Chikungunya: The Global Spread of a Re-emerging Virus
African Mosquito-borne Virus Arriving in Western Hemisphere
Chikungunya virus, an arthropod-borne virus thought to have originated in Central/East Africa with first known human infections reported in Tanzania in 1955, has re-emerged with newly documented cases in the Caribbean and the United States raising concerns of among health officials for a new epidemic. The virus is transmitted to humans through the bite of an infected Aedes aegypti or Aedes albopictus mosquito. Though cases have been documented in countries in Asia and Africa and even Italy in 2007, the previously “tropical” disease is surprising health officials with its capacity for global spread. Also adding to official concerns: the newly reported cases in the Caribbean mark the first instance that the disease has been spread by locally infected mosquitoes among people who have not travelled to endemic areas recently.
In December 2013, at least 10 cases of Chikungunya were confirmed on the Carribean island of St. Martin by the World Health Organization (WHO) causing the U.S. health authorities to issue a travel advisory for the tourist island. By January 2014, the Public Health Agency of Canada had confirmed cases in surrounding areas such as St. Barthelemy, St. Vincent and the Grenadines, and the Dominican Republic and the Caribbean Public Health Authority had declared the spread of the Chikungunya virus an epidemic with an estimated 188,616 cases suspected among 19 countries in the region. As hospitals and public health officials in the Caribbean struggled to control the spread of the virus and to treat the infected, in May 2014 officials in Florida reported 10 imported cases of the virus from people who had recently traveled to endemic areas such as the Dominican Republic. Suspected cases of Chikungunya virus in the United States have since been reported in North Carolina, Georgia, and Mississippi among people who have traveled to infected areas though US officials are bracing themselves for the introduction of the virus into United States.
The more travelers coming back from an area with Chikungunya the higher the risk of an infected person coming back infected and starting an outbreak here,” notes Ann Powers, chief of the arbovirus disease branch at the CDC.
Twisted and Febrile
Chikungunya is derived from the local Tanzanian dialect Kimakonde word “to become contorted,” which refers to the fever and extremely debilitating joint pains that characterize the disease. Symptoms start abruptly with temperatures exceeding 40 Celsius (102.5 Fahrenheit) and with subsequent onset of symmetric and painful polyathralgias that affect the wrists, elbows, fingers, knees, and ankles. A maculopapular rash covering the trunk and extremities has also been reported along with nausea, vomiting, fatigue, headache and conjunctivitis. Death from the Chikungunya is rare though neurological sequelae such as Guillain-Barre Syndrome, acute flaccid paralysis, and meningoencephalitis have been documented. The diagnosis of Chikungunya is easy to confuse with dengue virus, and the CDC recommends that patients with Chikungunya should also be evaluated for dengue virus given the similar clinical presentation and geographic distribution of the diseases. Below is a chart that helps outline the similarities and differences between the clinical presentation of the two diseases:
The CDC is urging U.S. physicians to maintain a high clinical suspicion for the disease, especially among patients who have just returned from areas such as the Caribbean. Laboratory diagnosis by testing serum for viral, viral nucleic acid, or virus-specific immunoglobulin M is the preferred method for confirming a diagnosis of Chikungunya. Treatment for the virus is mostly supportive and includes anti-pyretics, analgesics, fluids, and rest. There is no vaccine or anti-viral medication available. CDC also recommends that physicians who suspect a case of Chikungunya in their community take the following steps:
- Consult with local health officials or CDC Arboviral Diseases Branch to determine if Aedes aegypti or Aedes albopictus mosquitoes are present or active within the area
- Work with local public health officials to perform surveillance of the community to assess if there are any more infected individuals
- Insure that the case-patient stays within an air-conditioned or screened accommodation for the first week of the illness
- Remove mosquito breeding sites such as stagnant water from around the patient’s house and the surrounding community to decrease chances of further spread
- Collaborate with the local health department to determine the best strategy for vector control should infected vectors be found in your community
- Conduct public education campaigns to inform communities regarding the risk of infection and prevention measures
Some easy steps that the public can take to keep prevent themselves and their loved ones from becoming infected with Chikungunya virus this summer include:
- Avoid mosquito bites and use repellent when outside
- Wear long-sleeved shirts and pants when outside to decrease risk of mosquito bites
- Use air-conditioning and screens when indoors
- Remove stagnant water sources such as empty plastic pots or pet dishes which can serve as mosquito breeding grounds
- Keep informed about travel notices related to chikungunya virus and minimize travel to affected regions
Below is a video from ABC News that provides a succinct introduction to the Chikungunya virus and its spread in the United States:
Report written by Saadiyah Bilal, M.D.