Richmond, Va.
Monday, Sept. 22, 2014

Chikungunya: What it is, how it got here

Monday, June 23, 2014

Chikungunya, a debilitating virus carried by mosquitoes, has been spreading in the Caribbean since December, and it has recently spread to the United States.

The virus has traditionally occurred in Africa, Asia and the Indian subcontinent, according to the World Health Organization, but reports of cases in the Caribbean – and now confirmed cases in Georgia, Tennessee and North Carolina – signal the first outbreak of chikungunya in the Americas.

Michael Stevens, M.D., assistant professor in the Division of Infectious Diseases at Virginia Commonwealth University School of Medicine, has treated patients with the disease and directs the Travel and Tropical Medicine Clinic at VCU Medical Center.

Stevens wrote a blog post in 2012 about the potential for chikungunya to reach the U.S. and wrote about the disease again when it reached the Caribbean. Now that the illness has reached the U.S., he has answered some questions for VCU News.

What is chikungunya? What are the symptoms?

Chikungunya is a viral disease that is transmitted via mosquitoes. Three to seven days after infection, people develop fever and severe joint pain, often involving the hands and feet. People can also experience headaches, joint swelling, muscle pains and rash.

How is chikungunya making its way into the United States?

Chikungunya originated in Africa and over the past 60 years or so has spread to India, Southeast Asia, Southern Europe and now to the Caribbean and the U.S. People who travel to the Caribbean can suffer mosquito bites, become infected, and return back to the U.S. and develop symptoms.

Can mosquitoes in the U.S. carry the illness?

Yes, the Aedes species mosquitoes that carry the virus are here in the U.S.

Since 2012, the number of countries reporting human chikungunya virus infections has grown to include the Americas for the first time. Do we know how an illness carried by mosquitoes crosses an ocean?

The mosquitoes that transmit chikungunya are widespread in tropical and subtropical areas. A person who went to an area where the disease is widespread most likely became infected there, brought the virus back to his/her home (where the disease was previously unknown) and another mosquito picked up the virus when the infected person was bitten. This mosquito could then go on to bite others, thereby spreading the disease into the new territory.

Do you predict more reported infections in the United States? How will it spread?

In the absence of better mosquito control in tropical areas we will likely see a similar expansion of chikungunya cases. In the short time since Chikungunya was identified in the Caribbean we have already seen an explosion in cases (more than 100,000 suspected cases) to date; this is significant in that it was first reported in St. Martin in December 2013.

Also, as people travel more there will be more people at risk to acquire the virus and bring this back to the U.S. The cases we see in the U.S. will most likely be imported from areas where the virus is widespread. However, there have been dengue outbreaks in the U.S. (in Florida, Texas and Hawaii); as the same mosquitoes that carry dengue can also carry chikungunya, presumably we could see outbreaks in the U.S. as well.

Some people fear climate change will expand the geographic range of Aedes mosquitoea and promote potential outbreaks this way. Our mosquito control is generally pretty good in the U.S. and this will be critical in stopping local transmission of mosquito-borne viruses brought in by returning travelers.

How is chikungunya treated? Is there a cure?

The disease is treated symptomatically; there is no cure.

What has been your experience treating chickungunya?

One of the disturbing things about chikungunya is that it can cause prolonged joint symptoms, from pain to pain and swelling. These symptoms can last for months to even years.

Can people take steps to reduce their chances of contracting chikungunya?

People should be aware of the disease and take careful efforts to prevent mosquito bites when traveling to tropical and subtropical areas. This includes using mosquito repellents, using permethrin-treated clothing and using window and door screens and mosquito nets when in high-risk environments.

 

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Michael Stevens, M.D., and a student treating a patient in Honduras through VCU’s Global Health and Health Disparities Program (GH2DP). Stevens is assistant professor in the Division of Infectious Diseases at VCU School of Medicine and directs the Travel and Tropical Medicine Clinic at VCU Medical Center.

Chikungunya, a debilitating virus carried by mosquitoes, has been spreading in the Caribbean since December, and it has recently spread to the United States. Michael Stevens, M.D., assistant professor in the Division of Infectious Diseases at Virginia Commonwealth University School of Medicine, has treated patients with the disease and directs the Travel and Tropical Medicine Clinic at VCU Medical Center.

Michael P. Stevens, M.D.