Epidemiological characteristics of cases with scrub typhus and their correlation with chigger mite occurrence (2019–2021): A focus on case occupation and activity locations

Scrub typhus, transmitted through chigger mite bites, is a febrile disease associated with agricultural activities and primarily occurs in autumn. To address the increasing number of cases with scrub typhus over the past 3 years, we analyzed activity, visit history, and occupation data of 12,462 cases reported to the Korea Disease Control and Prevention Agency (KDCA) between January 2019 and December 2021. We examined changes in incidence and general characteristics by visualizing the incidence and eschar bite locations using population data and a geographic information system. Gyeongsangnam-do had the highest overall incidence rate (22.7%), followed by Jeollanam-do (19.0%) and Jeollabuk-do (11.2%), during the study period. However, when considering the incidence rate per 100,000 people, Jeollanam-do had the highest number of cases at 129.1, followed by Gyeongsangnam-do (85.1 cases) and Jeollabuk-do (78.1 cases). Most cases were women (61.0%) in their 70s (28.4%), and the highest incidence occurred in the agricultural worker group during autumn (October–December). Bites occurred most frequently in the abdomen (18.1%), and fever (79.2%) and muscle pain (49.8%) were the main symptoms. We also found a positive correlation (r = 0.848) between chigger mite populations and disease outbreaks over 3 years. In conclusion, it is crucial to provide education on identifying the habitats of chigger mites and rodents (vectors), as well as the appropriate application of repellents. Promoting awareness and preventive measures against infectious diseases is of utmost importance for rural areas and the general public who frequently come into contact with natural environments.     

Genetic typing of the 56-kDa type-specific antigen gene of contemporary Orientia tsutsugamushi isolates causing human scrub typhus at two sites in north-eastern and western Thailand

Orientia tsutsugamushi is the causative agent of scrub typhus, a major cause of febrile illness in the rural areas of Southeast Asia. Twenty-three strains of O. tsutsugamushi were isolated from patients with scrub typhus in north-east (Udorn Thani province) and western Thailand (Tak province) between 2003 and 2005. The isolates were characterized by sequencing the entire ORF of the 56-kDa-type-specific antigen gene, followed by phylogenetic analysis. The majority (15/23) of isolates clustered with the Karp-type strain, six with a Gilliam-type strain and one each with the TA716- and TA763-type strains. Overall, there was considerable diversity in sequence, comparable to that seen in strains from across the rest of the scrub typhus-endemic world. There was no significant difference in the distributions of strains between the two provinces (P=0.08, Fisher's exact) nor a temporal change in distribution with year of isolation (P=0.80, Fisher's exact). Within this diversity there were also examples of isolates with identical 56-kDa genotypes that were cultured from patients from the same geographical areas.     

家禽主要组织相容性复合体的研究进展

随着家禽基因组计划的开展,对家禽的主要组织相容性复合体（MHC）的研究取得了较大的进展。关于家禽MHC的各部分基因研究正在逐步深入,并且完成了MHC部分测序和染色体定位工作。 本文介绍近些年来对家禽MHC的基因结构和作用、与抗体的作用以及相关的基因组研究所取得的进展。人、小鼠及其他动物的相关研究结果将对家禽MHC研究的发展产生重要的影响。Abstract:As the development of poultry genome project,it has been acquired many advances in the study of poultry MHC.At present,we have achieved some MHC sequences 、 locations of MHC on chromosome and some MHC gene functions.This article give a detailed introduction about gene structure of poultry MHC and its role in immune reaction、relation with antibody and advances in poultry genome about MHC.With the development of related research,how to use the result of the study more efficiently become more and more important to the poultry MHC study.     

鸡MHC与传染性疾病遗传抗性的相关性研究进展

鸡是我国主要的家禽品种,抗病分子育种在鸡的疾病尤其是传染病控制中有着重要地位,抗性基因选择是其技术关键。鸡主要组织相容性复合体(MHC)基因具有高度多态性,与多种传染性疾病抗性紧密相关,受到家禽育种专家的高度关注。文章介绍国外有关鸡MHC与传染性疾病抗性的相关性及抗性基因研究进展,并展望其在鸡抗病育种中的应用前景。     

DETECTION OF RICKETTSIA TSUTSUGAMUSHI FROM VECTOR TROMBICULID MITE BY DNA AMPLIFICATION USING POLYMERASE CHAIN REACTION TECHNIQUE*

Abstract With reference to the Sta 58 major antigen gene of Rickettsia tsutsugamushi (Karp strain), we had designed and synthesized a pair of DNA primers; and a kilobase fragment of Sta 58 is amplified for using in polymerase chain reaction (PCR) with the primers. This is the first report on detection of R. tsutsugamushi in trombiculids by using PCR technique. The experimental results indicated that the time for which R. tsutsugamushi could exist in the adult of Leptotromhidium deliense when inoculated into its abdomenal cavity was 360 days at least and R. tsutsugamushi could be transovarially transmitted to the offsprings for 4 generations; and the time for which R. tsutsugamushi could exist in L. deliense after biting the infective mouse was 270 days at least and R. tsutsugamushi could be transmitted transovarially to the offsprings for 2 generations. The results also showed that the PCK technique was highly specific and sensitive for detection of R. tsutsugamushi; and the amplification of gene outside body to detect the rickettsiae in the body of trombiculid and mouse can be used as a new method for investigation of scrub typhus epidemiology.     

The evolution of MHC diversity: evidence of intralocus gene conversion and recombination in a single-locus system

Gene conversion, the unidirectional exchange of genetic material between homologous sequences, is thought to strongly influence patterns of genetic diversity. The high diversity of major histocompatibility complex (MHC) genes in many species is thought to reflect a long history of gene conversion events both within and among loci. Theoretical work suggests that intra- and interlocus gene conversion leave characteristic signatures of nucleotide diversity, but empirical studies of MHC variation have rarely been able to analyze the effects of conversion events in isolation, due to the presence of multiple gene copies in most species. The potbellied seahorse (Hippocampus abdominalis), a species with a single copy of the MH class II beta-chain gene (MHIIb), provides an ideal system in which to explore predictions on the effects of intralocus gene conversion on patterns of genetic diversity. The genetic diversity of the MHIIb peptide binding region (PBR) is high in the seahorse, similar to other vertebrate species. In contrast, the remainder of the gene shows a total absence of synonymous variation and low levels of intronic sequence diversity, concentrated in 3 short repetitive regions and 1-12 SNPs per intron. The distribution of substitutions across the gene results in a patchwork pattern of shared polymorphism between otherwise divergent sequences. The pattern of nucleotide diversity observed in the seahorse MHIIb gene is congruent with theoretical expectations for intralocus gene conversion, indicating that this evolutionary mechanism has played an important role in MHC gene evolution, contributing to both the high diversity in the PBR and the low diversity outside this region. Neutral variation at this locus may be further reduced due to biases in nucleotide composition and functional constraints.     

扬子鳄种群MHC Ⅱ类B基因第3外元多态性分析

分析了取自安徽宣城野生种群、安徽省扬子鳄繁殖研究中心和浙江长兴养殖种群的14条扬子鳄MHCⅡ类B基因第3外元的多态性。在这些扬子鳄样本中共检测到34个单倍型,每个亚种群内检测到的单倍型数量分别为15,9和10个,与其他一些动物如哺乳动物和鲤科鱼类相比,扬子鳄MHCⅡ类B基因第3外元多态性较高。另外,非同义替换率显著小于同义替换率,这可能表明扬子鳄种群MHCⅡ类B基因第3外元的多态性不是由平衡选择保持的。Tajima的中性检测拒绝了扬子鳄MHCⅡ类B基因第3外元多态性是由遗传漂变引起的零假设。D=-0．401也暗示了扬子鳄种群中存在较多的稀有变异。同时我们也分析了核苷酸多样性和系统发生关系,结果表明扬子鳄的3个种群遗传多样性无显著性差异。     

应用PCR技术检测媒介恙螨体内恙虫病立克次体(英语)

本文PCR技术的引物是参考恙虫病立克次体Karp株Sta 58序列设计合成的一对DNA引物.以恙虫病立克次体DNA为模板,成功扩增长约1kb的DNA片段.该对引物首次应用于人工成虫腹内接种羔虫病立克次体(人工接种法)和幼虫叮咬恙虫病鼠(叮咬病鼠法)的我国主要恙虫病媒介地里纤羔螨的研究.PCR检测人工接种法成虫的不同时期和经卵传递的子代立克次体DNA均获满意结果,立克次体在恙螨体内生长持续360天及产卵孵出的第4代幼虫均呈阳性.叮咬病鼠法立克次体在恙螨亲代饱食蚴、若蛹、若虫、成虫及第2代子产代幼虫,PCR检测均呈阳性.结果显示PCR技术检测恙螨体内恙虫病立克次体的特异性和敏感性高;体外基因扩增检测恙螨体内及鼠宿主体内立克次体是流行病学调查的新的敏感方法.本法为恙虫病分子体流行病学调查提供了新的应用技术,亦为临床病人诊断提供了敏感方法.     

Use of the MHC for mate choice in wild house mice (Mus domesticus)

The mechanisms maintaining natural diversity at the major histocompatibility complex (MHC) are not well understood. To increase knowledge of one potential mechanism, I examined the use of MHC genes for mate choice by wild house mice in a controlled laboratory setting. Three rearing groups of wild test mice were produced: non‐fostered control mice, mice fostered into families of an inbred laboratory mouse strain, and mice fostered into families of a second, MHC‐congenic mouse strain. Mature test mice were given a choice of two opposite‐sex stimulus mice from the two MHC‐congenic strains used for fostering, and were scored for several measures of preference. The results were non‐significant in general, but females of two rearing groups spent significantly more time with mice of one MHC‐type, and in most rearing groups, mice tended to spend more time with this same MHC‐type. Other results showed that male test mice ejaculated indiscriminantly and that female wild mice mated to ejaculation more often in longer length trials, but showed no significant preferences. In this study, fostering seemed to have little or no effect on MHC‐based mate preferences of wild house mice, and wild mice did not appear to be using the MHC to avoid inbreeding. However, some wild female mice used the MHC to choose potential mates. This revised version was published online in July 2006 with corrections to the Cover Date.     

Molecular characterization of meiotic recombination within the major histocompatibility complex of the mouse: Mapping of crossover sites within theI region

The molecular analysis of crossing-over within the mouse major histocompatibility complex provides a useful approach for the study of the structural characteristics of meiotic recombination. In this study five intra-I-region recombinants, each derived fromI ^k/I ^b heterozygotes, were characterized for restriction-fragment length polymorphisms (RFLPs) characteristic of theI region of the two parental strains. Southern blot analysis of intra-I recombinant strains A.TBR2, A.TBR3, A.TBR5, A.TBR13, and A.TBR17 using sixI-region DNA probes revealed that the point of crossing-over in all five recombinants occurred within a 6.2-kbKpnI-EcoRI segment located within theE gene. The segments of DNA containing the crossover point from each of the recombinant chromosomes were cloned by screening partial genomic libraries constructed in gt7 bacteriophage. Construction of partial restriction maps of the cloned segments from the parental and recombinant chromosomes permitted the boundaries of the area containing the crossover site to be narrowed to a 4.0-kb segment located almost entirely within an intron of theE gene. The recognition that the points of crossing-over in all five recombinants studied are clustered in a relatively small area of theI region provides further evidence for a hot spot of recombination associated with theE _ß gene.This work was supported by Grants AI14424 and AI20317 from the National Institutes of Health. J. Kobori was supported by a postdoctoral fellowship from the Arthritis Foundation. E. Zimmerer was supported by a postdoctoral fellowship from the Charles and Johanna Busch Fund of the Bureau of Biological Research. D. Spinella was supported by a predoctoral fellowship from the Charles and Johanna Busch Fund.     

Sequence variability analysis on major histocompatibility complex class II DRB alleles in three felines

The variation of the exon 2 of the major histo-compatibility complex (MHC) class II gene DRB locus in three feline species were examined on clouded leopard (Neofelis nebulosa), leopard (Panthera pardus) and Amur tiger (Panthera tigris altaica). A pair of degenerated primers was used to amplify DRB locus covering almost the whole exon 2. Exon 2 encodes the β1 domain which is the most variable fragments of the MHC class II molecule. Single-strand conformational polymorphism (SSCP) analysis was applied to detect different MHC class II DRB haplotypes. Fifteen recombinant plasmids for each individual were screened out, isolated, purified and sequenced finally. Totally eight distinct haplotypes of exon 2 were obtained in four individuals. Within 237 bp nucleotide sequences from four samples, 30 variable positions were found, and 21 putative peptide-binding positions were disclosed in 79 amino acid residues. The ratio of nonsynonymous substitutions (d _N ) was much higher than that of synonymous substitutions (d _S ), which indicated that balancing selection probably maintain the variation of exon 2. MEGA neighbor joining (NJ) and PAUP maximum parsimony (MP) methods were used to reconstruct phylogenetic trees among species, respectively. Results displayed a more close relationship between leopard and tiger; however, clouded leopard has a comparatively distant relationship form the other two. __________ Translated from Zoological Research, 2006, 27(2): 181-C188 [译自:动物学研究]     

Sequence variability analysis on major histocompatibility complex class Ⅱ DRB alleles in three felines

The variation of the exon 2 of the major histo-compatibility complex (MHC) class Ⅱ gene DRB locus in three feline species were examined on clouded leopard (Neofelis nebulosa), leopard (Panthera pardus) and Amur tiger (Panthera tigris altaica). A pair of degenerated primers was used to amplify DRB locus covering almost the whole exon 2. Exon 2 encodes the β1 domain which is the most vari-able fragments of the MHC class Ⅱ molecule. Single-strand conformational polymorphism (SSCP) analysis was applied to detect different MHC class Ⅱ DRB haplotypes. Fifteen recombinant plasmids for each individual were screened out, isolated, purified and sequenced finally. Totally eight distinct haplotypes of exon 2 were obtained in four individuals. With-in 237 bp nucleotide sequences from four samples, 30 vari-able positions were found, and 21 putative peptide-binding positions were disclosed in 79 amino acid residues. The ratio of nonsynonymous substitutions (dN) was much higher than that of synonymous substitutions (dS), which indicated that balancing selection probably maintain the variation ofexon 2. MEGA neighbor joining (N J) and PAUP maximum parsimo-ny (MP) methods were used to reconstruct phylogenetic trees among species, respectively. Results displayed a more close relationship between leopard and tiger; however, clouded leopard has a comparatively distant relationship form the other two.     

Joint report1 of the First International Workshop on Lymphocyte Alloantigens of the Horse held 24–29 October 1981

Six equine lymphocyte alloantigen (ELA) specificities were defined by an international antiserum comparison test and workshop held in 1981. Twelve laboratories from four countries submitted 195 antisera for analysis. The antisera were exchanged among the 12 laboratories and tested in a standard lymphocyte microcytoxicity assay against the isolated lymphocytes at 1009 horses of several breeds. The data was pooled and analysed by a single computer analysis. The calculated χ² values of all cells with all antisera provided comparisons between antisera. Fifteen antisera clusters were formed by this analysis, but only six of these clusters met the criteria established by the workshop for the identification of ELA antigens. No horses of the cell panel positively reacted with more than two of these six specificities. The consensus of the participants, although not substantiated in this workshop, was that these six clusters of antisera define alleles of a single genetic region, the ELA region, and it is likely that this genetic region is the major histocompatibility complex of the horse.