Name: W.M.K.T. de A.W. Gunasekera
Affiliation: National Research Center for Protozoan Diseases
Position: Foreign Visiting Researcher
Term: December 2018 to March 2019
Host researcher: Professor Shin-ichiro Kawazu (English / Japanese)
Circumstances of application:
During the period 2006/2007, I had the opportunity of following the ten month Postgraduate Diploma in Zoonoses for food safety, at National Research Centre for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro funded by JICA. Again in 2017, I attended a follow up training for JICA knowledge corporation programme. In both occasions, I had the opportunity of gaining knowledge and practical skills in molecular parasitology, including malaria. It was also an occasion to experience the extensive international research cooperation, and research promoting environment at NRCPD. This was very useful for the work I carried out in the malaria control programme in Sri Lanka. Even though Sri Lanka has been certified by the WHO as a country that has eliminated malaria, the country is still at high risk of re-establishment of disease due to very high receptivity and vulnerability risk. Hence, I submitted a research proposal on molecular genotyping to determine the dynamics of imported malaria in Sri Lanka.
Research activity in NRCPD:
Genotyping of MSP1, MSP2 and GLURP genes which are known to be highly diverse have been widely used in malaria endemic countries. In this study, for MSP1 genotyping, K1, MAD20, Ro33 allelic families were determined while in MSP2 the 3D7and FC27 allelic families were determined. In GLURP, the RII repeat region allelic variants of GLURP genes were assessed. Out of the 63 samples in which genotyping was performed, 65.1%, 74.6% and 36.5% were positive for a range of different alleles of MSP1, MSP2 and GLURP genes respectively. Among MSP1 (which had the highest frequency), MSP1-K1 allelic family was the highest followed by MSP1-RO33 and MSP1 MAD20. Among MSP2 allelic families MSP2-N5 had the highest gene frequency. When considering the multiplicity of infection, GLURP showed the lowest diversity and multiplicity of infections (MOI). The highest multiplicity of infection was observed in MSP1 genotypes which had MSP1-K1, MSP1-MAD20 and MSP1-RO33 allelic families. The highest MOI in this allelic family was 6. MSP2 had MOI of in between, the highest number of MOI being 4.
In a country that has eliminated malaria the behavior and capacity of previous primary and secondary vector populations in transmitting new exotic parasite strains is not known. Thus the threat of getting exotic strains imported poses a threat to reintroduction of the disease. Even though previous indigenous samples were not available for genotyping, the high genotype diversity and MOI observed in this study indicate that the risk of introduction of highly diverse and polyclonal genotypes of malaria parasites is possible and hence careful preventive measures have to be taken to prevent reintroduction of malaria to Sri Lanka.
Hence, a continuous study will be planned in collaboration with NRCPD in near future, combining the epidemiological aspects and vector dynamics.
It is expected to publish a manuscript using the results obtained during this period.