralgia or arthritis affecting multiple joints.[3] Other nonspecific symptoms can include headache, conjunctival injection, and slight photophobia. Typically, the fever lasts for two days and then ends abruptly. However, other symptoms, namely joint pain, intense headache, insomnia and an extreme degree of prostration last for a variable period; usually for about 5 to 7 days.[3] Patients have complained of joint pains for much longer time periods depending on their age.

Prevention

The most effective means of prevention are those that protect against any contact with the disease-carrying mosquitoes. These include using insect repellents with substances like DEET (also called NNDB or N,N’-Diethyl-3-methylbenzamide), icaridin (also known as picaridin and KBR3023), PMD (p-menthane-3,8-diol, a substance derived from the lemon eucalyptus tree), or IR3535. Wearing bite-proof long sleeves and trousers (pants) also offers protection. In addition, garments can be treated with pyrethroids, a class of insecticides that often has repellent properties. Vaporized pyrethroids (for example in mosquito coils) are also insect repellents. Securing screens on windows and doors will help to keep mosquitoes out of the house. In the case of the day active Aedes aegypti and Aedes albopictus, however, this will only have a limited effect, since many contacts between the vector and the host occur outside. Thus, mosquito control is especially important.

Treatment

There are no specific treatments for Chikungunya. There is no vaccine currently available. A Phase II vaccine trial, sponsored by the US Government and published in the American Journal of Tropical Medicine and Hygiene in 2000, used a live, attenuated virus, developing viral resistance in 98% of those tested after 28 days and 85% still showed resistance after one year.[8]

A serological test for Chikungunya is available from the University of Malaya in Kuala Lumpur, Malaysia.

Chloroquine is gaining ground as a possible treatment for the symptoms associated with chikungunya, and as an antiviral agent to combat the Chikungunya virus. A University of Malaya study found that for arthritis-like symptoms that are not relieved by aspirin and non-steroidal anti-inflammatory drugs (NSAID), chloroquine phosphate (250 mg/day) has given promising results.[9] Research by an Italian scientist, Andrea Savarino, and his colleagues together with a French government press release in March 2006[10] have added more credence to the claim that chloroquine might be effective in treating chikungunya. Unpublished studies in cell culture and monkeys show no effect of chloroquine treatment on reduction of chikungunya disease. The fact sheet on Chikungunya advises against using aspirin, ibuprofen, naproxen and other NSAIDs that are recommended for arthritic pain and fever.

Infected persons should limit further exposure to mosquito bites, stay indoors and under a mosquito net. Further, “supportive care with rest is preferred during the acute joint symptoms. Movement and mild exercise tend to improve stiffness and morning arthralgia, but heavy exercise may exacerbate rheumatic symptoms.”[11] Arthralgia remains troublesome even after 8 months. In Kerala, patients use honey-and-lime mix. Some people cite relief from consuming turmeric in low volumes.