Genetic diversity of Plasmodium vivax in Kolkata, India.
BACKGROUND
Plasmodium vivax malaria accounts for approximately 60% of malaria cases in Kolkata, India. There has been limited information on the genotypic polymorphism of P. vivax in this malaria endemic area. Three highly polymorphic and single copy genes were selected for a study of genetic diversity in Kolkata strains.


METHODS
Blood from 151 patients with P. vivax infection diagnosed in Kolkata between April 2003 and September 2004 was genotyped at three polymorphic loci: the P. vivax circumsporozoite protein (pvcs), the merozoite surface protein 1 (pvmsp1) and the merozoite surface protein 3-alpha (pvmsp3-alpha).


RESULTS
Analysis of these three genetic markers revealed that P. vivax populations in Kolkata are highly diverse. A large number of distinguishable alleles were found from three genetic markers: 11 for pvcs, 35 for pvmsp1 and 37 for pvmsp3-alpha. These were, in general, randomly distributed amongst the isolates. Among the 151 isolates, 142 unique genotypes were detected the commonest genotype at a frequency of less than 2% (3/151). The overall rate of mixed genotype infections was 10.6%.


CONCLUSIONS
These results indicate that the P. vivax parasite population is highly diverse in Kolkata, despite the low level of transmission. The genotyping protocols used in this study may be useful for differentiating re-infection from relapse and recrudescence in studies assessing of malarial drug efficacy in vivax malaria.
Kim
Jung-Ryong
JR
Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. lukimjy@yahoo.com
Imwong
Mallika
M
Nandy
Amitabha
A
Chotivanich
Kesinee
K
Nontprasert
Apichart
A
Tonomsing
Naowarat
N
Maji
Ardhendu
A
Addy
Manjulika
M
Day
Nick P J
NP
White
Nicholas J
NJ
Pukrittayakamee
Sasithon
S
D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics*; D005787:Gene Frequency; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D007194:India; D020066:Merozoite Surface Protein 1 / Q000235:genetics; D010802:Phylogeny; D010966:Plasmodium vivax / Q000145:classification / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length
D000953:Antigens, Protozoan; D005819:Genetic Markers; D020066:Merozoite Surface Protein 1; C436735:merozoite surface protein 3beta