Chikungunya Fever (CHIKV)

 
***New:  In November 2023, the U.S. Food and Drug Administration licensed the first vaccine for chikungunya virus (Ixchiq, Vaneva) for adults aged 18 years and older. It is a live attenuated, single-dose vaccine. On 28 February 2024, the Advisory Committee on Immunization Practices (ACIP) made the following recommendations for Ixchiq use:

• Recommended for 18 years of age and older who are traveling to a country or territory where there is currently a CHIKV outbreak per CDC.
• Recommended for laboratory workers with potential exposure to the virus
• It may be considered for people who are traveling to a country or territory without an outbreak but with evidence of CHIKV transmission within the last five years if they are:
  • Older than 65, and who are likely to have at least moderate exposure to mosquitos (at least two weeks, cumulatively) or
  • Will be staying in such an area for six months or more.

Chikungunya vaccine is not yet available to order within DoD, but will be available through Prime Vendor in the near future. 
 
Chikungunya (CHIKV) is a viral illness transmitted primarily by mosquito bites. Like dengue and Zika virus, the most common mosquito vectors are Aedes aegypti and Aedes albopictus. Both mosquito species prefer urban environments and are considered “day-biters,” although they are most active in the early mornings and evenings. While seldom fatal, severe and persistent joint pain and swelling after infection can be disabling.  Outbreaks have occurred in countries in Africa, the Americas, Asia, Europe, the Caribbean, and the Indian and Pacific Oceans, but there is also risk for spread to unaffected areas by infected travelers. Imported cases and small outbreaks have occurred in the Southeastern U.S. Regional explosive outbreaks have potential to disrupt military operations.
Prevention is mainly mosquito-bite avoidance, which is best accomplished by careful use of the DoD Insect Repellent System and Insect Repellent Treatment of Military Uniforms.  While the new Ixchik vaccine will be available soon, recommended use is limited to very specific circumstances (e.g. locations with a current, active outbreak per CDC).  Widespread vaccination is NOT currently recommended.
 
Locations with CHIKV can be found here:  CDC Chikungunya Map
 
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Clinical Features:
CHIKV has an incubation period of 4-7 days, with up to 50% of infections being asymptomatic.  Clinically, CHIKV is characterized by the abrupt onset of fever, rash, and joint pain, which can be severe and may include joint swelling. The joints most often affected are fingers, knees, ankles, and feet, often on both sides.  While CHIKV can be confused with dengue and zika, the joint pain and swelling are much more pronounced in CHIKV.  Mortality is very low.  Most patients recover in under 2 weeks, but up to half of patients continue to have joint pain after 6 weeks and some patients have persistent, disabling joint pain for months or even years.  
There is no specific treatment for CHIKV.  Since aspirin and NSAIDs (e.g. Motrin) can be dangerous with dengue, acetaminophen (Tylenol) should be used preferentially for fever and pain control until diagnostic testing rules out dengue.
CDC Clinician Fact Sheet
CDC Clinical Management in Dengue-endemic Areas
 

Web Resources

Center for Disease Control and Prevention (CDC):  Chikungunya Virus
Center for Disease Control and Prevention (CDC) “Yellow Book”, 2024: Chikungunya
FDA Vaccine Approval Announcement: FDA Approves First Vaccine to Prevent Chikungunya
World Health Organization: Chikungunya
NECE Chikungunya Fact Sheet
 

Policy and Guidance

 

• BUMED Chikungunya Medical and Mosquito Vector Surveillance Message
• OPNAVINST 6250.4C- Navy Pest Management Programs
• DoD Inst 4150.07 DoD Pest Management Program
• NAVMED P-5010-8 Navy Entomology and Pest Control Technology
• AFPMB TG 47- Aedes Mosquito Vector Control
• AFPMB TG 36- PPM against Insects and other Arthropods

 

Mosquito Bite Avoidance-Vector Control

• Apply 25-30% DEET or 20% picaridin based repellents on exposed skin and treat clothing with a permethrin-containing product.
• Wear long-sleeved light-colored shirts and pants whenever outdoors or in places where mosquitoes may be present.
• Reduce the number of breeding mosquitoes by removing water from any containers around buildings.
• Limit vegetation around buildings to prevent overgrowth and potential mosquito harborages.

• Aedes Surveillance and Control Plan for US Navy and Marine Corps Installations (NMCPHC)
• NAVMED P-5010-8 Navy Entomology and Pest Control Technology
• DoD Insect Repellent System and Insect Repellent Treatment of Military Uniforms
• AFPMB TG 47- Aedes Mosquito Vector Control
• AFPMB TG 36- PPM against Insects and other Arthropods

 

Diagnostic Testing

CHIKV infection should be considered in patients with acute onset of fever and polyarthralgia travelers who recently returned from areas with known virus transmission. Laboratory diagnosis is generally accomplished by testing serum or plasma to detect virus, viral nucleic acid, or virus-specific immunoglobulin (Ig) M and neutralizing antibodies. 
Diagnostic Testing can be performed within the DoD at NIDDL (Sept 2023): ChikV-Dengue-Zika Testing

Reporting

CHIKV is a nationally notifiable disease.  BUMEDINST 6220.12C and NMCPHC-TM-PM 6220.12 require that all cases of chikungunya must be reported to Preventive Medicine authorities.  Notify your Public Health Emergency Officer, cognizant  Navy Environmental and Preventive Medicine Unit (NEPMU), and state or local health department so that measures can be taken to mitigate the risk of local transmission. NEPMU staff can advise on and/or assist with case investigation activities, laboratory testing, and vector control measures. NMCFHPC Medical Surveillance and Reporting Resources
Case Classification per Armed Forces Medical Reportable Events Guide
Probable:
A case that meets the clinical description as described above with ALL of the following:  
Confirmed:
A case that meets the clinical description as described above with any of the following:  
Critical Reporting Elements:  Travel and/or deployment history during the incubation period, circumstances of exposure if known (e.g. duty, occupation, environmental factors).
 

Epidemiology and Publications

NMCFHPC- EpiData Center: *CAC required*   EDC Case Finding Profile

AFHSD MSMR December 2023 Vol. 30 No. 12 Surveillance Snapshot-1Dec2023: Chikungunya in U.S. Servicemembers; 2016-2022

AFHSD MSMR Feb 2021 Vo1 28 No. 2  Surveillance for Vector Borne Diseases among AD, 2016-2020

AFHSD MSMR 2018 Vol 25 No. 2 Surveillance for Vector Borne Diseases among AD, 2010-2016

AFHSD MSMR October 2015 Vol. 22 No. 10 Chikungunya Infection in DoD Healthcare Beneficiaries Jan 2014-Feb2015: Chikungunya infection in DoD Beneficiaries Jan 2014-Feb 2015

Frickmann H, Herchenröder O. Chikungunya Virus Infections in Military Deployments in Tropical Settings-A Narrative Minireview. Viruses. 2019 Jun 14;11(6):550. doi: 10.3390/v11060550. PMID: 31197085; PMCID: PMC6631184. Chikungunya Virus Infections in Military Deployments

Center for Disease Control and Prevention (CDC): Geography and US Cases