Assessing dried blood spots as an alternative sample type in environments of extreme heat and humidity or low resource settings for pathogen detection

Background

Tropical and sub-tropical environments pose a significant vector borne disease (VBDs) risk to deployed service persons. Recent deployments have reported undifferentiated febrile illnesses (UFIs) as being the most common presentation ​(Bailey et al. 2021)​, likely due to VBDs. Constraints around the ability to repatriate conventional sample types or deploy diagnostics have prevented opportunity to determine the exact aetiological cause of UFIs.

Dried blood spots (DBS) are emerging as an alternative sample type of choice in low resource settings for the diagnosis of infectious diseases and in seroprevalence studies ​(Amini et al. 2021)​. DBS can be transported at ambient temperature and have good pathogen stabilisation properties. As the use of DBS expands, more work needs to be done to understand the consequences of environmental conditions on the stability of pathogen targets (antigen, antibody and nucleic acids) during the drying and transportation phase.

Methods

DBS will be inoculated with whole blood known to be positive for selected pathogen targets. These will then be dried in an artificial environment of 9 variables of temperature and humidity, then tested in triplicate using conventional assays.

Results

One-way ANOVA analysis of initial data shows a statistically significant difference between the means of the results; however, this is generally isolated to the results from DBS dried in the most extreme temperature and humidity, 50 degrees Celsius with 75% and 90% relative humidity. Further work continues.

Conclusions

These initial data show reliable detection of pathogen antigen, antibody and nucleic acids from DBS prepared in several variables of heat and humidity. This is reassuring for any future research being conducted to determine the aetiological causes of UFIs where these provisional data support DBS being a reliable sample of choice.

Outputs

As the project is still progressing at the time of this submission there have been no outputs as of yet.