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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 2 162,831
923
250156 116192
32 36
05001,0001,5002,0002,5003,000
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021Number 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)
0100200300400500600700800900
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecNumber of cases
Month of illness onset
Month of onset of travel- associated chikungunya cases,
2006 –2021 (N=4,590)
0100200300400500600
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecNumber of cases
Month of illness onset2014
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 ageAge (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 infection2,4946705663542936156
0 500 1,000 1,500 2,000 2,500 3,000CaribbeanCentral AmericaAsiaSouth AmericaNorth AmericaAfricaOceania/Pacific
Number of cases
Regions of probable acquisition of travel- associated
chikungunya, 2017 –2021 (N=532)
25cases unknown location of infection44253174333423
0 50 100 150 200 250 300 350CaribbeanCentral AmericaAsiaSouth AmericaNorth AmericaAfricaOceania/Pacific
Number of cases
Most common locations of probable acquisition of
travel -associated chikungunya, 2006 –2021 (N=4,590)
95 cases unknown location of infection1,01649946039729326625914213596
0 200 400 600 800 1,000 1,200Dominican RepublicPuerto RicoHaitiIndiaMexicoJamaicaEl SalvadorGuatemalaNicaraguaHonduras
Most common locations of probable acquisition of
travel -associated chikungunya, 2017 –2021 (N=532)
25cases unknown location of infection199333328242311109
0 50 100 150 200 250IndiaBangladeshMexicoBrazilPhilippinesThailandPakistanPuerto RicoMyanmar
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