RESUMO
During a scrub typhus outbreak investigation in Thailand, 4 isolates of O. tsutsugamushi were obtained and established in culture. Phylogenetic analysis based on the 56-kDa type-specific antigen gene demonstrated that the isolates fell into 4 genetic clusters, 3 of which had been previously reported and 1 that represents a new genotype.
Assuntos
Anticorpos Antibacterianos/sangue , Surtos de Doenças , Orientia tsutsugamushi/genética , Doenças dos Roedores/epidemiologia , Roedores/microbiologia , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/veterinária , Adolescente , Animais , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/sangue , Antígenos de Bactérias/imunologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Orientia tsutsugamushi/classificação , Orientia tsutsugamushi/imunologia , Orientia tsutsugamushi/isolamento & purificação , Filogenia , Doenças dos Roedores/sangue , Doenças dos Roedores/microbiologia , Tifo por Ácaros/sangue , Tifo por Ácaros/microbiologia , Tailândia/epidemiologia , Trombiculidae/microbiologiaRESUMO
This study was undertaken to ascertain the extent of polymorphism in the C-terminal region of Plasmodium falciparum merozoite surface protein (MSP-1) from 119 malaria patients in Tak Province on the western border of Thailand, who were admitted to the Bangkok Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. P. falciparum infection was confirmed by microscopic examination of peripheral blood smears. Clinical manifestations were categorized into 2 groups: uncomplicated (94 cases) and complicated/severe (25 cases). A 1,040 basepair fragment of P. falciparum MSP-1 gene was compared with MSP-1 of reference strains retrieved from GenBank. The consensus sequences of MSP-1 block 16 showed it belonged to MAD20 genotype, which is the major allele of falciparum malaria from the western border of Thailand. MSP-1 block 16 amino acid fragment could be separated into 2 groups: similar and dissimilar to reference sequence. Four variations in MSP-1 block 16 were -1494K, D1510G, D1556N, and K1696I. MSP-1 block 16 diversity is not significantly associated with clinical manifestation although MAD 20 genotype is the predominant genotype in this area. The genetic data of MSP1 gene of faciparum malaria isolated from western Thai border contribute to the existing genetic database of Thai P. falciparum strain.
