• Parasites, Hosts and Diseases
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• 제59권4호
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• pp.377-392
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• 2021

This paper is to illustrate the infestation and related ecological characteristics of chigger mites on the Asian house rat (Rattus tanezumi). A total of 17,221 chigger mites were collected from 2,761 R. tanezumi rats, and then identified as 131 species and 19 genera in 2 families. Leptotrombidium deliense, the most powerful vector of scrub typhus in China, was the first major dominant species on R. tanezumi. All the dominant mite species were of an aggregated distribution among different individuals of R. tanezumi. The species composition and infestations of chiggers on R. tanezumi varied along different geographical regions, habitats and altitudes. The species-abundance distribution of the chigger mite community was successfully fitted and the theoretical curve equation was ${\hat{S}}(R)={37e^{-(0.28R)}}^2$. The total chigger species on R. tanezumi were estimated to be 199 species or 234 species, and this further suggested that R. tanezumi has a great potential to harbor abundant species of chigger mites. The results of the species-plot relationship indicated that the chig-ger mite community on R. tanezumi in Yunnan was an uneven community with very high heterogeneity. Wide geographi-cal regions with large host samples are recommended in the investigations of chigger mites.

• Animal cells and systems
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• 제13권3호
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• pp.331-337
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• 2009

Twenty-eight Anopheles species has been so-far identified in Iran, while only 8 species was proved as malaria vector. In this study, we principally examined the cuticular hydrocarbon (CHC) potency in identification of Iranian vectors of malaria and then differentiation of vector and non-vector species of Anopheles. Seven species of malaria vectors and the non-vector species, Anopheles claviger were collected throughout Iran. Female extracts were made out of every five conspecific specimens by surface immersion in pure n-hexane. Each sample was injected into a FID-GC instrument along with the known concentrations of standards. CHC profiles of the eight Anopheles species indicated no qualitative difference. The average mass of each eluted CHC were compared using Repeated ANOVA and Mann-Whitney tests. Results confirmed a significant difference in mass of each single CHC at a specific retention time (RT). Statistical comparison of CHC mass in An. sacharovi, An. stephensi, An. culicifacies and An. fluviatilis at RT 39.6 indicated significant differences (P<0.05) among these species. Analysis of CHC mass of An. dthali, An. superpictus & An. sacharovi at RT 28.5, An. stephensi & An. sacharovi at RT 30.7 and An. sacharovi & An. claviger at RT 30.6 similarly indicated significant differences (P<0.05). An. sacharovi could be distinguished from other species, which showed only trace, by integratable peaks at retention times of 29.7, 31 and 32.6. Similarly, An. claviger could be distinguished from the other species with a trace peak at RT 30.6. In order to separate An. stephensi from the five other species, the integratable peak at RT 30.7 was used. An. dthali could be identified at RT 26.2 by an integratable peak v.s. the trace peaks of other species. An. superpictus had indicator peaks at RTs 27.4 & 28.5 v.s. trace peaks of other species. An. maculipennis with its trace peak at RT 39.6 could be easily differentiated from An. fluviatilis & An. culicifacies. This study proved that all of the examined species of Anopheles could be well identified based on their quantitative differences in CHCs, except for An. fluviatilis & An. culicifacies for which no CHC indicator peak was detected.

• Parasites, Hosts and Diseases
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• 제29권1호
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• pp.87-92
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• 1991

1989년 7월∼11월에 걸쳐 9개 지역에서 생포한 48마리의 등줄쥐(Apodemus agrarius)로부터 4,142개체의 털진드기(Acarina: Trombiculidae) 유충을 채집하였다. 이들 중 10종 990개체를 해부하여 그 내용 물질로부터 쭈쭈가무시병의 병원체를 간접 면역형광항체법으로 조사하였다 L. pallidum 유충 447개체 가운데 2개체에서 병원체인 Rickettsia tsutsugamushi를 발견하여 본중이 쭈쭈가무시병의 매개종임을 확인하였고, 감염률은 0.4%이었다.

• The Plant Pathology Journal
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• 제40권2호
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• pp.171-191
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• 2024

Identification of Helicotylenchus species is very challenging due to phenotypic plasticity and existence of cryptic species complexes. Recently, the use of rDNA barcodes has proven to be useful for identification of Helicotylenchus. Molecular markers are a quick diagnostic tool and are crucial for discriminating related species and resolving cryptic species complexes within this speciose genus. However, DNA barcoding is not an error-free approach. The public databases appear to be marred by incorrect sequences, arising from sequencing errors, mislabeling, and misidentifications. Herein, we provide a comprehensive analysis of the newly obtained, and published DNA sequences of Helicotylenchus, revealing the potential faults in the available DNA barcodes. A total of 97 sequences (25 nearly full-length 18S-rRNA, 12 partial 28S-rRNA, 16 partial internal transcribed spacer [ITS]-rRNA, and 44 partial cytochrome c oxidase subunit I [COI] gene sequences) were newly obtained in the present study. Phylogenetic relationships between species are given as inferred from the analyses of 103 sequences of 18S-rRNA, 469 sequences of 28S-rRNA, 183 sequences of ITS-rRNA, and 63 sequences of COI. Remarks on suggested corrections of published accessions in GenBank database are given. Additionally, COI gene sequences of H. dihystera, H. asiaticus and the contentious H. microlobus are provided herein for the first time. Similar to rDNA gene analyses, the COI sequences support the genetic distinctness and validity of H. microlobus. DNA barcodes from type material are needed for resolving the taxonomic status of the unresolved taxonomic groups within the genus.

• 한국동물학회지
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• 제34권2호
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• pp.257-264
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• 1991

과거의 국내 털진드기에 관한 연구는 종 동정에 관한 것이 대부분이었고 근래에 와서 지역적 분포상을 조사한 몇개의 보고 예가 있을 뿐, 털진드기의 계절적 소장을 체계적으로 조사한 것은 아직 없는 실정이다. 이에 저자들은 1989년 7월부터 1990년 10월에 걸쳐 털진드기 개체군에 대한 지역적 분포상과 계절적 소장에 관한 조사를 쭈쭈가무시병의 매개종인 Leptotrombidium pallidum을 중심으로 실시하였다. 조사기간 중 Sherman식 live trap을 사용하여 포힉한 총 111마리의 들쥐로부터 4,498 개체의 털진드기를 채집하여 4속 12종을 동종하였는데, 쭈쭈가무시병의 매개종인 L. paflidum이 2,951 개체로 전체의 65.6%를 차지하여 우점종이었다. 일본에서 매개종으로 알려진L. scutellare는 1개체만 채집되었다. 털진드기의 개체군 밀도의 지리적 분포상이 종에 따라 심한 차이를 보여 각 조사 지역마다 우점종이 다르게 나타났다. 9개 조사지역 가운데 L. paflidum 개체군 밀도가 특히 높은 지역은 경기도 고양군 도래 5리와 경기도 부천시 부곡동의 2개 지역이었고, 다른 3개 지역에서는 타 종에 비해 극히 낮은 밀도를 보였다. 매개종 L. paflidum 개체군의 계절적 소장을 보면 9월(9.8%)에 출현하기 시작하여 10월(45.4%)과 11월(30.6%)에 집중적으로 발생하였고, 그 후 거의 자취를 감추었다가 4월(12.7%)에 일시적 증가를 보인 후 9월까지 거의 나타나지 않았다. L. palpale는 겨울과 봄에만 주로 출현하는 것으로 확인되었다.

• 대한의생명과학회지
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• 제17권4호
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• pp.367-370
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• 2011

Studies on the relative abundance of potential vectors of scrub typhus was conducted from April to October 2009 at the Jangseong of Jeonnam Province, Korea. Among the total 62 field rodents collected by the Sherman collapsible traps, 56 rodents were $Apodemus$ $agrarius$ (90.3%), 4 were $Crocidura$ $lasiura$ (6.4%) and 2 were $Cricetulus$ $triton$ $nester$ (3.2%). Out of the 62 field rodents, 39 were parasitized by chiggers, showing 62.9% of the infestation rate and 80.0 of the chigger index. Chigger index of $A.$ $agrarius$ and $C.$ $triton$ $nester$ were 79.9, 82.0, respectively. But chigger mite was not collected from $C.$ $lasiura$. From the trapped field rodents, 3,120 chiggers were collected and identified with 6 species of 2 genera. $Leptotrombidium$ $scutellare$, the vector species of tsutsugamushi disease, was the dominant species, showing 2,276 chiggers (72.9%). $L.$ $pallidum$ was the second dominant species showing 346 chiggers (11.0%). The distribution of chigger mites was showed the different dominant species according to seasons. $L.$ $pallidum$ was the predominant chigger collected in April (34.8%), May (77.8%) and Jun (39.3%), whereas $L.$ $scutellare$ was the predominant chigger collected in September (78.78%) and October (76.8%).

• 한국음향학회지
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• 제36권6호
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• pp.401-406
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• 2017

본 논문에서는 양서류 울음소리를 통한 종 인식 시스템 개발을 위해, 음향 신호 분석에서 활용되는 주요 알고리즘의 인식 성능을 평가했다. 먼저, 멸종위기 종을 포함하여 총 9 종의 양서류를 선정하여, 각 종별 울음소리를 야생에서 녹음하여 실험 데이터를 구축했다. 성능평가를 위해, MFCC(Mel Frequency Cepstral Coefficient), RCGCC(Robust Compressive Gammachirp filterbank Cepstral Coefficient), SPCC(Subspace Projection Cepstral Coefficient)의 세 특징벡터와 GMM(Gaussian Mixture Model), SVM(Support Vector Machine), DBN-DNN(Deep Belief Network - Deep Neural Network)의 세 인식기가 고려됐다. 추가적으로, 화자 인식에 널리 사용되는 i-vector를 이용한 인식 실험도 수행했다. 인식 실험 결과, SPCC-SVM의 경우 98.81 %로 가장 높은 인식률을 확인 할 수 있었으며, 다른 알고리즘에서도 90 %에 가까운 인식률을 확인했다.

• Parasites, Hosts and Diseases
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• 제58권2호
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• pp.153-159
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• 2020

The chigger mite Leptotrombidium sialkotense is one of the 6 main vectors of scrub typhus in China. Before present study, L. sialkotense was found in some parts of Hunan province, China with a narrow geographical distribution. During field investigation 2016-2017, we found L. sialkotense in Jingha, southern Yunnan, China. Of 15 small mammal host species, L. sialkotense were collected from 6 species of the hosts. Rattus brunneusculus was a dominant host of L. sialkotense, from which 98.3% of the mites were collected. The chigger mite showed a relatively high infestation prevalence (P_M =11.7%) and mean abundance (MA=0.5) in comparison with the rest 5 host species. These results reveal a certain host specificity of L. sialkotense to a rat R. brunneusculus. The mite L. sialkotense showed an aggregated distribution on the host (P<0.05). A positive correlation observed between L. sialkotense and the body length of hosts. There was a positive interspecific association between L. sialkotense and 2 other dominant vectors, L. deliense and L. scutellare.

• Parasites, Hosts and Diseases
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• 제59권1호
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• pp.1-8
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• 2021

Leptotrombidium scutellare is one of the 6 main vectors of scrub typhus in China. It has been found in more than 15 provinces of China. Especially in Yunnan, it was found to be mainly distributed in some mountainous areas with high altitude, low temperature and low precipitation. Rodents and some other small mammals were the most common hosts of L. scutellare. To date, more than 40 host species of L. scutellare have been recorded with very low host specificity, and the main hosts varied in different geographical regions. L. scutellare had a strong resistance against the cold environment, and the temperature and humidity were 2 important factors affecting its growth and development. Among different individuals of their rodent hosts, L. scutellare mites often showed an aggregated distribution pattern, which reflected the interspecific cooperation of the mites. The chromosome karyotype of L. scutellare was 2n=16 and all the 8 pairs of chromosomes were short rod-shaped with metacentric or sub-metacentric types. The isozyme spectrum supported that L. scutellare, L. deliense and L. rubellum were in the same species group. Based on the natural infection, experimental transmission and epidemiological evidence, L. scutellare has been eventually confirmed as the second major vector of scrub typhus in China, which is second only to L. deliense.

• Parasites, Hosts and Diseases
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• 제47권1호
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• pp.13-17
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• 2009

Dung beetles (family Scarabaeidae) are one of the largest families of beetles worldwide. Due to biological behavior of these arthropods, they are considered to play an important role in the life cycle of some helminths. In the present study, dung beetles collected from cattle pastures in rural areas of Ardabil province, north-west of Iran were examined for infection with larval stages of helminths. According to the results, nematodes of 2 genera were identified including Rhabditis and Gongylonema. The more common species was Rhabditis sp. which was found in 9 species of beetles. Out of 15 different species of dung beetles, Copris lunaris was the only scarabaeid to be found naturally infected with the larval stages of Gongylonema sp. Our new findings introduce C. lunaris as a potential biological vector for transmission of Gongylonema sp. to vertebrates in the surveyed region.