Chikungunya (symptoms,diagnosing,treatments and complications) The chikungunya virus infects humans through the bite of a mosquito and causes fever and joint pain. It is rarely fatal, but the symptoms can be severe, long-lasting and debilitating.
Once considered a disease of the tropics, cases have now been documented in more than one quarter of the countries on earth.
This article will discuss the chikungunya virus, its causes, symptoms, treatment and diagnosis; it will also cover ways to avoid the virus.
The chikungunya virus is predominantly transmitted by a bite from an infected female mosquito. In rare cases, the virus can be transmitted through contact with an infected individual's blood.
The virus causes a fever that lasts a few days and joint pain (polyarthralgia) that can last weeks or months (on rare occasions, joint pain can last for a year or more).
Once the virus has entered the bloodstream, it can divide and multiply within a number of different cell types, including epithelial cells (lining the outside of the body and internal cavities), endothelial cells (lining the inside of blood vessels) and primary fibroblasts (common connective tissue cells).
Chikungunya is an RNA virus and a member of the Togaviridae family. The disease was first described during an outbreak in Tanzania in 1952.
Symptoms normally appear between 2 and 7 days after the initial mosquito bite; up to 96% of those who are infected will develop symptoms.
Symptoms of chikungunya virus
The symptoms of chikungunya virus normally appear just a few days after an individual has been bitten by a mosquito. The most prevalent symptoms are fever (sometimes as high as 40 °C) and joint pain but may also include headache, muscle pain, rash and swelling around the joints.
Less commonly, symptoms can be accompanied by a maculopapular rash (similar to measles or heat rash), conjunctivitis, nausea and vomiting.
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% of patients report recurring joint pain.
The disease is more serious if contracted by anyone particularly old or young, or those with high blood pressure (hypertension) or diabetes. Any individual who has experienced or is experiencing rheumatic-like symptoms before infection may find the pains return or worsen. These patients are more likely to have longer-lasting rheumatic effects.
Mortality is predominantly reserved for aging patients.
Diagnosing chikungunya virus
The symptoms of chikungunya virus are similar to those of other diseases such as dengue fever. Only a blood test can definitively diagnose chikungunya.
It is important to rule out dengue fever as quickly as possible because of its higher rate of mortality - up to 50% if untreated, compared with 0.1% for chikungunya. If an individual with the symptoms outlined above has recently visited an area where either disease is common, it is advised that medical help should be sought.
Treatment for chikungunya
There are no specific drugs to treat chikungunya; doctors simply recommend rest and plenty of fluids. Over-the-counter medications such as naproxen, ibuprofen or acetaminophen will help ease fever and joint pain. For longer-lasting aches, physiotherapy may be helpful in some cases.
The National Institute of Health (NIH) are currently funding a phase 2 clinical trial of a chikungunya vaccine. The vaccine consists of so-called virus-like particles (VLPs) rather than inactivated or weakened viruses.
VLP-based vaccines can stimulate immune responses similar to those generated by naturally acquired immunity following infection. As an additional bonus, because whole viruses are not used to produce VLP vaccines, they do not need to be prepared in specialized biocontainment facilities.
Complications of chikungunya
Complications are rare, but 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 diseases characterized by muscle weakness
• Cranial nerve palsies: loss of function in the cranial nerves.
Preventing chikungunya
Because the major mode of chikungunya transmission is via mosquitos, the best methods of prevention involve minimizing contact with mosquitos.
Steps that can be taken to prevent chikungunya include:
• Use insect repellent containing DEET (N,N-Diethyl-meta-toluamide) or picaridin on skin and clothing
• Wear clothing that covers the whole body
• Stay indoors as much as possible, especially during early morning and late afternoon
• Avoid traveling to areas experiencing outbreaks
• Products containing oil of lemon eucalyptus or PMD (p-Menthane-3,8-diol) can be effective
• Air-conditioning deters mosquitos from entering rooms
• Sleep under a mosquito net
• Use mosquito coils and insecticide vaporizers
Although chikungunya is very rarely fatal, the symptoms are distressing and can be long-lived. Avoiding mosquitos is key.