National Center for Emerging and Zoonotic Infectious Diseases

Chikungunya in US travelers

Nicole Lindsey, MS

CDC Deputy Lead, Chikungunya Vaccines Work Group

Arboviral Diseases Branch

Centers for Disease Control and Prevention
National surveillance data for chikungunya virus disease 

in US travelers

 Data presented include confirmed and probable cases in residents of US 

states reported to CDC (excludes US territories and associated states) 

 Prior to 2006, very rarely identified in US travelers; data are included from 

2006–2021

– Not nationally-notifiable from 2006–2014

 From 2006–2021, 4,590 cases in US travelers reported to CDC
Chikungunya virus disease cases in US travelers, 

2006–2021 (N=4,590)

9 13 0 2 11 1 2 16

2,831

923

250 156 116 192

32 36

0

500

1,000

1,500

2,000

2,500

3,000

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

Number of cases
Sex of travel-associated chikungunya cases, 

2006–2021 (N=4,590) 

Sex No. (%)

Male 1,614 (35%)

Female 2,973 (65%)

3 cases unreported sex
Age of travel-associated chikungunya cases, 

2006–2021 (N=4,590) 

Years No. (%)

0–19 445 (10%)

20–39 1,166 (25%)

40–59 1,927 (42%)

60–79 952 (21%)

80+ 86 (2%)

14 cases unreported age
Month of onset of travel-associated chikungunya cases, 

2006–2021 (N=4,590)

0

100

200

300

400

500

600

700

800

900

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Number of cases

Month of illness onset
Month of onset of travel-associated chikungunya cases, 

2006–2021 (N=4,590)

0

100

200

300

400

500

600

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Number of cases

Month of illness onset

2014

All other years
Outcomes of travel-associated chikungunya 

cases, 2006–2021 (N=4,590) 

Outcome No. (%)

Hospitalized 834 (18%)

Died* 4 (0.1%)

*Cause of death unknown: All aged 63–84 years and died 36–61 days after illness onset
Hospitalization rates by age among travel-associated 

chikungunya cases, 2006–2021 (N=4,590)

14 cases unreported age

Age (years) No. Hospitalized (%)

0–1 17 7 (41%)

2–9 101 31 (31%)

10–19 327 60 (18%)

20–39 1,166 192 (16%)

40–59 1,927 295 (15%)

60–79 952 220 (23%)

80+ 86 33 (38%)
Regions of probable acquisition of travel-associated 

chikungunya, 2006–2021 (N=4,590)

95 cases unknown location of infection

2,494

670

566

354

293

61

56

0 500 1,000 1,500 2,000 2,500 3,000

Caribbean

Central America

Asia

South America

North America

Africa

Oceania/Pacific

Number of cases
Regions of probable acquisition of travel-associated 

chikungunya, 2017–2021 (N=532)

25 cases unknown location of infection

44

25

317

43

33

42

3

0 50 100 150 200 250 300 350

Caribbean

Central America

Asia

South America

North America

Africa

Oceania/Pacific

Number of cases
Most common locations of probable acquisition of 

travel-associated chikungunya, 2006–2021 (N=4,590)

95 cases unknown location of infection

1,016

499

460

397

293

266

259

142

135

96

0 200 400 600 800 1,000 1,200

Dominican Republic

Puerto Rico

Haiti

India

Mexico

Jamaica

El Salvador

Guatemala

Nicaragua

Honduras
Most common locations of probable acquisition of 

travel-associated chikungunya, 2017–2021 (N=532)

25 cases unknown location of infection

199

33

33

28

24

23

11

10

9

0 50 100 150 200 250

India

Bangladesh

Mexico

Brazil

Philippines

Thailand

Pakistan

Puerto Rico

Myanmar
Limitations of national surveillance data

 Reported cases likely underestimate true incidence of chikungunya 

disease among travelers

 Reported cases likely represent higher proportion of severe outcomes

 Complete data often unavailable, particularly for travel history

– No information on duration of travel or activities during travel

 No information on duration of symptoms or long-term sequalae
Summary

 Relatively few traveler cases reported annually except during time of large 

outbreaks in Americas 

 Reported cases likely underestimate true incidence but overestimate 

proportions of severe outcomes

 Very young children and older adults have highest hospitalization rates

 Cases have occurred among travelers to all regions with chikungunya risk 

and can occur year-round

– Case numbers reflect level of chikungunya virus activity in, and number of 

travelers to, destinations with risk