Chapter 4 Travel-Related Infectious Diseases
J. Erin Staples, Susan L. Hills, Ann M. Powers, Kristina M. Angelo
Chikungunya virus is a single-stranded RNA virus that belongs to the family Togaviridae, genus Alphavirus.
Chikungunya virus is transmitted to humans via the bite of an infected mosquito of the Aedes spp., predominantly Aedes aegypti and Ae. albopictus. Mosquitoes become infected when they feed on viremic nonhuman or human primates, which are likely the main amplifying reservoirs of the virus. Humans are typically viremic shortly before and in the first 2–6 days of illness. Bloodborne transmission is possible; 1 case has been documented in a health care worker who was stuck with a needle after drawing blood from an infected patient. Furthermore, chikungunya virus has been identified in donated blood products undergoing screening, though no transfusion-associated cases have been identified to date. Cases have also been documented among laboratory personnel handling infected blood and through aerosol exposure in the laboratory. Maternal–fetal transmission has been documented during pregnancy; the highest risk occurs in the perinatal period when a woman is viremic at the time of delivery. Studies have not found virus in breast milk.
Chikungunya virus often causes large outbreaks with high attack rates, affecting one-third to three-quarters of the population in areas where the virus is circulating. Outbreaks of chikungunya have occurred in Africa, Asia, Europe, the Americas, and islands in the Indian and Pacific Oceans. In late 2013, the first locally acquired cases of chikungunya were reported in the Americas on islands in the Caribbean. By the end of 2017, more than 2.6 million suspect cases of chikungunya had been reported in the Americas. Since then, the virus has continued to circulate and cause sporadic disease cases and periodic outbreaks in many areas of the world.
Risk to travelers is highest in areas experiencing ongoing epidemics of the disease. Most epidemics occur during the tropical rainy season and abate during the dry season. However, outbreaks in Africa have occurred after periods of drought, where open water containers near human habitation served as vector-breeding sites. Risk of infection exists primarily during the day, as the primary vector, Ae. aegypti, aggressively bites during the daytime. Ae. aegypti mosquitoes bite indoors or outdoors near dwellings. They lay their eggs in domestic containers that hold water, including buckets and flowerpots.
Both adults and children can become infected and symptomatic with the disease. From 2010 through 2013, 110 cases of chikungunya were identified or reported among US travelers, who predominantly traveled to areas with known ongoing outbreaks. However, following the outbreaks in the Americas, from 2014–2017, >4,000 chikungunya cases were reported among US travelers, and 13 locally acquired cases were reported in the continental United States. In addition, US territories (Puerto Rico, US Virgin Islands, and American Samoa) reported locally acquired cases during 2014–2015, with Puerto Rico also reporting sporadic cases since 2016.
Characteristics of chikungunya and other arboviral diseases are shown in Box 4-01.
Approximately 3%–28% of people infected with chikungunya virus will remain asymptomatic. For people who develop symptomatic illness, the incubation period is typically 3–7 days (range, 1–12 days). Disease is most often characterized by sudden onset of high fever (temperature typically >102°F [39°C]) and joint pains. Other symptoms may include headache, myalgia, arthritis, conjunctivitis, nausea, vomiting, or a maculopapular rash. Fevers typically last from several days up to 1 week; the fever can be biphasic. Joint symptoms are typically severe and can be debilitating. They usually involve multiple joints, typically bilateral and symmetric. The joint pains occur most commonly in hands and feet, but they can affect more proximal joints. Rash usually occurs after onset of fever. It typically involves the trunk and extremities but also can include the palms, soles, and face.
Abnormal laboratory findings can include thrombocytopenia, lymphopenia, and elevated creatinine and liver function tests. Rare but serious complications of the disease can occur, including myocarditis, ocular disease (uveitis, retinitis), hepatitis, acute renal disease, severe bullous lesions, and neurologic disease, such as meningoencephalitis, Guillain-Barré syndrome, myelitis, or cranial nerve palsies. Groups identified as having increased risk for more severe disease include neonates exposed intrapartum, adults >65 years of age, and people with underlying medical conditions, such as hypertension, diabetes, or heart disease.
Acute symptoms of chikungunya typically resolve in 7–10 days. Fatalities associated with infection occur but are rare and most commonly reported in older adults and those with comorbidities. Some patients will have a relapse of rheumatologic symptoms such as polyarthralgia, polyarthritis, tenosynovitis, or Raynaud syndrome in the months after acute illness. Studies have reported variable proportions, ranging from 5% to 80%, of patients with persistent joint pains, as well as prolonged fatigue, for months or years after their illness.
Pregnant women have symptoms and outcomes similar to those of other people, and most infections that occur during pregnancy will not result in the virus being transmitted to the fetus. However, intrapartum transmission can result in neonatal complications, including neurologic disease, hemorrhagic symptoms, and myocardial disease. There are also rare reports of spontaneous abortions after maternal infection during the first trimester.
The differential diagnosis of chikungunya virus infection depends on the clinical signs and symptoms as well as where the person was suspected of being infected. Diseases that should be considered in the differential diagnosis include dengue, Zika, malaria, leptospirosis, parvovirus, enterovirus, group A Streptococcus, rubella, measles, adenovirus, postinfectious arthritis, rheumatologic conditions, or alphavirus infections (including Mayaro, Ross River, Barmah Forest, o’nyong’nyong, and Sindbis viruses).
Preliminary diagnosis is based on the patient’s clinical features, places and dates of travel, and exposures. Laboratory diagnosis is generally accomplished by testing serum to detect virus, viral nucleic acid, or virus-specific IgM and neutralizing antibodies. During the first week after onset of symptoms, chikungunya can often be diagnosed by performing viral culture or nucleic acid amplification on serum. Virus-specific IgM and neutralizing antibodies normally develop toward the end of the first week of illness. Therefore, to definitively rule out the diagnosis, convalescent-phase samples should be obtained from patients whose acute-phase samples test negative.
Testing for chikungunya virus is performed at several state health department laboratories and commercial laboratories. Confirmatory testing for virus-specific neutralizing antibodies is available through CDC (Division of Vector-borne Diseases, 970-221-6400). Health care providers should report suspected chikungunya cases to their state or local health departments to facilitate diagnosis and mitigate the risk of local transmission. Because chikungunya is a nationally notifiable disease, state health departments should report laboratory-confirmed cases to CDC through ArboNET, the national surveillance system for arboviral diseases.
Box 4-01. Arboviral diseases
Viruses that are spread to humans by an infected arthropod vector, such as ticks, mosquitoes, and sandflies.
What are the general characteristics of arboviral diseases?
- Include a number of emerging and reemerging infectious diseases.
- Vary by geographic distribution and clinical syndrome.
- Classified into 7 main families: Flaviviridae, Togaviridae, Peribunyaviridae, Phenuiviridae, Nairoviridae, Orthoviridae, and Reoviridae.
Table 4-01a. Arboviral Diseases
|FAMILY||VIRUS||GEOGRAPHIC DISTRIBUTION||VECTOR||TYPICAL CLINICAL SYNDROME|
|Flaviviridae||Alkhurma virus||Egypt, Saudi Arabia||Tick||Hemorrhagic fever|
|Dengue viruses||Americas, Caribbean, Africa, Asia, Middle East||Mosquito||Febrile illness, arthralgia, rash, hemorrhagic fever, rarely shock|
|Japanese encephalitis virus||Asia, Western Pacific||Mosquito||Encephalitis|
|Kyasanur Forest disease virus||India||Tick||Hemorrhagic fever|
|Louping ill virus||Europe||Tick||Encephalitis|
|Murray Valley encephalitis virus||Australia, Papua New Guinea||Mosquito||Encephalitis|
|Omsk hemorrhagic fever virus||Siberia||Tick||Hemorrhagic fever|
|Powassan virus||North America||Tick||Encephalitis|
|Rocio virus||South America||Mosquito||Encephalitis|
|Saint Louis encephalitis virus||North America||Mosquito||tEncephalitis|
|Tickborne encephalitis virus||Europe, Asia (Russia)||Tick||Encephalitis|
|West Nile virus||Africa, Europe, Middle East, North America, West Asia, SE Asia||Mosquito||Febrile illness, neuroinvasive disease (rare|
|Yellow fever virus||Africa, South America||Mosquito||Hemorrhagic fever, hepatitis|
|Zika virus||Americas, Caribbean, Africa, Asia, Western Pacific||Mosquito||Febrile illness, arthralgia, rash|
|Togaviridae||Barmah Forest virus||Australia||Mosquito||Febrile illness, arthralgia, rash|
|Chikungunya virus||Americas, Caribbean, Africa, Asia, Europe, Western Pacific||Mosquito||Febrile illness, arthralgia, rash|
|Eastern equine encephalitis virus||North America, Caribbean||Mosquito||Encephalitis|
|Mayaro virus||Americas, Caribbean||Mosquito||Febrile illness, arthralgia, rash|
|Madariaga virus||Central and South America||Mosquito||Febrile illness, encephalitis|
|O’nyong-nyong virus||Africa||Mosquito||Febrile illness, arthralgia, rash|
|Ross River virus||Australia, South Pacific||Mosquito||Febrile illness, arthralgia, rash|
|Semliki Forest virus||Africa||Mosquito||Febrile illness, rare encephalitis|
|Sindbis virus||Northern Europe, Asia, Africa, Australia||Mosquito||Febrile illness, arthralgia, rash|
|Venezuelan equine encephalitis virus||Americas||Mosquito||Encephalitis|
|Western equine encephalitis virus||Americas||Mosquito||Encephalitis|
|Peribunyaviridae||Bunyamwera virus||Africa||Mosquito||Febrile illness, arthralgia, rash|
|Bwamba virus||Africa||Mosquito||Febrile illness, arthralgia, rash|
|California encephalitis virus||North America||Mosquito||Encephalitis|
|Jamestown Canyon virus||North America||Mosquito||Encephalitis|
|La Crosse encephalitis virus||North America||Mosquito||Encephalitis|
|Oropouche virus||Americas, Caribbean||Mosquito||Febrile illness, arthralgia, rash|
|Rift Valley fever virus||Africa, Middle East||Mosquito||Febrile illness, myalgia, rare encephalitis, rare hemorrhage|
|Phenuiviridae||Heartland virus||North America||Tick||Febrile illness, arthralgia|
|Rift Valley fever virus||Africa, Middle East||Mosquito||Febrile illness, myalgia, rare|
|Sandfly fever viruses||North Africa, Mediterranean, Middle East||Sandfly||Febrile illness, myalgia|
|Severe fever with thrombocytopenia syndrome virus||East Asia||Tick||Hemorrhagic fever|
|Nairoviridae||Crimean Congo hemorrhagic fever virus||Africa, Middle East, Asia, Eastern Europe||Tick||Hemorrhagic fever|
|Reoviridae||Banna virus||Asia||Mosquito||Febrile illness, rare encephalitis|
|Colorado tick fever virus||North America||Tick||Febrile illness, arthralgia, rash|
|Orthomyxoviridae||Bourbon virus||North America||Tick||Fever, acute respiratory distress, multiorgan failure|
|Thogoto virus||Africa, Europe||what's the vector, victor?||Meningoencephalitis|
No specific antiviral treatment is available for chikungunya; however, a number of therapeutic options are being investigated. Treatment for symptoms can include rest, fluids, and use of analgesics and antipyretics. Nonsteroidal anti-inflammatory drugs can be used to help with acute fever and pain. In dengue-endemic areas, however, acetaminophen is the preferred first-line treatment for fever and joint pain until dengue can be ruled out, to reduce the risk of hemorrhage. For patients with persistent joint pain, use of nonsteroidal anti-inflammatory drugs, corticosteroids including topical preparations, and physical therapy may help lessen the symptoms.
Currently, no vaccine or preventive drug is available. However, several candidate vaccines are in various stages of development. The best way to prevent infection is to avoid mosquito bites (see Chapter 3, Mosquitoes, Ticks & Other Arthropods). Travelers at increased risk for more severe disease, including travelers with underlying medical conditions and women who are late in their pregnancy (as their fetuses are at increased risk), may consider avoiding travel to areas with ongoing outbreaks. If travel is unavoidable, emphasize the need for protective measures against mosquito bites.
CDC website: www.cdc.gov/chikungunya
- CDC. Chikungunya virus in the United States. Atlanta: CDC; 2017 [cited 2018 Mar 23]. Available from: www.cdc.gov/chikungunya/geo/united-states.html.
- Duvignaud A, Fianu A, Bertolotti A, Jaubert J, Michault A, Poubeau P, et al. Rheumatism and chronic fatigue, the two facets of post-chikungunya disease: the TELECHIK cohort study on Reunion Island. Epidemiol Infect. 2018 Apr;146(5):633–41.
- Lindsey NP, Staples JE, Fischer M. Chikungunya virus disease among travelers—United States, 2014–2016. Am J Trop Med Hyg. 2018 Jan;98(1):192–7.
- Mehta R, Soares CN, Medialdea-Carrera R, Ellul M, da Silva MTT, Rosala-Hallas A, et al. The spectrum of neurological disease associated with Zika and chikungunya viruses in adults in Rio de Janeiro, Brazil: a case series. PLoS Negl Trop Dis. 2018 Feb 12;12(2):e0006212.
- Pan American Health Organization. Chikungunya: Data, Maps and Statistics. Washington, DC: Pan American Health Organization; 2018 [cited 2018 Mar 23]. Available from: www.paho.org/hq/index.php?option=com_topics&view=readall&cid=5927&Itemid=40931&lang=en.
- Powers AM. Vaccine and therapeutic options to control chikungunya virus. Clin Microbiol Rev. 2017 Dec;31(1):e00104–16.
- Simon F, Javelle E, Cabie A, Bouquillard E, Troisgros O, Gentile G, et al. French guidelines for the management of chikungunya (acute and persistent presentations). November 2014. Med Mal Infect. 2015 Jul;45(7):243–63.
- Tomashek KM, Lorenzi OD, Andújar-Pérez DA, Torres-Velásquez BC, Hunsperger EA, et al. Clinical and epidemiologic characteristics of dengue and other etiologic agents among patients with acute febrile illness, Puerto Rico, 2012–2015. PLoS Negl Trop Dis. 2017 Sep;11(9):e0005859.
- World Health Organization. Chikungunya: case definitions for acute, atypical and chronic cases. Conclusions of an expert consultation, Managua, Nicaragua, 20–21 May 2015. Wkly Epidemiol Rec. 2015 Aug 14;90(33):410–14.
- Page created: July 17, 2019
- Page last updated: July 17, 2019
- Page last reviewed: July 17, 2019
- Content source: