Strongyloides Stercoralis Infection Among Patients at a Long-Term Care Facility — Florida, 2010–2012

BACKGROUND: Strongyloidiasis is a parasitic disease that most commonly presents as a chronic infection. While the majority of patients remain asymptomatic, those who are immunosupressed and/or co-infected with HTLV-1 are at high risk of life-threatening complications. The report to the local health department in 2011 of 3 cases of fecal microscopy-diagnosed strongyloidiasis in a long-term care center triggered a serosurvey of residents and staff to estimate the proportion infected.

METHODS: Blood specimens were collected between May and December 2012. A convenience sample of residents and staff were enrolled and consented for testing. Blood samples were tested for S. stercoralis–specific antibody testing by Crude Antigen Enzyme-Linked Immunosorbent Assay (CrAg ELISA). Databases were created with Microsoft Access 2010. Frequency and Chi-Square tests were employed to describe the percentage of respondents and test the association among categorical variables.  P-values were considered significant when less than 0.05. Data analysis was conducted using SAS version 9.3 (SAS Inc., Cary, NC).

RESULTS: From a sample of 106 of the 176 facility residents, 12 (11%) had a positive result, as did 3 (12%) from a sample of 26 of the 238 staff members. All positive individuals reported being born either in North America (5/15) or the West Indies (10/15). Thirty-seven long-term care facility residents in the sample were born in the United States or Mexico, and 10.8% (4/37) had positive results for S. stercoralis-specific antibody; only one of these persons reported no travel outside of the United States. Of the seven staff born in the US, one tested positive (14%) and this individual reported no travel outside the US. Six long-term care facility residents reported corticosteroid use in the last 3 months, and none were infected. Residents who spent more time on the facility patio were more likely to test positive (p=0.009).

CONCLUSIONS: Since no prior testing had been performed it was not possible to assess whether any of the infections had been acquired within the facility. Our findings suggest the risk of Strongyloides infection in long-term care facilities might be high, and screening upon admission to facilities might be warranted. Recommendations included offering testing and treatment to the residents and staff members who had not tested and to extend this offer to incoming residents. Further research is needed to determine the prevalence of Strongyloides infection and the risk for transmission to help inform screening strategies for long-term care facilities.