Distribution of the two forms of Plasmodium falciparum erythrocyte binding antigen-175 (eba-175) gene in Lao PDR

Background: The erythrocyte binding antigen 175 (EBA-175) is a 175
kDa antigen of Plasmodium falciparum and plays a major role in
erythrocyte recognition by the parasite. The antigen is also
supposed to be partly responsible for the invasion of erythrocytes
by merozoites. EBA-175 has been sequenced from the FCR-3 and CAMP
strains of P. falciparum. The sequences were identical in most
parts of the gene. Differences were apparent in a 423 bp segment in
the FCR-3 strain, the F-Fragment, that is not found in the
CAMP-strain and a 342 bp segment, the C-Fragment, which is present
in the CAMP-strain but not in the FCR-3-strain. The aim of this
study was to assess the distribution of the two EBA-175-alleles in
the Lao PDR. Materials & Methods: Altogether, 240 blood-samples
were collected in two areas of the country: Attapeu in the south
and Lung Namtha in the north. Subsequently, the material was
scanned for the F- and C-fragments. Results: In the whole study
population, 52% carried the F- fragment, and 41% the C-fragment
while seven percent of the patients were infected with at least two
parasite strains and showed both alleles. Conclusion: Distribution
of the alleles showed significant differences between the north and
the south province. Reasons for this include possible importation
of different parasite strains from neighbouring countries.