An investigation of depression and fatigue post West Nile virus infection

The purpose of this study was to examine depression and fatigue in individuals with a seropositive confirmed history of West Nile virus (WNV) infection.

The South Dakota State Epidemiologist sent 218 letters inviting residents with a diagnosis of WNV to participate in the study. Forty-five subjects were tested. An occupational therapist and a physical therapist met with each participant to assess performance parameters, including depression and fatigue levels. Subjects (n=42) completed the Revised Center for Epidemiologic Studies Depression Scale (CES-D) during the assessment. The Modified Fatigue Impact Scale (MFIS) was sent to participants as a follow-up questionnaire, and 29 were returned. Subjects were placed within one of three diagnosis groups: West Nile Fever (WNF), West Nile Neuroinvasive Disease (WNND) and WNV without fever or neuroinvasive disease (clinical/unspecified).

Frequency of those reporting low risk of depression was similar between diagnosis groups (each approximating 75 percent). Depression severity differences were noted, with subjects diagnosed with WNND more likely to report "severe" risk for depression. Low correlations between depression and overall fatigue, depression and cognitive fatigue, and depression and psychosocial fatigue indicators were found. There was little if any correlation between depression and physical fatigue indicators. Mean CES-D scores for subjects between 13 to 18 months post infection fell within the mild-moderate risk for depression category.

Identifying depression risk is useful for patient referral purposes and may help minimize symptoms of depression correlated with fatigue, especially following hospitalization for WNV infection.