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Notes from the Field: Chikungunya Virus Spreads in the Americas—Caribbean and South America, 2013–2014
INFECTIOUS DISEASE/CDC UPDATE
Update on Emerging Infections: News From the Centers for Disease Control and Prevention Commentators Manish Garg, MD; Victor Alcalde, MD
Editor’s note: This article is part of a regular series on emerging infection from the Centers for Disease Control and Prevention (CDC) and the EMERGEncy ID NET, an emergency department–based and CDC-collaborative surveillance network. Important infectious disease public health information with relevance to emergency physicians is reported. The goal of this series is to advance knowledge about communicable diseases in emergency medicine and foster cooperation between the front line of clinical medicine and public health agencies.
Notes from the Field: Chikungunya Virus Spreads in the Americas—Caribbean and South America, 2013–2014 [Centers for Disease Control and Prevention. Notes from the field: chikungunya virus spreads in the Americas—Caribbean and South America, 2013–2014. MMWR Morb Mortal Wkly Rep. 2014;63:500-501.] In December 2013, the World Health Organization (WHO) reported the first local transmission of chikungunya virus in the Western Hemisphere, with autochthonous cases identified in Saint Martin.1 Since then, local transmission has been identified in 17 countries or territories in the Caribbean or South America (Anguilla, Antigua and Barbuda, British Virgin Islands, Dominica, Dominican Republic, French Guiana, Guadeloupe, Guyana, Haiti, Martinique, Puerto Rico, Saint Barthelemy, Saint Kitts and Nevis, Saint Lucia, Saint Martin, Saint Vincent and the Grenadines, and Sint Maarten). As of May 30, 2014, a total of 103,018 suspected and 4,406 laboratory-confirmed chikungunya cases had been reported from these areas. The number of reported cases nearly doubled during the previous 2 weeks. More than 95% of the cases have been reported from 5 jurisdictions: Dominican Republic (38,656 cases), Martinique (30,715), Guadeloupe (24,428), Haiti (6,318), and Saint Martin (4,113). The highest incidences have been reported from Saint Martin (115 cases per 1,000 population), Martinique (76 per 1,000), Saint Barthelemy (74 per 1,000), and Guadeloupe (52 per 1,000). Further expansion of these outbreaks and spread to other countries in the region are likely. Chikungunya virus is a mosquito-borne alphavirus transmitted primarily by Aedes aegypti and A albopictus mosquitoes.1-3 These vectors also transmit dengue virus and are found throughout much of the Americas, including parts of the United States. Humans are the primary amplifying host
552 Annals of Emergency Medicine
for chikungunya virus, and most infected persons develop symptomatic disease.2 The most common clinical findings are acute onset of fever and polyarthralgia. Joint pains are usually bilateral and symmetric; they can be severe and debilitating. Mortality is rare and occurs mostly in older adults. Chikungunya outbreaks previously have been documented in countries in Africa, Asia, Europe, and the Indian and Pacific Oceans. Before the cases on Saint Martin, the only chikungunya cases identified in the Americas were in travelers going to or from known endemic areas. None of these cases resulted in local transmission or outbreaks. Chikungunya is not a nationally notifiable disease in the United States. However, chikungunya cases can be reported to ArboNET, a national passive surveillance system for arthropod-borne diseases. During 2006 to 2013, studies identified an average of 28 persons per year (range 5 to 65) with positive test results for recent chikungunya virus infection from one of the 4 US laboratories that perform testing. All were travelers visiting or returning to the United States from affected areas, mostly in Asia.1,4 Only 23% of the cases were reported to ArboNET. Beginning in 2014, cases have been identified in travelers returning from the Caribbean. As of June 2, a total of 28 chikungunya cases had been reported to ArboNET from US states and territories. On May 30, the Puerto Rico Department of Health reported their first locally transmitted case; local transmission has not been identified in other US states or territories. The remaining US cases have occurred in travelers returning from affected areas, including 26 travelers returning from the Caribbean (Dominica, Dominican Republic, Haiti, Martinique, Saint Martin, and Saint Maarten) and 1 traveler returning from Asia (Indonesia). With the recent outbreaks in the Caribbean and the Pacific, the number of chikungunya cases among travelers visiting or returning to the United States from affected areas will likely increase. These imported cases could result in local spread of the virus in other parts of the United States. Chikungunya virus infection should be considered in patients with acute onset of fever and polyarthralgia, especially travelers who recently returned from areas with known virus transmission. Chikungunya virus diagnostic testing currently is performed at the Centers for Disease Control and Prevention (CDC), 3 state health departments (California, Florida, and New York), and 1 commercial laboratory (Focus Diagnostics). No specific treatment, vaccine, or preventive drug is available for chikungunya virus infection. Treatment is palliative and can include rest, fluids, and use of analgesics and antipyretics.1,3
Volume 64, no. 5 : November 2014
CDC Update Most patients’ symptoms improve within 1 week. In some persons, joint pain can persist for months.2,3 The best way to prevent chikungunya virus infection is to avoid mosquito bites: use air conditioning or screens when indoors, use insect repellents, and wear long sleeves and pants when outdoors. Persons infected with chikungunya virus should be protected from mosquito exposure during the first week of illness to prevent further spread of the virus. Health care providers are encouraged to report suspected chikungunya cases to their state or local health department to facilitate diagnostic testing and mitigate the risk for local transmission. CDC and the Council of State and Territorial Epidemiologists urge health departments to perform surveillance for chikungunya cases in returning travelers and be aware of the risk for possible local transmission in areas where Aedes species mosquitoes are active. State health departments are encouraged to report confirmed chikungunya virus infections to CDC through ArboNET.1 Reported by: Marc Fischer, MD, J. Erin Staples, MD (Corresponding author: Marc Fischer, mfi[email protected], 970-221-6400). Section editors: David A. Talan, MD; Gregory J. Moran, MD; Satish K. Pillai, MD, MPH; Scott Santibanez, MD, MPHTM Author affiliations: From the Department of Emergency Medicine, Temple University Hospital, Philadelphia, PA. http://dx.doi.org/10.1016/j.annemergmed.2014.08.002
REFERENCES 1. Centers for Disease Control and Prevention. Chikungunya Virus. Atlanta, GA: US Dept of Health & Human Services; 2014. Available at: http:// www.cdc.gov/chikungunya. Accessed July 20, 2014. 2. Staples JE, Hills SL, Powers AM. Chikungunya. In: CDC Health Information for International Travel, 2014. New York, NY: Oxford University Press:156-158. Available at: http://wwwnc.cdc.gov/travel/ yellowbook/2014/chapter-3-infectious-diseases-related-to-travel/ chikungunya. Accessed July 20, 2014. 3. Pan American Health Organization; Centers for Disease Control and Prevention. Preparedness and Response for Chikungunya Virus Introduction in the Americas. Washington, DC: Pan American Health Organization, World Health Organization; 2011. Available at: http:// new.paho.org/hq/index.php?option¼com_docman&task¼doc_ download&gid¼16984&itemid. Accessed July 20, 2014. 4. Gibney KB, Fischer M, Prince HE, et al. Chikungunya fever in the United States: a fifteen year review of cases. Clin Infect Dis. 2011;52:e121-e126.
COMMENTARY [Ann Emerg Med. 2014;64:553-555.] Emergency physicians are front-line providers for diagnosis and management of febrile systemic illness. This CDC report notes that chikungunya virus has transitioned from an uncommon traveler’s illness from faraway locales to a disease we may see more frequently in the United States because of local transmission in the Caribbean. On July 17, shortly after this Volume 64, no. 5 : November 2014
report was published, the CDC reported the first locally acquired case of chikungunya illness in the continental United States.1 Chikungunya illness is primarily a tropical disease transmitted by mosquito vectors that are also found in the Gulf Coast and southeastern regions of the United States.1 Humans serve as the viral reservoir during epidemics, and outbreaks are temporally associated with rainy seasons when the vector density is the highest.2,3 Transmission of the virus is conducted by a humanmosquito-human cycle3; thus, an infected human host cannot horizontally transmit to another human without a mosquito vector. Although horizontal transmission is the primary mode of spread, vertical transmission between mother and fetus has been reported in recent epidemics.2,4 The incubation period after a mosquito bite varies from 1 to 12 days, with an average of 2 to 4 days.5 The majority of infected individuals will be symptomatic; 3% to 25% of those who have serologic evidence of infection will be asymptomatic.5 The classically reported triad of symptoms for chikungunya infection is fever, polyarthralgia, and maculopapular rash. Common presenting symptoms and their frequencies are fever (92%), polyarthralgia (87%), backache (67%), headache (62%), and rash (50%).3,6 Chikungunya infection will manifest as acute, subacute, or chronic disease.6 Acute chikungunya disease occurs in the first 2 weeks after infection and is characterized by an abrupt onset of high fever that is typically greater than 38.5 C (101.3 F), followed by polyarthralgia in virtually all patients. The arthralgias are described as erratic and incapacitating. In fact, “chikungunya” is derived from a Tanzanian Makonde word meaning “that which bends up,” and refers to the bent or stooped posture that infected patients take because of their joint pain.5 The arthralgias may be associated with transient effusions, are typically bilateral and symmetric, and are located predominantly in the distal joints of the fingers, wrists, elbows, toes, ankles, and knees but can be more proximal.5,6 Half of infected individuals will experience a transient maculopapular rash that occurs 2 to 5 days after the onset of fever. The rash is usually located on the trunk and extremities but can include the palms, soles, and face.7 In children, the rash can be bullous or sloughing. Petechiae and bleeding gums are cutaneous manifestations that have also been reported.2,5 Most patients have improvement in symptoms from the acute disease within 1 to 2 weeks after onset. There is considerable evidence within the last decade that chikungunya virus is also capable of neurologic presentations during infection. In adults, this may manifest as encephalopathy, acute flaccid paralysis, or Guillain-Barré syndrome. In neonates exposed intrapartum, this may manifest as encephalopathy or febrile seizure. The estimated mortality rate caused by chikungunya infection is 1:1,000 and is highest in neonates, the elderly, and adults with underlying disease.5 The main causes of death in patients with chikungunya illness include heart failure, multiple organ failure, hepatitis, and encephalopathy.5 Subacute chikungunya disease occurs 2 to 3 months after infection and is characterized by a return of the distal polyarthritis. Patients complain of general fatigue, weakness, and symptoms of depression and may develop transient vascular disorders (eg, Annals of Emergency Medicine 553
Update on Emerging Infections: News From the Centers for Disease Control and Prevention Commentators Manish Garg, MD; Victor Alcalde, MD
Editor’s note: This article is part of a regular series on emerging infection from the Centers for Disease Control and Prevention (CDC) and the EMERGEncy ID NET, an emergency department–based and CDC-collaborative surveillance network. Important infectious disease public health information with relevance to emergency physicians is reported. The goal of this series is to advance knowledge about communicable diseases in emergency medicine and foster cooperation between the front line of clinical medicine and public health agencies.
Notes from the Field: Chikungunya Virus Spreads in the Americas—Caribbean and South America, 2013–2014 [Centers for Disease Control and Prevention. Notes from the field: chikungunya virus spreads in the Americas—Caribbean and South America, 2013–2014. MMWR Morb Mortal Wkly Rep. 2014;63:500-501.] In December 2013, the World Health Organization (WHO) reported the first local transmission of chikungunya virus in the Western Hemisphere, with autochthonous cases identified in Saint Martin.1 Since then, local transmission has been identified in 17 countries or territories in the Caribbean or South America (Anguilla, Antigua and Barbuda, British Virgin Islands, Dominica, Dominican Republic, French Guiana, Guadeloupe, Guyana, Haiti, Martinique, Puerto Rico, Saint Barthelemy, Saint Kitts and Nevis, Saint Lucia, Saint Martin, Saint Vincent and the Grenadines, and Sint Maarten). As of May 30, 2014, a total of 103,018 suspected and 4,406 laboratory-confirmed chikungunya cases had been reported from these areas. The number of reported cases nearly doubled during the previous 2 weeks. More than 95% of the cases have been reported from 5 jurisdictions: Dominican Republic (38,656 cases), Martinique (30,715), Guadeloupe (24,428), Haiti (6,318), and Saint Martin (4,113). The highest incidences have been reported from Saint Martin (115 cases per 1,000 population), Martinique (76 per 1,000), Saint Barthelemy (74 per 1,000), and Guadeloupe (52 per 1,000). Further expansion of these outbreaks and spread to other countries in the region are likely. Chikungunya virus is a mosquito-borne alphavirus transmitted primarily by Aedes aegypti and A albopictus mosquitoes.1-3 These vectors also transmit dengue virus and are found throughout much of the Americas, including parts of the United States. Humans are the primary amplifying host
552 Annals of Emergency Medicine
for chikungunya virus, and most infected persons develop symptomatic disease.2 The most common clinical findings are acute onset of fever and polyarthralgia. Joint pains are usually bilateral and symmetric; they can be severe and debilitating. Mortality is rare and occurs mostly in older adults. Chikungunya outbreaks previously have been documented in countries in Africa, Asia, Europe, and the Indian and Pacific Oceans. Before the cases on Saint Martin, the only chikungunya cases identified in the Americas were in travelers going to or from known endemic areas. None of these cases resulted in local transmission or outbreaks. Chikungunya is not a nationally notifiable disease in the United States. However, chikungunya cases can be reported to ArboNET, a national passive surveillance system for arthropod-borne diseases. During 2006 to 2013, studies identified an average of 28 persons per year (range 5 to 65) with positive test results for recent chikungunya virus infection from one of the 4 US laboratories that perform testing. All were travelers visiting or returning to the United States from affected areas, mostly in Asia.1,4 Only 23% of the cases were reported to ArboNET. Beginning in 2014, cases have been identified in travelers returning from the Caribbean. As of June 2, a total of 28 chikungunya cases had been reported to ArboNET from US states and territories. On May 30, the Puerto Rico Department of Health reported their first locally transmitted case; local transmission has not been identified in other US states or territories. The remaining US cases have occurred in travelers returning from affected areas, including 26 travelers returning from the Caribbean (Dominica, Dominican Republic, Haiti, Martinique, Saint Martin, and Saint Maarten) and 1 traveler returning from Asia (Indonesia). With the recent outbreaks in the Caribbean and the Pacific, the number of chikungunya cases among travelers visiting or returning to the United States from affected areas will likely increase. These imported cases could result in local spread of the virus in other parts of the United States. Chikungunya virus infection should be considered in patients with acute onset of fever and polyarthralgia, especially travelers who recently returned from areas with known virus transmission. Chikungunya virus diagnostic testing currently is performed at the Centers for Disease Control and Prevention (CDC), 3 state health departments (California, Florida, and New York), and 1 commercial laboratory (Focus Diagnostics). No specific treatment, vaccine, or preventive drug is available for chikungunya virus infection. Treatment is palliative and can include rest, fluids, and use of analgesics and antipyretics.1,3
Volume 64, no. 5 : November 2014
CDC Update Most patients’ symptoms improve within 1 week. In some persons, joint pain can persist for months.2,3 The best way to prevent chikungunya virus infection is to avoid mosquito bites: use air conditioning or screens when indoors, use insect repellents, and wear long sleeves and pants when outdoors. Persons infected with chikungunya virus should be protected from mosquito exposure during the first week of illness to prevent further spread of the virus. Health care providers are encouraged to report suspected chikungunya cases to their state or local health department to facilitate diagnostic testing and mitigate the risk for local transmission. CDC and the Council of State and Territorial Epidemiologists urge health departments to perform surveillance for chikungunya cases in returning travelers and be aware of the risk for possible local transmission in areas where Aedes species mosquitoes are active. State health departments are encouraged to report confirmed chikungunya virus infections to CDC through ArboNET.1 Reported by: Marc Fischer, MD, J. Erin Staples, MD (Corresponding author: Marc Fischer, mfi[email protected], 970-221-6400). Section editors: David A. Talan, MD; Gregory J. Moran, MD; Satish K. Pillai, MD, MPH; Scott Santibanez, MD, MPHTM Author affiliations: From the Department of Emergency Medicine, Temple University Hospital, Philadelphia, PA. http://dx.doi.org/10.1016/j.annemergmed.2014.08.002
REFERENCES 1. Centers for Disease Control and Prevention. Chikungunya Virus. Atlanta, GA: US Dept of Health & Human Services; 2014. Available at: http:// www.cdc.gov/chikungunya. Accessed July 20, 2014. 2. Staples JE, Hills SL, Powers AM. Chikungunya. In: CDC Health Information for International Travel, 2014. New York, NY: Oxford University Press:156-158. Available at: http://wwwnc.cdc.gov/travel/ yellowbook/2014/chapter-3-infectious-diseases-related-to-travel/ chikungunya. Accessed July 20, 2014. 3. Pan American Health Organization; Centers for Disease Control and Prevention. Preparedness and Response for Chikungunya Virus Introduction in the Americas. Washington, DC: Pan American Health Organization, World Health Organization; 2011. Available at: http:// new.paho.org/hq/index.php?option¼com_docman&task¼doc_ download&gid¼16984&itemid. Accessed July 20, 2014. 4. Gibney KB, Fischer M, Prince HE, et al. Chikungunya fever in the United States: a fifteen year review of cases. Clin Infect Dis. 2011;52:e121-e126.
COMMENTARY [Ann Emerg Med. 2014;64:553-555.] Emergency physicians are front-line providers for diagnosis and management of febrile systemic illness. This CDC report notes that chikungunya virus has transitioned from an uncommon traveler’s illness from faraway locales to a disease we may see more frequently in the United States because of local transmission in the Caribbean. On July 17, shortly after this Volume 64, no. 5 : November 2014
report was published, the CDC reported the first locally acquired case of chikungunya illness in the continental United States.1 Chikungunya illness is primarily a tropical disease transmitted by mosquito vectors that are also found in the Gulf Coast and southeastern regions of the United States.1 Humans serve as the viral reservoir during epidemics, and outbreaks are temporally associated with rainy seasons when the vector density is the highest.2,3 Transmission of the virus is conducted by a humanmosquito-human cycle3; thus, an infected human host cannot horizontally transmit to another human without a mosquito vector. Although horizontal transmission is the primary mode of spread, vertical transmission between mother and fetus has been reported in recent epidemics.2,4 The incubation period after a mosquito bite varies from 1 to 12 days, with an average of 2 to 4 days.5 The majority of infected individuals will be symptomatic; 3% to 25% of those who have serologic evidence of infection will be asymptomatic.5 The classically reported triad of symptoms for chikungunya infection is fever, polyarthralgia, and maculopapular rash. Common presenting symptoms and their frequencies are fever (92%), polyarthralgia (87%), backache (67%), headache (62%), and rash (50%).3,6 Chikungunya infection will manifest as acute, subacute, or chronic disease.6 Acute chikungunya disease occurs in the first 2 weeks after infection and is characterized by an abrupt onset of high fever that is typically greater than 38.5 C (101.3 F), followed by polyarthralgia in virtually all patients. The arthralgias are described as erratic and incapacitating. In fact, “chikungunya” is derived from a Tanzanian Makonde word meaning “that which bends up,” and refers to the bent or stooped posture that infected patients take because of their joint pain.5 The arthralgias may be associated with transient effusions, are typically bilateral and symmetric, and are located predominantly in the distal joints of the fingers, wrists, elbows, toes, ankles, and knees but can be more proximal.5,6 Half of infected individuals will experience a transient maculopapular rash that occurs 2 to 5 days after the onset of fever. The rash is usually located on the trunk and extremities but can include the palms, soles, and face.7 In children, the rash can be bullous or sloughing. Petechiae and bleeding gums are cutaneous manifestations that have also been reported.2,5 Most patients have improvement in symptoms from the acute disease within 1 to 2 weeks after onset. There is considerable evidence within the last decade that chikungunya virus is also capable of neurologic presentations during infection. In adults, this may manifest as encephalopathy, acute flaccid paralysis, or Guillain-Barré syndrome. In neonates exposed intrapartum, this may manifest as encephalopathy or febrile seizure. The estimated mortality rate caused by chikungunya infection is 1:1,000 and is highest in neonates, the elderly, and adults with underlying disease.5 The main causes of death in patients with chikungunya illness include heart failure, multiple organ failure, hepatitis, and encephalopathy.5 Subacute chikungunya disease occurs 2 to 3 months after infection and is characterized by a return of the distal polyarthritis. Patients complain of general fatigue, weakness, and symptoms of depression and may develop transient vascular disorders (eg, Annals of Emergency Medicine 553