Chikungunya - Caused by the Aedes albopictus mosquito, is a non-fatal viral disease. These mosquitoes breed in stagnant water and can bite you not only during the night but also during the day. ‘Chikungunya’ means 'that which bends up' and is called so because of its distinct arthritic symptoms (pain in the joints and bones, stiffness).
Signs and symptoms
The virus causes a fever that lasts a few days and joint pain that can last weeks or months.
The symptoms of chikungunya virus are similar to those of other diseases such as dengue fever. The symptoms normally appear just a few days after a mosquito has bitten an individual. The most common symptoms are:
- fever (sometimes as high as 104 °F)
- joint pain
- headache
- muscle pain
- rash
- swelling around the joints
- Less commonly, symptoms can be accompanied by a maculopapular rash (similar to measles or heat rash), conjunctivitis, nausea, and vomiting.
Transmission
- Chikungunya has been identified in over 60 countries in Asia, Africa, Europe and the Americas.
- The virus is transmitted from human to human by the bites of infected female mosquitoes. Most commonly, the mosquitoes involved are Aedes aegypti and Aedes albopictus, two species which can also transmit other mosquito-borne viruses, including dengue. These mosquitoes can be found biting throughout daylight hours, though there may be peaks of activity in the early morning and late afternoon. Both species are found biting outdoors, but Ae. aegypti will also readily feed indoors.
- After the bite of an infected mosquito, onset of illness occurs usually between 4 and 8 days but can range from 2 to 12 days.
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 illness and persist for about 2 months. Samples collected during the first week after the onset of symptoms should be tested by both serological and virological methods (RT-PCR).
The virus may be isolated from the blood during the first few days of infection. Various reverse transcriptase–polymerase chain reaction (RT–PCR) methods are available but are of variable sensitivity. Some are suited to clinical diagnosis. RT–PCR products from clinical samples may also be used for genotyping of the virus, allowing comparisons with virus samples from various geographical sources.
Complications of Chikungunya
Complications can include:
- Uveitis–inflammation of the layer in the eye between the inner retina and the outer fibrous layer composed of the sclera and cornea.
- Retinitis–inflammation of the retina.
- Myocarditis–inflammation of the heart muscle.
- Hepatitis–inflammation of the liver.
- Nephritis–inflammation of the kidneys.
- Hemorrhage–bleeding.
- Meningoencephalitis–inflammation of the membranes of the brain and adjoining cerebral tissue.
- Myelitis–inflammation of the spinal cord.
- Guillain-Barré syndrome–rare peripheral nervous system disease characterized by muscle weakness.
- Cranial nerve palsies–loss of function in the cranial nerves.
Treatment
The virus is rarely fatal, but the symptoms can be severe and disabling. Most patients recover from the fever within a week, but the joint pain has been known to persist for months. Even after 1 year, 20 percent of patients report recurring joint pain.
- There are no specific drugs to treat chikungunya; doctors simply recommend rest and plenty of fluids.
- For longer-lasting aches, physiotherapy may be helpful.
Prevention and control
- Using insect repellent containing DEET (N, N-Dimethyl-meta-dolomite) or picaridin on skin and clothing.
- Wearing clothing that covers the whole body.
- Staying indoors as much as possible, especially during early morning and late afternoon.
- Avoiding traveling to areas experiencing outbreaks.
- Using products containing oil of lemon eucalyptus or PMD (p-Menthane-3,8-diol) can be effective.
- Using air-conditioning–this deters mosquitoes from entering rooms.
- Sleeping under a mosquito net.
- Using mosquito coils and insecticide vaporizers.
- Although chikungunya is very rarely fatal, the symptoms are distressing and can be long-lived. Avoiding mosquitoes is key.
