Search

Background: Understanding the induction of immune regulatory cells upon helminth infection is important for understanding the control of autoimmunity and allergic inflammation in helminth infection. Babesia microti,an intraerythrocytic protozoan of the genus Babesia, is a major cause of the emerging human disease babesiosis, an asymptomatic malaria-like disease. We examined the influence of acute B. microti infection on the development of regulatory B cells together with regulatory T cells. Principal Findings: Our data demonstrate that B cells stimulated in vitro with B. microti produce interleukin (IL)-10. This cytokine is also secreted by B cells isolated from B. microti-infected mice in response to lipopolysaccharide stimulation. In addition, high levels of IL-10 were detected in the serum of mice after infection with B. microti. The frequency of IL-10- producing CD1dhigh CD5+ regulatory B cells (Bregs) and CD4+ CD25+ FoxP3+ T cells increased during the course of B. microti infection. Furthermore, adoptive transfer of IL-10-producing B cells induced by B. microti infection led to increased susceptibility of recipient mice to infection with B. microti. In contrast, experiments with B cell-deficient (μMT) mice demonstrated that lack of B cells enhances susceptibility to B. microti infection. Conclusions: This study is the first demonstration of the expansion of Bregs following infection by an intraerythrocytic protozoan parasite. These data suggest that B. microti infection in mice provides an excellent model for studying Breg- mediated immune responses and begins to elucidate the mechanism by which helminth infection regulates autoimmunity and allergic inflammation. [ABSTRACT FROM AUTHOR]

We assessed the prevalence of Enterobius vermicularis infection and changes in the egg positive rate (EPR) over 1-year time, using the adhesive cellophane-tape perianal swab method in 2,347 preschool children in Muan-gun, Jeollanam- do, Republic of Korea in 2008 and 2009. The overall EPR for E. vermicularis was 4.1% in 2008 and 4.5% in 2009. A study population of 389 children was repeatedly examined for 2 years. Within this group, the EPR in 2009 was twice higher than in 2008, and the EPR of the group of 5-7-year-old children was significantly higher than that of other age groups. Moreover, in the group of 5-7-year-old children in 2009, the rates of positive and negative conversion were significantly higher and lower, respectively, than in other age groups. Conclusively, enterobiasis was prevalent during 2008-2009 among preschool children in Muan-gun, Jeollanam-do, and the increased EPR in 2009 was due to an increase in newly acquired infections among 5-7-year-old children. [ABSTRACT FROM AUTHOR]

Malaria continues to be a major health threat near the Demilitarized Zone (DMZ) that separates North and South Korea. Adult mosquitoes were collected from 20 July through 21 October, 2010 at Daeseongdong, a small village within the DMZ. Molecular techniques were used to identify Anopheles to species and for detection of Plasmodium vivax sporozoites in their head and thorax. Trap catches showed concordant peaks of Anopheles belenrae and An. kleini early in the study period and concordant peaks of An. pullus and An. sinensis later in the season. Three well defined peaks of the 107 sporozoite positive mosquitoes were observed: 34.6% were An. kleini, 23.4% were An. belenrae, 21.5% were An. sinensis, 19.6% were An. pullus, and 0.9% were An. lesteri. Estimation of the extrinsic incubation period from daily temperatures did not help identify preceding biting peaks of An. pullus and An. sinensis, when infection should have been acquired. We explore possible reasons for the sudden appearance and disappearance of sporozoite-infected mosquitoes, including the influx of infected mosquitoes from adjoining areas, and weather patterns. Regular surveillance for infected mosquitoes near border areas of the Republic of Korea may provide advance warning of increased malaria risk potential. [ABSTRACT FROM AUTHOR]

Background: The malaria aldolase is widely used as rapid diagnostic test (RDT), but the efficacy in aspect of its serological effectiveness in diagnosis is not known. The genetic variation of Korean isolates was analysed and recombinant aldolase was evaluated as a serological antigen in Plasmodium vivax malaria. Methods: Genomic DNA was purified and the aldolase gene of P. vivax from 25 patients' blood samples was amplified. The samples came from 5 epidemic areas; Bucheon-si, Gimpo-si, Paju-si of Gyeonggido, Gangwha-gun of Incheon metropolitan city, and Cheorwon of Gangwon-do, South Korea. The antigenicity of the recombinant aldolase was tested by western blot and enzyme-linked immunosorbent assay (ELISA). Results: Sequence analysis of 25 Korean isolates of P. vivax showed that the open reading frame (ORF) of 1,110 nucleotides encoded a deduced protein of 369 amino acids (aa). This ORF showed 100% homology with the P. vivax Sal I strain (XM_00165894) and P. vivax WDK strain (AF247063), 87.4% homology with Plasmodium falciparum (AF179421), 90.6% homology with Plasmodium chabaudi (AF247060), 89.5% homology with Plasmodium vinckei (AF247061), and 96.7% homology with Plasmodium knowlesi. A single nucleotide polymorphism (SNP) at nucleotide 180 (G to A, n = 5) was also observed in the isolates. The expressed recombinant protein had a molecular weight of approximately 31 kDa (monomeric form) and 62 kDa (dimeric form) as analysed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) analysis. Among 109 P. vivax patients, 32 (29.4%) had positive in an enzyme-linked absorbance assay (ELISA). This result showed significant correlation between ELISA and an indirect fluorescent antibody test (IFAT) (P<0.0001). Conclusions: The aldolase gene from Korean isolates of P. vivax showed one SNP at nucleotide position 180; this SNP mutant was discovered in only the western part of Han River, and included the regions of Ganghwa, Gimpo, and Bucheon. Based on the results, the relationship between antibody production against aldolase and the pattern of disease onset should be more investigated before using aldolase for serodiagnosis. [ABSTRACT FROM AUTHOR]

Amebiasis is a protozoan disease caused by Entamoeba histolytica and a potential health threat in areas where sanitation and hygiene are inappropriate. Highly sensitive PCR methods for detection of E. histolytica in clinical and environmental samples are extremely useful to control amebiasis and to promote public health. The present study compared several primer sets for small subunrt (SSU) rDNA and histone genes of E. histolytica cysts. A 246 bp of the SSU rDNA gene of pure cysts contained in phosphate-buffered saline (PBS) and in stool samples was successfully amplified by nested PCR, using the 1,147-246 bp primer set, of the primary PCR products which were pre-amplified using the 1,147 bp primer as the template. The detection limit of the nested PCR using the 1,147-246 primer set was 10 cysts in both groups (PBS and stool samples). The PCR to detect histone gene showed negative results. We propose that the nested PCR technique to detect SSU rDNA can be used as a highly sensitive genetic method to detect E. histolytica cysts in stool samples. [ABSTRACT FROM AUTHOR]

Background: First reemerged malaria case was reported in 1993 after two decades absent in South Korea. Thereafter, Plasmodium vivax spreads out near demilitarized zone (DMZ). This study investigated the prevalence of P. vivax after the malaria transmission season in Gimpo-si where adjacent to DMZ of South Korea. An indirect fluorescent antibody test (IFAT) was performed to evaluate anti-malaria antibodies in blood samples. Methods: Microscopic examinations were performed to identify the presence of malaria parasites. Antibodies against P. vivax were detected using IFAT, and blood samples from antibody-positive cases were tested using a polymerase chain reaction (PCR) assay that detects malaria parasites. Results: A total of 5,797 blood samples were collected from residents in Gimpo-si. The positivity rate by IFAT was 2.16% (n = 125). Yangchon-myeon (3.28%) had the highest positivity rate of the seven administrative districts tested. Positivity rates increased with age (P < 0.05). Sixteen of the IFAT positive samples (12.80%, n = 125) were positive for malaria DNA according to PCR. Blood samples with an antibody titer over 1:256 had high positivity rates in the PCR analysis (P < 0.05). Conclusions: These results indicate that antibody titers obtained using IFAT may provide useful information about the prevalence of P. vivax in low endemic areas and could be used to detect asymptomatic patients. Finding asymptomatic patients is important in eliminating vivax malaria in South Korea. [ABSTRACT FROM AUTHOR]

There has been a great increase of Plasmodium vivax incidences in the Republic of Korea and the genetic diversity of the parasite became more complex with the rapid dissemination of newly introduced genotypes. Surveillance of imported malaria is very important, but there is no good way to determine imported vs. internal cases. In this study, we characterized imported vivax cases, analyzed the genetic sequence of three imported vivax malaria cases for the merozoite surface protein-1 (MSP-1) and circumsporozoite protein (CSP) genes, and clearly discriminated an imported vivax case that was misdiagnosed as indigenous by genetic analysis. PCR reaction for the merozoite surface protein-1 (MSP-1) and circumsporozoite protein (CSP) genes from three imported vivax cases were amplified and sequenced. The genetic variations were compared with a previously constructed database of South Korean isolates. The imported vivax cases showed various patterns on incubation period before onset. Most cases were from other parts of Asia. The MSP-1 gene sequence analysis of three imported cases showed that the imported cases had completely different sequences from any subtypes from Korean isolates. Case-1 and Case-2 exact match with an Indian isolate, and Case-3 had great similarity with isolates from countries neighboring Indonesia. CSP gene analysis based on the repeat patterns showed similar results that the sequences from the imported cases well matched with the patient's traveled countries and completely discriminated with indigenous cases. AMA-1 gene analysis also supported these results. We were able to clearly distinguish three imported vivax cases from indigenous by using a genetic database of Korean isolates and were able to suspect its origin by genotyping. This study demonstrated the usefulness of genetic survey on imported malaria cases. [ABSTRACT FROM AUTHOR]

The Ookinete surface proteins of Plasmodium vivax (P. vivax), Pvs25 and Pvs28, were candidates for the transmission blocking vaccine (TBV), which exhibited great antigenic diversities among various isolates. Polymorphisms of these genes in the isolates from Republic of Korea (ROK) were analysed, which provided valuable baseline data for the field trials of TBV-based vaccines. A total of 98 isolates were collected over 11 years from 1996 to 2007. pvs25 and pvs28 genes from the above isolates were amplified, sequenced and compared against Sal-1 strain. Sequencing analysis of PCR products from P. vivax pvs25 revealed two allelic types, Q97T130 and E97/T130 alleles with the frequencies of 54.5% and 45.5%, respectively, in comparison with Sal I type sequence (E97/I130). From pvs28 gene, polymorphisms at M52L and T140S in the first and third EGF-like domains in comparison to Sal-1 strain were detected, respectively. Six GSGGE tandem repeats followed by GSGGDT or SSGGDT were identified at the end of the fourth EGF-like domain in all Korean isolates. Interestingly, different tandem repeats of amino acid substitutions were observed from isolates collected after 2006 in comparison with preceding years. The ROK isolates revealed limited sequence polymorphisms in pvs25 and tandem repeats in pvs28 in comparison with reported isolates from other nations. Current observations suggested the rapid progresses of genetic changes among Korean isolates. [ABSTRACT FROM AUTHOR]

After re-emergence of malaria in 1993, a continued increase in Plasmodium vivax cases was observed from 1993 to 2006 in northern Gyeonggi and Gangwon Provinces adjacent to the demilitarized zone separating North from South Korea. Annual parasite incidence per 1000 people ranged from 0.33 in 2004 to 0.89 in 2006. While malaria case rates declined (22.6%) in 2004, they increased 75.1% in 2005 and 51.7% in 2006 from the previous years. An initial incorrect diagnosis of 46.8% of malaria cases as common cold resulted in a mean delay of 1.3 days for the detection malarial parasites. Of the total cases, 10.2% from December to May were due to latent intrinsic incubation infections acquired the previous malaria season and the rest of the cases from June to November were either latent or short incubation infections. Overall, the peak anopheline population occurred from July to September, resulting in a similar peak in malaria cases. While malaria cases increased during 2005–2006, anopheline populations, based on trap indices, were not significantly different during 4 years of surveillance. To decrease the malaria patient infective period to mosquitoes, public health centers in Paju and Cheorwon in 2006 prescribed chloroquine + primaquine at days 0–3 after initial malaria diagnosis followed by an additional 11 days of primaquine (early primaquine treatment), rather than chloroquine on days 0–3 and primaquine on days 4–17 (delayed primaquine treatment). A reduction in the malaria parasite incidence during 2007 was recorded for the two locations offering the early primaquine treatment relative to other locations using the delayed primaquine treatment. [ABSTRACT FROM AUTHOR]

To understand protozoan, viral, and bacterial infections in diarrheal patients, we analyzed positivity and mixed-infection status with 3 protozoans, 4 viruses, and 10 bacteria in hospitalized diarrheal patients during 2004-2006 in the Republic of Korea. A total of 76,652 stool samples were collected from 96 hospitals across the nation. The positivity for protozoa, viruses, and bacteria was 129, 1,759, and 1,797 per 10,000 persons, respectively. Especially, Cryptosporidium parvum was highly mixed-infected with rotavirus among pediatric diarrheal patients (29.5 per 100 C. parvum positive cases), and Entamoeba histolytica was mixed-infected with Clostridium perfringens (10.3 per 100 E. histolytica positive cases) in protozoan-diarrheal patients. Those infected with rotavirus and C. perfringens constituted relatively high proportions among mixed infection cases from January to April. The positivity for rotavirus among viral infection for those aged ≤ 5 years was significantly higher, while C. perfringens among bacterial infection was higher for ≥ 50 years. The information for association of viral and bacterial infections with enteropathogenic protozoa in diarrheal patients may contribute to improvement of care for diarrhea as well as development of control strategies for diarrheal diseases in Korea. [ABSTRACT FROM AUTHOR]

Background: To use pyrimethamine as an alternative anti-malarial drug for chloroquine-resistant malaria parasites, it was necessary to determine the enzyme's genetic variation in dihydrofolate reductase-thymidylate syntase (DHFR-TS) among Korean strains. Methods: Genetic variation of dhfr-ts genes of Plasmodium vivax clinical isolates from patients who did not respond to drug treatment (n = 11) in Korea were analysed. The genes were amplified using the polymerase chain reaction (PCR) with genomic DNA as a template. Results: Sequence analysis showed that the open reading frame (ORF) of 1,857 nucleotides encoded a deduced protein of 618 amino acids (aa). Alignment with the DHFR-TS genes of other malaria parasites showed that a 231- residue DHFR domain and a 286-residue TS domain were seperated by a 101-aa linker region. This ORF shows 98.7% homology with the P. vivax Sal I strain (XM001615032) in the DHFR domain, 100% in the linker region and 99% in the TS domain. Comparison of the DHFR sequences from pyrimethamine-sensitive and pyrimethamineresistant P. vivax isolates revealed that nine isolates belonged to the sensitive strain, whereas two isolates met the criteria for resistance. In these two isolates, the amino acid at position 117 is changed from serine to asparagine (S117N). Additionally, all Korean isolates showed a deletion mutant of THGGDN in short tandem repetitive sequences between 88 and 106 amino acid. Conclusions: These results suggest that sequence variations in the DHFR-TS represent the prevalence of antifolateresistant P. vivax in Korea. Two of 11 isolates have the Ser to Asn mutation in codon 117, which is the major determinant of pyrimethamine resistance in P. vivax. Therefore, the introduction of pyrimethamine for the treatment of chloroquine-resistant vivax malaria as alternative drug in Korea should be seriously considered. [ABSTRACT FROM AUTHOR]

A survey to determine the geographical distribution and relative abundance of potential vectors of scrub typhus was conducted from October to November 2006 at 13 localities throughout the Republic of Korea. Apodemus agrarius accounted for 97.6% (80/82) of all rodents, while only 2 Myodes regulus (2/82) were collected. A total of 10,860 chiggers were collected from A. agrarius belonging to 4 genera and 8 species, while only Walchia fragilis (40) was collected from Myodes regulus. Leptotrombidium pallidum (8,137; 74.9%), a vector of scrub typhus, was the predominant species collected from A. agrarius followed by Leptotrombidium scutellare (2,057, 18.9%), Leptotrombidium palpale (279; 2.7%), Leptotrombidium orientale (232; 2.1%), and Leptotrombidium zetum (79; 0.7%), Neotrombicula tamiyai (58; 0.5%), Euschoengastica koreaensis (16; 0.1%), and Cheladonta ikaoensis (2; < 0.1%). L. pallidum was the predominant chigger collected at collection sites in Gangwon (100%), Gyeonggi (87.2%), Chungnam (100%), Chungbuk (100%), Jeonbuk (73.9%), Jeonnam (77.0%), and Gyeongbuk (66.1%) provinces, whereas L. scutellare was the predominant chigger collected in Gyeongnam province (77.9%) and Jeju Island (62.3%). Data suggest a correlation between chigger population abundance and human cases of scrub typhus in Korea. [ABSTRACT FROM AUTHOR]

Anopheles lindesayi japonicus Yamada is an uncommonly collected mosquito in Korea, and its presence is based upon limited collection data and anecdotal reports in Korean mosquito literature: 45 specimens collected from 15 identified sites. This study reports the collection of 538 specimens from 16 sites as part of the authors' 2004-2007 anopheline surveillance. Larvae were collected from stream margins, stream pools, rock pools, seepage springs, artificial containers, swamps, and ditches and were found in association with seven other culicid species. Inclusion of the authors' data with previous published and unpublished records makes this a comprehensive report on this species in Korea. New province records are reported for this species at Hwacheon and Wonju in Gangwon Province, Mt. Palgong in Daegu Metropolitan, and Chungju and Mt. Worak in Chungcheongbuk Province in the Republic of Korea. [ABSTRACT FROM AUTHOR]

In 2005, adult and larval mosquito surveillance was conducted at selected sites in Korea to associate larval habitats with species distribution of mosquitoes of the Anopheles Hyrcanus Group ( An. sinensis, An. lesteri, An. pullus, An. belenrae and An. kleini) and other mosquito species. Anopheles specimens belonging to the Anopheles Hyrcanus Group were identified to species level by molecular confirmation using the internal transcribed spacer (ITS)-2 within nuclear ribosomal (r)DNA. A total of 6644 mosquitoes from resting and light trap collections (4451; 67.0%) and larval collections (2193; 33.0%) comprising 32 species and nine genera ( Culex [11], Anopheles [8], Ochlerotatus [5], Aedes [3], Armigeres [1], Coquillettidia [1], Mansonia [1], Tripteroides [1] and Lutzia [1]) were collected. Larval habitats were characterized into 14 categories. Of a total of 4534 Anopheles spp. collected (3766 resting and light trap collections and 768 larval collections), Anopheles sinensis (3194; 70.4%) was the most frequently captured, followed by An. kleini (813; 17.9%), An. pullus (299; 6.6%) and An. belenrae (129; 2.8%). Four species of Anopheles ( An. lesteri, An. sineroides, An. koreicus and An. lindesayi) were infrequently collected (<3.0%) at all sites surveyed by all methods of collection. Anopheles kleini, An. pullus and An. belenrae were collected in greater proportions in malaria high-risk areas north of Seoul, and were infrequently collected in other parts of Korea, where An. sinensis was the predominant Anopheles spp. captured. A total of 2110 culicine mosquitoes (685 adult collections and 1425 larval collections) comprising 24 species and eight genera were collected. [ABSTRACT FROM AUTHOR]

Patch and skin bioassays were used in laboratory and indoor tests to evaluate the repellency of (E)-cinnamaldehyde, identified in Cinnamomum cassia Blume bark and essential oil, and a cream containing 5% (w/w) cassia oil against Aedes aegypti (L.) females. Results were compared with those of a known C. cassia compound cinnamyl alcohol, N,N-diethyl-m-toluamide (DEET) and two commercial repellents: MeiMei® cream containing citronella and geranium oils and Repellan S® aerosol containing 19% DEET. In patch bioassay tests with A. aegypti females, (E)-cinnamaldehyde at 0.153 mg cm-2 and DEET at 0.051 mg cm-2 provided 93 and 89% protection at 40 min after exposure. In skin bioassay tests, (E)-cinnamaldehyde at 0.051 mg cm-2 and DEET at 0.025 mg cm-2 provided 87 and 95% protection at 30 min after application. (E) -Cinnamaldehyde was significantly more effective than cinnamyl alcohol in both bioassays. In indoor tests with four human volunteers, 5% cassia oil cream provided 94, 83 and 61% protection against A. aegypti females exposed for 30, 50 and 70 min after application respectively. Cassia oil cream was a slightly less effective repellent than MeiMei cream. Repellan S aerosol provided 91% repellency at 120 min after application. Products containing cassia oil merit further study as potential repellents for the protection of humans and domestic animals from blood-feeding vectors and the diseases they transmit. [ABSTRACT FROM AUTHOR]

The vertical distribution of mosquitoes (Diptera, Culicidae) was evaluated in Paju County in northern South Korea by using Centers for Disease Control and Prevention (CDC) miniature light traps with ultraviolet light and dry ice (CO2) as attractants. CDC traps were placed at 1, 3, and 5 m above the ground near rice paddies in a relatively open agricultural area. Traps were hung on two scaffold towers (6 m height) spaced approximately 300 m apart. Each trap operated 9 nights from August 3 to 16, 2002, and collected 9,971 mosquitoes: Aedes vexans nipponii, 145.2; Culex tritaeniorhynchus, 34.9; Anopheles sinensis, 21.3; and Culex pipiens, 17.3 female mosquitoes/trap/night. Average flight height was calculated from the total number of catches in both stations. Overall, Cx. pipiens (2.52 ± 0.35 m) was found to be the highest flying species followed by An. sinensis (2.04 ± 0.79 m), Ae. vexans nipponii (1.96 ± 0.44 m), and Cx. tritaeniorhynchus (1.76 ± 0.68 m), respectively. Although no significant difference in flying height among species was encountered, every species showed their own flight preference range, matching with their host preference. [ABSTRACT FROM AUTHOR]

Background: Plasmodium vivax malaria reemerged in the Republic of Korea in 1993, with more than 2,000 cases reported in the northwestern part of the country over the last 10 years. To better assess the risk of malaria transmission we conducted a surveillance study to identify and characterize the habitats that produce potential Anopheles vector mosquitoes. Immature and adult mosquito collection data were incorporated into a Geographic Information System (GIS) along with remotely sensed satellite imagery, and imagery classified to land use to determine if remote sensing data could be used to estimate mosquito habitats. Results: More than 2,100 anopheline larvae were collected and mapped from 186 immature habitats, which were categorized into 9 types. Anopheles sinensis was the most commonly collected species, representing more than 97% of the specimens, followed by Anopheles pullus 1.0%, Anopheles lesteri 1.0%, and Anopheles sineroides 0.8%. Anopheles sinensis, pullus, and lesteri were found most frequently in rice paddies followed by: ditches, flooded areas, ground pools, wheel tracks, swamps, irrigation canals, and stream margins. Anopheles sineroides was found most commonly in flooded areas. Supervised classification was conducted on a LANDSAT 7 ETM+ image to identify 5-6 landuse classes that were considered to be of interest. The spatial distribution of the larval mosquito collections was overlaid on the land-use image derived from the LANDSAT image, and the number of mosquitoes habitats in each class calculated. On Ganghwa Island 67% of the immature habitats containing Anopheles sinensis were in the Paddy land-use class, although the class only represented 17% of the land area. In Paju District 53% of the immature habitats containing Anopheles sinensis were in the Paddy land-use class which represented only 9 % of the area of the district. There was significant (p < 0.05) correlation between habitats containing all four species and land use on Ganghwa Island; however, only Anopheles sinensis was significantly correlated with land-use in Paju District. In Ganghwa Island almost 50% of the Anopheles sinensis adults were collected in the paddy land-use class, and there was a positive correlation between larval and adult distributions. However, in Paju District adult Anopheles sinensis adults were most commonly collected in the Bare land-use class and only 17% collected in the Paddy class. There was a negative correlation between larval and adult distributions. Conclusion: Immature habitats most commonly associated with Anopheles sinensis, Anopheles pullus, Anopheles sineroides and Anopheles lesteri were flooded rice paddies. Adult Anopheles sinensis, the most commonly collected anopheline, were found closely associated with rice habitats on Ganghwa Island but not in Paju District. Both QuickBird and LANDSAT satellite data were used to display spatial data in the form of geographic coverage and descriptive information in the form of relational databases associated with the mapped features. Supervised classification of LANDSAT imagery permitted good separation between Paddy, Forest, and Water land-use classes. The immature collections of Anopheles sinensis were significantly correlated with land-use as determined in the land-use classification in both Ganghwa Island and Paju District. These data suggest that classified remotely sensed data could potentially be used to estimate the distribution of immature and adult mosquito populations in the Republic of Korea. [ABSTRACT FROM AUTHOR]

Of the 27 healthcare workers (HCWs) who had contact with a fatally ill patient with severe thrombocytopenia syndrome in Korea (SFTS), 4 who were involved in cardiopulmonary resuscitation complained of fever and were diagnosed with SFTS via seroconversion. Exposure to respiratory secretions, blood, or gowns soiled by body fluids was significantly associated with infection of HCWs. [ABSTRACT FROM AUTHOR]

There are approximately 20 known species of the genus Cryptosporidium, and among these, 8 infect immunocompetent or immunocompromised humans. C. hominis and C. parvum most commonly infect humans. Differentiating between them is important for evaluating potential sources of infection. We report here the development of a simple and accurate real-time PCR-based restriction fragment length polymorphism (RFLP) method to distinguish between C. parvum and C. hominis. Using the CP2 gene as the target, we found that both Cryptosporidium species yielded 224 bp products. In the subsequent RFLP method using Taqi, 2 bands (99 and 125 bp) specific to C. hominis were detected. Using this method, we detected C. hominis infection in 1 of 21 patients with diarrhea, suggesting that this method could facilitate the detection of C. hominis infections. [ABSTRACT FROM AUTHOR]

Malaria was eradicated and the Republic of Korea (ROK) declared "malaria free" in 1979. However, in 1993, a temperate strain of vivax malaria, expressing both latent and nonlatent disease populations, re-emerged near the demilitarized zone (DMZ), rapidly spread to civilian sectors near the DMZ, and increased exponentially in ROK military, veteran, and civilian populations through 1998. Malaria among all ROK populations decreased 5-fold from a high of 4,142 cases in 2000 to a low of 826 cases in 2004, before increasing again to 2,180 cases by 2007. Each malaria case in the ROK is reported in the metropolitan area/province where the diagnosis is made, which may be at some distance from the area where infection occurred. Therefore, it is difficult to ascertain transmission sites since approximately 60% of vivax malaria in Korea is latent with symptoms occurring >1 month to 24 months after infection. A review of case diagnosis for civilian, veteran, and military populations shows that nearly all malaria south of Gyeonggi and Gangwon Provinces is the result of veterans exposed in malaria high-risk areas along the DMZ and returning to their hometowns where they later develop malaria. Thus, malaria currently remains localized near the DMZ with limited transmission in provinces south of Seoul and has not spread throughout Korea as previously hypothesized. This report describes the reemergence of vivax malaria cases in civilian and military ROK populations and U.S. military personnel and assesses variables related to its transmission and geographic distribution. [ABSTRACT FROM AUTHOR]

Malaria is a significant health threat to U.S. combat forces that are deployed to malaria-endemic regions. From 1979. when the Republic of Korea (ROK) was declared malaria free, malaria did not present a health threat to U.S. forces deployed in Korea until the early 1990s, In 1993, a temperate strain of vivax malaria expressing both latent (long prepatent incubation periods of usually 6-18 months after infection) and nonlatent (short prepatent incubation periods <30 days after infection) disease reemerged near the demilitarized zone (DMZ) and once again presented a primary health threat to U.S. military populations in the ROK. Following its reemergence, malaria rates increased dramatically through 1998 and accounted for >44% of all malaria cases among U.S. Army soldiers from 1997 to 2002. More than 60% of all Korean-acquired malaria among U.S. soldiers was identified as latent malaria. Nearly 80% of all latent malaria attributed to exposure in Korea was diagnosed in the U.S. or other countries where soldiers were deployed, These data illustrate the requirement for a comprehensive malaria education program, especially for those soldiers residing or training in malaria high-risk areas, to inform soldiers and providers of the risk of developing malaria after leaving Korea. [ABSTRACT FROM AUTHOR]