Chikungunya

Chikungunya Virus

Chikungunya is a viral illness transmitted by mosquitoes that causes sudden fever (three to seven days) and severe joint pain. Although most people infected with chikungunya will develop symptoms that are extremely painful, the disease does not often cause death. Most people partially recover in a week or two, but joint pain persists for months and sometimes years.

The word chikungunya meaning “to become contorted,” is from the Kimakonda language of present-day Tanzania. It describes the virus’s primary symptom: severe joint pain.

Transmission

The virus is usually spread to people by the Aedes aegypti (yellow fever mosquito) and Aedes albopictus (Asian tiger mosquito). Mosquitoes become infected when they feed on a person that is already infected with the chikungunya virus, and then they spread it by feeding on other people. However, it can be transmitted from mother to child during pregnancy or at birth.

Signs and Symptoms

Along with debilitating joint pain, other symptoms include fever, muscle pain, headache, rash, and joint inflammation.  The joint swelling can last for a few days or, in some cases, months to years. Because of that, the chikungunya virus can cause chronic arthritis.

Chikungunya symptoms are similar to those of the Dengue virus, and as such, chikungunya is sometimes misdiagnosed. The main difference is that chikungunya can cause lingering joint paint that can last years.

Treatment and Vaccine

There is no vaccine available to prevent this virus, nor is there an antiviral drug for chikungunya infection. Treatment focuses on alleviating the pain of the symptoms and supporting the immune system through bed rest and hydration.

Mosquitoes that transmit chikungunya

For chikungunya transmission, the two mosquitoes of primary concern are the Aedes aegypti and the Aedes albopictus.

Aedes aegypti, the yellow fever mosquito, has a black body with a white violin shape design on its thorax. These mosquitoes do not fly far from their breeding grounds and usually take their blood meals in the early morning or late afternoon. The Aedes aegypti mosquito is also known to transmit other diseases, such as Zika, yellow fever, and dengue.

Aedes albopictus, better known as the Asian tiger mosquito, is black with white stripes on its head and thorax. It has been adapting to our cooler regions by diapausing (a period of suspending its development) in the winter. The Asian tiger mosquito is also known to transmit flaviviruses such as Zika, West Nile Virus, and yellow fever.

Aedes aegypti and Aedes albopictus are both floodwater mosquitoes, meaning that they lay their eggs in containers that will flood with water. When the rainwater fills the container to the point it reaches the eggs, under the right circumstances such as time of year and temperature, the eggs will hatch. These mosquito species practice skip oviposition in which they lay eggs in many different places. The eggs hatch into larvae and live in the water before they transform into a pupa and then emerge as adult mosquitoes. They cannot survive without this water, and this is why the practice of “tipping and tossing” any standing water on your property during mosquito season is essential.