Testing for Antibodies to Four Parasites in Residual Blood Specimens from Trachoma Surveys in Kiribati, 2015-2019

To assess the prevalence of several parasitic infections in Kiribati, dried blood spots collected during trachoma prevalence surveys in the two major population centers in 2015, 2016, and 2019 were tested using multiplex bead-based serologic assays to detect IgG antibodies against four pathogens of public health interest: Toxoplasma gondii (T. gondii), Taenia solium (T. solium), Strongyloides stercoralis (S. stercoralis), and Toxocara canis (T. canis). In Kiritimati Island, the seroprevalences of T. solium recombinant antigen for detection of cysticercosis antibodies (T24H) and recombinant antigen for detection of taeniasis antibodies (ES33) were ≤4% in both surveys, whereas in Tarawa, the T24H seroprevalence was 2% (2016) and 7% (2019) and the ES33 seroprevalence was ≤3% in both surveys. At both sites, the seropositivity of S. stercoralis recombinant antigen for detection of Strongyloides was 0-4%, and for T. canis, the C-type lectin-1 antigen was 0-1% in all surveys. For T. gondii, the surface antigen glycoprotein 2A antigen seroprevalences on Kiritimati Island were 41% (2015) and 36% (2019), and in Tarawa, they were 36% (2016) and 22% (2019), suggesting that T. gondii infections are common in Kiribati, whereas the other pathogens are not.