Chikungunya is coming!
Chikungunya is hyper-endemic in the islands of the Indian Ocean. Travel by air will import the infected mosquitoes and humans —Dr James Diaz
The ink hadn’t quite dried on
in which the FEWW Moderators, discussing the dire effects of climate change on human health, wrote:
‘Warmer [and dirtier] waters increase mosquito reproduction, which in turn increase the incidence of mosquito-borne infectious diseases.’
When the news of Chikungunya arrived.
Chikungunya, a mosquito-borne disease, much worse than the West Nile virus, could become the next nightmare epidemic in the US and Europe.
Stegomyia aegypti (formerly Aedes aegypti) mosquito siting on a human. Photo: USDA.
Who’s Afraid of Chikungunya?
“We’re very worried,” Dr. James Diaz of the Louisiana University Health Sciences Center told a meeting on airlines, airports and disease transmission sponsored by the independent U.S. National Research Council.
“Unlike West Nile virus, where nine out of 10 people are going to be totally asymptomatic, or may have a mild headache or a stiff neck, if you get Chikungunya you’re going to be sick,” he said.
“The disease can be fatal. It’s a serious disease [and] there is no vaccine.” Diaz added.
The virus can be carried by the Asian tiger mosquito, which is abundant in Asia, Africa, Australia and New Zealand, as well as Europe, the Americas.
Chikungunya has also been reported in the islands of Mauritius, Seychelles and Reunion, in the Indian ocean, which are among prime beach resorts destinations visited by European tourists.
“It is hyper-endemic in the islands of the Indian Ocean,” Diaz told the meeting.
“Travel by air will import the infected mosquitoes and humans. Chikungunya is coming.” Diaz added.”
Chikungunya fever is a viral disease transmitted to humans by the bite of infected mosquitoes. Chikungunya virus is a member of the genus Alphavirus, in the family Togaviridae. Chikungunya fever is diagnosed based on symptoms, physical findings (e.g., joint swelling), laboratory testing, and the possibility of exposure to infected mosquitoes. There is no specific treatment for chikungunya fever; care is based on symptoms. Chikungunya infection is not usually fatal. Steps to prevent infection with chikungunya virus include use of insect repellent, protective clothing, and staying in areas with screens. Chikungunya virus was first isolated from the blood of a febrile patient in Tanzania in 1953, and has since been cited as the cause of numerous human epidemics in many areas of Africa and Asia and most recently in limited areas of Europe.—CDC
Chikungunya Distribution and Global Map
The geographic range of chikungunya virus is mainly in Africa and Asia. Given the current large chikungunya virus epidemics and the worldwide distribution of Aedes aegypti and Aedes albopictus mosquitoes, there is a risk of importing chikungunya virus into new area through infected travelers. —CDC
|Countries where people have become infected with chikungunya virus.
|Central African Republic
|This list does not include countries where only imported cases have been reported.
Chikungunya Fact Sheet (CDC update: March 4, 2008)
Chikungunya fever is a viral disease transmitted to humans by the bite of infected mosquitoes. Chikungunya virus was first isolated from the blood of a febrile patient in Tanzania in 1953, and has since been cited as the cause of numerous human epidemics in many areas of Africa and Asia, and most recently in a limited area of Europe.
What causes chikungunya fever?
Chikungunya fever is caused by a virus which belongs to the genus Alphavirus, in the family Togaviridae.
How do humans become infected with chikungunya virus?
Humans become infected with chikungunya virus by the bite of an infected mosquito. Aedes aegypti, a household container breeder and aggressive daytime biter which is attracted to humans, is the primary vector of chikungunya virus to humans. Aedes albopictus has also played a role in human transmission.
What can people do to prevent becoming infected with chikungunya virus?
The best way to prevent chikungunya virus infection is to avoid mosquito bites. There is no vaccine or preventive drug currently available. Prevention tips are similar to those for other viral diseases transmitted by mosquitoes, such as dengue or West Nile:
- Use insect repellent containing DEET, Picaridin, oil of lemon eucalyptus, or IR3535 on exposed skin. Always follow the directions on the package.
- Wear long sleeves and pants (ideally treat clothes with permethrin or another repellent).
- Have secure screens on windows and doors to keep mosquitoes out.
- Get rid of mosquito sources in your yard by emptying standing water from flower pots, buckets and barrels. Change the water in pet dishes and replace the water in bird baths weekly. Drill holes in tire swings so water drains out. Keep children’s wading pools empty and on their sides when they aren’t being used.
- Additionally, a person with chikungunya fever should limit their exposure to mosquito bites to avoid further spreading the infection. The person should use repellents when outdoors exposed to mosquito bites or stay indoors in areas with screens or under a mosquito net.
What is the basic chikungunya virus transmission cycle?
Mosquitoes become infected with chikungunya virus when they feed on an infected person. Infected mosquitoes can then spread the virus to other humans when they bite them. Monkeys, and possibly other wild animals, may also serve as reservoirs of the virus. Aedes aegypti, a household container breeder and aggressive daytime biter which is attracted to humans, is the primary vector of chikungunya virus to humans. Aedes albopictus (the Asian tiger mosquito) has also played a role in human transmission is Asia, Africa, and Europe. Various forest-dwelling mosquito species in Africa have been found to be infected with the virus.
What type of illness does chikungunya virus cause?
Chikungunya virus infection can cause a debilitating illness, most often characterized by fever, headache, fatigue, nausea, vomiting, muscle pain, rash, and joint pain. “Silent” chikungunya virus infections (infections without illness) do occur; but how commonly this happens is not yet known. Chikungunya virus infection (whether clinically apparent or silent) is thought to confer life-long immunity. Acute chikungunya fever typically lasts a few days to a couple of weeks, but as with dengue, West Nile fever, o’nyong-nyong fever and other arboviral fevers, some patients have prolonged fatigue lasting several weeks. Additionally, some patients have reported incapacitating joint pain, or arthritis which may last for weeks or months.
What is the incubation period for chikungunya fever?
The incubation period (time from infection to illness) can be 2-12 days, but is usually 3-7 days.
Can pregnant women become infected with chikungunya virus and pass the infection to their child?
Pregnant women can become infected with chikungunya virus during all stages of pregnancy and have symptoms similar to other individuals. Most infections will not result in the virus being transmitted to the fetus. The highest risk for infection of the fetus/child occurs when a woman has virus in her blood (viremic) at the time of delivery. There are also rare reports of first trimester abortions occurring after chikungunya infection. Pregnant women should take precautions to avoid mosquito bites. Products containing DEET can be used in pregnancy without adverse effects.
Can the virus be transmitted to a child by breastfeeding?
Currently, there is no evidence that the virus is transmitted through breast milk
What is the mortality rate of chikungunya fever?
Fatalities related to chikungunya virus are rare and appear to be associated to increased age.
How is chikungunya virus infection treated?
There is no vaccine or specific antiviral treatment currently available for chikungunya fever. Treatment is symptomatic and can include rest, fluids, and medicines to relieve symptoms of fever and aching such as ibuprofen, naproxen, acetaminophen, or paracetamol. Aspirin should be avoided. Infected persons should be protected from further mosquito exposure (staying indoors in areas with screens and/or under a mosquito net) during the first few days of the illness so they can not contribute to the transmission cycle.
Where does chikungunya virus occur?
The geographic range of the virus is primarily in Africa and Asia. For information on current outbreaks, consult CDC’s Travelers’ Health website (http://wwwn.cdc.gov/travel/default.aspx). Given the current large chikungunya virus epidemics and the world wide distribution of Aedes aegypti and Aedes albopictus, there is a risk of importation of chikungunya virus into new areas by infected travelers.
Division of Vector Borne Infectious Diseases
National Center for Zoonotic, Vector-Borne, and Enteric Diseases