Chikungunya fever is a viral disease primarily spread to humans through the bites of infected mosquitoes. This illness is caused by the chikungunya virus (CHIKV), an RNA virus belonging to the alphavirus genus. The name “chikungunya” originates from the Kimakonde language of Tanzania, meaning “that which bends up,” a description of the stooped posture often adopted by individuals experiencing the severe joint pain characteristic of the disease.
How Chikungunya Spreads
Chikungunya virus is transmitted by two mosquito species: Aedes aegypti and Aedes albopictus. Mosquitoes acquire the virus by feeding on an infected person, then transmit it to others through subsequent bites. This cycle typically occurs in urban settings, with humans serving as primary hosts during outbreaks.
Both Aedes aegypti and Aedes albopictus are day-biting mosquitoes, most active in early morning and late afternoon. While Aedes aegypti is more prevalent in tropical and subtropical regions, Aedes albopictus has a broader geographical distribution, including temperate areas, due to its adaptability. These mosquitoes lay their eggs in containers with standing water, facilitating their presence near human dwellings. The disease has been identified in over 110 countries across Africa, Asia, Europe, the Americas, and islands in the Indian and Pacific Oceans.
Recognizing Chikungunya
Symptoms of chikungunya usually appear within three to seven days after a mosquito bite, though the incubation period can range from two to twelve days. The illness begins with a sudden onset of high fever, often accompanied by severe joint pain, known as arthralgia. This joint pain is symmetrical and can affect multiple joints, particularly in the wrists, fingers, ankles, feet, and knees.
Other symptoms include muscle pain, headaches, fatigue, and a maculopapular rash on the torso and limbs. Nausea, vomiting, or joint swelling may also occur. While most acute symptoms resolve within seven to ten days, joint pain can sometimes persist for months or even years, especially in older adults. Diagnosis usually involves blood tests to detect the virus or antibodies.
Managing the Illness
Currently, no specific antiviral treatment or vaccine is widely available for chikungunya fever. Management is primarily supportive, focusing on relieving symptoms and aiding recovery. Rest and adequate fluid intake are recommended to prevent dehydration. Over-the-counter medications, such as paracetamol (acetaminophen), are typically used to manage fever and alleviate joint pain.
It is advised to avoid medications like aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) until dengue fever is ruled out, as these can increase bleeding risk in dengue. Medical consultation is important for proper diagnosis and symptom management, particularly if symptoms are severe or persistent. While most people recover fully, some may experience prolonged joint pain requiring further medical attention or physical therapy.
Stopping the Spread
Preventing chikungunya infection primarily involves avoiding mosquito bites and controlling mosquito populations. Using insect repellents with active ingredients like DEET, picaridin, or oil of lemon eucalyptus on exposed skin and clothing can deter mosquitoes. Wearing long-sleeved shirts, long pants, and socks, especially during the day when mosquitoes are most active, provides a physical barrier against bites. Staying in screened or air-conditioned environments also reduces mosquito exposure.
Controlling mosquito breeding sites is another effective prevention strategy. Aedes mosquitoes lay eggs in standing water, so regularly emptying and cleaning containers like flowerpots, bird baths, and old tires, eliminates their breeding grounds. Covering water storage containers and properly disposing of waste also reduces mosquito habitats. During outbreaks, public health authorities may implement community-level measures like insecticide spraying to kill adult mosquitoes and applying larvicides to water where mosquitoes develop.