About chikungunya

What is chikungunya?

The virus is spread by mosquitoes and can cause severe joint pain.

Chikungunya is viral infection that's spread among humans by mosquitoes that carry the virus.

The infection is known for the sudden high fever and severe joint pain or stiffness it can cause. Other common symptoms include rash, muscle pain, headache, nausea, and fatigue.

After a bite from an infected-mosquito, you'll usually develop symptoms in three to seven days, although they can start anywhere from two to 12 days after the bite.

Most people recover fully from chikungunya and become immune to it for life. But the pain may last for weeks or recur months later, and in up to 15 percent of cases it may become chronic, lasting years and sometimes mistaken for symptoms of rheumatoid arthritis.

Rarely, chikungunya infections can lead to severe problems on the skin, or in the eyes, kidneys, heart, or nervous system.

There is currently no cure or vaccine for chikungunya. Treatment is aimed at relieving symptoms.

The name "chikungunya" comes from a word in the Makonde (or Kimakonde) language of Southern Africa, meaning "to walk bent over," describing the stooped appearance of those suffering from intense joint pain.

Transmission of Chikungunya

During epidemics, the cycle of chikungunya transmission is mainly between humans and mosquitoes. In parts of Africa, however, wild primates and bats have been known to contribute to human epidemics through mosquitoes.

Other animals, including birds, cattle, and rodents, may also become infected and contribute to spreading the disease through mosquitoes.

You can spread the virus to others if you are bitten by a mosquito about two to six days into your illness.

Blood-borne transmission is also possible. It has been documented in laboratory workers exposed to infected blood.

Newborns may also contract chikungunya from infected mothers during a limited number of days before and after birth. Breastfeeding is not thought to spread the infection, since the virus has not been found in breast milk.

Two species of aggressive mosquitoes in the United States are known to carry chikungunya, mostly in the daytime and at twilight. They are the Aedes aegypti, or yellow fever mosquito, in the South; and the Aedes albopictus, or Asian tiger mosquito, found in much of the country.

Mosquito-breeding sites near human habitation pose a significant risk for chikungunya.

Chikungunya Prevalence Worldwide

Chikungunya has mainly affected people in Africa, Asia, and India, where millions have been infected since epidemics re-emerged in 2004, according to the Centers for Disease Control and Prevention (CDC).

More recently, it has been found in Europe and North and South America, including the Caribbean.

From 2006 to 2013 in the United States, an average of 28 cases of chikungunya (ranging from five to 65) has been reported each year, according to the CDC, and everyone was infected outside the country.

That number jumped in 2014 to more than 2,000 cases reported in the continental United States, according to the CDC. Eleven of those people were infected locally while they were in Florida.

Hundreds of thousands of infections were reported in the Caribbean for the first time in 2013 and 2014, according to the World Health Organization and the CDC, including thousands of cases contracted in Puerto Rico and the U.S. Virgin Islands.

In 2007, disease transmission was reported for the first time in Europe in a localized outbreak in northeastern Italy.

The actual number of U.S. cases through the year 2014 is not known, because doctors were not required by the CDC to report chikungunya. In 2015, however, the agency requested it become a nationally notifiable disease.

Outbreaks of Chikungunya

Outbreaks of chikungunya are usually large, with high percentages of people contracting the disease.

The virus that causes chikungunya was first described during an outbreak in southern Tanzania in 1952. It has caused periodic epidemics in Africa and Asia since the 1960s.

Recent significant outbreaks include:

  • 1999 to 2000: Democratic Republic of the Congo
  • 2005 and 2006: Indian Ocean islands, with some cases traveling to Europe
  • 2006 and 2007: India and other countries in the region
  • 2007: Gabon
  • 2011 to 2014: the Pacific Islands
  • 2014: the Caribbean islands, Central America, some South American countries, and the United States

One high-profile case involving actress Lindsay Lohan demonstrated the risks of traveling to regions where there is a chikungunya outbreak.

Lohan made headlines in December, 2014, after she reportedly contracted the virus while vacationing in French Polynesia.

Chikungunya or Rheumatoid Arthritis?

Chikungunya is sometimes misdiagnosed as rheumatoid arthritis (RA), especially in the elderly.

A 2015 report from the journal Arthritis & Rheumatology described a group of 10 people who traveled to Haiti in 2014, eight of whom developed symptoms that pointed to a diagnosis of rheumatoid arthritis.

Blood testing, however, revealed that the group had developed antibodies to the chikungunya virus, though their initial blood work and symptoms mimicked RA.

Onset of Illness

The chikungunya virus is transmitted to humans by the bites of infected mosquitoes.

The onset of illness usually occurs three to seven days after the mosquito bite, but symptoms may start anywhere from 2 to 12 days after the bite.

The virus remains in the person's system for about a week. During that time, any mosquito that feeds on the infected person may spread the infection to other people.

After you contract chikungunya, you are likely to be immune to the disease in the future.

What are the causes for chikungunya?

The infection caused by Chikungunya virus is was first described in East Africa in 1952. The virus is transmitted by mosquitoes and belongs to the family Togaviridae in the genus Alphavirus.

What are the risk factors for chikungunya?

Although Chikungunya virus has been mainly reported in Africa, Asia, Europe, and the islands in the Indian and Pacific oceans, it has spread to the Americas recently. However, you no longer have to travel to a faraway place such as French Polynesia like Lindsay Lohan did in December 2014 to become infected. In 2013 the virus had spread to the Caribbean islands. As of December 2014, 41 countries or territories in the Caribbean, Central America, South America and North America have had laboratory-confirmed Chikungunya infections.

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