Hydroxychloroquine (HCQ) is an antimalarial drug used as chemoprophylaxis against malaria caused byPlasmodium vivax in the Republic of Korea Army (ROKA). In this study, we evaluated the pharmacokinetics (PK) of HCQ and its metabolites and the relationship between the PK of HCQ and the effect of treatment of HCQ on vivax malaria in South Koreans. Three PK studies of HCQ were conducted with 91 healthy subjects and patients with vivax malaria. Plasma concentrations were analyzed by noncompartmental and mixed-effect modeling approaches. A two-compartment model with first-order absorption best described the data. The clearance and the central and peripheral volumes of distribution were 15.5 liters/h, 733 liters, and 1,630 liters, respectively. We measured the plasma concentrations of HCQ in patients with prophylactic failure of HCQ and compared them with the prediction intervals of the simulated concentrations for HCQ from the final PK model built in this study. In 71% of the patients with prophylactic failure, the plasma concentrations of HCQ were below the lower bounds of the 95% prediction interval, while only 8% of them showed higher levels than the upper bounds of the 95% prediction interval. We report that a significant cause of prophylactic failure among the individuals in ROKA was ascribed to plasma concentrations of HCQ lower than those predicted by the PK model. However, prophylactic failure despite sufficient plasma concentrations of HCQ was confirmed in several individuals, warranting continued surveillance to monitor changes in the HCQ susceptibility of Plasmodium vivax in the Republic of Korea.

In order to investigate the prevalence of tick-borne infectious agents among ticks, ticks comprising five species from two genera (Hemaphysalis spp. and Ixodes spp.) were screened using molecular techniques. Ticks (3,135) were collected from small wild-caught mammals or by dragging/flagging in the Republic of Korea (ROK) and were pooled into a total of 1,638 samples (1 to 27 ticks per pool). From the 1,638 tick samples, species-specific fragments of Anaplasma phagocytophilum (

Until recently, the single known exception to the rodent-hantavirus association was Thottapalayam virus (TPMV), a long-unclassified virus isolated from the Asian house shrew (Suncus murinus)Hantaviruses (family Bunyaviridae, genus Hantavirus) are medically important rodent-borne pathogens, causing hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS). The belief in long-standing coevolutionary relationships between hantaviruses and their reservoir rodent host species is supported by virus and rodent gene phylogenies. That is, phylogenetic analyses, based on full-length viral genomic sequences and rodent mitochondrial DNA (mtDNA) or nuclear gene sequences, indicate that antigenically distinct hantaviruses segregate into clades, which parallel the evolution of rodents in the subfamilies Murinae, Arvicolinae, Neotominae, and Sigmodontinae (23,25,26,28,39,54). Previously, this phylogenetic insight has been successfully employed to direct the discovery of new hantaviruses, such as those found in the Korean field mouse (Apodemus peninsulae) (5) and the royal vole (Myodes regulus) (47).Renewed interest in the role of nonrodent reservoirs in the evolution of hantaviruses has been spurred by recent analysis of the entire genome of Thottapalayam virus (TPMV), a hantavirus isolated from the Asian house shrew (Suncus murinus) (10, 61), which revealed a separate phylogenetic clade, suggesting early evolutionary divergence from rodent-borne hantaviruses (44, 56). Armed with oligonucleotide primers designed on the basis of conserved regions of the TPMV genome and guided by long-ignored reports of serologic and antigenic evidence of hantavirus infection in shrews (20, 33, 52), we have previously detected genetically distinct hantaviruses in the Eurasian common shrew (Sorex araneus) from Switzerland (45); the Chinese mole shrew (Anourosorex squamipes) from Vietnam (46); and the northern short-tailed shrew (Blarina brevicauda), masked shrew (Sorex cinereus), and dusky shrew (Sorex monticolus) from the United States (1, 2) by reverse transcription-PCR (RT-PCR). Novel hantavirus genomes in Therese's shrew (Crocidura theresae) from Guinea (29); the vagrant shrew (Sorex vagrans), Trowbridge's shrew (Sorex trowbridgii), and the American water shrew (Sorex palustris) from the United States (H. J. Kang and R. Yanagihara, unpublished data); and the flat-skulled shrew (Sorex roboratus) and Laxmann's shrew (Sorex caecutiens) from Russia (Kang and Yanagihara, unpublished) have also been detected.Here, we report the antigenic, genetic, and phylogenetic characterization of a newly identified hantavirus, designated Imjin virus (MJNV), isolated from Ussuri white-toothed shrews of the species Crocidura lasiura (order Soricomorpha, family Soricidae, subfamily Crocidurinae) captured near the demilitarized zone (DMZ) in the Republic of Korea. The discovery of MJNV and other soricid-borne hantaviruses from widely separated geographic regions, spanning four continents,

We report here a previously unrecognized mosquito species from the Republic of South Korea that is closely related to Anopheles (Anopheles) sinensis. We also present an rDNA ITS2-based method for identification of this and the other morphologically similar Anopheles from the country. The PCR assay is a multiplex of seven primers in a single reaction that unambiguously identifies all included species. The other species include An. sinensis, An. lesteri, An. pullus, and a previously reported unknown Anopheles. Based on the ITS2 sequence, the two unnamed species have genetic distances from An. sinensis of 9.1% (unknown 1) and 10.7% (unknown 2), and are 10.6% different from each other. Adult females of An. sinensis and unknown 2 are morphologically indistinguishable, while unknown 1, An. lesteri and An. pullus can usually be separated from each other and from An. sinensis using available keys and descriptions. This PCR identification tool offers vector biologists and malaria epidemiologists a means to identify the potential vectors of malaria parasites in South Korea.

BackgroundJapanese encephalitis virus (JEV) genotype V reemerged in Asia (China) in 2009 after a 57-year hiatus from the continent, thereby emphasizing a need to increase regional surveillance efforts. Genotypic characterization was performed on 19 JEV-positive mosquito pools (18 pools of Culex tritaeniorhynchus and 1 pool of Cx. bitaeniorhynchus) from a total of 64 positive pools collected from geographically different locations throughout the Republic of Korea (ROK) during 2008 and 2010.FindingsTwo regions of the JEV genome were sequenced from 19 pools; the envelope gene and the nonstructural protein 5 (NS5)/3'-untranslated region (UTR). Eighteen pools of Culex tritaeniorhynchus and one pool of Cx. bitaeniorhynchus were positive for genotype I and genotype V, respectively. Sequence alignment of the complete E gene from Cx. bitaeniorhynchus showed high amino acid similarity (98.8%) to the Muar strain, characterized as the first report of genotype V, isolated from an encephalitis patient in Malaysia in 1952.ConclusionThis study represents the first report of JEV genotype V in the ROK. The reemergence of genotype V in Asia (China and ROK) after more than a half-century and its discovery in Cx. bitaeniorhynchus, a mosquito species previously unknown to carry JEV in the ROK, emphasizes the need for enhanced JE surveillance to monitor the dynamics of JEV strains within the region. Future findings may have implications with regard to JEV vaccination/prevention strategies.

As part of a comprehensive study on the ecology of arthropod-borne viruses in the Amazon Basin region of Peru, we assayed 539,694 mosquitoes captured in Loreto Department, Peru, for arboviruses. Mosquitoes were captured either by dry ice-baited miniature light traps or with aspirators while mosquitoes were landing on human collectors, identified to species, and later tested on Vero cells for virus. In total, 164 virus isolations were made and included members of the Alphavirus (eastern equine encephalomyelitis, Trocara, Una, Venezuelan equine encephalomyelitis, and western equine encephalomyelitis viruses), Flavivirus (Ilheus and St. Louis encephalitis), and Orthobunyavirus (Caraparu, Itaqui, Mirim, Murutucu, and Wyeomyia viruses) genera. In addition, several viruses distinct from the above-mentioned genera were identified to the serogroup level. Eastern equine encephalomyelitis virus was associated primarily with Culex pedroi Sirivanakarn & Belkin, whereas Venezuelan equine encephalomyelitis virus was associated primarily with Culex gnomatos Sallum, Huchings & Ferreira. Most isolations of Ilheus virus were made from Psorophora ferox (Von Humboldt). Although species of the Culex subgenus Melanoconion accounted for only 45% of the mosquitoes collected, 85% of the virus isolations were made from this subgenus. Knowledge of the viruses that are being transmitted in the Amazon Basin region of Peru will enable the development of more effective diagnostic assays, more efficient and rapid diagnoses of clinical illnesses caused by these pathogens, risk analysis for military/civilian operations, and development of potential disease control measures.

Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) analysis was applied to samples from widespread populations of the poorly characterized Anopheles (Nyssorhynchus) albitarsis Lynch-Arribálzaga species complex, and 4 genetically differentiated species were distinguished. A screen of 65 random decamer oligonucleotide primers identified 12 primers, which produced 19 reproducible species-specific genetic markers and 4 markers common to 2 or more species. These markers were correlated in nearly all individuals of each species throughout the ranges sampled, including populations as far apart as 2,500 km. Each individual analyzed was from a different isofemale progeny brood, with associated morphological specimens. These specimens will facilitate studies to relate these species to previously reported chromosomal and enzymatic variation as well as to their feeding behavior and potential as malaria vectors. We hypothesize that 3 of the species have recognized valid names: An. (Nys.) albitarsis Lynch-Arribálzaga, An. (Nys.) marajoara Galvão and Damasceno, and An. (Nys.) deaneorum Rosa-Freitas, whereas the 4th is undescribed.

Vivax malaria reemerged in the Republic of Korea in 1993. Most of the cases occurred among soldiers in the region adjacent to the Demilitarized Zone (DMZ) until 1995. To determine the rate of dispersion of vivax malaria, we evaluated its epidemiologic characteristics. Of 13,903 cases of vivax malaria reported in 2000, 40.1% (5,577) were reported among Republic of Korea military personnel, 26.2% (3,641) among veterans discharged less than two years from the military, and 33.7% (4,685) among civilians. Cases of vivax malaria have rapidly increased annually among counties bordering the DMZ, and have spread to approximately 40 km south of the DMZ. Chemoprophylaxis administered to military personnel may have been responsible for the decreasing number of cases among the Republic of Korea military population. The first mosquito-transmitted cases appeared in early June. Therefore, chemoprophylaxis should be instituted in early April to reduce the number of infected mosquitoes. Extensive intervention is warranted to reduce the spread of vivax malaria in the Republic of Korea.