Seroprevalence of sarcocystosis in the local communities of Pangkor and Tioman Islands using recombinant surface antigens 3 (rSAG3) of Sarcocystis falcatula

Abstract

Objective To investigate the seroprevalence of Sarcocystosis in the local communities of Pangkor and Tioman islands, Malaysia, by using antigenic recombinant surface antigens 2 and 3 from Sarcocystis falcatula (rSfSAG2 and rSfSAG3) as the target proteins via Western blot and ELISA assays. Methods SfSAG2 and SfSAG3 genes were isolated from S. falcatula and expressed in Escherichia coli expression system. A total of 348 serum samples [volunteers from both islands (n = 100), non‐Sarcocystis parasitic infections patients (n = 50) and healthy donors (n = 100)] were collected and tested with purified SfSAGs in Western blot and ELISA assays to measure the seroprevalence of human sarcocystosis. Results None of the sera in this study reacted with rSfSAG2 by Western blot and ELISA. For rSfSAG3, relatively high prevalence of sarcocystosis was observed in Tioman Island (75.5%) than in Pangkor Island (34%) by Western blot. In ELISA, the different prevalence rate was observed between Tioman Island (43.8%) and Pangkor Island (37%). The prevalence rate in other parasitic infections (amoebiasis, cysticercosis, filariasis, malaria, toxocariasis and toxoplasmosis) was 30% by Western blot and 26% by ELISA. Only 8% (by Western blot) and 10% (by ELISA) of healthy donors showed reactivity towards rSfSAG3. Conclusion This is the first study reporting a seroprevalence of sarcocystosis in Pangkor and Tioman Islands, Malaysia. The combination of Western blot and ELISA is suitable to be used for serodiagnosis of sarcocystosis. With further evaluations, SfSAG3 can potentially be used to confirm infection, asymptomatic screening, surveillance and epidemiological studies.

Seroprevalence of Sarcocystis falcatula in Two Islands of Malaysia using Recombinant Surface Antigen 4

“…This is a continuation study from our previous work on rSf-SAG3, where rSfSAG3 showed immunodominant characteristic and a suitable protein candidate for the development of serodiagnostic tools. The experimental design and the type of tested sera were the same as our previous work [17]. We were unable to test sensitivity and specificity of rSfSAG4 due to absence of true positive serum (patient infected with S. nesbitti) in this study.…”

“…Co-infection of Sarcocystis and Toxoplama was reported in Malaysia although no report on the co-infection between Sarcocystis and Plasmodium [9,21]. Similar to rSfSAG3 evaluation [17], rSfSAG4 was tested with anti-T. gondii and anti-Plasmodium via Western blot to eliminate potential cross-reactivity. Additionally, sequence of rSfSAG4 was subjected to BLAST analysis to check for the potential similarity with the antigens for other parasites resulted in no significant similarity.…”

“…Surface protein is antigenic and useful to develop diagnostic test [14][15][16]. Previous evaluation was done on S. falcatula surface antigen 3 (Sf-SAG3) showed the potential antigenic property that can be used to determine seroprevelance of sarcocystosis [17]. There-fore, Western blot and ELISA analyses using the (SfSAG4) may provide additional information on seroprevalence of sarcocystosis in both islands.…”