Limitations to the adoption of a standardized Strongyloides stercoralis diagnostic method: Case study in the Caribbean

BackgroundStrongyloides stercoralis is frequently under-diagnosed due to the low sensitivity of common faecal diagnostic methods used in clinical laboratories. This leads to a belief that prevalence is low and that S. stercoralis is not an important soil-transmitted helminth (STH). S. stercoralis diagnostic methods with higher sensitivity are available but often not used. Reasons for their lack of use need to be identified and addressed in order to increase awareness of this neglected parasite.Methodology/principal findingsA survey was conducted with public health (14) and private laboratories (15) within the Caribbean region to determine current diagnostic methods used and technological capabilities within the laboratories. Formal-ether concentration and direct smears were the primary methods used. Five of the laboratories used a specific method for S. stercoralis (Baermann and/or agar plate culture). A Standard Operating Procedure (SOP) for a modified Baermann tailored to be compatible with the technological capabilities of the laboratories was developed and demonstrated at ten laboratories to determine limitations to adopting a S. stercoralis specific method. The primary limitations were: cost of using two diagnostic methods for one submitted sample; lack of communication with the physician regarding the reason for the faecal analysis; general lack of awareness of S. stercoralis; and lack of awareness of differences in sensitivity of diagnostic methods.Conclusions/significanceChanging diagnostic methods involves more than ensuring the method fits within the technological capabilities of the laboratories. Several factors that influence the method used are external to the laboratory. To improve diagnosis of any of the STHs, these external factors must be addressed. Within the laboratory, more education on the sensitivity of diagnostic methods, differences in excretion levels of diagnostic stages with low infection, and increased awareness of S. stercoralis is required.