Chikungunya Fever Cases Identified in the Veterans Health Administration System, 2014

Abstract

BackgroundDuring December 2013, the first locally transmitted chikungunya virus (CHIKV) infections in the Americas were reported in the Caribbean. Although CHIKV infection is rarely fatal, risk for severe disease increases with age and medical comorbidities. Herein we describe characteristics of Veterans Health Administration (VHA) patients with CHIKV infection and, among those with infections diagnosed in Puerto Rico, investigated risk factors for hospitalization.MethodologyWe queried VHA’s national electronic medical records to identify patients with CHIKV testing during 2014. Demographics, clinical history, laboratory results, and outcomes were abstracted. We investigated risk factors for hospitalization among patients with laboratory-confirmed CHIKV infection in Puerto Rico.Principal FindingsWe identified 180 laboratory-confirmed CHIKV infections; 148 (82.2%) were diagnosed in Puerto Rico, and 32 (17.8%) were diagnosed among returning travelers elsewhere in the United States. In Puerto Rico, where more patients were hospitalized (55.4% versus 20.0%) and died (4.1% versus 0%), risk for hospitalization increased with age (relative risk [RR]/each 10-year increase, 1.19; 95% confidence interval [CI], 1.06–1.32) and, adjusted for age, increased among patients with congestive heart failure (RR, 1.58; 95% CI, 1.25–1.99), chronic kidney disease (RR, 1.52; 95% CI, 1.19–1.94), diabetes mellitus (RR, 1.39; 95% CI, 1.06–1.84), or chronic lung disease (RR, 1.37; 95% CI, 1.03–1.82).Conclusions/SignificanceCHIKV infection is an emerging problem among Veterans residing in or visiting areas with CHIKV transmission. Although overall mortality rates are low, clinicians in affected areas should be aware that older patients and patients with comorbidities may be at increased risk for severe disease.

Chikungunya Virus Infection: Why Should U.S. Geriatricians Be Aware of It?

“…It is transmitted though the bites of infected female mosquitoes ( Aedes species), which are aggressive daytime and nighttime biters. They also transmit the Dengue and Zika viruses . When these viruses co‐circulate in the same geographic area, it can be challenging to differentiate between the three pathogens purely on the basis of their clinical manifestations (Table ).…”

“…Moreover, 40% of these cases could not be classified in any of the four categories listed above. Age‐related changes in the immune system and the coexistence of multiple comorbid conditions are some of the major factors that may contribute to the higher incidence of atypical and severe cases in these older adults …”

“…They then accentuate the negative functional effect of the virus and its associated morbidity. Comorbidities such as underlying respiratory disease, hypertension, or chronic cardiac disorders have been associated with need for hospitalization and greater disease severity . Second, although an individual's age is a major contributing indicator of disease severity, there is no single cause for the age‐associated immune remodeling.…”

“…The intake of medications such as immunosuppressive drugs and nonsteroidal antiinflammatory drugs (NSAIDs) particularly has, for example, a deleterious effect in the context of this acute viral infection . NSAIDs have been associated with hospitalization, disease severity, and mortality . Delayed or mistaken diagnosis may also contribute to greater polypharmacy.…”

“…In addition to the acute responses (fever in 1–8 days, rash in 3–5 days) and symptoms, affected individuals may experience rheumatological symptoms for months and even years (5–60%) . Moreover, severe responses such as meningoencephalitis, multiorgan failure, hepatitis, and myocarditis or atypical presentation mainly occur in older adults, especially those with chronic medical conditions, resulting in higher mortality . Incapacity or limitations in normal activity occur in more than 60% of cases and significant or very significant tiredness in 47% .…”