Chikungunya Virus Infection

• Chikungunya virus is an illness transmitted by the bite of an infected mosquito.
• Aedes aegypti and Aedes albopictus mosquitoes feed on a person already infected with the virus. They then spread the virus to others through bites. The chikungunya virus does not spread directly from person to person.
• The incubation period for chikungunya ranges from three to seven days. The acute illness usually lasts one week to 10 days.
• Signs and symptoms of chikungunya virus infection include fever, joint pain, headache, muscle pain, joint swelling, and rash.
• Blood tests are usually used to diagnose chikungunya virus infection.
• Chikungunya virus infection may resemble other illnesses such as dengue fever, Zika virus, malaria, mononucleosis, strep, and others, and it is important to rule out other causes for symptoms and signs.
• There is no specific medical treatment for chikungunya virus infection. Treatment is generally home remedies such as rest, fluids, and over-the-counter pain and fever medicines aimed at relief of symptoms and signs.
• Chikungunya virus is usually self-limiting, and most cases resolve on their own in seven to 10 days. In some individuals, joint pain can persist and lead to long-term disability.
• There is currently no vaccine to prevent chikungunya virus infection. The best way to prevent chikungunya infection is to prevent mosquito bites. Use insect repellent, wear long sleeves and long pants, and control mosquitoes. If you are already infected, avoid mosquitoes to prevent the disease from spreading to others.

Chikungunya virus is a mosquito-borne illness transmitted by the bite of an infected mosquito. Both Aedes aegypti and Aedes albopictus mosquitoes can spread chikungunya. A. aegypti lives in the tropics and sub-tropics, and A. albopictus lives in temperate and cold areas.

Some symptoms of chikungunya are similar to those of dengue fever and the Zika virus, and diagnosis can be difficult.

People first described the viral illness in 1953 during an outbreak in a Swahili village in Tanzania, Africa. The name chikungunya comes from an African language, and it means "that which bends up," which describes the stooped walk that results from the joint pain the disease causes.

Originally, Chikungunya existed mainly in Africa, Asia, and India. Since 2005, people reported more than 1.9 million cases in the islands and countries near the Indian Ocean including India, Indonesia, Maldives, Myanmar, Mauritius, Malaysia, and Thailand.

In 2007, a local outbreak occurred in Italy, the first time people reported the disease in Europe. In 2008, there was an outbreak in Singapore, and in 2011, an outbreak occurred in Indonesia.

In 2013, the first documented outbreak of chikungunya occurred in the Americas when people reported two cases in the French part of the Caribbean island of St. Martin. Since spring 2015, more than 1.3 million suspected cases of chikungunya have been reported in the Caribbean, Latin America, and Central America, and the U.S. Canada and Mexico also have reported cases.

Other outbreaks include the following:

2014: Montpelier, France; Pacific Islands; Caribbean Islands (Dominican Republic, Haiti, and others)

2015: Dakar, Senegal; Punjab, India; Colombia; Honduras; Nicaragua; Costa Rica

2016: Brazil, Bolivia, Colombia, Argentina, Kenya, Pakistan

2017: Pakistan

2018: Cook Islands and Marshall Islands

As of May 2018, the countries and territories where chikungunya virus caused infections; image courtesy of the CDC.

The chikungunya virus does not spread directly from person to person. Transmission of chikungunya comes from an infected person through a mosquito bite.

The chikungunya virus spreads through mosquito bites. Aedes aegypti and Aedes albopictus mosquitoes feed on a person already infected with the virus. They then spread the virus to others through bites.

In rare cases, the chikungunya virus can spread from mother to newborn child, and in theory, it can spread from infected blood, though no one has reported such a case.

Following a bite from a mosquito carrying the chikungunya virus, the incubation period for chikungunya is typically three to seven days (range one to 14 days) before symptoms and signs appear.

The acute illness usually lasts one week to 10 days.

Signs and symptoms of chikungunya virus infection in adults and children are similar and include the following:

• Fever (usually lasts three to five days)
• Joint pain (begins two to five days after the onset of fever)
• Headache
• Muscle pain
• Joint swelling
• Rash
• Nosebleeds or bleeding gums (uncommon)

Symptoms of chikungunya can be severe and disabling in some people. Recovery time for most people is about a week to 10 days, but for some people, joint pain may persist for months.

Women infected with chikungunya during pregnancy are at increased risk for miscarriage.

Medical professionals usually use the following blood tests to diagnose chikungunya virus infection:

• Enzyme-linked immunosorbent assays (ELISA)
• Reverse transcriptase-polymerase chain reaction (RT-PCR) tests

In addition, a medical professional needs to complete a history and physical to help rule out other similar illnesses. Chikungunya virus infection may resemble the following:

• Dengue fever
• Zika virus
• Malaria
• Infectious mononucleosis
• HIV infection
• Group A Streptococcus
• Meningococcal infection
• Ross river virus
• Parvovirus
• Rubella
• Other viruses, including enterovirus, adenovirus, other alphaviruses, and hepatitis C
• Measles
• Leptospirosis
• African tick bite fever
• Relapsing fever
• Enteric fever

There is no specific medical treatment for chikungunya virus infection. Treatment focuses on relief of symptoms and signs and includes the following home remedies:

• Rest
• Drink plenty of fluids
• Take over-the-counter pain relievers such as acetaminophen (Tylenol) to relieve fever and pain. Only take aspirin (no aspirin in the pediatric population) and other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) or naproxen (Aleve) if a medical professionals has ruled out dengue fever.

Some individuals may use prescription medications:

• Disease-modifying anti-rheumatic drug (DMARD) therapy such as methotrexate (MTX) for persistent joint pain
• Pregabalin (Lyrica) or gabapentin (Neurontin, Gralise, Horizant) for nerve pain
• Prednisone for pain and inflammation in patients who do not respond to NSAIDs
• Physicians may recommend physical therapy.

Home remedies for chikungunya virus infection aim to relieve signs and symptoms and include the following:

• Rest
• Drinking fluids (avoid alcohol)
• Over-the-counter (OTC) pain relievers for fever and pain

A healthy balanced diet can be helpful in recovery.

In general, chikungunya virus is self-limiting, and most cases resolve on their own in seven to 10 days. After effects may include joint pain (arthritis) that persists. In some cases, joint pain can persist and lead to long-term disability.

Severe complications and death from chikungunya are uncommon. Those most at risk for complications of chikungunya virus infection are the elderly, patients with heart or lung disease, patients with diabetes, neonates, and immunocompromised individuals.

There is currently no vaccine to prevent chikungunya virus infection, but research is ongoing to develop one.

The best way to prevent chikungunya infection is to prevent mosquito bites. Aedes mosquitoes bite primarily during the daytime, but they can also bite at night, so it is important to protect yourself around the clock.

• Use insect repellant.
• Wear long-sleeved shirts and long pants.
• Treat clothing and gear.
• Control mosquitoes indoors by use of screens or mosquito nets and outdoors by clearing standing water where mosquitoes breed.
• If you are already infected, avoid getting bitten by mosquitoes to prevent the disease from spreading to others.